WorldWideScience

Sample records for dual-purpose reinforced-concrete mass

  1. Continuous Reinforced Concrete Beams

    DEFF Research Database (Denmark)

    Hoang, Cao Linh; Nielsen, Mogens Peter

    1996-01-01

    This report deals with stress and stiffness estimates of continuous reinforced concrete beams with different stiffnesses for negative and positive moments e.g. corresponding to different reinforcement areas in top and bottom. Such conditions are often met in practice.The moment distribution...

  2. Continuous Reinforced Concrete Beams

    DEFF Research Database (Denmark)

    Hoang, Cao Linh; Nielsen, Mogens Peter

    1996-01-01

    This report deals with stress and stiffness estimates of continuous reinforced concrete beams with different stiffnesses for negative and positive moments e.g. corresponding to different reinforcement areas in top and bottom. Such conditions are often met in practice.The moment distribution...... at the limit state of serviceability is in some simple cases determined by setting up the statical and the compatibility conditions.With these moment distributions, the maximum deflection and the reinforcement stresses at the span middle and at a support are calculated.The results are compared with results...

  3. Corrosion Inhibitors for Reinforced Concrete

    OpenAIRE

    ECT Team, Purdue

    2007-01-01

    Steel corrosion in reinforced concrete structures has been a major problem across the U.S. Steel-reinforced concrete structures are continually subject to attack by corrosion brought on by naturally occurring environmental conditions. FerroGard, a corrosion inhibitor, developed by Sika Corporation, penetrates hardened concrete to dramatically reduce corrosion by 65% and extend the structure's service life.

  4. Optimization of reinforced concrete slabs

    Science.gov (United States)

    Ferritto, J. M.

    1979-01-01

    Reinforced concrete cells composed of concrete slabs and used to limit the effects of accidental explosions during hazardous explosives operations are analyzed. An automated design procedure which considers the dynamic nonlinear behavior of the reinforced concrete of arbitrary geometrical and structural configuration subjected to dynamic pressure loading is discussed. The optimum design of the slab is examined using an interior penalty function. The optimization procedure is presented and the results are discussed and compared with finite element analysis.

  5. Optimization of reinforced concrete slabs

    Science.gov (United States)

    Ferritto, J. M.

    1979-01-01

    Reinforced concrete cells composed of concrete slabs and used to limit the effects of accidental explosions during hazardous explosives operations are analyzed. An automated design procedure which considers the dynamic nonlinear behavior of the reinforced concrete of arbitrary geometrical and structural configuration subjected to dynamic pressure loading is discussed. The optimum design of the slab is examined using an interior penalty function. The optimization procedure is presented and the results are discussed and compared with finite element analysis.

  6. Comparison of Seismic Responses for Reinforced Concrete Buildings with Mass and Stiffness Irregularities Using Pushover and Nonlinear Time History Analysis

    Science.gov (United States)

    Teruna, D. R.

    2017-03-01

    Pushover analysis or also known as nonlinear static procedures (NSP) have been recognized in recent years for practical evaluation of seismic demands and for structural design by estimating a structural building capacities and deformation demands. By comparing these demands and capacities at the performance level interest, the seismic performance of a building can be evaluated. However, the accuracy of NSP for assessment irregular building is not yet a fully satisfactory solution, since irregularities of a building influence the dynamic responses of the building. The objective of the study presented herein is to understand the nonlinear behaviour of six story RC building with mass irregularities at different floors and stiffness irregularity at first story (soft story) using NSP. For the purpose of comparison on the performance level obtained with NSP, nonlinear time history analysis (THA) were also performed under ground motion excitation with compatible to response spectra design. Finally, formation plastic hinges and their progressive development from elastic level to collapse prevention are presented and discussed.

  7. Fatigue Performance of Fiber Reinforced Concrete

    DEFF Research Database (Denmark)

    Jun, Zhang; Stang, Henrik

    1996-01-01

    The objective of the present study is to obtain basic data of fibre reinforced concrete under fatigue load and to set up a theoretical model based on micromechanics. In this study, the bridging stress in fiber reinforced concrete under cyclic tensile load was investigted in details. The damage...... mechanism of the interface between fiber and matrix was proposed and a rational model given. Finally, the response of a steel fiber reinforced concrete beam under fatigue loading was predicted based on this model and compared with experimental results....

  8. Design Methods for Fibre Reinforced Concrete

    DEFF Research Database (Denmark)

    Stang, Henrik

    1996-01-01

    The present paper describes the outline of a research project on Fibre Reinforced Concrete (FRC) currently being carried out in Denmark under the supervision of Danish Council of Technology, Danish Technical Research Council and Danish Natural Science Research Counsil....

  9. Topology optimization of reinforced concrete structures

    DEFF Research Database (Denmark)

    Amir, Oded

    Recent advances regarding topology optimization procedures of reinforced concrete structures are presented. We discuss several approaches to the challenging problem of optimizing the distribution of concrete and steel reinforcement. In particular, the consideration of complex nonlinear constitutive...

  10. Ductility Performance of Hybrid Fibre Reinforced Concrete

    OpenAIRE

    S. Eswari; P.N. Raghunath; Suguna, K

    2008-01-01

    This study presents a study on the ductility performance of hybrid fibre reinforced concrete. The influence of fibre content on the ductility performance of hybrid fibre reinforced concrete specimens having different fibre volume fractions was investigated. The parameters of investigation included modulus of rupture, ultimate load, service load, ultimate and service load deflection, crack width, energy ductility and deflection ductility. A total of 27 specimens, 100×100×500 mm, were tested to...

  11. Shaking Table Tests of Reinforced Concrete Frames

    DEFF Research Database (Denmark)

    Skjærbæk, P. S.; Kirkegaard, Poul Henning; Nielsen, Søren R.K.

    -varying systems and to verify various methods for damage assessment of reinforced concrete structures from soft motion measurements. In this study the maximum softening concept will be evaluated. In the paper the assessment obtained by this method is compared to visual damage assessment. The structures considered...... vector ARMA model is suitable for modal identification of degrading reinforced concrete structures and the maximum softening damage index calculated from the obtained identification provides a valuable tool for assessment of the damage state of the structure....

  12. Seismic fragility of a reinforced concrete structure

    Energy Technology Data Exchange (ETDEWEB)

    Kurmann, Davide [Axpo Power AG, Baden (Switzerland); Proske, Dirk [Axpo Power AG, Doettingen (Switzerland); Cervenka, Jan [Cervenka Consulting, Prague (Czech Republic)

    2013-05-15

    Structures can be exposed to seismic loading. For structures of major importance, extreme seismic loadings have to be considered. The proof of safety for such loadings requires sophisticated analysis. This paper introduces an analysis method which of course still includes simplifications, but yields to a far more realistic estimation of the seismic load bearing capacity of reinforced concrete structures compared to common methods. It is based on the development of pushover curves and the application of time-histories for the dynamic model to a representative harmonic oscillator. Dynamic parameters of the oscillator, such as modal mass and damping are computed using a soil-structure-interaction analysis. Based on the pushover-curve nonlinear force-deformation-capacities are applied to the oscillator including hysteresis behaviour characteristics. The oscillator is then exposed to time-histories of several earthquakes. Based on this computation the ductility is computed. The ductility can be scaled based upon the scaling of the time-histories. Since both, the uncertainty of the earthquake by using different timehistories and the uncertainty of the structure by using characteristic and mean material values, are considered, the uncertainty of the structure under seismic loading can be explicitly represented by a fragility. (orig.)

  13. STRUCTURAL PERFORMANCE OF DEGRADED REINFORCED CONCRETE MEMBERS.

    Energy Technology Data Exchange (ETDEWEB)

    Braverman, J.I.; Miller, C.A.; Ellingwood, B.R.; Naus, D.J.; Hofmayer, C.H.; Bezler, P.; Chang, T.Y.

    2001-03-22

    This paper describes the results of a study to evaluate, in probabilistic terms, the effects of age-related degradation on the structural performance of reinforced concrete members at nuclear power plants. The paper focuses on degradation of reinforced concrete flexural members and shear walls due to the loss of steel reinforcing area and loss of concrete area (cracking/spalling). Loss of steel area is typically caused by corrosion while cracking and spalling can be caused by corrosion of reinforcing steel, freeze-thaw, or aggressive chemical attack. Structural performance in the presence of uncertainties is depicted by a fragility (or conditional probability of failure). The effects of degradation on the fragility of reinforced concrete members are calculated to assess the potential significance of various levels of degradation. The fragility modeling procedures applied to degraded concrete members can be used to assess the effects of degradation on plant risk and can lead to the development of probability-based degradation acceptance limits.

  14. Self-compacting fibre-reinforced concrete

    NARCIS (Netherlands)

    Grunewald, S.; Walraven, J.C.

    2001-01-01

    The project 'self-compacting fibre-reinforced concrete (SCFRC)' is part of the Dutch STW/PPM program - 'cement-bonded materials' - DCT.4010. Subproject III to which the project ,SCFRC' belongs deals with the development of new high performance concretes. The project 'SCFRC' aims at investigating the

  15. Fracture Toughness of Fiber Reinforced Concrete.

    Science.gov (United States)

    1983-06-01

    14, 1979, pp. 443-449. 5 Mindess , S., Lawrence, F. V., and Kesler, C. E., "The J-Integral as a Fracture Criterion for Fiber Reinforced Concrete...34 Cement and Con- crete Research, Vol. 7, 1977 , pp. 731-742. 6 Velazco, G., Visalvanich, K., and Shah, S. P., "Fracture Behavior and Analysis of Fiber

  16. Degradation of Waterfront Reinforced Concrete Structures

    African Journals Online (AJOL)

    Key words: Degradation, reinforced concrete, Dar es Salaam port. Abstract—One of the .... Plate 2. Typical cracks on concrete piers found on berth. 4 through 8. Plate 3. Exposed .... Rubaratuka, I. A. and Mulungu, D., 1999: Defects in reinforced ...

  17. Rotational Capacity of Reinforced Concrete Beams

    DEFF Research Database (Denmark)

    Ulfkjær, J. P.; Henriksen, M. S.; Brincker, Rune

    1995-01-01

    The European Structural Integrity Society-Technical Committee 9, has initiated a Round Robin on 'Scale Effects and Transitional Failure Phenomena of Reinforced Concrete Beams in Flexure'. In Denmark, Aalborg University is participating. The programme for Aalborg University involves an experimental...

  18. Strength of Cracked Reinforced Concrete Disks

    DEFF Research Database (Denmark)

    Hoang, Cao Linh; Nielsen, Mogens Peter

    1999-01-01

    The paper deals with models, based on the theory of plasticity, to be used in strength assessments of reinforced concrete disks suffering from different kinds of cracking. Based on the assumption that the sliding strength of concrete is reduced in sections where cracks are located, solutions...

  19. Corrosion and Cracking of Reinforced Concrete

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    Modelling of the deterioration of reinforced concrete has in recent years changed from being a deterministic modelling based on experience to be stochastic modelling based on sound and consistent physical, chemical and mechanical principles. In this paper is presented a brief review of modern mod...... for time to initial corrosion, time to initial cracking, and time to a given crack width may be obtained....

  20. Random Time Dependent Resistance Analysis on Reinforced Concrete Structures

    Institute of Scientific and Technical Information of China (English)

    GUAN Chang-sheng; WU Ling

    2002-01-01

    The analysis method on random time dependence of reinforced concrete material is introduced,the effect mechanism on reinforced concrete are discussed, and the random time dependence resistance of reinforced concrete is studied. Furthermore, the corrosion of steel bar in reinforced concrete structures is analyzed. A practical statistical method of evaluating the random time dependent resistance, which includes material, structural size and calculation influence, is also established. In addition, an example of predicting random time dependent resistance of reinforced concrete structural element is given.

  1. Influence of Additives on Reinforced Concrete Durability

    OpenAIRE

    2014-01-01

    The article presents the results of the research on carbonation and chloride induced corrosion mechanisms in reinforced concrete structures, based on three commercially available concrete admixtures: Xypex Admix C-1000, Penetron Admix and Elkem Microsilica. Carbonation takes place due to carbon dioxide diffusion, which in the required amount is present in the air. Chlorides penetrate concrete in case of the use of deicing salt or structure exploitation in marine atmosphere. Based on the imple...

  2. Behavior of Partially Restrained Reinforced Concrete Slabs.

    Science.gov (United States)

    1986-09-01

    Takehira, Derecho , and Iqbal [34] followed a similar approach to arrive at recommended design criteria for 1 the Naval Facilities Engineering Command...Datta, T. K., "Ultimate Strength of Reinforced Concrete Slab-Beam Systems: A New Approach," r Indian Concrete Journal, Bombay, India , Vol. 47, 1973, pp...Journal of Solids and Structures, Vol. 1, 1965, pp. 97-111. 34. Takehira, T., Derecho , A.T., and Iqbal, M., "Design Criteria for Deflection Capacity

  3. Modelling localised fracture of reinforced concrete structures

    OpenAIRE

    Liao, F; Huang, Z.

    2015-01-01

    This paper presents a robust finite element procedure for simulating the localised fracture of reinforced concrete members. In this new model the concrete member is modelled as an assembly of plain concrete, reinforcing steel bar and bond-link elements. The 4-node quadrilateral elements are used for 2D modelling of plain concrete elements, in which the extended finite element method is adopted to simulate the formation and growth of individual cracks. The reinforcing steel bars are modelled b...

  4. Ductility Performance of Hybrid Fibre Reinforced Concrete

    Directory of Open Access Journals (Sweden)

    S. Eswari

    2008-01-01

    Full Text Available This study presents a study on the ductility performance of hybrid fibre reinforced concrete. The influence of fibre content on the ductility performance of hybrid fibre reinforced concrete specimens having different fibre volume fractions was investigated. The parameters of investigation included modulus of rupture, ultimate load, service load, ultimate and service load deflection, crack width, energy ductility and deflection ductility. A total of 27 specimens, 100×100×500 mm, were tested to study the above parameters. The specimens incorporated 0.0 to 2.0% volume fraction of polyolefin and steel fibres in different proportions. The ductility performance of hybrid fibre reinforced concrete specimens was compared with that of plain concrete. The test results show that addition of 2.0% by volume of hybrid fibres improves the ductility performance appreciably. An adaptive Neuro-Fuzzy based model has been proposed to predict the ductility performance characteristics. A reasonably close agreement has been obtained between the experimental and predicted results.

  5. ANALYSIS OF EXPOSURE OF REINFORCED CONCRETE BUILDINGS TO TEMPERATURE LOADS

    OpenAIRE

    2012-01-01

    The co-authors consider the problem of analysis of building structures in respect of combined effects of forces and temperatures. Results of fire tests of reinforced concrete walls and slabs are presented. Overview of the analysis of the fire resistance of reinforced-concrete buildings is also provided. As a result of the research, numerical solutions were obtained in respect of deflections, stresses, deformations and internal forces arising in a reinforced concrete bearing wall and plate...

  6. Flexural strength enhancement of confined reinforced concrete columns

    OpenAIRE

    Pam, HJ; Ho, JCM

    2001-01-01

    As part of a continuing research study, this paper proposes a new design aid to calculate the actual moment capacity of confined reinforced concrete columns. Up to now the moment capacity of a reinforced concrete column is calculated based on the code's guidelines for an unconfined section. As most reinforced concrete columns contain transverse or confining reinforcement, which will enhance the column moment capacity, the actual moment capacity will be much higher than the unconfined moment c...

  7. Influence of Additives on Reinforced Concrete Durability

    Directory of Open Access Journals (Sweden)

    Neverkovica Darja

    2014-12-01

    Full Text Available The article presents the results of the research on carbonation and chloride induced corrosion mechanisms in reinforced concrete structures, based on three commercially available concrete admixtures: Xypex Admix C-1000, Penetron Admix and Elkem Microsilica. Carbonation takes place due to carbon dioxide diffusion, which in the required amount is present in the air. Chlorides penetrate concrete in case of the use of deicing salt or structure exploitation in marine atmosphere. Based on the implemented research, Elkem Microsilica is the recommended additive for the use in aggressive environmental conditions. Use of Xypex Admix C-1000 and Penetron Admix have only average resistance to the aggressive environmental impact.

  8. Durability of cracked fibre reinforced concrete structures

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan De Place

    1998-01-01

    Durability studies are carried out at BKM as part of the research project "Design Methods for Fibre Reinforced Concrete" (FRC) involving BKM, The Concrete Research Center at DTI, Building Technology at Aalborg University, Rambøll, 4K-Beton and Rasmussen & Schiøtz. Concrete beams with or without...... structure are made on specimens drilled or sawed from beams after unloading (mechanical load). The pore structure of the concretes will be studied by microscopy, sorption and suction curves. The test programme involves three different concrete qualities (water-cement ratios). Both steel fibres (ZP...

  9. Strength of Cracked Reinforced Concrete Disks

    DEFF Research Database (Denmark)

    Hoang, Cao Linh; Nielsen, Mogens Peter

    1999-01-01

    The paper deals with models, based on the theory of plasticity, to be used in strength assessments of reinforced concrete disks suffering from different kinds of cracking. Based on the assumption that the sliding strength of concrete is reduced in sections where cracks are located, solutions...... for the shear strength of disks with initial cracks and disks suffering from isotropic cracking are presented. Furthermore, in the case of isotropicly cracked disks subjected to arbitrary in-plane loading, a general yield condition is derived....

  10. Reliability of Reinforced Concrete Buildings During Construction

    Institute of Scientific and Technical Information of China (English)

    方东平; 耿川东; 张传敏; 祝宏毅; 刘西拉

    2004-01-01

    The safety analysis of reinforced concrete buildings during construction should be based on the comprehensive understanding of loads, load effects, structural resistance, and available safety index of the structure. This paper analyzes the characteristics and probabilistic models of resistance, loads, and load effects. A method was developed to calculate the probability of failure based on Monte Carlo simulation and models proposed in previous articles. Construction examples were used to analyze the influence of live load on the probability of failure. The results show that when the live load increases, the maximum probability of failure increases with acceleration. The results suggest that the construction live load should be carefully addressed during construction.

  11. Design of Reinforced Concrete Elements Under Fire

    Directory of Open Access Journals (Sweden)

    P. Mihai

    2008-01-01

    Full Text Available Fire safety regulations can have a major impact on many aspects of the overall design of a building, including layout, aesthetics, function, and cost. Rapid developments in modern building technology in the last decades often have resulted in unconventional structures and design solutions. Because the world is developed continuously, the physical size of buildings increases continually; there is a tendency to build large underground car parks, warehouses, and shopping complexes. As a result, we have a worldwide movement to replace prescriptive building codes with ones based on performance. The paper presents the basic principles for the designing process of reinforced concrete elements under fire.

  12. Applications and Properties of Fibre Reinforced Concrete

    Directory of Open Access Journals (Sweden)

    Amit Rai1 ,

    2014-05-01

    Full Text Available In conventional concrete, micro-cracks develop before structure is loaded because of drying shrinkage and other causes of volume change. When the structure is loaded, the micro cracks open up and propagate because of development of such micro-cracks, results in inelastic deformation in concrete. Fibre reinforced concrete (FRC is cementing concrete reinforced mixture with more or less randomly distributed small fibres. In the FRC, a numbers of small fibres are dispersed and distributed randomly in the concrete at the time of mixing, and thus improve concrete properties in all directions. The fibers help to transfer load to the internal micro cracks. FRC is cement based composite material that has been developed in recent years. It has been successfully used in construction with its excellent flexural-tensile strength, resistance to spitting, impact resistance and excellent permeability and frost resistance. It is an effective way to increase toughness, shock resistance and resistance to plastic shrinkage cracking of the mortar. These fibers have many benefits. Steel fibers can improve the structural strength to reduce in the heavy steel reinforcement requirement. Freeze thaw resistance of the concrete is improved. Durability of the concrete is improved to reduce in the crack widths. Polypropylene and Nylon fibers are used to improve the impact resistance. Many developments have been made in the fiber reinforced concrete.

  13. Rockfall vulnerability assessment for reinforced concrete buildings

    Directory of Open Access Journals (Sweden)

    O. Mavrouli

    2010-10-01

    Full Text Available The vulnerability of buildings to the impact of rockfalls is a topic that has recently attracted increasing attention in the scientific literature. The quantification of the vulnerability, when based on empirical or heuristic approaches requires data recorded from historical rockfalls, which are not always available. This is the reason why appropriate alternatives are required. The use of analytical and numerical models can be one of them. In this paper, a methodology is proposed for the analytical evaluation of the vulnerability of reinforced concrete buildings. The vulnerability is included in the risk equation by incorporating the uncertainty of the impact location of the rock block and the subsequent damage level. The output is a weighted vulnerability that ranges from 0 to 1 and expresses the potential damage that a rock block causes to a building in function of its velocity and size. The vulnerability is calculated by the sum of the products of the probability of block impact on each element of the building and its associated damage state, the latter expressed in relative recovery cost terms. The probability of exceeding a specific damage state such as non-structural, local, partial, extensive or total collapse is also important for the quantification of risk and to this purpose, several sets of fragility curves for various rock diameters and increasing velocities have been prepared. An example is shown for the case of a simple reinforced concrete building and impact energies from 0 to 4075 kJ.

  14. Seismic Analysis of Reinforced Concrete Shaft Support Water Storage Tank

    Directory of Open Access Journals (Sweden)

    Bharti Tekwani

    2016-05-01

    Full Text Available This paper compares the results of Seismic Analysis of Reinforced Concrete Shaft Support Water Storage Tank carried out in accordance with IS: 1893- 1984 and IS: 1893-2002 (Part-2 draft code. The analysis is carried out for shaft supported water tank of 500,750 and 1000 Cu.m capacity, located in four seismic zones (Zone-II, Zone -III, Zone-IV, Zone-V and on three different soil types (Hard rock, Medium soil, Soft soil. Further, 1000 kl tank for conditions - tank full, tank empty are also considered in this study. The analysis was performed using MAT LAB. The parameters of comparison include base shears, base moments and time history analysis. The above models are analyzed for different time history data such as El Centro, Kobe, Ji-Ji, Erzincan. The comparison is made between the structural responses of one mass and two mass models of above capacity.

  15. Long term behavior of self-compacting reinforced concrete beams

    Institute of Scientific and Technical Information of China (English)

    LIU Xiao-jie; YU Zhi-wu; JIANG Li-zhong

    2008-01-01

    Tests were carded out on 8 self-compacting reinforced concrete(SCC) beams and 4 normal reinforced concrete beams. The effects of mode of consolidation, load level, reinforcing ratio and structural type on long term behavior of SCC were investigated. Under the same environmental conditions, the shrinkage-time curve of self-compacting concrete beam is very similar to that of normal concrete beam. For both self-compacting reinforced concrete beams and normal reinforced concrete beams, the rate of shrinkage at early stages is higher, the shrinkage strain at 2 months is about 60% of the maximum value at one year. The shrinkage strain of self-compacting reinforced concrete beam after one year is about 450×10-6. Creep deflection of self-compacting reinforced concrete beam decreases as the tensile reinforcing ratio increases. The deflection creep coefficient of self-compacting reinforced concrete beam after one and a half year is about 1.6, which is very close to that of normal reinforced concrete beams cast with vibration. Extra cautions considering shrinkage and creep behavior are not needed for the use of SCC in engineering practices.

  16. Normal Strength Steel Fiber Reinforced Concrete Subjected to Explosive Loading

    Directory of Open Access Journals (Sweden)

    Mohammed Alias Yusof

    2011-07-01

    Full Text Available This paper presents the results of an experimental investigation on the behavior of plain reinforced concrete and Normal strength steel fiber reinforced concrete panels (SFRC subjected to explosive loading. The experiment were performed by the Blast Research Unit Faculty of Engineering, University Pertahanan Nasional Malaysia A total of 8 reinforced concrete panels of 600mm x 600mm x 100mm were tested. The steel fiber reinforced concrete panels incorporated three different volume fraction, 0.5%, 1.0%, and 1.5% of hooked end steel fibers. The panels were subjected to explosive loading generated by the detonation of 1kg of explosive charge located at a 0.6m standoff. This investigation indicates that the steel fiber reinforced concrete panel containing of 1.5% volume fraction gave the best performance under explosive loading.

  17. Frost resistance of fibre reinforced concrete structures

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan De Place

    1999-01-01

    of 0.4-1% by volume of fibres cannot replace air entrainment in order to secure a frost resistant concrete; the minimum amount of air needed to make the concrete frost resistant is not changed when adding fibres· the amount of air entrainment must be increased when fibres are added to establish......Frost resistance of fibre reinforced concrete with 2.5-4.2% air and 6-9% air (% by volume in fresh concrete) casted in the laboratory and in-situ is compared. Steel fibres with hooked ends (ZP, length 30 mm) and polypropylene fibres (PP, CS, length 12 mm) are applied. It is shown that· addition...

  18. Ductility of Reinforced Concrete Structures in Flexure

    DEFF Research Database (Denmark)

    Hestbech, Lars

    2013-01-01

    In this thesis, a rotational capacity model for flexural reinforced concrete elements is presented. The model is based on the general assumption, that any other failure mode than bending is prevented by proper design. This includes failure due to shear, anchorage, concentrated loads etc. Likewise......, beams governed by failure described by Kani’s Valley are not covered by the presented model. Hence, the model is delimited to shear reinforced elements failing in flexure. The rotational capacity model is divided into the following calculation procedures. 1. A cross sectional analysis of the critical...... are not necessarily so. An example shows the applicability of the model and a parametric study shows the advantages of the model compared with code provisions. Finally, improvements of the compression zone modelling is performed in order to include a better performance when concrete crushing is the failure criterion...

  19. Modelling Tension Stiffening in Reinforced Concrete Structures

    DEFF Research Database (Denmark)

    Christiansen, Morten Bo; Nielsen, Mogens Peter

    1997-01-01

    flexure.In the first model, the yield zone model, it is assumed that the mean crack distance is a descending function of the reinforcement stress in a crack. Furthermore it is assumed that in certain zones between the cracks the concrete is carrying its full effective tensile strength, i.e. the concrete...... with deformations in reinforced concrete disks subjected to pure shear.A physical model for the shear stress-shear strain behaviour of disks, including tension stiffening, is proposed.In the disk model it is assumed that the tensile principal stress in the concrete decreases linearly from the initiation of cracking...... until a certain load level. At any load level the model can predict the shear strains of the disk and the inclination of the crack system. When regarding tension stiffening this latter parameter will be a function of the load level.The model is compared with experimental data, and in the light...

  20. Numerical Limit Analysis of Reinforced Concrete Structures

    DEFF Research Database (Denmark)

    Larsen, Kasper Paaske

    methods provide engineers with valuable tools for limit sta- te analysis, their application becomes difficult with increased structural complexity. The main challenge is to solve the optimization problem posed by the extremum principles. This thesis is a study of how numerical methods can be used to solve...... limit state analysis problems. The work focuses on determination of the load bearing capacity of reinforced concrete structures by employing the lower bound theorem and a finite element method using equilibrium elements is developed. The recent year’s development within the field of convex optimization...... is developed for improved perfor- mance. An example is given in which an inverse T-beam is analyzed and the numerical results are compared to laboratory tests. The third and final element is a plane shell element capable of modeling membrane and plate bending behavior. The element employs a layered disk...

  1. Reinforced concrete design to Eurocode 2

    CERN Document Server

    Toniolo, Giandomenico

    2017-01-01

    This textbook describes the basic mechanical features of concrete and explains the main resistant mechanisms activated in the reinforced concrete structures and foundations when subjected to centred and eccentric axial force, bending moment, shear, torsion and prestressing,. It presents a complete set of limit-state design criteria of the modern theory of RC incorporating principles and rules of the final version of the official Eurocode 2. This textbook examines methodological more than notional aspects of the presented topics, focusing on the verifications of assumptions, the rigorousness of the analysis and the consequent degree of reliability of results. Each chapter develops an organic topic, which is eventually illustrated by examples in each final paragraph containing the relative numerical applications. These practical end-of-chapter appendices and intuitive flow-charts ensure a smooth learning experience. The book stands as an ideal learning resource for students of structural design and analysis cou...

  2. Tendons Arrangement Effects on Reinforced Concrete Frames

    Directory of Open Access Journals (Sweden)

    Ayad B. Bahnam

    2013-05-01

    Full Text Available  The tendons arrangement effects on the response of reinforced concrete frame experiencing blast loads is investigated in this paper. The structure is modeled using nonlinear finite elements employing a bilinear hysteretic model. So that elements are used so that yielding of the structures could be accurately modeled and captured. The frame is analyzed using a non-linear, elastic-plastic finite element program written in code MATLAB. Six tendon architectures were investigated. A single tendon was placed between different floors and its effects investigated. From the obtained results, the ideal case which causes a reduction in the maximum displacement and the amount of permanent deflection without increase in the maximum structural shear forces greatly is obtained.

  3. Limit analysis of solid reinforced concrete structures

    DEFF Research Database (Denmark)

    Larsen, Kasper Paaske

    2009-01-01

    element for lower bound analysis of reinforced concrete structures is presented. The method defines the stress state at a point within the solid as a combination of concrete- and reinforcement stresses and yield criterions are applied to the stress components separately. This method allows for orthotropic......Recent studies have shown that Semidefinite Programming (SDP) can be used effectively for limit analysis of isotropic cohesive-frictional continuums using the classical Mohr-Coulomb yield criterion. In this paper we expand on this previous research by adding reinforcement to the model and a solid...... reinforcement and it is therefore possible to analyze structures with complex reinforcement layouts. Tests are conducted to validate the method against well-known analytical solutions....

  4. Frost resistance of fibre reinforced concrete structures

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan De Place

    1999-01-01

    Frost resistance of fibre reinforced concrete with 2.5-4.2% air and 6-9% air (% by volume in fresh concrete) casted in the laboratory and in-situ is compared. Steel fibres with hooked ends (ZP, length 30 mm) and polypropylene fibres (PP, CS, length 12 mm) are applied. It is shown that· addition...... of 0.4-1% by volume of fibres cannot replace air entrainment in order to secure a frost resistant concrete; the minimum amount of air needed to make the concrete frost resistant is not changed when adding fibres· the amount of air entrainment must be increased when fibres are added to establish...... the same amount of air pores as in the corresponding concrete without fibres...

  5. Ambient Vibration Test on Reinforced Concrete Bridges

    Directory of Open Access Journals (Sweden)

    Idris Nurul Shazwin

    2016-01-01

    Full Text Available An investigation was carried out to determine dynamic characteristic of reinforced concrete (RC bridges by using ambient vibration test (AVT. The ambient vibration sources on bridges may come from traffic, wind, wave motion and seismic events. AVT describes the dynamic characteristics of the bridge and ground by measuring the natural frequencies using highly sensitive seismometer sensor. This test is beneficial due to light weight equipment and smaller number of operator required, cheap and easy to be handled. It is able to give a true picture of the bridge dynamic behavior without any artificial force excitation when vibration data is recorded. A three-span reinforced concrete bridge located in Sri Medan, Batu Pahat, Johor was measured by using microtremor equipment consist of three units of 1 Hz eigenfrequency passive sensors used in this test was performed in normal operating condition without excitation required from any active sources or short period noise perturbations. Ten measurements were conducted on the bridge deck and ten measurements on the ground surface in order to identify the natural frequencies of the bridge. Several peak frequencies were identified from three components of Fourier Amplitude Spectra (FAS in transverse (North-South, longitudinal (East-West and vertical (Up-Down direction as well as squared average Horizontal to Vertical Spectral Ratio (HVSR of ground response, computed by using Geopsy software. From the result, it was expected the bridge have five vibration modes frequencies in the range of 1.0 Hz and 7.0 Hz with the first two modes in the transverse and longitudinal direction having a frequency 1.0 Hz, the third mode is 2.2 Hz in transverse direction, fourth and fifth mode is 5.8 Hz and 7.0 Hz. For ground natural frequencies are in range 1.0 Hz to 1.3 Hz for North-South direction and 1.0 Hz to 1.6 Hz for East-West direction. Finally the results are compared with several empirical formulas for simple

  6. Ultra thin continuously reinforced concrete pavement research in south Africa

    CSIR Research Space (South Africa)

    Perrie, BD

    2007-08-01

    Full Text Available Ultra thin continuously reinforced concrete pavements (UTCRCP), in literature also referred to as Ultra Thin Reinforced High Performance Concrete (UTHRHPC), have been used in Europe successfully as a rehabilitation measure on steel bridge decks...

  7. Experimental Study on Electric Properties of Carbon Fiber Reinforced Concrete

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    According to the phenomenon that the physical properties have a great effect on the electric capability of carbon fiber reinforced concrete, the author researched the relationship between DC resistance of carbon fiber reinforced concrete and curing age using the two-probe method. Then the effect of insulative area,location and quantity on DC resistance of carbon fiber reinforced concrete was investigated at different curing age with analysis of hydration. The results suggest that DC resistance increases greatly with its curing age, which illustrates the relationship like Gaussian curve. In every curing ages the electric capability of carbon fiber reinforced concrete weakenes with the increase of insulative area. In same curing ages, section and insulative area, the more the quantity of insulation, the stronger the conductibility. The insulative location in optimal position can only result in optimal conductibility.

  8. Impact of biofouling on corrosion resistance of reinforced concrete

    Digital Repository Service at National Institute of Oceanography (India)

    Patil, B.T.; Gajendragad, M.R.; Ranganna, G.; Wagh, A.B.; Sudhakaran, T.

    the structure from deterioration; a nonuniform deposit can lead to severe localized pitting corrosion. To study this cylindrical reinforced concrete electrodes were exposed to seawater. They were periodically removed and examined for the presence of fouling...

  9. FLEXURAL TOUGHNESS OF STEEL FIBER REINFORCED CONCRETE

    Directory of Open Access Journals (Sweden)

    Fehmi ÇİVİCİ

    2006-02-01

    Full Text Available Fiber concrete is a composite material which has mechanical and physical characteristics unlike plain concrete. One of the important mechanical characteristics of fiber concrete is its energy absorbing capability. This characteristics which is also called toughness, is defined as the total area under the load-deflection curve. A number of composite characteristics such as crack resistance, ductility and impact resistance are related to the energy absorbtion capacity. According to ASTM C 1018 and JSCE SF-4 the calculation of toughness is determined by uniaxial flexural testing. Fiber concrete is often used in plates such as bridge decks, airport pavements, parking areas, subjected to cavitation and erosion. In this paper, toughness has been determined according to ASTM C 1018 and JSCE SF-4 methods by testing beam specimens. Energy absorbing capacities of plain and steel fiber reinforced concrete has been compared by evaluating the results of two methods. Also plain and steel fiber reinforced plate specimens behaviors subjected to biaxial flexure are compared by the loaddeflection curves of each specimen.

  10. CREATION OF MUSIC WITH FIBER REINFORCED CONCRETE

    Science.gov (United States)

    Kato, Hayato; Takeuchi, Masaki; Ogura, Naoyuki; Kitahara, Yukiko; Okamoto, Takahisa

    This research focuses on the Fiber Reinforcement Concrete(FRC) and its performance on musical tones. Thepossibility of future musical instruments made of this concrete is discussed. Recently, the technical properties of FRC had been improved and the different production styles, such as unit weight of binding material and volume of fiber in the structure, hardly affects the results of the acoustics. However, the board thickness in the FRC instruments is directly related with the variety of musical tone. The FRC musical effects were compared with those produced with wood on wind instruments. The sounds were compared with those produced with woodwind instruments. The sound pressure level was affected by the material and it becomes remarkably notorious in the high frequency levels. These differences had great influence on the spectrum analysis of the tone in the wind instruments and the sensory test. The results from the sensory test show dominant performances of brightness, beauty and power in the FRC instruments compared with those made of wood.

  11. Flexural strength and ductility of reinforced concrete beams

    OpenAIRE

    Kwan, AKH; Ho, JCM; Pam, HJ

    2002-01-01

    In the design of reinforced concrete beams, especially those made of high-strength concrete and those in earthquake-resistant structures, both the flexural strength and ductility need to be considered. From the numerical results obtained in a previous study on the post-peak behaviour and flexural ductility of reinforced concrete beams, the interrelation between the flexural strength and the flexural ductility that could be simultaneously achieved was evaluated and plotted in the form of chart...

  12. Strength Evaluation of Steel-Nylon Hybrid Fibre Reinforced Concrete

    OpenAIRE

    Maniram Kumar; Er. Ankush Khadwal

    2014-01-01

    When fibres like steel, glass, polypropylene, nylon, carbon, aramid, polyester, jute, etc are mixed with concrete known as fibre reinforced concrete. To overcome the deficiencies of concrete; fibres are added to improve the performance of concrete. In this research hybrid reinforced concrete is made by using steel and nylon 6 fibres. The inclusion of both steel and nylon 6 fibres are used in order to combine the benefits of both fibers; structural improvements provided by stee...

  13. Analysis of reinforced concrete building according to the EC 8

    OpenAIRE

    Dimec, Andrej

    2009-01-01

    In the Thesis the analysis and the software based design of the six-storey reinforced concrete wall building according to the European Standard Eurocode is presented. The structural system of the building consists of reinforced concrete walls. First the calculation of the self weight, variable actions, snow and the wind loads has been examined. The major part of the thesis deals with seismic analysis, which was performed by the modal analysis and simplified non-linear seismic a...

  14. Behavior of reinforced concrete beams reinforced with GFRP bars

    Directory of Open Access Journals (Sweden)

    D. H. Tavares

    Full Text Available The use of fiber reinforced polymer (FRP bars is one of the alternatives presented in recent studies to prevent the drawbacks related to the steel reinforcement in specific reinforced concrete members. In this work, six reinforced concrete beams were submitted to four point bending tests. One beam was reinforced with CA-50 steel bars and five with glass fiber reinforced polymer (GFRP bars. The tests were carried out in the Department of Structural Engineering in São Carlos Engineering School, São Paulo University. The objective of the test program was to compare strength, reinforcement deformation, displacement, and some anchorage aspects between the GFRP-reinforced concrete beams and the steel-reinforced concrete beam. The results show that, even though four GFRP-reinforced concrete beams were designed with the same internal tension force as that with steel reinforcement, their capacity was lower than that of the steel-reinforced beam. The results also show that similar flexural capacity can be achieved for the steel- and for the GFRP-reinforced concrete beams by controlling the stiffness (reinforcement modulus of elasticity multiplied by the bar cross-sectional area - EA and the tension force of the GFRP bars.

  15. Neutron imaging of water penetration into cracked steel reinforced concrete

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, P. [Center for Durability and Sustainability Studies of Shandong Province, Qingdao Technological University, Qingdao 266033 (China); Wittmann, F.H., E-mail: wittmann@aedificat.d [Center for Durability and Sustainability Studies of Shandong Province, Qingdao Technological University, Qingdao 266033 (China); Aedificat Institute Freiburg, Schlierbergstr. 80, D-79100 Freiburg (Germany); Zhao, T. [Center for Durability and Sustainability Studies of Shandong Province, Qingdao Technological University, Qingdao 266033 (China); Lehmann, E.H. [Neutron Imaging and Activation Group (NIAG), Paul Scherrer Institute, CH-5232 Villigen PSI (Switzerland)

    2010-04-01

    Service life and durability of reinforced concrete structures have become a crucial issue because of the economical and ecological implications. Service life of reinforced concrete structures is often limited by penetration of water and chemical compounds dissolved in water into the porous cement-based material. By now it is well-known that cracks in reinforced concrete are preferential paths for ingress of aggressive substances. Neutron radiography was successfully applied to study the process of water penetration into cracked steel reinforced concrete. In addition, the effectiveness of integral water repellent concrete to prevent ingress of water and salt solutions was investigated. Results are described in detail in this contribution. It will be shown that neutron radiography is a powerful method to visualize the process of water penetration into cracked and uncracked cement-based materials. On the basis of the obtained experimental data, it is possible to quantify the time-dependent water distributions in concrete with high accuracy and spatial resolution. It is of particular interest that penetration of water and salt solutions into damaged interfaces between concrete and steel can be visualized by means of neutron radiography. Deteriorating processes in cracked reinforced concrete structures can be studied in a completely new way. This advanced technology will help and find adequate ways to improve durability and service life of reinforced concrete structures. This will mean at the same time an essential contribution to improved sustainability.

  16. Highly Deformable Energy-Dissipating Reinforced Concrete Elements in Seismic Design of Reinforced Concrete Structures

    Directory of Open Access Journals (Sweden)

    Momoh Emmanuel Owoichoechi

    2017-06-01

    Full Text Available Incorporating scrap tyre rubber particles as partial replacement for aggregates has been found to produce concrete with improved ductility, deformability and damping which are desired characteristics of a viable material for enhancing structural response to earthquake vibrations. An analytical study using Drain-2dX was carried out to investigate the response of 4-storey, 3-bay reinforced concrete frames on innovative rubberised concrete deformable foundation models to simulated earthquake scaled to 5 different peak ground accelerations. Stress-strain properties of 3-layers aramid fibre-reinforced polymer (FRP-confinement for concrete incorporating waste rubber from scrap vehicle tyres were used to model the elements of this foundation models. With a partial decoupling of the superstructure from the direct earthquake force, the models showed up to 70% reduction in base shear, an improved overall q-factor of 7.1, and an estimated frame acceleration of 0.11g for an earthquake peak ground acceleration of 0.44g. This implies that a non-seismically designed reinforced concrete frame on the proposed rubberised concrete deformable foundation system would provide a simple, affordable and equally efficient alternative to the conventional and usually expensive earthquake resistant concrete frames. A supplementary Arrest System (SAS was proposed to anchor the frame from the resulting soft storey at the rubberised concrete foundation. A further research is recommended for the design of concrete hinges with rubberised concrete as used in the model with the most impressive response.

  17. Tensile behavior and tension stiffening of reinforced concrete

    Energy Technology Data Exchange (ETDEWEB)

    Choun, Young Sun; Seo, Jeong Moon

    2001-03-01

    For the ultimate behavior analysis of containment buildings under severe accident conditions, a clear understanding of tensile behaviors of plain and reinforced concrete is necessary. Nonlinear models for tensile behaviors of concrete are also needed. This report describe following items: tensile behaviors of plain concrete, test results of reinforced concrete panels in uniaxial and biaxial tension, tension stiffening. The tensile behaviors of reinforced concrete are significantly influenced by the properties of concrete and reinforcing steel. Thus, for a more reliable evaluation of tensile behavior and ultimate pressure capacity of a reinforced or prestressed concrete containment building, an advanced concrete model which can be considered rebar-concrete interaction effects should be developed. In additions, a crack behavior analysis method and tension stiffening models, which are based on fracture mechanics, should be developed. The model should be based on the various test data from specimens considering material and sectional properties of the containment building.

  18. A New Type Anticorrosion Coating for Ocean Reinforced Concrete Structures

    Institute of Scientific and Technical Information of China (English)

    CHENG Qi; GENG Guisheng; LUO Feng; WU Sanyu; ZHAO Dalin

    2000-01-01

    Corrosion of reinforced concrete structures is a serious problem in ocean engineering. As an orientation of study, anticorrosion coating technique is developed and widely applied, but many problems need to be solved. LSW-2 type anticorrosion coating for maritime reinforced concrete structures is charac lerized by sea water resistance, salt fog resistance, moisture and heat resistance as well as impermeability to chlorions. The new type coating can be applied to wet concrete surface by conventional construction lechnique. It is a breakthrough in solving the above-mentioned problem. The paper mainly introduces the test results, the property indices, coating procedure, construction technique and economic benefit of the coating.

  19. Inspection of reinforcement concrete structures with active infrared thermography

    Science.gov (United States)

    Szymanik, Barbara; Chady, Tomasz; Frankowski, Paweł

    2017-02-01

    In this article the reinforced concrete non-destructive evaluation using active thermography is discussed. There are several aspects of possible non-destructive testing of mentioned structures. One of them is the detection and assessment of the reinforcement itself. In case of active thermography, the external energy source has to be used to induce the thermal response of the inspected specimen. Here, authors propose two different techniques: microwave heating and induction heating. In this article authors will present several experimental results which will allow to compare mentioned two techniques of heating. suitability of each one to assess the reinforced concrete by using the active thermography will be discussed.

  20. Optimization Design and Application of Underground Reinforced Concrete Bifurcation Pipe

    Directory of Open Access Journals (Sweden)

    Chao Su

    2015-01-01

    Full Text Available Underground reinforced concrete bifurcation pipe is an important part of conveyance structure. During construction, the workload of excavation and concrete pouring can be significantly decreased according to optimized pipe structure, and the engineering quality can be improved. This paper presents an optimization mathematical model of underground reinforced concrete bifurcation pipe structure according to real working status of several common pipe structures from real cases. Then, an optimization design system was developed based on Particle Swarm Optimization algorithm. Furthermore, take the bifurcation pipe of one hydropower station as an example: optimization analysis was conducted, and accuracy and stability of the optimization design system were verified successfully.

  1. Design Basis for Fibre Reinforced Concrete (FRC) Pavements

    DEFF Research Database (Denmark)

    Bendixen, Søren; Stang, Henrik

    1996-01-01

    -crack opening relationship can beused to descibe the properties of fibre reinforced concrete (FRC) intension and how the stress-crack opening relationship can beapplied in a simple design scheme for pavements. The projectincludes development of design tools, experiments to determine thestress-crack opening......The paper summarises a Ph.D. project on development of a new design basis for fibre reinforced concrete ground slabs. The stress-crack openingrelationship is a well know basic material property of theso-called fictitious crack model for concrete. In the presentstudy it is shown how the stress...

  2. DAMAGE LOCATION DUE TO CORROSION IN REINFORCED CONCRETE STRUCTURES

    Institute of Scientific and Technical Information of China (English)

    WUJin; ChengJi-xin; LUMing-sheng

    2004-01-01

    An investigation on damage location due to the corrosion in reinforced concrete structures is conducted. The frequency change square ratio is used as a parameter for the damage. It is theoretically verified that the parameter is a function of the damage location. Experimental results of the corrosion in reinforced concrete structures show that the predicted damage location is in agreement with the real damage location. The modal parameters are used to detect the damages in structural concrete elements, and so they are useful for structural appraisal.

  3. Experiment and calculation of reinforced concrete at elevated temperatures

    CERN Document Server

    Guo, Zhenhai

    2011-01-01

    Concrete as a construction material goes through both physical and chemical changes under extreme elevated temperatures. As one of the most widely used building materials, it is important that both engineers and architects are able to understand and predict its behavior in under extreme heat conditions. Brief and readable, this book provides the tools and techniques to properly analysis the effects of high temperature of reinforced concrete which will lead to more stable, safer structures. Based on years of the author's research, Reinforced Concrete at Elevated Temperatures four par

  4. Stochastic modeling of reinforced concrete structures exposed to chloride attack

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Frier, Christian

    2004-01-01

    the reinforcement exceeds a critical threshold value. In the present paper a stochastic model is described by which the chloride content in a reinforced concrete structure can be estimated. The chloride ingress is modeled by a 2-dimensional diffusion process and the diffusion coefficient, surface chloride......For many reinforced concrete structures corrosion of reinforcement is an important problem since it can result in expensive maintenance and repair actions. Further, a significant reduction of the load-bearing capacity can occur. One mode of corrosion initiation is that the chloride content around...

  5. Diagonal Cracking and Shear Strength of Reinforced Concrete Beams

    DEFF Research Database (Denmark)

    Zhang, Jin-Ping

    1997-01-01

    found by the usual plastic theory, a physical explanation is given for this phenomenon and a way to estimate the shear capacity of reinforced concrete beams, based on the theory of plasticity, is described. The theoretical calculations are shown to be in fairly good agreement with test results from......The shear failure of non-shear-reinforced concrete beams with normal shear span ratios is observed to be governed in general by the formation of a critical diagonal crack. Under the hypothesis that the cracking of concrete introduces potential yield lines which may be more dangerous than the ones...

  6. Shear Capacity of Steel and Polymer Fibre Reinforced Concrete Beams

    DEFF Research Database (Denmark)

    Kragh-Poulsen, Jens C.; Hoang, Cao Linh; Goltermann, Per

    2011-01-01

    This paper deals with the application of a plasticity model for shear strength estimation of fibre reinforced concrete beams without stirrups. When using plastic theory to shear problems in structural concrete, the so-called effective strengths are introduced, usually determined by calibrating...... the plastic solutions with tests. This approach is, however, problematic when dealing with fibre reinforced concrete (FRC), as the effective strengths depend also on the type and the amount of fibres. In this paper, it is suggested that the effective tensile strength of FRC can be determined on the basis...

  7. Ultimate deformation capacity of reinforced concrete slabs underblast load

    NARCIS (Netherlands)

    Doormaal, J.C.A.M. van; Weerheijm, J.

    1996-01-01

    In this paper a test method to determine the deformation capacity and the resistance-deformation curve of blast-loaded slabs is described. This method was developed at TNO-PML. The method has been used to determine the ultimate deformation capacity of some simply supported reinforced concrete slabs

  8. Comparison of two novel approaches to model fibre reinforced concrete

    NARCIS (Netherlands)

    Radtke, F.K.F.; Simone, A.; Sluys, L.J.

    2009-01-01

    We present two approaches to model fibre reinforced concrete. In both approaches, discrete fibre distributions and the behaviour of the fibre-matrix interface are explicitly considered. One approach employs the reaction forces from fibre to matrix while the other is based on the partition of unity f

  9. Service Life and Maintenance Modelling of Reinforced Concrete Bridge Decks

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    Recent research in the area of assessment and maintenance of reinforced concrete bridge decks is presented in this paper. Three definitions of service lifetime are introduced and the difficult problem of assessing the service life is discussed. A stochastic modelling of corrosion and corrosion...

  10. Limit Analysis of 3D Reinforced Concrete Beam Elements

    DEFF Research Database (Denmark)

    Larsen, Kasper P.; Nielsen, Leif Otto; Poulsen, Peter Noe

    2012-01-01

    A new finite-element framework for lower-bound limit analysis of reinforced concrete beams, subjected to loading in three dimensions, is presented. The method circumvents the need for a direct formulation of a complex section-force-based yield criterion by creating a discrete representation of th...

  11. Stress wave propagation in reinforced concrete piles during driving

    NARCIS (Netherlands)

    Zorn, N.F.

    1983-01-01

    The aim of this report is to give an insight into what happens in a reinforced concrete pile during driving, and to contribute to design requirements for the loading case pile driving. Since the behaviour of stress waves in piles is influenced by a various number of parameters, the fewest of which r

  12. What Happens with Reinforced Concrete Structures when the Reinforcement Corrodes

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    In this paper, corrosion of reinforced concrete structures is discussed from the point of view of corrosion products. The different types of corrosion products are presented and a detailed study of the important diffusion coefficient is performed. Stochastic modelling of corrosion initiated...

  13. Optimisation of the Crack Pattern in Continuously Reinforced Concrete Pavements

    NARCIS (Netherlands)

    Ren, D.

    2015-01-01

    Recent field investigations on several new Continuously Reinforced Concrete Pavements (CRCP) in Belgium indicate that its crack pattern is characterized by low mean crack spacing along with a high percentage of clusters of closely spaced cracks. Field surveys also indicate that it is difficult to si

  14. Stress wave propagation in reinforced concrete piles during driving

    NARCIS (Netherlands)

    Zorn, N.F.

    1983-01-01

    The aim of this report is to give an insight into what happens in a reinforced concrete pile during driving, and to contribute to design requirements for the loading case pile driving. Since the behaviour of stress waves in piles is influenced by a various number of parameters, the fewest of which

  15. Optimisation of the Crack Pattern in Continuously Reinforced Concrete Pavements

    NARCIS (Netherlands)

    Ren, D.

    2015-01-01

    Recent field investigations on several new Continuously Reinforced Concrete Pavements (CRCP) in Belgium indicate that its crack pattern is characterized by low mean crack spacing along with a high percentage of clusters of closely spaced cracks. Field surveys also indicate that it is difficult to si

  16. Bending Resistance of Steel Plate-Reinforced Concrete Beam

    Institute of Scientific and Technical Information of China (English)

    TIAN Zhimin; CHEN Jie

    2006-01-01

    The formulas for calculating bending-resistant capacity of a steel plate-reinforced concrete composite beam are derived.To validate the formulas,experiments of the composite beam under three-point bending are carried out.Calculated results based on the formulas are in good agreement with experimental results.

  17. Dynamic Elasto-Plastic Model for Reinforced Concrete Members

    NARCIS (Netherlands)

    Van der Veen, C.; Blaauwendraad. J.

    1983-01-01

    It is becoming increasingly necessary to investigate the strength of reinforced concrete structures subjected to dynamic loading. Experience and knowledge relating to the non-linear dynamic behaviour of such structures is still limited, however. Attempts to solve this type of problems with the aid o

  18. Applicability Problem in Optimum Reinforced Concrete Structures Design

    Directory of Open Access Journals (Sweden)

    Ashara Assedeq

    2016-01-01

    Full Text Available Optimum reinforced concrete structures design is very complex problem, not only considering exactness of calculus but also because of questionable applicability of existing methods in practice. This paper presents the main theoretical mathematical and physical features of the problem formulation as well as the review and analysis of existing methods and solutions considering their exactness and applicability.

  19. Probabilistic Fatigue Model for Reinforced Concrete Onshore Wind Turbine Foundations

    DEFF Research Database (Denmark)

    Marquez-Dominguez, Sergio; Sørensen, John Dalsgaard

    2013-01-01

    Reinforced Concrete Slab Foundation (RCSF) is the most common onshore wind turbine foundation type installed by the wind industry around the world. Fatigue cracks in a RCSF are an important issue to be considered by the designers. Causes and consequences of the cracks due to fatigue damage in RCSFs...

  20. Shear strength of non-shear reinforced concrete elements

    DEFF Research Database (Denmark)

    Hoang, Cao linh

    1997-01-01

    The report deals with the shear strength of statically indeterminate reinforced concrete beams without shear reinforcement. Solutions for a number of beams with different load and support conditions have been derived by means of the crack sliding model developed by Jin- Ping Zhang.This model...

  1. Performance based design of reinforced concrete beams under impact

    Directory of Open Access Journals (Sweden)

    S. Tachibana

    2010-06-01

    Full Text Available The purpose of this research is to collect fundamental data and to establish a performance-based design method for reinforced concrete beams under perpendicular impact load.

    Series of low speed impact experiments using reinforced concrete beams were performed varying span length, cross section and main reinforcement.

    The experimental results are evaluated focusing on the impact load characteristics and the impact behaviours of reinforced concrete beams. Various characteristic values and their relationships are investigated such as the collision energy, the impact force duration, the energy absorbed by the beams and the beam response values. Also the bending performance of the reinforced concrete beams against perpendicular impact is evaluated.

    An equation is proposed to estimate the maximum displacement of the beam based on the collision energy and the static ultimate bending strength. The validity of the proposed equation is confirmed by comparison with experimental results obtained by other researchers as well as numerical results obtained by FEM simulations. The proposed equation allows for a performance based design of the structure accounting for the actual deformation due to the expected impact action.

  2. Computational modelling of chloride ion transport in reinforced concrete

    NARCIS (Netherlands)

    Meijers, S.J.H.; Bijen, J.M.J.M.; De Borst, R.; Fraaij, A.L.A.

    2001-01-01

    Exposure to a saline environment is a major threat with respect to the durability of reinforced concrete structures. The chloride ions, which are present in seawater and de-icing salts, are able to penetrate the concrete up to the depth of the reinforcement. They can eventually trigger a pitting cor

  3. Probabilistic Fatigue Model for Reinforced Concrete Onshore Wind Turbine Foundations

    DEFF Research Database (Denmark)

    Marquez-Dominguez, Sergio; Sørensen, John Dalsgaard

    2013-01-01

    Reinforced Concrete Slab Foundation (RCSF) is the most common onshore wind turbine foundation type installed by the wind industry around the world. Fatigue cracks in a RCSF are an important issue to be considered by the designers. Causes and consequences of the cracks due to fatigue damage in RCSFs...

  4. Optimisation of the Crack Pattern in Continuously Reinforced Concrete Pavements

    NARCIS (Netherlands)

    Ren, D.

    2015-01-01

    Recent field investigations on several new Continuously Reinforced Concrete Pavements (CRCP) in Belgium indicate that its crack pattern is characterized by low mean crack spacing along with a high percentage of clusters of closely spaced cracks. Field surveys also indicate that it is difficult to

  5. Rigid-plastic seismic design of reinforced concrete structures

    DEFF Research Database (Denmark)

    Costa, Joao Domingues; Bento, R.; Levtchitch, V.

    2007-01-01

    In this paper a new seismic design procedure for Reinforced Concrete (R/C) structures is proposed-the Rigid-Plastic Seismic Design (RPSD) method. This is a design procedure based on Non-Linear Time-History Analysis (NLTHA) for systems expected to perform in the non-linear range during a lifetime...

  6. Ultimate deformation capacity of reinforced concrete slabs underblast load

    NARCIS (Netherlands)

    Doormaal, J.C.A.M. van; Weerheijm, J.

    1996-01-01

    In this paper a test method to determine the deformation capacity and the resistance-deformation curve of blast-loaded slabs is described. This method was developed at TNO-PML. The method has been used to determine the ultimate deformation capacity of some simply supported reinforced concrete slabs

  7. Acrylic Rubber Latex in Ferrocement for Strengthening Reinforced Concrete Beams

    Directory of Open Access Journals (Sweden)

    D. R. Kumar

    2010-01-01

    Full Text Available Problem statement: In India, the early deterioration of reinforced concrete structures has become a big social problem in recent years. An essential research is needed for the development of effective repair materials and their execution systems comes to an important issue from the viewpoint of the longevity of infrastructures at present. Ferrocement laminates are introduced to enhance the overall performance of Reinforced Concrete (RC structures and these days the use of it is a promising technology for increasing the flexural strength of deficient reinforced concrete members. Approach: The repair system aims to provide quantitative repair enhancement as well as extending the life of deteriorated concrete members. This research in particular inspired the initiation of the present work which aimed to develop a material with unique properties and a very wide range of practical applications. The mechanical properties of mortar through difference in polymer content with Acrilic Latex by ferrocement among three different volume fractions of mesh reinforcement were studied. Following the encouraging progress made in the formulation and evaluation of the polymer modified repair mortar, tests were carried out involving the application of the reinforced repair material to the soffit of the reinforced concrete beams of 3 m length. Results: The levels of damage of the original beams prior to repair did not affect the ultimate load of the strengthened beams tested. The performance of the strengthened beams was compared to the control beams with respect to cracking, deflection and ultimate strength which confirm preeminent results. Conclusion: This accomplished the fact that acrylic rubber latex modified ferrocement is a doable alternative strengthening component for the rehabilitation of reinforced concrete structures. Further developments in these systems will create dramatic improvement into the field of rehabilitation of old privileged structures.

  8. Crack Identification in Reinforced Concrete Beams Using Ansys Software

    Directory of Open Access Journals (Sweden)

    T. Subramani

    2014-06-01

    Full Text Available Analytical determination of displacements and stresses in reinforced concrete material was difficult task and engineers had to rely on empirical formulas because concrete consists of heterogeneous material and creep and shrinkage influenced deformations in it. Due to these complexities engineers in past had been facing difficulties in coping such problems, but with the advancement of digital computerization and modern numerical methods for analysis such as finite element method, these problems can be addressed in a very efficient way. There were two ways to carry out modelling in ANSYS software, one was smeared approach and the other one was discrete. In the past, Smeared approach was used to identify the cracks in RC beam using ANSYS but in this work it was extended using discrete approach of modelling and shear cracks were identified in RC beam and load deflection curve was simulated which showed good agreement with the experimental results. Beams, made of brittle materials like concrete or cement, show increasing crack development during their service life due to mechanical and environmental loadings. This local damage can be translated into a reduction of the local bending stiffness. Stiffness modifications, while assuming constant mass distribution, can be observed by monitoring the vibration behaviour of the beam. In this paper the modal parameters of an undamaged beam are monitored and compared with the vibration behaviour of the beam subjected to controlled damaging. Selected stiffness parameters in the finite element model are adjusted in such a way that the computed modal quantities match the measured quantities. FEMtools has been used to establish a damage distribution in beams associated with increasing stress patterns. State of the art scanning laser modal equipment has been used for this purpose. It has been found that modal updating is indeed a possible tool to reconstruct the damage patterns.

  9. Simulation analysis of impact tests of steel plate reinforced concrete and reinforced concrete slabs against aircraft impact and its validation with experimental results

    Energy Technology Data Exchange (ETDEWEB)

    Sadiq, Muhammad, E-mail: muhammad.sadiq@pnra.org [Center for Nuclear Safety (CNS), Pakistan Nuclear Regulatory Authority (PNRA), PO Box 1912, Islamabad (Pakistan); Xiu Yun, Zhu, E-mail: lyzhuxiuyun@163.com [Nuclear and Radiation Safety Center (NSC), Ministry of Environmental Protection (MEP), Beijing (China); Rong, Pan, E-mail: panrong@chinansc.cn [Nuclear and Radiation Safety Center (NSC), Ministry of Environmental Protection (MEP), Beijing (China)

    2014-07-01

    Highlights: • Simulation analysis is carried out with two constitutive concrete models. • Winfrith model can better simulate nonlinear response of concrete than CSCM model. • Performance of steel plate concrete is better than reinforced concrete. • Thickness of safety related structures can be reduced by adopting steel plates. • Analysis results, mainly concrete material models should be validated. - Abstract: The steel plate reinforced concrete and reinforced concrete structures are used in nuclear power plants for protection against impact of an aircraft. In order to compare the impact resistance performance of steel plate reinforced concrete and reinforced concrete slabs panels, simulation analysis of 1/7.5 scale model impact tests is carried out by using finite element code ANSYS/LS-DYNA. The damage modes of all finite element models, velocity time history curves of the aircraft engine and damage to aircraft model are compared with the impact test results of steel plate reinforced concrete and reinforced concrete slab panels. The results indicate that finite element simulation results correlate well with the experimental results especially for constitutive winfrith concrete model. Also, the impact resistance performance of steel plate reinforced concrete slab panels is better than reinforced concrete slab panels, particularly the rear face steel plate is very effective in preventing the perforation and scabbing of concrete than conventional reinforced concrete structures. In this way, the thickness of steel plate reinforced concrete structures can be reduced in important structures like nuclear power plants against impact of aircraft. It also demonstrates the methodology to validate the analysis procedure with experimental and analytical studies. It may be effectively employed to predict the precise response of safety related structures against aircraft impact.

  10. Steel fiber reinforced concrete behavior, modelling and design

    CERN Document Server

    Singh, Harvinder

    2017-01-01

    This book discusses design aspects of steel fiber-reinforced concrete (SFRC) members, including the behavior of the SFRC and its modeling. It also examines the effect of various parameters governing the response of SFRC members in detail. Unlike other publications available in the form of guidelines, which mainly describe design methods based on experimental results, it describes the basic concepts and principles of designing structural members using SFRC as a structural material, predominantly subjected to flexure and shear. Although applications to special structures, such as bridges, retaining walls, tanks and silos are not specifically covered, the fundamental design concepts remain the same and can easily be extended to these elements. It introduces the principles and related theories for predicting the role of steel fibers in reinforcing concrete members concisely and logically, and presents various material models to predict the response of SFRC members in detail. These are then gradually extended to d...

  11. Surface treated polypropylene (PP) fibres for reinforced concrete

    Energy Technology Data Exchange (ETDEWEB)

    López-Buendía, Angel M., E-mail: buendia@uv.es [AIDICO Technological Institute of Construction, Benjamin Franklin 17, 46380 Paterna, Valencia (Spain); Romero-Sánchez, María Dolores [AIDICO Technological Institute of Construction, Marble Technical Unit, Camí de Castella 4, 03660 Novelda. Alicante (Spain); Climent, Verónica [Lafarge Cementos, Polígono Sepes, Isaac Newton s/n, 46500 Sagunto, Valencia (Spain); Guillem, Celia [AIDICO Technological Institute of Construction, Marble Technical Unit, Camí de Castella 4, 03660 Novelda. Alicante (Spain)

    2013-12-15

    Surface treatments on a polypropylene (PP) fibre have contributed to the improvement of fibre/concrete adhesion in fibre-reinforced concrete. The treatments to the PP fibre were characterized by contact angle measurements, ATR-IR and XPS to analyse chemical alterations. The surface topography and fibre/concrete interaction were analysed by several microscopic techniques, namely optical petrographic, and scanning electron microscopy. Treatment modified the surface chemistry and topography of the fibre by introducing sodium moieties and created additional fibre surface roughness. Modifications in the fibre surface led to an increase in the adhesion properties between the treated fibres and concrete and an improvement in the mechanical properties of the fibre-reinforced concrete composite as compared to the concrete containing untreated PP fibres. Compatibility with the concrete and increased roughness and mineral surface was also improved by nucleated portlandite and ettringite mineral association anchored on the alkaline PP fibre surface, which is induced during treatment.

  12. Dynamic behavior of reinforced concrete frame structure during construction

    Institute of Scientific and Technical Information of China (English)

    TIAN Ming-ge; YI Wei-jian

    2008-01-01

    The effects of concrete's time-variant elastic modulus, casting structural components, assembling temporary shoring framework system, and shock by operating construction equipment on dynamic behavior of the reinforced concrete frame structure during construction were investigated. The dynamic tests of an eight-storey reinforced concrete frame structure during full-scaled stages of the sixth storey construction cycle were carried out by ambient vibration. Natural frequencies, corresponding mode shapes and damping ratio were determined by power spectrum processing the tested signal data in frequency domain. The changes of frequencies, mode shapes and damping ratios at different construction stages were given. The results show that natural frequencies and modal damping ratios reach the maximum at stage of casting fresh concrete, especially for higher modes. Modal damping ratios at each construction stage are less than 5% of those during usage.

  13. Flexural Strength and Behavior of Polypropylene Fiber Reinforced Concrete Beams

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The strength and deformation characteristics of polypropylene fiber reinforced concrete (PFRC) beams were investigated by four-point bending procedures in this paper.Two kinds of polypropylene fibers with different fiber contents (0.2%, 0.5%, 1.0% and 1.5%) by volume were used in the beam, which measured 100×100 mm with a span of 300 mm.It was found that the strength of the reinforced concrete beams was significantly decreased,whereas the flexural toughness was improved,compared to those unreinforced concrete beams.Geometry properties and volume contents of polypropylene fiber were considered to be important factors for improving the flexural toughness.Moreover,the composite mechanism between polypropylene fiber and concrete was analyzed and discussed.

  14. Transport and Corrosion Behavior of Cracked Reinforced Concrete

    DEFF Research Database (Denmark)

    Pease, Bradley Justin

    to enter the concrete. This is, among others, important in the corrosion of reinforcing steel. When cracks protrude to the depth of reinforcing steel, liquids containing aggressive ions (i.e. chlorides associated with salts and sea water) may rapidly access and initiate corrosion of the reinforcing...... structures. These models currently lack some of the scientific validity to fully represent actual field structures, i.e. structures containing cracks. Further understanding, therefore is needed on the effect cracks have on transport and corrosion in reinforced concrete. The fundamental mechanisms...... of transport and corrosion in cracked, reinforced concrete are not yet fully understood. The scope of this study therefore is to develop a link between concrete cracks and the relevant transport mechanism(s) under particular environmental conditions. It is envisioned that a finite element model...

  15. Mixed Consolidation Solution for a Reinforced Concrete Structure

    Science.gov (United States)

    Lute, M.

    2016-06-01

    During the last years, reinforced concrete structures become subject for rehabilitation due to two factors: their long life span and large change in norms that leaded to a large increase of seismic loads in Eastern Europe. These lead to a necessity for rehabilitation of existing building stock in order to use them during their entire life span at the maximum potential. The present paper proposes a solution for rehabilitation for three reinforced concrete building of a hospital, that consumed a half of their life span and do not correspond anymore to present norms. The chosen solution is a combination between CFRP rehabilitation and increase of structural elements cross section in order to achieve the stiffness balance in the structure nodes that is required by present norms. As a further matter, correction in stiffness of local elements diminished the lateral drifts of the structure and improved the global seismic response of the building.

  16. Prediction of residual shear strength of corroded reinforced concrete beams

    Science.gov (United States)

    Imam, Ashhad; Azad, Abul Kalam

    2016-09-01

    With the aim of providing experimental data on the shear capacity and behavior of corroded reinforced concrete beams that may help in the development of strength prediction models, the test results of 13 corroded and four un-corroded beams are presented. Corrosion damage was induced by accelerated corrosion induction through impressed current. Test results show that loss of shear strength of beams is mostly attributable to two important damage factors namely, the reduction in stirrups area due to corrosion and the corrosion-induced cracking of concrete cover to stirrups. Based on the test data, a method is proposed to predict the residual shear strength of corroded reinforced concrete beams in which residual shear strength is calculated first by using corrosion-reduced steel area alone, and then it is reduced by a proposed reduction factor, which collectively represents all other applicable corrosion damage factors. The method seems to yield results that are in reasonable agreement with the available test data.

  17. COMPOSITE STRENGTHENING SOLUTIONS FOR REINFORCED CONCRETE LOAD BEARING ELEMENTS

    Directory of Open Access Journals (Sweden)

    Nicolae ȚĂRANU

    2015-11-01

    Full Text Available The results of a complex research and development program relating to the use of fiber reinforced polymeric composite strengthening solutions carried out at the Faculty of Civil Engineering and Building Services Iasi, are presented in this paper. The program has included the conceiving of the structural rehabilitation systems, the detailing and experimental testing of some solutions applied to reinforced concrete beams, slabs and columns (with circular and square cross-section. An efficient use of the component materials to improve the structural performance of the studied reinforced concrete element has been the main target of the research program. The main benefits resulted from the research program refer to the increase of the load capacities, the improvement of the structural response of all strengthened elements and a better control of the failure modes.

  18. The Mechanical Properties of Polypropylene Fiber Reinforced Concrete

    Institute of Scientific and Technical Information of China (English)

    LI Bei-xing; CHEN Ming-xiang; CHENG Fang; LIU Lu-ping

    2004-01-01

    The compressive, shear strengths and abrasion-erosion resistance as well as flexural properties of two polypropylene fiber reinforced concretes and the comparison with a steel fiber reinforced concrete were reported.The exprimental results show that a low content of polypropylene fiber (0.91kg/m3 of concrete) slightly decreases the compressive and shear strengths, and appreciably increased the flexural strength, but obviously enhances the toughness index and fracture energy for the concrete with the same mix proportion, consequently it plays a role of anti-cracking and improving toughness in concrete. Moreover, the polypropylene mesh fiber is better than the polypropylene monofilament fiber in improving flexural strength and toughness of concrete, but the two types of polypropylene fibers are inferior to steel fiber. All the polypropylene and steel fibers have no great beneficial effect on the abrasion-erosion resistance of concrete.

  19. Quantitative approach for damage detection of reinforced concrete frames

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The objective of this paper is to provide an analytical basis for the quantitative evaluation of damage to a reinforced concrete structure based on the vibration data obtained by using the damage detection technique. A partial reinforced concrete system of a weak beam/strong column moment frame is chosen as an example. A pushover analysis is carried out in order to numerically examine both the story shear-relative displacement characteristics and the associated damage level. In the analysis, a two dimensional nonlinear finite element analysis is employed considering several constitutive models. As a result, the degradation of the stiffness at the damaged story is characterized in association with the story relative displacement. It is also pointed out that the rotation angle of the column-base is highly correlated with the story relative displacement. Based on the analytical findings, quantitative approaches for a structural health monitoring system are suggested considering both the current sensor technologies and those available in the future.

  20. Cracking in reinforced concrete structures due to imposed deformations

    Energy Technology Data Exchange (ETDEWEB)

    Nagy, A.

    1997-04-01

    This thesis is concerned with modeling of the cracking process in reinforced concrete due to imposed deformations. Cracking is investigated both at early ages, during hydration, and at mature age when the final properties of the concrete are reached. One of the most important material characteristics of the concrete at early ages, the Young`s modulus is determined by means of a dynamic method called the resonance frequency method. 40 refs

  1. Collapse mechanisms and strength prediction of reinforced concrete pile caps

    DEFF Research Database (Denmark)

    Jensen, Uffe G.; Hoang, Linh Cao

    2012-01-01

    This paper describes an upper bound plasticity approach for strength prediction of reinforced concrete pile caps. A number of collapse mechanisms are identified and analysed. The procedure leads to an estimate of the load-carrying capacity and an identification of the critical collapse mechanism....... It is argued that the upper bound approach may be a useful complement to the widely used lower bound strut-and-tie method. Especially when dealing with strength assessment of existing structures....

  2. Strength Evaluation of Steel-Nylon Hybrid Fibre Reinforced Concrete

    Directory of Open Access Journals (Sweden)

    Maniram Kumar

    2014-07-01

    Full Text Available When fibres like steel, glass, polypropylene, nylon, carbon, aramid, polyester, jute, etc are mixed with concrete known as fibre reinforced concrete. To overcome the deficiencies of concrete; fibres are added to improve the performance of concrete. In this research hybrid reinforced concrete is made by using steel and nylon 6 fibres. The inclusion of both steel and nylon 6 fibres are used in order to combine the benefits of both fibers; structural improvements provided by steel fibers and the resistance to plastic shrinkage improvements provided by nylon fibers. So the aim of this project is to investigate the mechanical properties (compressive strength, flexure strength and split tensile strength of hybrid fiber reinforced concrete under compression, flexure & tension. The total volume of fibre was taken 0.75 % of total volume of concrete. In this experimental work, four different concrete mix proportions were casted with fibres and one mix without fibres. Four different mix combinations of steel- nylon 6 fibres were 100-00%, 75-25%, 50-50% and 25-75%. Superplasticizer was used in all mixes to make concrete more workable. The results shown that compressive, split tensile and flexural strength of hybrid fibre reinforced concrete increase by increasing quantity of steel and nylon 6 fibres. The increase in compressive and tensile strength due to incorporation of steel fibre is greater than that of using nylon fibre. For the nylon 6 fibres, adding more fibres into the concrete has a limited improvement on splitting tensile strength. Inclusion of nylon 6 fibres along with steel fibres results in considerable improvement in flexural strength as compared to solo steel fibre.

  3. Crack Identification in Reinforced Concrete Beams Using Ansys Software

    OpenAIRE

    2014-01-01

    Analytical determination of displacements and stresses in reinforced concrete material was difficult task and engineers had to rely on empirical formulas because concrete consists of heterogeneous material and creep and shrinkage influenced deformations in it. Due to these complexities engineers in past had been facing difficulties in coping such problems, but with the advancement of digital computerization and modern numerical methods for analysis such as finite element metho...

  4. Engineered cementitious composites for strengthening masonry infilled reinforced concrete frames

    DEFF Research Database (Denmark)

    Dehghani, Ayoub; Nateghi-Alahi, Fariborz; Fischer, Gregor

    2015-01-01

    The results of the second part of a comprehensive experimental program, aimed at investigating the behavior of masonry infilled reinforced concrete (RC) frames strengthened with fiber reinforced engineered cementitious composites (ECC) used as an overlay on the masonry wall, are presented in this...... and energy absorption capacity of the infilled frame, prevent brittle failure modes in the infill wall, and provide a reasonable system overstrength....

  5. Fatigue testing of reinforced-concrete steel bars

    Science.gov (United States)

    Maropoulos, S.; Fasnakis, D.; Voulgaraki, Ch; Papanikolaou, S.; Maropoulos, A.; Antonatos, A.

    2016-11-01

    A number of low-cycle fatigue tests were conducted on reinforced-concrete steel bars of various diameters to study their behaviour under axial loading according to EN 10080 and EN 1421-3. Scanning electron microscopy was used to study the specimen fracture surfaces. The problems faced during testing are presented and a specimen preparation method is described that will aid researchers on fatigue testing to obtain accurate test results and save on material and time.

  6. Cost analysis of reinforced concrete slabs and columns

    OpenAIRE

    Spuś, Piotr

    2013-01-01

    The construction industry is increasingly looking for solutions that are both simple and effective and that provide cost savings, speed and flexibility of execution. Two-way slabs are a form of construction unique to reinforced concrete comparing with the other major structural materials. It is an efficient, economical, and widely used structural system. The present dissertation aims to analyze and compare costs between four types of slabs: waffle slab with recuperate molds, flat slabs wit...

  7. Thermal analysis of reinforced concrete beams and frames

    Directory of Open Access Journals (Sweden)

    Essam H. El-Tayeb

    2017-04-01

    The obtained results of the studied cases reveal that material modeling of reinforced concrete beams and frames plays a major role in how these structures react to temperature variation. Cracking contributes to the release of significant portion of temperature restrain and in some cases this restrain is almost eliminated. The response of beams and frames deviates significantly based on the temperature gradient, linear or nonlinear; hence, the nonlinear temperature gradient which is the realistic profile is important to implement in the analysis.

  8. ANALYSIS OF EXPOSURE OF REINFORCED CONCRETE BUILDINGS TO TEMPERATURE LOADS

    Directory of Open Access Journals (Sweden)

    Mkrtychev Oleg Vartanovich

    2012-10-01

    Full Text Available The co-authors consider the problem of analysis of building structures in respect of combined effects of forces and temperatures. Results of fire tests of reinforced concrete walls and slabs are presented. Overview of the analysis of the fire resistance of reinforced-concrete buildings is also provided. As a result of the research, numerical solutions were obtained in respect of deflections, stresses, deformations and internal forces arising in a reinforced concrete bearing wall and plate exposed to a combination of forces and thermal loads. Comparative analysis of the experimental data and the results of the numerical solution was performed. The conclusion is that the experimental data are in good fit to the results of the numerical solution. Overall limit state of the monolithic building under consideration in terms of its fire resistance means its failure as a result of collapse. The limit state value is equal to 60; therefore, it is equal to 60 minutes. This value, if considered in respect of separate bearing elements, fits the fire resistance limit of buildings of Grade III (Fire Resistance that is equal to 45. Evidently, assurance of higher fire resistance limits of the building under consideration requires special fire safety actions to be applied.

  9. Seismic Behaviour of Reinforced Concrete Slit Shear Walls Energy Dissipators

    Directory of Open Access Journals (Sweden)

    Sergiu Băetu

    2010-01-01

    Full Text Available The types of slit walls energy dissipators, from monolith or precast reinforced concrete, proposed by researchers and the seismic behaviour of these types of walls are described. The overall ductility of the structure increases, considering the energy dissipation solutions proposed by the researchers of the reinforced concrete walls, resulting a supplementary safety for the structure. The objective of these solutions is to create an ideal structure for tall multi-storey buildings, that behaves as a rigid structure at low seismic action and turns into a flexible one in case of a high intensity earthquake action. The solutions for increasing ductility proposed in this paper are viable and easily to use in constructions practice. For the analysis of slit wall, the researchers used a series of analytical calculation methods, among the most important being the equivalent frame method and the finite element method, both presented s. 3 of the paper. The researchers concluded that by using this calculations methods, the dynamic behaviour of the reinforced concrete slit walls can be simulated very accurate and realistic.

  10. Report on aging of nuclear power plant reinforced concrete structures

    Energy Technology Data Exchange (ETDEWEB)

    Naus, D.J.; Oland, C.B. [Oak Ridge National Lab., TN (United States); Ellingwood, B.R. [Johns Hopkins Univ., Baltimore, MD (United States). Dept. of Civil Engineering

    1996-03-01

    The Structural Aging Program provides the US Nuclear Regulatory Commission with potential structural safety issues and acceptance criteria for use in continued service assessments of nuclear power plant safety-related concrete structures. The program was organized under four task areas: Program Management, Materials Property Data Base, Structural Component Assessment/Repair Technology, and Quantitative Methodology for Continued Service Determinations. Under these tasks, over 90 papers and reports were prepared addressing pertinent aspects associated with aging management of nuclear power plant reinforced concrete structures. Contained in this report is a summary of program results in the form of information related to longevity of nuclear power plant reinforced concrete structures, a Structural Materials Information Center presenting data and information on the time variation of concrete materials under the influence of environmental stressors and aging factors, in-service inspection and condition assessments techniques, repair materials and methods, evaluation of nuclear power plant reinforced concrete structures, and a reliability-based methodology for current and future condition assessments. Recommendations for future activities are also provided. 308 refs., 61 figs., 50 tabs.

  11. Numerical modelling of reinforced concrete beams with fracture-plastic material

    Directory of Open Access Journals (Sweden)

    O. Sucharda

    2014-10-01

    Full Text Available This paper describes the use of models of fracture-plastic materials for reinforced concrete in numerical modelling of beams made from reinforced concrete. The purpose of the paper is to use of a model of concrete for modelling of a behaviour of reinforced concrete beams which have been tested at the University of Toronto within re-examination of classic concrete beam tests. The original tests were performed by Bresler- Scordelis. A stochastic modelling based on LHS (Latin Hypercube Sampling has been performed for the reinforced concrete beam. An objective of the modelling is to evaluate the total bearing capacity of the reinforced concrete beams depending on distribution of input data. The beams from the studied set have longitudinal reinforcement only. The beams do not have any shear reinforcement. The software used for the fracture-plastic model of the reinforced concrete is the ATENA.

  12. Nonlinear Earthquake Analysis of Reinforced Concrete Frames with Fiber and Bernoulli-Euler Beam-Column Element

    Directory of Open Access Journals (Sweden)

    Muhammet Karaton

    2014-01-01

    Full Text Available A beam-column element based on the Euler-Bernoulli beam theory is researched for nonlinear dynamic analysis of reinforced concrete (RC structural element. Stiffness matrix of this element is obtained by using rigidity method. A solution technique that included nonlinear dynamic substructure procedure is developed for dynamic analyses of RC frames. A predicted-corrected form of the Bossak-α method is applied for dynamic integration scheme. A comparison of experimental data of a RC column element with numerical results, obtained from proposed solution technique, is studied for verification the numerical solutions. Furthermore, nonlinear cyclic analysis results of a portal reinforced concrete frame are achieved for comparing the proposed solution technique with Fibre element, based on flexibility method. However, seismic damage analyses of an 8-story RC frame structure with soft-story are investigated for cases of lumped/distributed mass and load. Damage region, propagation, and intensities according to both approaches are researched.

  13. Nonlinear earthquake analysis of reinforced concrete frames with fiber and Bernoulli-Euler beam-column element.

    Science.gov (United States)

    Karaton, Muhammet

    2014-01-01

    A beam-column element based on the Euler-Bernoulli beam theory is researched for nonlinear dynamic analysis of reinforced concrete (RC) structural element. Stiffness matrix of this element is obtained by using rigidity method. A solution technique that included nonlinear dynamic substructure procedure is developed for dynamic analyses of RC frames. A predicted-corrected form of the Bossak-α method is applied for dynamic integration scheme. A comparison of experimental data of a RC column element with numerical results, obtained from proposed solution technique, is studied for verification the numerical solutions. Furthermore, nonlinear cyclic analysis results of a portal reinforced concrete frame are achieved for comparing the proposed solution technique with Fibre element, based on flexibility method. However, seismic damage analyses of an 8-story RC frame structure with soft-story are investigated for cases of lumped/distributed mass and load. Damage region, propagation, and intensities according to both approaches are researched.

  14. Healing Effectiveness of Cracks Rehabilitation in Reinforced Concrete Using Electrodeposition Method

    Institute of Scientific and Technical Information of China (English)

    JIANG Zhengwu; XING Feng; SUN Zhenping; WANG Peiming

    2008-01-01

    An electrodeposition method and its experimental device for rehabilitation of cracks in reinforced concrete were proposed.Porous concrete is proposed to simulate cracked concrete,and mass increment,permeation coefficient and sound velocity of ultrasonic wave were used to be evaluating indicators of healing effectiveness of crack rehabilitation in this method.Effect of currency density,concentration of electrolyte solution on healing effectiveness of porous reinforced concretes with different total void ratio was studied.The experimental results indicate that the simulation of porous concrete for cracks can reflect the healing effectiveness of electrodeposition method effectively.Total void ratio of porous concrete has little effect on healing effectiveness of electrodeposition at early ages.The higher the currency density or concentration of electrolyte solution is,the higher the electrodeposition rate and sound velocity in porous concrete are,and the lower the permeation coefficient of porous concrete will be.Mg(OH)2 crystals produced in high current density are large,thin sheet-shaped and arranged loosely.

  15. Laboratory Assessment of Select Methods of Corrosion Control and Repair in Reinforced Concrete Bridges

    Directory of Open Access Journals (Sweden)

    Matthew D. Pritzl

    2014-01-01

    Full Text Available Fourteen reinforced concrete laboratory test specimens were used to evaluate a number of corrosion control (CoC procedures to prolong the life of patch repairs in corrosion-damaged reinforced concrete. These specimens included layered mixed-in chlorides to represent chloride contamination due to deicing salts. All specimens were exposed to accelerated corrosion testing for three months, subjected to patch repairs with various treatments, and further subjected to additional three months of exposure to accelerated corrosion. The use of thermal sprayed zinc, galvanic embedded anodes, epoxy/polyurethane coating, acrylic coating, and an epoxy patch repair material was evaluated individually or in combination. The specimens were assessed with respect to corrosion currents (estimated mass loss, chloride ingress, surface rust staining, and corrosion of the reinforcing steel observed after dissection. Results indicated that when used in patch repair applications, the embedded galvanic anode with top surface coating, galvanic thermal sprayed zinc, and galvanic thermal sprayed zinc with surface coating were more effective in controlling corrosion than the other treatments tested.

  16. Neural Network Model for Moment-Curvature Relationship of Reinforced Concrete Sections

    OpenAIRE

    Bağcı, Muhiddin

    2010-01-01

    The analysis of moment-curvature relationship of reinforced concrete sections is complex due to large number of variables as well as non-linear material behavior involved. Artificial Neural Networks (ANNs) are found to be a tool capable of solving such problems. This has led to increasing use of ANN for analyzing the behavior of reinforced concrete sections. This paper reports the details of a study conducted using ANN for predicting moment-curvature relationship of a reinforced concrete sect...

  17. Acoustic emission characteristics on microscopic damage behavior of carbon fiber sheet reinforced concrete

    Science.gov (United States)

    Lee, Jin Kyung; Lee, Joon Hyun

    2002-05-01

    In this study, a three-point bend test has been carried out to understand the damage progress and the micro-failure mechanism of carbon fiber sheet (CFS) reinforced concretes. For these purposes, four kinds of specimens were used; unreinforced concrete, steel bar reinforced concrete, CFS reinforced concrete, and concrete reinforced by both steel bar and CFS. Acoustic Emission (AE) technique was used to evaluate the characteristics of damage progress and the failure mechanism of the specimens.

  18. Micro-Mechanical Modeling of Fiber Reinforced Concrete

    DEFF Research Database (Denmark)

    Stang, Henrik

    1999-01-01

    of Fiber Reinforced Concrete (FRC) on the micro- the meso- as well as the macro-level, i.e. modeling aspects of fiber-matrix interaction, overall constitutive modeling and structural modeling. Emphasis is placed on the micro- and meso-aspects, however, some basic results on the macro-level are also......The paper is a contribution to the course Cement-Based Composites for the Building Industry, organized by POA Foundation for Postgraduate Studies in Civil Engineering in cooperation with Priority Programme Material Research (PPM) in the Netherlands. The text deals with mechanical modeling aspects...

  19. Stochastic Modeling of Reinforced Concrete Structures Exposed to Chloride Attack

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Frier, Christian

    2003-01-01

    concentration and reinforcement cover depth are modeled by stochastic fields. The paper contains a description of the parameters to be included in a stochastic model and a proposal for the information needed to obtain values for the parameters in order to be ab le to perform reliability investigations...... the reinforcement exceeds a critical threshold value. In the present paper a stochastic model is described by which the chloride content in a reinforced concrete structure can be estimated. The chloride ingress is modeled by a 2-dimensional diffusion process and the diffusion coefficient, surface chloride...

  20. Mechanical Properties of Layered Hybrid Fiber Reinforced Concrete

    Institute of Scientific and Technical Information of China (English)

    YUAN Hai-qing; CHEN Jing-tao; ZHU Ji-dong

    2003-01-01

    To improve the mechanical properties of concrete,Layered Hybrid Fiber Reinforced Concrete (LHFRC) was developed in this paper.Through comparative tests,the effects of layered hybrid fibers on a series of mechanical properties of concrete were discussed.The mechanical properties include compressive strength,tensile strength,flexural strength,compressive stress-strain relationship,flexural toughness and cracking resistance of concrete.The testing results and analysis demonstrate that layered hybrid fibers can significantly improve the flexural strength,toughness and cracking resistance of concrete while the cost of concrete increases slightly.

  1. Stochastic Models for Chloride-Initiated Corrosion in Reinforced Concrete

    DEFF Research Database (Denmark)

    Engelund, S.; Sørensen, John Dalsgaard

    1996-01-01

    Corrosion of the reinforcement in concrete structures can lead to a substantial decrease of the load-bearing capacity. One mode of corrosion initiation is when the chloride content around the reinforcement exceeds a threshold value. In the present paper a statistical model is developed by which...... the chloride content in a reinforced concrete structure can be predicted. The model parameters are estimated on the basis of measurements. The distribution of the time to initiation of corrosion is estimated by FORM/SORM-analysis....

  2. Compressive behaviour at High Temperatures of Fibre Reinforced Concretes

    Directory of Open Access Journals (Sweden)

    S. O. Santos

    2009-01-01

    Full Text Available This paper summarizes the research that is being carried out at the Universities of Coimbra and Rio de Janeiro, on fibre reinforced concretes at high temperatures. Several high strength concrete compositions reinforced with fibres (polypropylene, steel and glass fibres were developed. The results of compressive tests at high temperatures (300 °C, 500 °C and 600 °C and after heating and cooling down of the concrete are presented in the paper. In both research studies, the results indicated that polypropylene fibers prevent concrete spalling. 

  3. Design of Ultra High Performance Fiber Reinforced Concrete Shells

    DEFF Research Database (Denmark)

    Jepsen, Michael S.; Lambertsen, Søren Heide; Damkilde, Lars

    2013-01-01

    Fiber Reinforced Concrete shell. The major challenge in the design phase has been securing sufficient stiffness of the structure while keeping the weight at a minimum. The weight/stiffness issue has been investigated by means of the finite element method, to optimize the structure regarding overall......The paper treats the redesign of the float structure of the Wavestar wave energy converter. Previously it was designed as a glass fiber structure, but due to cost reduction requirements a redesign has been initiated. The new float structure will be designed as a double curved Ultra High Performance...

  4. Monitoring Corrosion of Steel Bars in Reinforced Concrete Structures

    Directory of Open Access Journals (Sweden)

    Sanjeev Kumar Verma

    2014-01-01

    Full Text Available Corrosion of steel bars embedded in reinforced concrete (RC structures reduces the service life and durability of structures causing early failure of structure, which costs significantly for inspection and maintenance of deteriorating structures. Hence, monitoring of reinforcement corrosion is of significant importance for preventing premature failure of structures. This paper attempts to present the importance of monitoring reinforcement corrosion and describes the different methods for evaluating the corrosion state of RC structures, especially hal-cell potential (HCP method. This paper also presents few techniques to protect concrete from corrosion.

  5. Monitoring corrosion of steel bars in reinforced concrete structures.

    Science.gov (United States)

    Verma, Sanjeev Kumar; Bhadauria, Sudhir Singh; Akhtar, Saleem

    2014-01-01

    Corrosion of steel bars embedded in reinforced concrete (RC) structures reduces the service life and durability of structures causing early failure of structure, which costs significantly for inspection and maintenance of deteriorating structures. Hence, monitoring of reinforcement corrosion is of significant importance for preventing premature failure of structures. This paper attempts to present the importance of monitoring reinforcement corrosion and describes the different methods for evaluating the corrosion state of RC structures, especially hal-cell potential (HCP) method. This paper also presents few techniques to protect concrete from corrosion.

  6. In-plane shear test of fibre reinforced concrete panels

    DEFF Research Database (Denmark)

    Solgaard, Anders Ole Stubbe; Stang, Henrik; Goltermann, Per

    2008-01-01

    contributes to the investigation of fibers as reinforcement in panels with experimental results and a consistent approach to material characterization and modeling. The proposed model draws on elements from the classical yield line theory of rigid, perfectly plastic materials and the theory of fracture......The present paper concerns the investigation of polymer Fiber Reinforced Concrete (FRC) panels subjected to in-plane shear. The use of fibers as primary reinforcement in panels is a new application of fiber reinforcement, hence test methods, design bases and models are lacking. This paper...

  7. Observations on the electrical resistivity of steel fibre reinforced concrete

    DEFF Research Database (Denmark)

    Solgaard, Anders Ole Stubbe; Geiker, Mette Rica; Edvardsen, Carola;

    2014-01-01

    Steel fibre reinforced concrete (SFRC) is in many ways a well-known construction material, and its use has gradually increased over the last decades. The mechanical properties of SFRC are well described based on the theories of fracture mechanics. However, knowledge on other material properties......, including the electrical resistivity, is sparse. Among others, the electrical resistivity of concrete has an effect on the corrosion process of possible embedded bar reinforcement and transfer of stray current. The present paper provides experimental results concerning the influence of the fibre volume...

  8. STUDIES ON STRESS TRANSFERENCE MECHANISM OF STEEL FIBRE REINFORCED CONCRETE

    Institute of Scientific and Technical Information of China (English)

    杨佑发; 许绍乾; 钟正华

    2001-01-01

    The stress transfer mechanism of steel fibre reinforced concrete is studied. The solutions for the stress and displacement were regarded as the superposition of "the elementary solutions" and "the improved solutions". The elementary solutions were found by using two-dimensional elastic theory and the improved solutions were found by using the Love displacement function method. The calculated results indicate that the solutions possess good convergence. By comparing the three-dimensional solutions with the shear-lag solutions, evident difference may be found.

  9. Process of cracking in reinforced concrete beams (simulation and experiment

    Directory of Open Access Journals (Sweden)

    I. N. Shardakov

    2016-10-01

    Full Text Available The paper presents the results of experimental and theoretical investigations of the mechanisms of crack formation in reinforced concrete beams subjected to quasi-static bending. The boundary-value problem has been formulated in the framework of brittle fracture mechanics and solved using the finite-element method. Numerical simulation of the vibrations of an uncracked beam and a beam with cracks of different size serves to determine the pattern of changes in the spectrum of eigenfrequencies observed during crack evolution. A series of sequential quasi-static 4-point bend tests leading to the formation of cracks in a reinforced concrete beam were performed. At each loading step, the beam was subjected to an impulse load to induce vibrations. Two stages of cracking were detected. During the first stage the nonconservative process of deformation begins to develope, but has not visible signs. The second stage is an active cracking, which is marked by a sharp change in eingenfrequencies. The boundary of a transition from one stage to another is well registered. The vibration behavior was examined for the ordinary concrete beams and the beams strengthened with a carbon-fiber polymer. The obtained results show that the vibrodiagnostic approach is an effective tool for monitoring crack formation and assessing the quality of measures aimed at strengthening concrete structures

  10. Experimental Study on Voided Reinforced Concrete Beams with Polythene Balls

    Science.gov (United States)

    Sivaneshan, P.; Harishankar, S.

    2017-07-01

    The primary component in any structure is concrete, that exist in buildings and bridges. In present situation, a serious problems faced by construction industry is exhaustive use of raw materials. Recent times, various methods are being adopted to limit the use of concrete. In structural elements like beams, polythene balls can be induced to reduce the usage of concrete. A simply supported reinforced concrete beam has two zones, one above neutral axis and other below neutral axis. The region below neutral axis is in tension and above neutral axis is in compression. As concrete is weak in tension, steel reinforcements are provided in tension zone. The concrete below the neutral axis acts as a stress transfer medium between the compression zone and tension zone. The concrete above the neutral axis takes minimum stress so that we could partially replace the concrete above neutral axis by creating air voids using recycled polythene balls. Polythene balls of varying diameters of 75 mm, 65 mm and 35 mm were partially replaced in compression zone. Hence the usage of concrete in beams and self-weight of the beams got reduced considerably. The Load carrying capacity, Deflection of beams and crack patterns were studied and compared with conventional reinforced concrete beams.

  11. Retrofitting of Reinforced Concrete Beams using Reactive Powder Concrete (RPC)

    Science.gov (United States)

    Karthik, S.; Sundaravadivelu, Karthik

    2017-07-01

    Strengthening of existing damaged structures is one of the leading studies in civil engineering. The purpose of retrofitting is to structurally treat the member with an aim to restore the structure to its original strength. The focus of this project is to study the behaviour of damaged Reinforced Concrete beam retrofitted with Reactive Powder Concrete (RPC) Overlay. Reinforced concrete beams of length 1200 mm, width 100 mm and depth 200 mm were casted with M30 grade of concrete in the laboratory and cured for 28 days. One beam is taken as control and are tested under two point loading to find out ultimate load. Remaining beams are subjected to 90 % ultimate load of control beams. The partially damaged beams are retrofitted with Reactive Powder Concrete Overlay at the full tension face of the beam and side overlay depends upon the respectable retrofitting techniques with 10 mm and 20 mm thick layer to find optimum. Materials like steel fibres are added to enhance the ductility by eliminating coarse particle for homogeneity of the structure. Finally, the modes of failure for retrofitted beams are analysed experimentally under two point loading & compared the results with Control beam.

  12. Resistance of reinforced concrete beams in explosive charges

    Directory of Open Access Journals (Sweden)

    Roman Krzewiński

    2016-12-01

    Full Text Available The paper presents an analysis of the dynamic interaction on reinforced concrete beams, caused by the outbreak of not-direct contact with the design. Depending on the distance of the source of the outbreak, the structure may be loaded with gas stream postexplosion or air shock wave. The impact of such influence on the reinforced concrete beam of a constant cross-section and small transverse dimensions compared with their length was assessed. For the beams located in the closer zone, there were evaluated the parameters of the destructive action of explosions limit case, in which the concrete chipping occurs at a length of at least the length of the buckling of steel rods. In case of loading of beams with air shock wave, using literature data, they determined the way of evaluating equivalent static load at which the boundary elastic deflection of beams occurs. The above analysis is shown by the example calculation, which sets the minimum length of the buckling of steel bars in the beam bending.[b]Keywords:[/b] civil engineering, the dynamics of the explosion, the noncontact loads, dynamic loads, reflectance

  13. The effects of steel fibre reinforced concrete on system ductility

    Directory of Open Access Journals (Sweden)

    Yilmaz, U. S.

    2007-03-01

    Full Text Available Steel fibre-reinforced concrete is being used extensively today in both field applications and experimental studies on concrete strength and ductility. The state of passive confinement generated by the fibre delays cracking and enhances ductility. The present paper reports on both experimental and analytical studies. In the former, a series of 16 steel-fibre reinforced concrete prismatic specimens were subjected to axial loads and the respective axial load-unit strain diagrams were subsequently plotted to determine the effect of steel fibres on reinforced concrete column ductility. Secondly, an analytical study was run to determine the additional ductility accruing to a frame system when steel fibres are included in the concrete. Analytical models were generated for 16 two-storey, single-span reinforced concrete frames. The columns in these frames were designed to the same characteristics as the specimens used in the experimental tests. Non-linear static (pushover analyses were performed for each frame to obtain load-displacement curves and determine the effect of steel fibres on reinforced concrete column ductility.El hormigón reforzado con fibra de acero se emplea actualmente tanto en obra como en los trabajos experimentales para estudiar la resistencia mecánica y ductilidad del hormigón. El estado de confinamiento pasivo producido por la fibra retrasa la fisuración y aumenta la ductilidad. El presente trabajo es de índole tanto experimental como analítica. En primer lugar, en la parte experimental se aplica una fuerza axial a 16 probetas prismáticas (160 x 160 x 840 mm de hormigón reforzado con fibra de acero para determinar su comportamiento, obteniéndose las curvas de fuerza axial-deformación unitaria correspondientes a partir de los resultados observados. A partir de una evaluación de dichos resultados experimentales, se determina el efecto que ejercen las fibras de acero sobre la ductilidad de las probetas de hormigón armado

  14. Modelling the Loss of Steel-Concrete Bonds in Corroded Reinforced Concrete Beams

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    2007-01-01

    The existing stochastic models for deterioration of reinforced concrete structures is extended by adding modelling of "loss of bond" due to corrosion between the reinforcement bars and the surrounding concrete.......The existing stochastic models for deterioration of reinforced concrete structures is extended by adding modelling of "loss of bond" due to corrosion between the reinforcement bars and the surrounding concrete....

  15. 77 FR 18973 - Reinforced Concrete in Construction, and Preventing Backover Injuries and Fatalities

    Science.gov (United States)

    2012-03-29

    ... Reinforced Concrete in Construction, and Preventing Backover Injuries and Fatalities AGENCY: Occupational... aware of employee safety risks in two areas, reinforcing operations in concrete work (construction only... following methods (submissions relating to Reinforced Concrete in Construction to Docket No. OSHA-2010-0058...

  16. Corrosion and protection in reinforced concrete: pulse cathodic protection: an improved cost-effective alternative

    NARCIS (Netherlands)

    Koleva, D.A.

    2007-01-01

    Corrosion and protection in reinforced concrete. Pulse cathodic protection: an improved cost-effective alternative. The aim of the research project was to study the possibilities for establishing a new or improved electrochemical method for corrosion prevention/protection for reinforced concrete. Th

  17. Optimal Material Layout - Applied on Reinforced Concrete Slabs

    DEFF Research Database (Denmark)

    Dollerup, Niels; Jepsen, Michael S.; Damkilde, Lars

    2015-01-01

    to determine the optimal material layout of a slab in the ultimate load state, based on simple inputs such as outer geometry, boundary conditions, multiple load cases and design domains. The material layout of the optimal design can either be fully orthotropic or isotropic, or a combination with a predefined......This paper introduces a general, finite-element-based optimisation tool for improving the material layout of concrete structures. The application presented is general and exemplified by material optimisation of reinforced concrete slabs. By utilising the optimisation tool, it is possible...... coupling between design domains and reinforcement directions. The implementation is a lower bound formulation, resulting in a convex optimisation problem that consists of a number of linear constraints from the equilibrium equations and a number of convex non-linear constraints from the yield criteria...

  18. Study of Reinforced Concrete Beam-Column Joint

    Directory of Open Access Journals (Sweden)

    Prakash Panjwania

    2015-06-01

    Full Text Available The beam column joint is the crucial zone in a reinforced concrete moment resisting frame. It is subjected to large forces during severe ground shaking and its behaviour has a significant influence on the response of the structure. The assumption of rigid joint fails to consider the effects of high shear forces developed within the joint. The shear failure is always brittle in nature which is not an acceptable structural performance especially in seismic conditions. This paper presents a review of the postulated theories associated with the behaviour of joints. Understanding the joint behaviour is essential in exercising proper judgments in the design of joints. The paper discusses about the seismic actions on various types of joints and highlights the critical parameters that affect joint performance with special reference to bond and shear transfer

  19. Tapered Polymer Fiber Sensors for Reinforced Concrete Beam Vibration Detection

    Directory of Open Access Journals (Sweden)

    Dong Luo

    2016-12-01

    Full Text Available In this study, tapered polymer fiber sensors (TPFSs have been employed to detect the vibration of a reinforced concrete beam (RC beam. The sensing principle was based on transmission modes theory. The natural frequency of an RC beam was theoretically analyzed. Experiments were carried out with sensors mounted on the surface or embedded in the RC beam. Vibration detection results agreed well with Kistler accelerometers. The experimental results found that both the accelerometer and TPFS detected the natural frequency function of a vibrated RC beam well. The mode shapes of the RC beam were also found by using the TPFSs. The proposed vibration detection method provides a cost-comparable solution for a structural health monitoring (SHM system in civil engineering.

  20. Effect of wind in the design of reinforced concrete buildings

    Directory of Open Access Journals (Sweden)

    L.S. Tapajós

    Full Text Available ABSTRACT This paper presents the results from a parametric study carried in order to quantify how far errors in the design stage related to the consideration of the wind action may put at risk the response and safety of reinforced concrete buildings. Using an architectural model as reference and varying the number of floors of the building, the structural safety was evaluated as a function of the wind action intensity. Results showed that even for low-rise buildings, with 10 floors, ignoring the wind action can significantly jeopardize their behaviour and safety. Yet, for slenderer buildings, up to 30 floors, it can lead to catastrophic results, as the ruin of the structure by progressive collapse.

  1. Corrosion of reinforcement bars in steel ibre reinforced concrete structures

    DEFF Research Database (Denmark)

    Solgaard, Anders Ole Stubbe

    Steel fibres have been known as an alternative to traditional reinforcement bars for special applications of structural concrete for decades and the use of steel fibre reinforced concrete (SFRC) has gradually increased in recent years. Steel fibres lead to reduced crack widths in concrete formed......, among other reasons, due to shrinkage and/or mechanical loading. Steel fibres are nowadays also used in combination with traditional reinforcement for structural concrete, where the role of the fibres is to minimize the crack widths whereas the traditional reinforcement bars are used for structural....... The aim of the work presented in this Ph.D. thesis was to quantify the influence of steel fibres on corrosion of traditional reinforcement bars embedded in uncracked concrete as well as cracked concrete. Focus of the work was set on the impact of steel fibres on corrosion propagation in uncracked concrete...

  2. Shear Strengthening of Reinforced Concrete Beams Using GFRP Wraps

    Directory of Open Access Journals (Sweden)

    M. A. A. Saafan

    2006-01-01

    Full Text Available The objective of the experimental work described in this paper was to investigate the efficiency of GFRP composites in strengthening simply supported reinforced concrete beams designed with insufficient shear capacity. Using the hand lay-up technique, successive layers of a woven fiberglass fabric were bonded along the shear span to increase the shear capacity and to avoid catastrophic premature failure modes. The strengthened beams were fabricated with no web reinforcement to explore the efficiency of the proposed strengthening technique using the results of control beams with closed stirrups as a  web reinforcement. The test results of 18 beams are reported, addressing the influence of different shear strengthening schemes and variable longitudinal reinforcement ratios on the structural behavior. The results indicated that significant increases in the shear strength and improvements in the overall structural behavior of beams with insufficient shear capacity could be achieved by proper application of GFRP wraps.

  3. Fatigue Defect of Layer Steel Fiber Reinforced Concrete

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    An experimental study is carried out on fatigue defect of layer steel fiber reinforced concrete (LSFRC). Based on experimental data,the various relation curves are given corresponding to different stress levels 0.9, 0.85, and 0.8. Furthermore, the fatigue defect degree is defined, and the strain-cycle ratio equations and defect-cycle ratio equations with the correlation coefficients very close to 1, are regressed in terms of the cubic polynomial,of which the fittings are preferable.In addition,the results show that the fatigue defect of LSFRC presents three-phase development regularity too.And in comparison with the plain concrete,the third phase of the fatigue defect of LSFRC is longer, therefore the fatigue failure of LSFRC is more ductile.The mechanism of the fatigue defect is discussed too.

  4. STUDIES OF DURABILITY ASPECTS OF FIBRE REINFORCED CONCRETE

    Directory of Open Access Journals (Sweden)

    D. MARUTHACHALAM

    2012-02-01

    Full Text Available This paper presents a detailed experimental study on sulphate attack, depth of carbonation, alkalinity measurement on fibre reinforced concrete at ages 28 days, 56 days, and 90 days. The main variable investigated in this study is variation of fibre dosage of 0.1%, 0.2%, and 0.3%. The concrete produced by the addition of fly ash and metakaolin as a partial replacement of cement. The compressive strength, weight loss and hardness of concrete were studied. Test results indicate that use of fibre in concrete has improved performance of concrete. A simple regression equation has been proposed to study the behaviour of concrete under sulphate attack, depth of carbonation.

  5. Behaviour of a Blast Loaded Laced Reinforced Concrete Structure

    Directory of Open Access Journals (Sweden)

    N. Anandavalli

    2012-09-01

    Full Text Available Normal 0 MicrosoftInternetExplorer4 According to existing provisions, large separation distance has to be maintained between two conventional explosive storage structures to prevent sympathetic detonation. In this paper, reduction of the separation distance with the use of earth covered laced reinforced concrete (LRC storage structure is demonstrated, which will result in saving of land cost. Details of blast resistant design of 75T (NEC storage structure based on unit risk principle are presented. Performance of the storage structure is evaluated in an actual blast trial. Strain and deflection profiles are obtained from the trial. Based on these, the storage structure is found to be re-usable after the blast trial.Defence Science Journal, 2012, 62(5, pp.284-289, DOI:http://dx.doi.org/10.14429/dsj.62.820

  6. Interfacial chemistry of zinc anodes for reinforced concrete structures

    Energy Technology Data Exchange (ETDEWEB)

    Covino, B.S. Jr.; Bullard, S.J.; Cramer, S.D.; Holcomb, G.R. [Dept. of Energy, Albany, OR (United States). Albany Research Center; McGill, G.E.; Cryer, C.B. [Oregon Dept. of Transportation, Salem, OR (United States); Stoneman, A. [International Lead Zinc Research Organization, Research Triangle Park, NC (United States); Carter, R.R. [California Dept. of Transportation, Sacramento, CA (United States)

    1997-12-01

    Thermally-sprayed zinc anodes are used in both galvanic and impressed current cathodic protection systems for reinforced concrete structures. The Albany Research Center, in collaboration with the Oregon Department of Transportation, has been studying the effect of electrochemical aging on the bond strength of zinc anodes for bridge cathodic protection systems. Changes in anode bond strength and other anode properties can be explained by the chemistry of the zinc-concrete interface. The chemistry of the zinc-concrete interface in laboratory electrochemical aging studies is compared with that of several bridges with thermal-sprayed zinc anodes and which have been in service for 5 to 10 years using both galvanic and impressed current cathodic protection systems. The bridges are the Cape Creek Bridge on the Oregon coast and the East Camino Undercrossing near Placerville, CA. Also reported are interfacial chemistry results for galvanized steel rebar from the 48 year old Longbird Bridge in Bermuda.

  7. Numerical Study of FRP Reinforced Concrete Slabs at Elevated Temperature

    Directory of Open Access Journals (Sweden)

    Masoud Adelzadeh

    2014-02-01

    Full Text Available One-way glass fibre reinforced polymer (GFRP reinforced concrete slabs at elevated temperatures are investigated through numerical modeling. Serviceability and strength requirements of ACI-440.1R are considered for the design of the slabs. Diagrams to determine fire endurance of slabs by employing “strength domain” failure criterion are presented. Comparisons between the existing “temperature domain” method with the more representative “strength domain” method show that the “temperature domain” method is conservative. Additionally, a method to increase the fire endurance of slabs by placing FRP reinforcement in two layers is investigated numerically. The amount of fire endurance gained by placing FRP in two layers increases as the thickness of slab increases.

  8. Analysis of reinforced concrete shells with transverse shear forces

    CERN Document Server

    Schulz, Mauro

    2013-01-01

    This research investigates the simultaneous effect of in-plane and transverse loads in reinforced concrete shells. The infinitesimal shell element is divided into layers (with triaxial behavior) that are analyzed according to the smeared rotating crack approach. The set of internals forces includes the derivatives of the in-plane components. The corresponding generalized strains are determined using an extension of the equivalent section method, valid for shells. The formulation yields through-the-thickness distributions of stresses and strains and the spatial orientation of the concrete struts. Although some simplifications are necessary to establish a practical first-order approximation, higher-order solutions could be developed. Despite the fact that constitutive matrices are not symmetric, because of the tension-softening formulation, the equilibrium and compatibility conditions are satisfied, the stiffness derivatives are explicitly calculated and the algorithms show good convergence. The formulation pre...

  9. Tapered Polymer Fiber Sensors for Reinforced Concrete Beam Vibration Detection.

    Science.gov (United States)

    Luo, Dong; Ibrahim, Zainah; Ma, Jianxun; Ismail, Zubaidah; Iseley, David Thomas

    2016-12-16

    In this study, tapered polymer fiber sensors (TPFSs) have been employed to detect the vibration of a reinforced concrete beam (RC beam). The sensing principle was based on transmission modes theory. The natural frequency of an RC beam was theoretically analyzed. Experiments were carried out with sensors mounted on the surface or embedded in the RC beam. Vibration detection results agreed well with Kistler accelerometers. The experimental results found that both the accelerometer and TPFS detected the natural frequency function of a vibrated RC beam well. The mode shapes of the RC beam were also found by using the TPFSs. The proposed vibration detection method provides a cost-comparable solution for a structural health monitoring (SHM) system in civil engineering.

  10. Stochastic Models for Chloride-Initiated Corrosion in Reinforced Concrete

    DEFF Research Database (Denmark)

    Engelund, Svend; Sørensen, John Dalsgaard

    Corrosion of the reinforcement in concrete structures can lead to a substantial decrease of the load-bearing capacity. One mode of corrosion initiation is when the chloride content around the reinforcement exceeds a threshold value. In the present paper a statistical model is developed by which t...... the chloride content in a 1reinforced concrete structure can be predicted. The model parameters are estimated on the basis of measurements. The distribution of the time to initiation of corrosion is estimated by FORMISORM-analysis.......Corrosion of the reinforcement in concrete structures can lead to a substantial decrease of the load-bearing capacity. One mode of corrosion initiation is when the chloride content around the reinforcement exceeds a threshold value. In the present paper a statistical model is developed by which...

  11. Analysis of cracking in reinforced concrete using accelerated tests

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Q.T.; Berthaud, Y. [Univ Paris 06, CNRS, ENSC, LMT, F-94235 Cachan (France); Care, S [CNRS, ENPC, LCPC, Inst Navier, LMSGC, F-77420 Champs Sur Marne (France); Millard, A. [CEA, DEN/DM2S/SEMT/LM2S, F-91191 Gif Sur Yvette (France)

    2007-02-15

    We present in this Note an experimental study-in a laboratory setup-of the mechanical effect (cracking of concrete) of corrosion on plates made of reinforced concrete. Due to the geometry it is possible to use digital image correlation to follow the evolution of strains induced by the corrosion of reinforcement. The corrosion is accelerated by the imposition of current density. Even if the representativeness of this test is still discussed, it allows one to record the entire strain history. The kinetics of cracking has been obtained and compared to a very simple model in which the increase of the corroded layer is modelled by a fictitious thermal load, the reinforcement remaining elastic and the concrete being damageable. (authors)

  12. Bond Properties and Experimental Methods of Textile Reinforced Concrete

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Textile reinforced concrete(TRC, for short) allows the low size production and offers a high effectiveness of the reinforcement by using continuous roving instead of short-chopped fibers. However, whether textiles can cooperate with concrete very well depends on the bond between them. In this paper, the bonding mechanism that the stress was transferred from fine concrete to textile was analyzed, and the influences of the initial bond length of textile, the surface treatment of textile, the strength and workability of concrete as well as the level of prestressing force on bond behavior were investigated on the basis of pull-out tests. The results reveal that with initial bond length increasing, the maximum pull force increases, and increasing concrete strength and improving workability of concrete matrix, epoxy resin impregnating and sand covering of textile as well as prestressing textile can obviously increase the bond strength between the textile and concrete.

  13. Analysis of reinforced concrete beams by the equivalent section method

    CERN Document Server

    Schulz, Mauro

    2014-01-01

    This research investigates the analysis of reinforced concrete beams subjected to combined axial load, bending moment and shear force. Cross-sections of general shape are divided, along the height, into plane elements. The biaxial behavior is represented according to the smeared rotating crack approach. Using traditionally accepted hypotheses for beams, the shear flow is determined by applying the Jouravski formula to an "equivalent section", which takes into account the nonlinear material behavior. The "Equivalent Section Method", originally proposed by Diaz (1980) and Diaz and Schulz (1981), is improved and simplified. The formulation is implemented applying the bidimensional constitutive model A, proposed by Vecchio and Collins (1993). The tension-stiffening effect is considered as adopted by Polak and Vecchio (1993). Shear slip at crack surfaces, Poisson's ratio and other secondary effects are not considered. Validation is undertaken by comparison with experimental results obtained by other researchers. T...

  14. Environmental Impact Optimization of Reinforced Concrete Slab Frame Bridges

    DEFF Research Database (Denmark)

    Yavari, Majid Solat; Du, Guangli; Pacoste, Costin

    2017-01-01

    The main objective of this research is to integrate environmental impact optimization in the structural design of reinforced concrete slab frame bridges in order to determine the most environmental-friendly design. The case study bridge used in this work was also investigated in a previous paper...... focusing on the optimization of the investment cost, while the present study focuses on environmental impact optimization and comparing the results of both of these studies. Optimization technique based on the pattern search method was implemented. Moreover, a comprehensive Life Cycle Assessment (LCA......) methodology of ReCiPe and two monetary weighting systems were used to convert environmental impacts into monetary costs. The analysis showed that both monetary weighting systems led to the same results. Furthermore, optimization based on environmental impact generated models with thinner construction elements...

  15. Evaluating plastic shrinkage and permeability of polypropylene fiber reinforced concrete

    Directory of Open Access Journals (Sweden)

    G.M. Sadiqul Islam

    2016-12-01

    Full Text Available Plastic concrete is susceptible to develop cracks due to shrinkage in dry and windy conditions. Addition of fibers could reduce propagation of this crack. On the other hand, permeability determines the durability properties of concrete. This study evaluated strength, plastic shrinkage and permeability (gas and water of concrete incorporating ‘polypropylene’ fiber (aspect ratio 300 in various proportions (viz. 0.10%, 0.15%, 0.2%, 0.25% and 0.3% by volume of concrete. Plane concrete samples were also prepared and tested for reference purpose. Inclusion of 0.1% fiber gave minor reduction (2% in compressive strength while the tensile strength increased by 39% with same fiber content compared to the plain concrete. A significant reduction in crack generation, appearance period of first crack and crack area between plane concrete and fiber reinforced concretes was found. The experimental result with inclusion of 0.1–0.3% fiber in concrete indicated that plastic shrinkage cracks were reduced by 50–99% compared to the plain concrete. For reference concrete (without fiber, test within the high temperature and controlled humidity chamber gave higher crack width than the acceptable limit (3 mm specified by the ACI 224. With the inclusion of 0.1% fiber reduced the crack width down to 1 mm and the trend was continued with the addition of more fibers. However, results showed that with the addition of polypropylene fiber both water and gas permeability coefficient was increased. Therefore, it is concluded that the fiber reinforced concrete would work better for plastic shrinkage susceptible structural elements (flat elements such as slab; however, it requires careful judgement while applying to a water retaining structures.

  16. Field Testing of High Current Electrokinetic Nanoparticle Treatment for Corrosion Mitigation in Reinforced Concrete

    Science.gov (United States)

    Cardenas, Henry; Alexander, Joshua; Kupwade-Patil, Kunal; Calle, Luz marina

    2010-01-01

    Electrokinetic Nanoparticle (EN) treatment was used as a rapid repair measure to mitigate chloride induced corrosion of reinforced concrete in the field. EN treatment uses an electric field to transport positively charged nanoparticles to the reinforcement through the concrete capillary pores. Cylindrical reinforced concrete specimens were batched with 4.5 wt % salt content (based on cement mass). Three distinct electrokinetic treatments were conducted using high current density (up to 5 A/m2) to form a chloride penetration barrier that was established in 5 days, as opposed to the traditional 6-8 weeks, generally required for electrochemical chloride extraction (ECE). These treatments included basic EN treatment, EN with additional calcium treatment, and basic ECE treatment. Field exposures were conducted at the NASA Beachside Corrosion Test Site, Kennedy Space Center, Florida, USA. The specimens were subjected to sea water immersion at the test site as a posttreatment exposure. Following a 30-day post-treatment exposure period, the specimens were subjected to indirect tensile testing to evaluate treatment impact. The EN treated specimens exhibited 60% and 30% increases in tensile strength as compared to the untreated controls and ECE treated specimens respectively. The surfaces of the reinforcement bars of the control specimens were 67% covered by corrosion products. In contrast, the EN treated specimens exhibited corrosion coverage of only 4%. Scanning electron microscopy (SEM) revealed a dense concrete microstructure adjacent to the bars of the treated specimens as compared to the control and ECE specimens. Energy dispersive spectroscopic (EDS) analysis of the polished EN treated specimens showed a reduction in chloride content by a factor of 20 adjacent to the bars. This study demonstrated that EN treatment was successful in forming a chloride penetration barrier rapidly. This work also showed that the chloride barrier was effective when samples were exposed to

  17. Brillouin Corrosion Expansion Sensors for Steel Reinforced Concrete Structures Using a Fiber Optic Coil Winding Method

    Directory of Open Access Journals (Sweden)

    Xingjun Lv

    2011-11-01

    Full Text Available In this paper, a novel kind of method to monitor corrosion expansion of steel rebars in steel reinforced concrete structures named fiber optic coil winding method is proposed, discussed and tested. It is based on the fiber optical Brillouin sensing technique. Firstly, a strain calibration experiment is designed and conducted to obtain the strain coefficient of single mode fiber optics. Results have shown that there is a good linear relationship between Brillouin frequency and applied strain. Then, three kinds of novel fiber optical Brillouin corrosion expansion sensors with different fiber optic coil winding packaging schemes are designed. Sensors were embedded into concrete specimens to monitor expansion strain caused by steel rebar corrosion, and their performance was studied in a designed electrochemical corrosion acceleration experiment. Experimental results have shown that expansion strain along the fiber optic coil winding area can be detected and measured by the three kinds of sensors with different measurement range during development the corrosion. With the assumption of uniform corrosion, diameters of corrosion steel rebars were obtained using calculated average strains. A maximum expansion strain of 6,738 με was monitored. Furthermore, the uniform corrosion analysis model was established and the evaluation formula to evaluate mass loss rate of steel rebar under a given corrosion rust expansion rate was derived. The research has shown that three kinds of Brillouin sensors can be used to monitor the steel rebar corrosion expansion of reinforced concrete structures with good sensitivity, accuracy and monitoring range, and can be applied to monitor different levels of corrosion. By means of this kind of monitoring technique, quantitative corrosion expansion monitoring can be carried out, with the virtues of long durability, real-time monitoring and quasi-distribution monitoring.

  18. Brillouin corrosion expansion sensors for steel reinforced concrete structures using a fiber optic coil winding method.

    Science.gov (United States)

    Zhao, Xuefeng; Gong, Peng; Qiao, Guofu; Lu, Jie; Lv, Xingjun; Ou, Jinping

    2011-01-01

    In this paper, a novel kind of method to monitor corrosion expansion of steel rebars in steel reinforced concrete structures named fiber optic coil winding method is proposed, discussed and tested. It is based on the fiber optical Brillouin sensing technique. Firstly, a strain calibration experiment is designed and conducted to obtain the strain coefficient of single mode fiber optics. Results have shown that there is a good linear relationship between Brillouin frequency and applied strain. Then, three kinds of novel fiber optical Brillouin corrosion expansion sensors with different fiber optic coil winding packaging schemes are designed. Sensors were embedded into concrete specimens to monitor expansion strain caused by steel rebar corrosion, and their performance was studied in a designed electrochemical corrosion acceleration experiment. Experimental results have shown that expansion strain along the fiber optic coil winding area can be detected and measured by the three kinds of sensors with different measurement range during development the corrosion. With the assumption of uniform corrosion, diameters of corrosion steel rebars were obtained using calculated average strains. A maximum expansion strain of 6,738 με was monitored. Furthermore, the uniform corrosion analysis model was established and the evaluation formula to evaluate mass loss rate of steel rebar under a given corrosion rust expansion rate was derived. The research has shown that three kinds of Brillouin sensors can be used to monitor the steel rebar corrosion expansion of reinforced concrete structures with good sensitivity, accuracy and monitoring range, and can be applied to monitor different levels of corrosion. By means of this kind of monitoring technique, quantitative corrosion expansion monitoring can be carried out, with the virtues of long durability, real-time monitoring and quasi-distribution monitoring.

  19. Multi-Physics and Multi-Scale Deterioration Modelling of Reinforced Concrete

    DEFF Research Database (Denmark)

    Michel, Alexander; Stang, Henrik; Lepech, M.;

    2016-01-01

    , methods and tools for modelling decades-long deterioration and maintenance are much less developed. In this paper, a multi-physics and multi-scale modelling approach for structural deterioration of reinforced concrete components due to reinforcement corrosion is presented. The multi-disciplinary modelling......Deterioration of reinforced concrete infrastructure such as bridges, tunnels, and buildings represents one of the major challenges currently facing developed countries. While engineering tools and methods for structural modelling and design of new reinforced concrete infrastructure are mature...

  20. Analysis of time-dependent reliability of degenerated reinforced concrete structure

    Directory of Open Access Journals (Sweden)

    Zhang Hongping

    2016-07-01

    Full Text Available Durability deterioration of structure is a highly random process. The maintenance of degenerated structure involves the calculation of the reliability of time-dependent structure. This study introduced reinforced concrete structure resistance decrease model and related statistical parameters of uncertainty, analyzed resistance decrease rules of corroded bending element of reinforced concrete structure, and finally calculated timedependent reliability of the corroded bending element of reinforced concrete structure, aiming to provide a specific theoretical basis for the application of time-dependent reliability theory.

  1. Corrosion of steel reinforced concrete in the tropical coastal atmosphere of Havana City, Cuba

    Directory of Open Access Journals (Sweden)

    Abel Castañeda

    2013-01-01

    Full Text Available The influence of chloride deposition rate on concrete using an atmospheric corrosion approach is rarely studied in the literature. Seven exposure sites were selected in Havana City, Cuba, for exposure of reinforced concrete samples. Two significantly different atmospheric corrosivity levels with respect to corrosion of steel reinforced concrete were observed after two years of exposure depending on atmospheric chloride deposition and w/c ratio of the concrete. Changes in corrosion current are related to changes in chloride penetration and chloride atmospheric deposition. The influence of sulphur compound deposition could also be a parameter to consider in atmospheric corrosion of steel reinforced concrete.

  2. Study of the shear behaviour of fibre reinforced concrete beams

    Directory of Open Access Journals (Sweden)

    Barragán, B.

    2008-12-01

    Full Text Available This study presents a series of tests for characterizing the structural behaviour of fibre reinforced concrete beams subjected to shear loading. The experimental program involves three types of fibres; two steel fibres and a polypropylene fibre. As a reference, plain concrete and conventionally reinforced concrete specimens have also been tested. The ultimate shear capacity of the beams is calculated and these values compared with those predicted by existing formulations. The study confirms that the toughness and shear crack resistance of the material is greatly enhanced by the fibres. However, the incorporation of 1% of fibres yielded lower shear strength than conventionally reinforced beams with the same amount of steel in the form of transversal stirrups. Existing design methods seem sufficiently robust to estimate the maximum shear load, even when using material properties (toughness, tensile strength extrapolated from code formulae.Este trabajo presenta una serie de ensayos para caracterizar el comportamiento estructural de vigas realizadas con hormigón reforzado con fibras sometidas a cortante. El programa de ensayos incluía tres tipos de fibras, dos de acero y una de polipropileno. Asimismo, se realizó una serie de ensayos con una viga confeccionada con hormigón armado convencional. La resistencia a cortante de las vigas es comparada con los valores que la formulación existente predice. El estudio confirma que la tenacidad y la resistencia a cortante son incrementadas tras la adición de fibras al hormigón. Sin embargo, la incorporación de un 1% en volumen de fibras conduce a valores de resistencia última a cortante inferiores a los obtenidos con vigas de hormigón convencional con la misma cantidad de acero dispuesta en forma de cercos de cortante. Los actuales métodos de cálculo parecen lo suficientemente precisos para evaluar la carga de cortante último, incluso cuando los parámetros mecánicos utilizados en las f

  3. Investigation of Corrosion and Cathodic Protection in Reinforced Concrete. II: Properties of Steel Surface Layers

    NARCIS (Netherlands)

    Koleva, D.A.; De Wit, J.H.W.; Van Breugel, K.; Lodhi, Z.F.; Ye, G.

    2007-01-01

    The present study explores the formation of corrosion products on the steel surface (using as-received low carbon construction steel) in reinforced concrete in conditions of corrosion and subsequent transformation of these layers in conditions of cathodic protection (CP).

  4. Analytical Study on the Beyond Design Seismic Capacity of Reinforced Concrete Shear Walls

    Energy Technology Data Exchange (ETDEWEB)

    Nugroho, Tino Sawaldi Adi [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Chi, Ho-Seok [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

    2015-10-15

    The OECD-NEA has organized an international benchmarking program to better understand this critical issue. The benchmark program provides test specimen geometry, test setup, material properties, loading conditions, recorded measures, and observations of the test specimens. The main objective of this research is to assess the beyond design seismic capacity of the reinforced concrete shear walls tested at the European Laboratory for Structural Assessment between 1997 and 1998 through participation in the OECD-NEA benchmark program. In this study, assessing the beyond design seismic capacity of reinforced concrete shear walls is performed analytically by comparing numerical results with experimental results. The seismic shear capacity of the reinforced concrete shear wall was predicted reasonably well using ABAQUS program. However, the proper calibration of the concrete material model was necessary for better prediction of the behavior of the reinforced concrete shear walls since the response was influenced significantly by the material constitutive model.

  5. Correlations Between Mechanical Properties of Steel Fiber Reinforced Concrete

    Directory of Open Access Journals (Sweden)

    Carrillo Julián

    2013-06-01

    Full Text Available Tension strength and post-cracking deformation capacities that exhibits steel fiber reinforced concrete (SFRC stimulate its use in elements governed by shear deformations. Aimed at developing design aids that promote the use of SFRC as web shear reinforcement of concrete walls for low-rise economic housing (LEH, an experimental study for describing the mechanical properties of SFRC was carried out. The experimental program included testing of 128 cylinder- and beam-type specimens. According to requirements specified by ACI-318, to thickness of walls used in LEH, and to results of previous studies, three Dramix fibers with length-diameter ratios of 55, 64 and 80 were selected. Fiber dosage was expressed in terms of the minimum fiber dosage specified by ACI-318 for replacing the minimum area of conventional shear reinforcement in beams (60 kg/m3. Therefore, five dosages were used: 0, 40, 45, 60 and 75 kg/m3. Mechanical properties of SFRC under compressive, tensile and flexural stresses were evaluated in this study. Based on trends of experimental results, numerical correlations for estimating both basic mechanical properties and properties that describe flexural performance of SFRC are proposed.

  6. Behavior of reinforced concrete columns strenghtened by partial jacketing

    Directory of Open Access Journals (Sweden)

    D. B. FERREIRA

    Full Text Available This article presents the study of reinforced concrete columns strengthened using a partial jacket consisting of a 35mm self-compacting concrete layer added to its most compressed face and tested in combined compression and uniaxial bending until rupture. Wedge bolt connectors were used to increase bond at the interface between the two concrete layers of different ages. Seven 2000 mm long columns were tested. Two columns were cast monolithically and named PO (original column e PR (reference column. The other five columns were strengthened using a new 35 mm thick self-compacting concrete layer attached to the column face subjected to highest compressive stresses. Column PO had a 120mm by 250 mm rectangular cross section and other columns had a 155 mm by 250mm cross section after the strengthening procedure. Results show that the ultimate resistance of the strengthened columns was more than three times the ultimate resistance of the original column PO, indicating the effectiveness of the strengthening procedure. Detachment of the new concrete layer with concrete crushing and steel yielding occurred in the strengthened columns.

  7. Polarization Induced Deterioration of Reinforced Concrete with CFRP Anode

    Directory of Open Access Journals (Sweden)

    Ji-Hua Zhu

    2015-07-01

    Full Text Available This paper investigates the deterioration of reinforced concrete with carbon fiber reinforced polymer (CFRP anode after polarization. The steel in the concrete was first subjected to accelerated corrosion to various extents. Then, a polarization test was performed with the external attached CFRP as the anode and the steel reinforcement as the cathode. Carbon fiber reinforced mortar and conductive carbon paste as contact materials were used to adhere the CFRP anode to the concrete. Two current densities of 1244 and 2488 mA/m2, corresponding to the steel reinforcements were applied for 25 days. Electrochemical parameters were monitored during the test period. The deterioration mechanism that occurred at the CFRP/contact material interface was investigated by scanning electron microscopy (SEM and X-ray diffraction (XRD techniques. The increase of feeding voltage and the failure of bonding was observed during polarization process, which might have resulted from the deterioration of the interface between the contact material and CFRP. The formation and accumulation of NaCl crystals at the contact material/CFRP interface were inferred to be the main causes of the failure at the interface.

  8. Nondestructive evaluation of dissipative behavior of reinforced concrete structure

    Energy Technology Data Exchange (ETDEWEB)

    Luong, M.P. [Ecole Polytechnique, LMS, CNRS, 91 - Palaiseau (France)

    2001-07-01

    Current technological developments tend toward increased exploitation of materials strengths and toward tackling extreme loads and environmental actions such as offshore structures subject to wind and wave loading, or buildings in seismic area. Concrete is widely used as a construction material because of its high strength-cost ratio in many applications. Experience of earthquakes and laboratory tests has shown that well designed and detailed reinforced concrete is suitable for earthquake resistant structures. The most severe likely earthquake can be survived if the members are sufficiently ductile to absorb and dissipate seismic energy by inelastic deformation. This requires a designer to assess realistically the acceptable levels of strength and to ensure adequate dissipation. This paper proposes the use of infrared thermography as a nondestructive, noncontact and real-time technique to examine diverse mechanisms of dissipation and to illustrate the onset of damage process, stress concentration and heat dissipation localization in loaded zone. In addition, this technique can be used as a nondestructive method for evaluating the fatigue limit of concrete structure subject to repeated loading.

  9. Rupture Directivity Effect on Seismic Vulnerability of Reinforced Concrete Bridge

    Science.gov (United States)

    Shirazian, Shadi; Nouri, Gholamreza; Ghayamghamian, Mohamadreza

    2017-04-01

    Earthquake catastrophes menace humans` lives and assets. Although earthquakes are inevitable, damage is not. To remedy this situation, significant amount of research is conducted in order to assess the performance of existent man-made structures, particularly infrastructures such as bridges which play a vital role in post earthquake services. The results can be used for assessing retrofit prioritization for structures and as a basis for economic loss estimations. The research presented here determines the vulnerability of a common typical two-span reinforced concrete bridge by generating fragility curves. Near-fault ground motions are different from ordinary ground motions, often containing strong coherent dynamic long-period pulses and permanent ground displacements. Here special attention is given to this type of ground motions, and their effects on the seismic behavior of structure are compared with ordinary motions. The results show near-fault ground motions exacerbate the seismic vulnerability of a bridge by about 68% in comparison with near-field ground motions. In other words, near-source ground motions with forward directivity effect are more dangerous.

  10. Uncertainty modelling of critical column buckling for reinforced concrete buildings

    Indian Academy of Sciences (India)

    Kasim A Korkmaz; Fuat Demir; Hamide Tekeli

    2011-04-01

    Buckling is a critical issue for structural stability in structural design. In most of the buckling analyses, applied loads, structural and material properties are considered certain. However, in reality, these parameters are uncertain. Therefore, a prognostic solution is necessary and uncertainties have to be considered. Fuzzy logic algorithms can be a solution to generate more dependable results. This study investigates the material uncertainties on column design and proposes an uncertainty model for critical column buckling reinforced concrete buildings. Fuzzy logic algorithm was employed in the study. Lower and upper bounds of elastic modulus representing material properties were defined to take uncertainties into account. The results show that uncertainties play an important role in stability analyses and should be considered in the design. The proposed approach is applicable to both future numerical and experimental researches. According to the study results, it is seen that, calculated buckling load values are stayed in lower and upper bounds while the load values are different for same concrete strength values by using different code formula.

  11. Nonlinear Finite Element Analysis of Reinforced Concrete Shells

    Directory of Open Access Journals (Sweden)

    Mustafa K. Ahmed

    2013-05-01

    Full Text Available This investigation is to develop a numerical model suitable for nonlinear analysis of reinforced concrete shells. A nine-node Lagrangian element Figure (1 with enhanced shear interpolation will be used in this study. Table (1 describes shape functions and their derivatives of this element.An assumed transverse shear strain is used in the formulation of this element to overcome shear locking. Degenerated quadratic thick plate elements employing a layered discrelization through the thickness will be adopted. Different numbers of layers for different thickness can be used per element. A number of layers between (6 and 10 have proved to be appropriate to represent the nonlinear material behavior in structures. In this research 8 layers will be adequate. Material nonlinearities due to cracking of concrete, plastic flow or crushing of concrete in compression and yield condition of reinforcing steel are considered. The maximum tensile strength is used as a criterion for crack initiation. Attention is given to the tension stiffening phenomenon and the degrading effect of cracking on the compressive and shear strength of concrete. Perfect bond between concrete and steel is assumed. Attention is given also to geometric nonlinearities. An example have been chosen in order to demonstrate the suitability of the models by comparing the predicted behaviour with the experimental results for shell exhibiting various modes of failure.

  12. Modelling Blast Effects on a Reinforced Concrete Bridge

    Directory of Open Access Journals (Sweden)

    Markellos Andreou

    2016-01-01

    Full Text Available The detailed investigation of blast phenomena and their catastrophic effects on existing structures are the main objectives of the present paper. It is well known that blast phenomena may be characterized by significant complexity, often involving complicated wave propagation effects as well as distinguishable material behaviors. Considering the above and in an attempt to provide a simplified modelling approach for the simulation of blast effects, a novel procedure is presented herein based on well-established methodologies and common engineering practices. In the above framework, firstly, the “predominant” deformation shape of the structure is estimated based on elastic finite element simulations under blast loads and then the structural response of the system is evaluated as a result of common computational beam-element tools such as displacement-based pushover analysis. The proposed methodology provides an immediate first estimation of the structural behavior under blast loads, based on familiar engineering procedures. A two-span reinforced concrete bridge was thoroughly investigated and the results provide insightful information regarding the damage patterns and localization.

  13. Using New Coating Materials for Corrosion Prevention of Reinforced Concrete

    Directory of Open Access Journals (Sweden)

    Elshami Ahmed

    2014-04-01

    Full Text Available Deterioration of reinforcing concrete structures is a common problem among all the Mediterranean countries. To protect steel from corrosion, cobalt oxide with zinc oxide were successfully deposited on silica and alumina layer according to Core–shell theory. This theory based on depositing a surface layer of expensive efficient anticorrosive coating on a cheap extender expressing the bulk. The combination of both core and shell compounds led to the production of new coating with improved properties different from each of its individual components. These improved properties lead to change in the efficiency of protection properties of coating films containing these new coating. The objective of the present work is to prepare a new ecologically friendly natural and inorganic coating of Egyptian mix (kaolin and ceramic waste and zinc phosphate as corrosion inhibitors based on the solid–solid interaction to protect steel from corrosion in buildings construction. The results revealed that these new coating gives the best results in protecting steel substrates from corrosion especial in aggressive environment.

  14. Shear Strength of Reinforced Concrete Beams Under Sea Water

    Institute of Scientific and Technical Information of China (English)

    阎西康; 王铁成; 张玉敏

    2004-01-01

    The marine structures such as harbour,pier and inshore concrete terrace are exposed in adverse circumstances in a long period of time . Owing to the attack of external corrosive medium, their safety, durability and reliability decline. Especially the reinforced concrete(RC) structures in the wave splash area are more likely to be subjected to destruction and the loss is vast. Now the safety ,durability and reliability of structure have become increasingly an important subject to be studied. By way of the soaking and drying cycle test on the different mix proportions oblique section of 10 pieces of RC beams suffered artificial sea water(ASW) corrosion under 0,35,70,105,140 times of dry-wet cycles ,the compared results of exerting pressure test of these beams under simply supporting were investigated. The law about the changes of the mechanical performance for RC beams with different mix proportions under different time periods for suffering corrosion of dry-wet cycles is as follows: the resistivity to ASW corrosion of the concrete specimens with various water cement ratio( various initial strength) is different; the characters of oblique section failure for RC beams attacked by sea water are about the same as those for ordinary RC beam; along with the extension of the time for sea water attack, the bearing capacity for oblique section of RC beams varies wave upon wave. The specimens attacked by sea water for about 35 times of corrosion cycle achieve minimum bearing capacity.

  15. Failure mode classification of reinforced concrete column using Fisher method

    Institute of Scientific and Technical Information of China (English)

    戚永乐; 韩小雷; 季静

    2013-01-01

    In order to apply the performance-based seismic design, an engineer must first find out whether the column is expected to fail in shear before or after flexural yielding. According to column failure characteristics and failure mode of reinforced concrete column, the UW-PEER structure performance database was discussed and analyzed. In order to investigate the relevance of failure mode and factors such as longitudinal reinforcement ratio, transverse reinforcement ratio, hoop spacing to depth ratio, aspect ratio, shearing resistance demand to shear capacity ratio and axial load ratio, Fisher’s discriminant analysis(FDA) of the above factors was carried out. A discriminant function was developed to identify column failure mode. Results show that three factors, i.e., Vp /Vn, hoop spacing to depth ratio and aspect ratio have important influence on the failure mode. The failure mode has less to do with longitudinal reinforcement ratio, transverse reinforcement ratio and axial load ratio. Through using these three factors and the model proposed, over 85.6% of the original grouped cases were correctly classified. The value of coefficient of Vp /Vn is the largest, which means that discriminant equation is most sensitive to the shearing resistance demand to shear capacity ratio.

  16. Marine durability of 23-year old reinforced concrete beams

    Energy Technology Data Exchange (ETDEWEB)

    Mohammed, T. U. [NEWJEC Inc., Technology Development Dept., Osaka (Japan); Otsuki, N. [Tokyo Inst. of Technology (Japan); Hisada, M. [Niigata Univ., (Japan); Hamada, H. [Ministry of Transport, Port and Harbor Research Inst., Yokosuka (Japan)

    2000-07-01

    Results of a study concerning the durability of 23-year old reinforced concrete beams exposed to marine tidal and atmospheric environments are presented. The study focused on the corrosion of steel bars with respect to orientation in concrete, carbonation and chloride ion-induced corrosion, quantitative evaluation of electrochemical data and the influence of stirrups on macrocell formation. Experimental work included half cell potential, polarization resistance, solution resistance investigations, chloride ion profile and carbonation depth measurements, microscopic observations of steel-concrete interfaces, and visual inspection of steel bars corrosion. Results showed that chloride ion-induced corrosion was significantly influenced by the orientation of the steel bars in the concrete. Macrocell corrosion was found to be the governing process of corrosion in atmospheric environment, while stirrups played an important role in macrocell formation. Assuming the use of a suitable pit concentration, polarization data was considered to provide an acceptable, although inexact, estimate of the depth of corrosion. Peak chloride ion concentration was not observed at the concrete surface but at some distance below the surface, probably due to the effect of wetting and drying cycles. 8 refs., 9 tabs., 11 figs.

  17. Humectant use in the cathodic protection of reinforced concrete

    Energy Technology Data Exchange (ETDEWEB)

    Holcomb, Gordon R.; Covino, Bernard S., Jr.; Russell, James H.; Bullard, Sophie J.; Cramer, Stephen D.; Collins, W.K.; Bennett, J.E. (JE Bennett Consulting); Laylor, H.M. (ODOT)

    2000-11-01

    Use of humectants to improve the thermal-sprayed zinc anode performance during the cathodic protection (CP) of reinforced concrete was examined. A humectant is a hygroscopic material. It is applied onto the surface of the zinc anode to keep the concrete-anode interface moist and a good conductor. The thermodynamics of humectants are discussed. Laboratory results are presented on the effects of using lithium bromide (LiBr) and lithium nitrate (LiNO{sub 3}) as humectants in galvanic cathodic protection (GCP) and impressed current cathodic protection (ICCP) systems, in high and low relative humidities, and on new and previously electrochemically aged CP systems. LiNO{sub 3} and LiBr promoted more effective CP performance. Both improved the performance of aged slabs, suggesting that application of humectants onto existing CP systems would be of benefit. Microscopy showed that humectant-treated slabs develop the same cement-reaction zone, zinc anode structures as untreated slabs. Microscopy of LiBr-treated slabs revealed that the highest concentration of bromide was in the reaction zone. In GCP tests, LiBr was more effective than LiNO{sub 3}. In accelerated ICCP tests, LiNO{sub 3} was more effective than LiBr. It was surmised that bromide could be oxidized in the high-voltage accelerated ICCP tests. At the lower impressed currents of most installed ICCP systems, LiBr may perform as well as or better than LiNO{sub 3}.

  18. Humectant use in the cathodic protection of reinforced concrete

    Energy Technology Data Exchange (ETDEWEB)

    Holcomb, G.R.; Covino, B.S. Jr.; Russell, J.H.; Bullard, S.J.; Cramer, S.D.; Collins, W.K.; Bennett, J.E. (not a DOE author); H.M. Laylor (not a DOE author)

    2000-03-01

    The use of humectants to improve the thermal-sprayed zinc anode performance during the cathodic protection (CP) of reinforced concrete is examined. A humectant is a hygroscopic material. It is applied onto the surface of the zinc anode to keep the concrete-anode interface moist and a good conductor. The thermodynamics of humectants are discussed. Laboratory results are presented on the effects of using LiBr and LiNO{sub 3} as humectants in galvanic (GCP) and impressed current (ICCP) systems, in high and low relative humidities, and on new and previously electrochemically aged CP systems. LiNO{sub 3} and LiBr promoted more effective CP performance. Both improved the performance of aged slabs, suggesting that application of humectants onto existing CP systems would be of benefit. Microscopy showed that humectant-treated slabs develop the same cement-reaction zone-zinc anode structures as untreated slabs. Microscopy of LiBr-treated slabs revealed that the highest concentration of bromide was in the reaction zone. In GCP tests, LiBr was more effective than LiNO{sub 3}. In accelerated ICCP tests, LiNO{sub 3} was more effective than LiBr. It was surmised that bromide could be oxidized in the high-voltage accelerated ICCP tests. At the lower impressed currents of most installed ICCP systems, LiBr may perform as well as or better than LiNO{sub 3}.

  19. Aftershock collapse vulnerability assessment of reinforced concrete frame structures

    Science.gov (United States)

    Raghunandan, Meera; Liel, Abbie B.; Luco, Nicolas

    2015-01-01

    In a seismically active region, structures may be subjected to multiple earthquakes, due to mainshock–aftershock phenomena or other sequences, leaving no time for repair or retrofit between the events. This study quantifies the aftershock vulnerability of four modern ductile reinforced concrete (RC) framed buildings in California by conducting incremental dynamic analysis of nonlinear MDOF analytical models. Based on the nonlinear dynamic analysis results, collapse and damage fragility curves are generated for intact and damaged buildings. If the building is not severely damaged in the mainshock, its collapse capacity is unaffected in the aftershock. However, if the building is extensively damaged in the mainshock, there is a significant reduction in its collapse capacity in the aftershock. For example, if an RC frame experiences 4% or more interstory drift in the mainshock, the median capacity to resist aftershock shaking is reduced by about 40%. The study also evaluates the effectiveness of different measures of physical damage observed in the mainshock-damaged buildings for predicting the reduction in collapse capacity of the damaged building in subsequent aftershocks. These physical damage indicators for the building are chosen such that they quantify the qualitative red tagging (unsafe for occupation) criteria employed in post-earthquake evaluation of RC frames. The results indicated that damage indicators related to the drift experienced by the damaged building best predicted the reduced aftershock collapse capacities for these ductile structures.

  20. Radiation exposure inside reinforced concrete buildings at Nagasaki

    Energy Technology Data Exchange (ETDEWEB)

    Rhoades, W.A.; Childs, R.L.; Ingersoll, D.T.

    1989-05-01

    The biological effects on the residents of Hiroshima and Nagasaki due to initial-irradiation exposure during the nuclear attacks of World War II was recognized immediately as an important source of information. After the war, an extensive effort gathered data concerning the locations of individuals at the time of the attack and their subsequent medical histories. The data from personnel located in reinforced concrete buildings are particularly significant, since large groups of occupants received radiation injury without complications due to blast and thermal effects. In order to correlate the radiation dose with physiological effects, the dose to each individual must be calculated. Enough information about the construction of the buildings was available after the war to allow a radiation transport model to be constructed, but the accurate calculation of penetration into such large, thick-walled three dimensional structures was beyond the scope of computing technology until recently. Now, the availability of Cray vector computers and the development of a specially-constructed discrete ordinates transport code, TORT, have combined to allow the successful completion of such a study. This document describes the radiation transport calculations and tabulates the resulting doses by source component and individual case location. An extensive uncertainty analysis is also included. These data are to be used in another study as input to a formal statistical analysis, resulting in a new value for the LD50 dose, i.e., the dose at which the mortality risk is 50%. 55 refs., 67 figs., 70 tabs.

  1. Seismic response of reinforced concrete frames at different damage levels

    Science.gov (United States)

    Morales-González, Merangeli; Vidot-Vega, Aidcer L.

    2017-03-01

    Performance-based seismic engineering is focused on the definition of limit states to represent different levels of damage, which can be described by material strains, drifts, displacements or even changes in dissipating properties and stiffness of the structure. This study presents a research plan to evaluate the behavior of reinforced concrete (RC) moment resistant frames at different performance levels established by the ASCE 41-06 seismic rehabilitation code. Sixteen RC plane moment frames with different span-to-depth ratios and three 3D RC frames were analyzed to evaluate their seismic behavior at different damage levels established by the ASCE 41-06. For each span-to-depth ratio, four different beam longitudinal reinforcement steel ratios were used that varied from 0.85 to 2.5% for the 2D frames. Nonlinear time history analyses of the frames were performed using scaled ground motions. The impact of different span-to-depth and reinforcement ratios on the damage levels was evaluated. Material strains, rotations and seismic hysteretic energy changes at different damage levels were studied.

  2. Bamboo Reinforced Concrete Truss Bridge for Rural Infrastructure

    Directory of Open Access Journals (Sweden)

    D. Nuralinah

    2014-04-01

    Full Text Available Bamboo is one of a potential renewable construction material in the village. Bamboo is known to have a high mechanical strength in direction of the fibers. The weakness of bamboo in lateral direction of the fiber could be solved by constructing a composite structure with the concrete. The appropriate construction with hold the loads in axial direction is a truss structure. In a bamboo concrete truss structure, the bars are composed from the concrete column with a bamboo reinforcement. The research studies about the performance of the bridge and the effect of loading position on the strain and deformation of bamboo reinforced concrete truss bridge. The bridge whose span and width are respectively 1.5 m and 1.2 m was prepared. Load applied to the truss bridge conducted by using vehicle load changes with position. Mounting the strains gauge in bamboo reinforcement of primary truss is to observe the strain. The LVDT is used to observe the deflection of the truss bridge. The results show that the loading position influences the strain and deformation as well as a theoretical view.

  3. Experimental data of the static behavior of reinforced concrete beams at room and low temperature.

    Science.gov (United States)

    Mirzazadeh, M Mehdi; Noël, Martin; Green, Mark F

    2016-06-01

    This article provides data on the static behavior of reinforced concrete at room and low temperature including, strength, ductility, and crack widths of the reinforced concrete. The experimental data on the application of digital image correlation (DIC) or particle image velocimetry (PIV) in measuring crack widths and the accuracy and precision of DIC/PIV method with temperature variations when is used for measuring strains is provided as well.

  4. Damage detection in reinforced concrete square slabs using modal analysis and artifical neural network

    OpenAIRE

    Ahmed, MS

    2016-01-01

    Reinforced concrete (RC) structures are usually subjected to various types of loadings, such as permanent, sustained and transient during their lifetime. Reinforced concrete slabs are one of the most fundamental structural elements in buildings and bridges, which might be exposed to unfavourable conditions such as, impaired quality control, lack of maintenance, adverse environmental effects, and inadequate initial design. Therefore, the resistant capacity of the affected elements would dramat...

  5. Experimental data of the static behavior of reinforced concrete beams at room and low temperature

    Directory of Open Access Journals (Sweden)

    M. Mehdi Mirzazadeh

    2016-06-01

    Full Text Available This article provides data on the static behavior of reinforced concrete at room and low temperature including, strength, ductility, and crack widths of the reinforced concrete. The experimental data on the application of digital image correlation (DIC or particle image velocimetry (PIV in measuring crack widths and the accuracy and precision of DIC/PIV method with temperature variations when is used for measuring strains is provided as well.

  6. Up-to-date technologies of producing reinforced concrete constructions in transport industry

    Directory of Open Access Journals (Sweden)

    Ю. А. Клімов

    2000-09-01

    Full Text Available Presented is the analysis of the works at XIII Congress of International Federeation of pre­reinforced concrete construction (FIP. Scientific researches and technical solutions of reinforced concrete constructions realized in the developed countries have determined the main trends in perfection of concrete constructions in the next century (perfection of data on quality of constructive solutions of reinforcement with on-metallic fibrous materials, energy saving technologies of concrete production, development and investigation of perspective technical solutions

  7. Performance Assessment of Discontinuous Fibers in Fiber Reinforced Concrete: Current State-of-the-Art

    Science.gov (United States)

    2017-07-01

    strength between 190 to 240 MPa and is broadly characterized as a reactive powder concrete (RPC). RPCs have fine aggregates and powders but do not...ER D C/ G SL T R- 17 -1 9 Performance Assessment of Discontinuous Fibers in Fiber-Reinforced Concrete : Current State-of-the-Art G eo te...Discontinuous Fibers in Ultra-High Performance Fiber-Reinforced Concrete : Current State-of-the-Art Charles A. Burchfield Geotechnical and

  8. Punching shear of flat reinforced-concrete s labs under fire conditions

    OpenAIRE

    Smith, Holly Kate Mcleod

    2016-01-01

    This thesis examines punching shear response of reinforced-concrete flat slabs under fire conditions. The shear behaviour of concrete in fire is relatively poorly understood compared to its flexural response. Failures such as the Gretzenbach car park failure in Switzerland (2004) have prompted concerns over the punching shear capacity of flat slabs in fire. The shear behaviour of reinforced-concrete in fire depends on degradation of the individual material properties with te...

  9. Numerical Simulation of Monitoring Corrosion in Reinforced Concrete Based on Ultrasonic Guided Waves

    OpenAIRE

    Zheng, Zhupeng; Lei, Ying; Xue, Xin

    2014-01-01

    Numerical simulation based on finite element method is conducted to predict the location of pitting corrosion in reinforced concrete. Simulation results show that it is feasible to predict corrosion monitoring based on ultrasonic guided wave in reinforced concrete, and wavelet analysis can be used for the extremely weak signal of guided waves due to energy leaking into concrete. The characteristic of time-frequency localization of wavelet transform is adopted in the corrosion monitoring of re...

  10. Corrosion Effects on the Strength Properties of Steel Fibre Reinforced Concrete Containing Slag and Corrosion Inhibitor

    OpenAIRE

    Sivakumar Anandan; Sounthararajan Vallarasu Manoharan; Thirumurugan Sengottian

    2014-01-01

    Corrosion in steel can be detrimental in any steel rebar reinforced concrete as well as in the case of steel fibre reinforced concrete. The process of corrosion occurring in steel fibre incorporated concrete subjected to corrosive environment was systematically evaluated in this study. Concrete specimens were prepared with steel fibre inclusions at 1.5% Vf (volume fraction) of concrete and were added in slag based concrete (containing manufactured sand) and replaced with cement at 20%, 40%, ...

  11. An extended finite element model for modelling localised fracture of reinforced concrete beams in fire

    OpenAIRE

    Liao, F; Huang, Z.

    2015-01-01

    Open Access funded by Engineering and Physical Sciences Research Council under a Creative Commons license. A robust finite element procedure for modelling the localised fracture of reinforced concrete beams at elevated temperatures is developed. In this model a reinforced concrete beam is represented as an assembly of 4-node quadrilateral plain concrete, 3-node main reinforcing steel bar, and 2-node bond-link elements. The concrete element is subdivided into layers for considering the temp...

  12. Performance based analysis of hidden beams in reinforced concrete structures

    Directory of Open Access Journals (Sweden)

    Helou Samir H.

    2014-01-01

    Full Text Available Local and perhaps regional vernacular reinforced concrete building construction leans heavily against designing slabs with imbedded hidden beams for flooring systems in most structures including major edifices. The practice is distinctive in both framed and in shear wall structures. Hidden beams are favoured structural elements due to their many inherent features that characterize them; they save on floor height clearance; they also save on formwork, labour and material cost. Moreover, hidden beams form an acceptable aesthetic appearance that does not hinder efficient interior space partitioning. Such beams have the added advantage of clearing the way for horizontal electromechanical ductwork. However, seismic considerations, in all likelihood, are seldom seriously addressed. The mentioned structural system of shallow beams is adopted in ribbed slabs, waffle slabs and at times with solid slabs. Ribbed slabs and waffle slabs are more prone to hidden beam inclusion due to the added effective height of the concrete section. Due to the presence of a relatively high reinforcement ratio at the joints the sections at such location tend to become less ductile with unreliable contribution to spandrel force resistance. In the following study the structural influence of hidden beams within slabs is investigated. With the primary focus on a performance based analysis of such elements within a structure. This is investigated with due attention to shear wall contribution to the overall behaviour of such structures. Numerical results point in the direction that the function of hidden beams is not as adequate as desired. Therefore it is strongly believed that they are generally superfluous and maybe eliminated altogether. Conversely, shallow beams seem to render the overall seismic capacity of the structure unreliable. Since such an argument is rarely manifested within the linear analysis domain; a pushover analysis exercise is thus mandatory for behaviour

  13. Seismic analysis of a reinforced concrete containment vessel model

    Energy Technology Data Exchange (ETDEWEB)

    RANDY,JAMES J.; CHERRY,JEFFERY L.; RASHID,YUSEF R.; CHOKSHI,NILESH

    2000-02-03

    Pre-and post-test analytical predictions of the dynamic behavior of a 1:10 scale model Reinforced Concrete Containment Vessel are presented. This model, designed and constructed by the Nuclear Power Engineering Corp., was subjected to seismic simulation tests using the high-performance shaking table at the Tadotsu Engineering Laboratory in Japan. A group of tests representing design-level and beyond-design-level ground motions were first conducted to verify design safety margins. These were followed by a series of tests in which progressively larger base motions were applied until structural failure was induced. The analysis was performed by ANATECH Corp. and Sandia National Laboratories for the US Nuclear Regulatory Commission, employing state-of-the-art finite-element software specifically developed for concrete structures. Three-dimensional time-history analyses were performed, first as pre-test blind predictions to evaluate the general capabilities of the analytical methods, and second as post-test validation of the methods and interpretation of the test result. The input data consisted of acceleration time histories for the horizontal, vertical and rotational (rocking) components, as measured by accelerometers mounted on the structure's basemat. The response data consisted of acceleration and displacement records for various points on the structure, as well as time-history records of strain gages mounted on the reinforcement. This paper reports on work in progress and presents pre-test predictions and post-test comparisons to measured data for tests simulating maximum design basis and extreme design basis earthquakes. The pre-test analyses predict the failure earthquake of the test structure to have an energy level in the range of four to five times the energy level of the safe shutdown earthquake. The post-test calculations completed so far show good agreement with measured data.

  14. Retrofitting Of Reinforced Concrete Column by Steel Jacketing

    Directory of Open Access Journals (Sweden)

    Abhishek Jodawat

    2016-07-01

    Full Text Available Reinforced concrete structures often require strengthening to increase their capacity to sustain additional loads, due to change in use that resulted in additional live loads, deterioration of the load carrying elements, design errors, construction problems during erection, aging of structure itself or upgrading to confirm to current code requirements. These situations may require additional concrete elements or the entire concrete structure to be strengthened, repaired or retrofitted. Common methods for strengthening columns include concrete jacketing, fiber reinforced polymer (FRP jacketing and steel jacketing. All these methods have been shown to effectively increase the axial load capacity of columns. The experimental study was carried out on RC column on designed and detailed using IS 456:2000 provisions. The concrete mix design being performed after conducting numerous material test and cube test to validate expected strength as per specified grade of concrete. The trial testing conducted to estimate load at 1st crack and failure load for normal RC column with capturing displacement using dial gauges at regular load increment in UTM. The loading conditions are decided based on failure load to induce cracks in column under 85% loading of the failure one. In all fifteen specimen casted and tested with three samples for failure load estimation, three samples each for plate jacketing & angle battening system and three samples each for plate jacketing & angle battening with column preloaded to 85% of its failure load. The angle batten system proves to be better compared to full plate retrofitting in terms of load carrying capacity and enhancing confinement effect.

  15. Strength Behaviour Of Biomass Fiber-Reinforced Concrete Slab

    Directory of Open Access Journals (Sweden)

    Chai Teck Jung

    2012-05-01

    Full Text Available This paper investigates the compressive strength and flexural strength of biomass fibre-reinforced concrete slab. The main objective of this study is to examine the effect of biomass aggregate and fibre glass on the concrete slab strength. The biomass aggregate is used to replace the natural aggregates. A total of 36 slab samples (250 mm x 600 mm x 50mm thick and 36 numbers of 150 mm cube samples containing 0%, 30%, 60% and 100% biomass aggregate were prepared.  The E-class fibre and Supracoat SP800 were added to increase the strength and to achieve the required workability. All the samples were cured in water with room temperature of around 27oC and tested at the age of 7, 14 and 28 days respectively. The result showed that cube specimens containing 30% biomass aggregate concrete achieved minimum strength of 15 MPa at 28 days. The flexural strength for slab specimens containing 30% biomass aggregate, Supracoat SP 800 and fibre glass gained higher strength compared with control specimens. The 100% biomass aggregate slab achieved 88% of the control specimen strength. The workability was between 150 mm to 170mm slump. The density of the specimens was reduced 20% for cube and 28% for slab compared with control specimens. It can be concluded that the biomass aggregate has good potential as partial aggregate replacement in slab construction when combined with the use of glass fibre and superplasticizer. However, more research needs to be carried out to self-compacting biomass aggregate concrete for sustainable construction

  16. Application of artificial neural networks to predict the deflections of reinforced concrete beams

    Science.gov (United States)

    Kaczmarek, Mateusz; Szymańska, Agnieszka

    2016-06-01

    Nonlinear structural mechanics should be taken into account in the practical design of reinforced concrete structures. Cracking is one of the major sources of nonlinearity. Description of deflection of reinforced concrete elements is a computational problem, mainly because of the difficulties in modelling the nonlinear stress-strain relationship of concrete and steel. In design practise, in accordance with technical rules (e.g., Eurocode 2), a simplified approach for reinforced concrete is used, but the results of simplified calculations differ from the results of experimental studies. Artificial neural network is a versatile modelling tool capable of making predictions of values that are difficult to obtain in numerical analysis. This paper describes the creation and operation of a neural network for making predictions of deflections of reinforced concrete beams at different load levels. In order to obtain a database of results, that is necessary for training and testing the neural network, a research on measurement of deflections in reinforced concrete beams was conducted by the authors in the Certified Research Laboratory of the Building Engineering Institute at Wrocław University of Science and Technology. The use of artificial neural networks is an innovation and an alternative to traditional methods of solving the problem of calculating the deflections of reinforced concrete elements. The results show the effectiveness of using artificial neural network for predicting the deflection of reinforced concrete beams, compared with the results of calculations conducted in accordance with Eurocode 2. The neural network model presented in this paper can acquire new data and be used for further analysis, with availability of more research results.

  17. Impact of rockfill deformation on stress-strain state on dam reinforced concrete face

    Directory of Open Access Journals (Sweden)

    Sainov Mikhail Petrovich

    2015-03-01

    Full Text Available The author considered the results of the numerical studies of stress-strain state of a 100 m high rockfill dam with a reinforced concrete face. In the analysis, the dam construction sequence and loads applied to it were considered; it was assumed that the reinforced concrete face was constructed after filling the dam. The calculations were carried out in the elastic formulation at various moduli of deformation and Poisson’s ratio. It was revealed that at rockfill settlement under the action of hydrostatic pressure the reinforced concrete face not only bends but also is subject to longitudinal force. The development of these forces is connected not only with rockfill shear deformation in horizontal direction. Depending on the value of rockfill Poisson’s ratio these longitudinal forces may be both compressive and tensile. At the Poisson’s ratio exceeding 0.25 the longitudinal forces are tensile, and when it is equal to 0.2 - they are compressive. Evidently these particular longitudinal forces are the course of crack formation in reinforced concrete faces of a number of constructed dams. The indirect confirmation of the development of tensile forces on the face is the fact that actually in all the dams with reinforced concrete face opening of perimeter joint was observed. Thus, in order to provide the strength of reinforced concrete it is important to increase rockfill shear modulus. Only the decrease of stone compressibility (i.e. increase of linear deformation modulus E will slightly improve the stress state of the face, as the value of E has less effect on settlements and shear of the dam than Poisson’s ratio. High rockfill dams with reinforced concrete face may have a favorable stress state only at narrow site when the face horizontal displacements are inconsiderable and due to the settlements of rockfill in the face the forces are compressive but not tensile longitudinal forces.

  18. Corrosion Assessment of Steel Bars Used in Reinforced Concrete Structures by Means of Eddy Current Testing.

    Science.gov (United States)

    de Alcantara, Naasson P; da Silva, Felipe M; Guimarães, Mateus T; Pereira, Matheus D

    2015-12-24

    This paper presents a theoretical and experimental study on the use of Eddy Current Testing (ECT) to evaluate corrosion processes in steel bars used in reinforced concrete structures. The paper presents the mathematical basis of the ECT sensor built by the authors; followed by a finite element analysis. The results obtained in the simulations are compared with those obtained in experimental tests performed by the authors. Effective resistances and inductances; voltage drops and phase angles of wound coil are calculated using both; simulated and experimental data; and demonstrate a strong correlation. The production of samples of corroded steel bars; by using an impressed current technique is also presented. The authors performed experimental tests in the laboratory using handmade sensors; and the corroded samples. In the tests four gauges; with five levels of loss-of-mass references for each one were used. The results are analyzed in the light of the loss-of-mass and show a strong linear behavior for the analyzed parameters. The conclusions emphasize the feasibility of the proposed technique and highlight opportunities for future works.

  19. Hybrid Effect Evaluation of Steel Fiber and Carbon Fiber on the Performance of the Fiber Reinforced Concrete

    OpenAIRE

    Weimin Song; Jian Yin

    2016-01-01

    Fiber reinforcement is an important method to enhance the performance of concrete. In this study, the compressive test and impact test were conducted, and then the hybrid effect between steel fiber (SF) and carbon fiber (CF) was evaluated by employing the hybrid effect index. Compressive toughness and impact toughness of steel fiber reinforced concrete (SFRC), carbon fiber reinforced concrete (CFRC) and hybrid fiber reinforced concrete (HFRC) were explored at steel fiber volume fraction 0.5%,...

  20. Evaluating cover depth of steel fiber reinforced concrete using impact-echo testing

    Science.gov (United States)

    Lin, Yu-Feng

    2014-04-01

    The purpose of this research is to estimate of the cover depth of steel fiber reinforced concrete using the impact-echo testing. In order to evaluate the security of the construction, usually need to estimate the cover depth of the reinforced concrete. At present, the examination technique of the cover depth of the reinforced concrete without the steel fiber is mainly applied in the magnetic and electrical methods, its rapid detection and good results. But the research of the reactive powder concrete be gradually progress, with the steel fiber concrete structure will be increased, if should still operate the examination with the magnetic and electrical methods, theoretically the steel fiber will have the interference to its electromagnetism field. Therefore, this research designs four kinds of reinforced concrete plate that include different steel fiber contents, to evaluate test results of estimate of the cover depth of the reinforcing bar. The results showed that: estimate of the cover depth of steel fiber reinforced concrete reinforcing bar using the impact-echo testing, the variety of the steel fiber content does not have much influence, the test measurement error within ± 10%, and the most important source of uncertainty is the velocity of concrete.

  1. High-Temperature Performance and Multiscale Damage Mechanisms of Hollow Cellulose Fiber-Reinforced Concrete

    Directory of Open Access Journals (Sweden)

    Liping Guo

    2016-01-01

    Full Text Available Spalling resistance properties and their damage mechanisms under high temperatures are studied in hollow cellulose fiber-reinforced concrete (CFRC used in tunnel structures. Measurements of mass loss, relative dynamic elastic modulus, compressive strength, and splitting tensile strength of CFRC held under high temperatures (300, 600, 800, and 1050°C for periods of 2.5, 4, and 5.5 h were carried out. The damage mechanism was analyzed using scanning electron microscopy, mercury intrusion porosimetry, thermal analysis, and X-ray diffraction phase analysis. The results demonstrate that cellulose fiber can reduce the performance loss of concrete at high temperatures; the effect of holding time on the performance is more noticeable below 600°C. After exposure to high temperatures, the performance of ordinary concrete deteriorates faster and spalls at 700–800°C; in contrast, cellulose fiber melts at a higher temperature, leaving a series of channels in the matrix that facilitate the release of the steam pressure inside the CFRC. Hollow cellulose fibers can thereby slow the damage caused by internal stress and improve the spalling resistance of concrete under high temperatures.

  2. Drying Shrinkage Behaviour of Fibre Reinforced Concrete Incorporating Polyvinyl Alcohol Fibres and Fly Ash

    Directory of Open Access Journals (Sweden)

    Amin Noushini

    2014-01-01

    Full Text Available The current study assesses the drying shrinkage behaviour of polyvinyl alcohol fibre reinforced concrete (PVA-FRC containing short-length (6 mm and long-length (12 mm uncoated monofilament PVA fibres at 0.125%, 0.25%, 0.375%, and 0.5% volumetric fractions. Fly ash is also used as a partial replacement of Portland cement in all mixes. PVA-FRC mixes have been compared to length change of control concrete (devoid of fibres at 3 storage intervals: early-age (0–7 days, short-term (0–28 days, and long-term (28–112 days intervals. The shrinkage results of FRC and control concrete up to 112 days indicated that all PVA-FRC mixes exhibited higher drying shrinkage than control. The shrinkage exhibited by PVA-FRC mixes ranged from 449 to 480 microstrain, where this value was only 427 microstrain in the case of control. In addition, the longer fibres exhibited higher mass loss, thus potentially contributing to higher shrinkage.

  3. Strengthening of Corrosion-Damaged Reinforced Concrete Beams with Glass Fiber Reinforced Polymer Laminates

    Directory of Open Access Journals (Sweden)

    A. L. Rose

    2009-01-01

    Full Text Available Problem statement: This study showed the results of an experimental investigation on the strengthening of corrosion damaged reinforced concrete beams with unidirectional cloth glass fiber reinforced polymer (UDCGFRP laminates. Approach: All the beam specimens 150×250×3000 mm were cast and tested for the present investigation. One beam specimen was neither corroded nor strengthened to serve as a reference. Two beams were corroded to serve as a corroded control. A reinforcement mass loss of approximately 10 and 25% were used to define medium and severe degrees of corrosion. The remaining two beams corroded and strengthened with GFRP. Results: The test parameters included first crack load, first crack deflection, yield load, yield deflection, service load, service deflection, ultimate load and ultimate deflection. Based on the results it was found that GFRP Laminates had beneficial effects even at the corrosion-damaged stage. Conclusion/Recommendations: The UDCGFRP laminated beams showed distinct enhancement in ultimate strength and ductility by 72.37 and 49.49% respectively.

  4. Passive Control Reinforced Concrete Frame Mechanism with High Strength Reinforcements and Its Potential Benefits Against Earthquakes

    Institute of Scientific and Technical Information of China (English)

    Asad Ullah Qazi; YE Lieping; LU Xinzheng

    2006-01-01

    Severe earthquakes continue to cause major catastrophes. Many devices in active, hybrid, and semi-active structural control systems which are used as controllable force devices are costly to build and maintain. The passive control reinforced concrete frame (PCRCF) reinforced with high strength steel only in the columns presented here provides structural systems more resistance to lateral earthquake loadings at comparatively lower cost. The effectiveness is demonstrated by a nonlinear static analysis using fiber model for a single story single bay frame. The study shows that the use of high performance steel in columns prevents formation of plastic hinges at the critical column base sections and failures are always initiated by reinforcement yielding at the beam ends. Furthermore, after experiencing severe lateral drift, the passive control design has small residual displacements compared to ordinary reinforced concrete frames. PCRCF rehabilitation and strengthening can be achieved more easily as compared with ordinary reinforced concrete frame.

  5. Fem Modelling and Analysis of Reinforced Concrete Section with Light Weight Blocks Infill

    Directory of Open Access Journals (Sweden)

    T. Subramani

    2014-06-01

    Full Text Available In an attempt to reduce the self weight of reinforced concrete structures, a new development of lightweight sandwich reinforced concrete (LSRC section has been proposed as an alternative option to solid section. LSRC section is a reinforced concrete section which contains lightweight blocks as infill material. An experimental investigation into the strength of LSRC beams has shown promising results under flexural tests. To ensure the serviceability of LSRC members under service load, it is necessary to accurately predict the cracking and deflection of this section. This paper will focus on analysing the behaviour of the tested beam specimens after cracking occurs. ANSYS 12.1 was employed to study the crack propagation of LSRC beams under bending. The numerical model shows the crack in the area of AAC blocks which associates with the brittle failure of LSRC beams. The crack propagation of the beams analysed by ANSYS agrees well with the results from the experimental investigation.

  6. The 2011 Earthquake in Simav, Turkey and Seismic Damage to Reinforced Concrete Buildings

    Directory of Open Access Journals (Sweden)

    Yücel Güney

    2013-02-01

    Full Text Available Reinforced concrete buildings suffered significant damage in the region affected by the 29 May 2011 earthquake in Simav (Kutahya, Turkey. Typical building damage is classified and potential causes of damage are investigated. Reinforced concrete moment resisting frames with hollow brick infill walls are the most common structural system in and around the Simav city center while masonry construction is common in rural areas. Although the Simav earthquake, with a magnitude of 5.7 to 5.9, can be classified as a moderate earthquake, many buildings experienced damage varying from frequent diagonal cracking and brittle failure of infill walls to collapse or severe damage to frames due to short columns, soft stories or other reasons including insufficient or poor detailing of reinforcement. This study investigates and presents the seismicity of the region, characteristics of the measured ground motions, seismic load demands including response spectra, and damage mechanisms, potential causes and classification of observed damage in reinforced concrete buildings.

  7. DUCTILITY BEHAVIOR FIBER REINFORCED CONCRETE BEAMS STRENGTHENED WITH EXTERNALLY BONDED GLASS FIBER REINFORCED POLYMER LAMINATES

    Directory of Open Access Journals (Sweden)

    Mariappan Mahalingam

    2013-01-01

    Full Text Available The study presents the results of an experimental investigation conducted on Steel Fiber Reinforced Concrete (SFRC beams with externally bonded Glass Fiber Reinforced Polymer (GFRP laminates with a view to study their strength and ductility. A total of ten beams, 150×250 mm in cross-section were tested in the laboratory over an effective span of 2800 mm. Three fiber reinforced concrete beams were used as reference beams. Six fiber reinforced concrete beams were provided with externally bonded GFRP laminates. One concrete beam was left virgin without any fiber reinforcement and external GFRP laminates. All the beams were tested until failure. The variables considered included volume fraction of fiber reinforcement and stiffness of GFRP laminates. The static responses of all the beams were evaluated in terms of strength, stiffness and ductility. The test results show that the beams provided with externally bonded GFRP laminates exhibit improved performance over the beams with internal fiber reinforcement.

  8. Finite Element Reliability Analysis of Chloride Ingress into Reinforced Concrete Structures

    DEFF Research Database (Denmark)

    Frier, Christian; Sørensen, John Dalsgaard

    2007-01-01

    For many reinforced concrete structures corrosion of the reinforcement is an important problem since it can result in maintenance and repair actions. Further, a reduction of the load-bearing capacity can occur. In the present paper the Finite Element Reliability Method (FERM) is employed for obta......For many reinforced concrete structures corrosion of the reinforcement is an important problem since it can result in maintenance and repair actions. Further, a reduction of the load-bearing capacity can occur. In the present paper the Finite Element Reliability Method (FERM) is employed...

  9. A Probabilistic Model for Chloride-Ingress and Initation of Corrosion in Reinforced Concrete Structures

    DEFF Research Database (Denmark)

    Engelund, S.; Sørensen, John Dalsgaard

    1998-01-01

    value. In the present paper a statistical model by which the chloride content in a reinforced concrete structure can be predicted, is developed. The model parameters are estimated on the basis of measurements. The distribution of the time to initiation of corrosion can now be estimated by traditional......Corrosion of the reinforcement is a major problem for a large number of reinforced concrete structures because it can lead to a substantial decrease of the load-bearing capacity. One mode of corrosion initiation is that the chloride content around the reinforcement exceeds a critical threshold...

  10. Review of Japanese recommendations on design and construction of different classes of fiber reinforced concrete and application examples

    DEFF Research Database (Denmark)

    Uchida, Yuichi; Fischer, Gregor; Hishiki, Yoshihiro

    2008-01-01

    Reinforced Cement Composites (HPFRCC) with strain hardening and multiple cracking behavior, and Ultra High-strength Fiber Reinforced concrete (UFC) with increased tensile strength. The recommendations on the design, production, and application of these classes of fiber reinforced concrete have been...

  11. Boiling water reactor in a prestressed reinforced concrete vessel for an atomic central heating-and-power plant

    Energy Technology Data Exchange (ETDEWEB)

    Tokarev, Yu.I.; Sokolov, I.N.; Skvortsov, S.A.; Sidorov, A.M.; Krauze, L.V.

    1978-04-01

    The possibility of using a boiling water reactor in a prestressed reinforced concrete vessel for an atomic central heating-and-power plant (CHPP) was considered, with design features of the reactor intended for a two-purpose plant. A prestressed reinforced concrete vessel and integral arrangement of the primary circuit ensured reliability of the atomic CHPP using various CHPP flowsheets.

  12. Effects of the zinc and zinc-nickel alloys electroplating on the corrodibility of reinforced concrete rebars

    Directory of Open Access Journals (Sweden)

    F. A. CEDRIM

    Full Text Available Abstract This paper shows the analysis performed on the corrosion parameters of three groups of reinforcing steel bars, two of these coated by electroplating process with Zinc (Zn and Zinc-Nickel (Zn-Ni, and the other without any coating. It was used reinforced concrete specimens, which ones were grouped and then subjected to two different corrosion accelerating methods: aging wetting/drying cycles and salt spray exposure. Corrosion potential was measured to qualitative monitoring of the process and, after the end of the tests, corrosion rate was estimated by measuring the mass loss, to quantitative analyses. As it was expected, coated bars presented a better performance than the average bars regarding the corrosion resistance in chloride ions containing environments. It was also observed that the drying/ NaCl solution wetting cycles seems to be more severe than salt spray fog apparatus with respect to the acceleration of corrosion process.

  13. Bond of reinforcing bars in self-compacting steel fiber reinforced concrete

    NARCIS (Netherlands)

    Schumacher, P.; Bigaj-van Vliet, A.J.; Braam, C.R.; Uijl, J.A. den; Walraven, J.C.

    2002-01-01

    Pull-out tests were performed on 10 mm diameter ribbed bars embedded along three times the bar diameter in 200 mm cubes made of plain and steel fiber reinforced concrete (SFRC) of normal strength (B45). The fiber content was 60 and 120 kg/m3, respectively, the aspect ratio of the fibers was 45 and 8

  14. Demonstration and Validation of a Lightweight Composite Bridge Deck Technology as an Alternative to Reinforced Concrete

    Science.gov (United States)

    2016-08-01

    78 Figure 103. Extensive missing grout revealed after steel strips removed. .......................... 79 Figure 104. Grout leaking through caulk...ERDC/CERL TR-16-16 79 Figure 103. Extensive missing grout revealed after steel strips removed. Figure 104. Grout leaking through caulk. ERDC...Abstract Cyclic loading and weathering of reinforced concrete bridge decks cause corrosion of reinforcement steel , which leads to cracking, potholes

  15. Conventional and Pulse Cathodic Protection of Reinforced Concrete: Electrochemical Approach and Microstructural Investigations

    NARCIS (Netherlands)

    Koleva, D.A.; Hu, J.; Van Breugel, K.; De Wit, J.H.W.; Boshkov, N.

    2006-01-01

    An improved cathodic protection (CP), based on pulse regime was investigated in reinforced concrete, compared to conventional CP. Both regimes used CP current in the range of 2 to15 mA/m2. A voltage-to-current converter maintained the pulse current, the latter adjusted with duty cycle of 12% to 50 %

  16. Response and Damage Assessment of Reinforced Concrete Frames subject to Earthquakes

    DEFF Research Database (Denmark)

    Skjærbæk, Poul

    When civil engineering structures made of reinforced concrete (RC) such as some types of apartment buildings, hospitals, office buildings, bridges etc. are subjected to sufficiently high dynamic loads it is well known that some kind of damage will occur in the structure. The damage introduced...

  17. Full-scale physical testing of a buried reinforced concrete pipe under axle load

    National Research Council Canada - National Science Library

    Lay, G.R; Brachman, R.W.I

    2014-01-01

    The structural response of a 600 mm inner diameter reinforced concrete pipe buried in a dense, well-graded sand and gravel soil and subjected to surface load from a single design truck axle with 0.3, 0.6...

  18. Recommendations for the shear assessment of reinforced concrete slab bridges from experiments

    NARCIS (Netherlands)

    Lantsoght, E.O.L.; Van der Veen, C.; Walraven, J.C.; De Boer, A.

    2013-01-01

    Upon assessment of existing reinforced concrete short-span solid slab bridges according to the recently implemented Eurocodes that include more conservative shear capacity provisions and heavier axle loads, a number of these structures were found to be shear-critical. The results from recent

  19. Local and Modal Damage Indicators for Reinforced Concrete Shear Frames Subject to Earthquakes

    DEFF Research Database (Denmark)

    Köylüoglu, H. U.; Nielsen, Søren R. K.; Abbott, J.

    Local, modal and overall damage indicators for reinforced concrete shear frames subject to seismic excitation are defined and studied. Each storey of the shear frame is represented by a Clough and Johnston hysteretic oscillator with degrading elastic fraction of the restoring force. The local max...

  20. Development of structural health monitoring and early warning system for reinforced concrete system

    Energy Technology Data Exchange (ETDEWEB)

    Iranata, Data, E-mail: iranata-data@yahoo.com, E-mail: data@ce.its.ac.id; Wahyuni, Endah [Civil Engineering Department, Institut Teknologi Sepuluh Nopember (ITS), Surabaya 60111 (Indonesia); Murtiadi, Suryawan [Civil Engineering Department, Universitas Mataram, Mataram 83125 (Indonesia); Widodo, Amien [Geophysical Engineering Department, Institut Teknologi Sepuluh Nopember (ITS), Surabaya 60111 (Indonesia); Riksakomara, Edwin; Sani, Nisfu Asrul [Information Systems Department, Institut Teknologi Sepuluh Nopember (ITS), Surabaya 60111 (Indonesia)

    2015-04-24

    Many buildings have been damaged due to earthquakes that occurred recently in Indonesia. The main cause of the damage is the large deformation of the building structural component cannot accommodate properly. Therefore, it is necessary to develop the Structural Health Monitoring System (SHMS) to measure precisely the deformation of the building structural component in the real time conditions. This paper presents the development of SHMS for reinforced concrete structural system. This monitoring system is based on deformation component such as strain of reinforcement bar, concrete strain, and displacement of reinforced concrete component. Since the deformation component has exceeded the limit value, the warning message can be sent to the building occupies. This warning message has also can be performed as early warning system of the reinforced concrete structural system. The warning message can also be sent via Short Message Service (SMS) through the Global System for Mobile Communications (GSM) network. Hence, the SHMS should be integrated with internet modem to connect with GSM network. Additionally, the SHMS program is verified with experimental study of simply supported reinforced concrete beam. Verification results show that the SHMS has good agreement with experimental results.

  1. Assessment of cracks in reinforced concrete by means of electrical resistance and image analysis

    NARCIS (Netherlands)

    Pacheco, J.; Šavija, B.; Schlangen, E.; Polder, R.B.

    2014-01-01

    The durability of cracked reinforced concrete is a serious concern in the construction industry. Cracks represent fast routes for chloride penetration, which can result in reinforcement corrosion. Bending or tapered cracks have the characteristic of being wider at the surface and becoming narrower t

  2. Shear-deforming textile reinforced concrete for the construction of double-curved structures

    NARCIS (Netherlands)

    Woodington, W.; Bergsma, O.K.; Schipper, H.R.

    2015-01-01

    A composite textile reinforced concrete (TRC) material is developed to overcome the difficulties of constructing double-curved freeform structures. This is possible by shear-deformation of the woven reinforcement. It affects the direction of reinforcement and thickness, resulting in variable orthotr

  3. Dynamic response of reinforced concrete building from the effects of rail transport

    Directory of Open Access Journals (Sweden)

    Demjan Ivo

    2014-06-01

    Full Text Available A 3D model of a reinforced concrete building and was created in software ANSYS. The dynamic analysis was focused on the spectral response of the object represented by a random excitation experiment found in records in the form of load spectra

  4. Investigation of longitudinal profile of rigid frogs on reinforced concrete sleepers

    Directory of Open Access Journals (Sweden)

    A.M. Orlovs’kyi

    2012-08-01

    Full Text Available In the paper the effect of longitudinal profile of rigid frogs of type R65 mark 1/11 on reinforced concrete sleepers on the interaction in the ‘wheel-rail’ system in the zone of rolling surface irregularities is investigated.

  5. Effect of corrosion on the fatigue service-life on steel and reinforced concrete beams

    NARCIS (Netherlands)

    Veerman, R.P.; van Breugel, K.; Koenders, E.A.B.

    2015-01-01

    Chloride-induced corrosion is a point of big concern in reinforced concrete (RC) structures. To monitor the actual health and to predict the remaining service-life of structures, it is important to understand the structural behaviour and the failure mechanism of structures exposed to chlorides under

  6. Effect of corrosion on the fatigue service-life on steel and reinforced concrete beams

    NARCIS (Netherlands)

    Veerman, R.P.; van Breugel, K.; Koenders, E.A.B.

    2015-01-01

    Chloride-induced corrosion is a point of big concern in reinforced concrete (RC) structures. To monitor the actual health and to predict the remaining service-life of structures, it is important to understand the structural behaviour and the failure mechanism of structures exposed to chlorides under

  7. Experimental and Empirical Time to Corrosion of Reinforced Concrete Structures under Different Curing Conditions

    Directory of Open Access Journals (Sweden)

    Ahmed A. Abouhussien

    2014-01-01

    Full Text Available Reinforced concrete structures, especially those in marine environments, are commonly subjected to high concentrations of chlorides, which eventually leads to corrosion of the embedded reinforcing steel. The total time to corrosion of such structures may be divided into three stages: corrosion initiation, cracking, and damage periods. This paper evaluates, both empirically and experimentally, the expected time to corrosion of reinforced concrete structures. The tested reinforced concrete samples were subjected to ten alternative curing techniques, including hot, cold, and normal temperatures, prior to testing. The corrosion initiation, cracking, and damage periods in this investigation were experimentally monitored by an accelerated corrosion test performed on reinforced concrete samples. Alternatively, the corrosion initiation time for counterpart samples was empirically predicted using Fick’s second law of diffusion for comparison. The results showed that the corrosion initiation periods obtained experimentally were comparable to those obtained empirically. The corrosion initiation was found to occur at the first jump of the current measurement in the accelerated corrosion test which matched the half-cell potential reading of around −350 mV.

  8. The Relationship between Rebar-Debonding and Cracking in Reinforced Concrete

    DEFF Research Database (Denmark)

    Thybo, Anna Emilie A.; Stang, Henrik; Olesen, John Forbes

    2012-01-01

    A mechanical model has been used to evaluate the rebar-concrete debonding length and Crack Mouth Opening Displacement (CMOD) in reinforced concrete. The modelling is based on the theory of the fictitious crack. It is shown that there is a non-trival relationship between the debonding length...

  9. Experimental Study on Common and Steel Fiber Reinforced Concrete Under Dynamic Tensile Stress

    Institute of Scientific and Technical Information of China (English)

    董新龙; 陈江瑛; 高培正; 祁振林; 王永忠; 王永刚; 王礼立

    2004-01-01

    Split Hopkinson technique has been developed to test the strength of common concrete and steel fiber reinforced concrete under dynamic tensile stress. Two types of test methods are considered, the splitting tensile test and a modified spalling test in which a specimen is loaded under uniaxial stress. The result shows that the dynamic strength enhancement of concrete is remarkable by using the reinforcing fiber. But for the common concrete, the base of compressive strength seems to show little effect on the tensile strength under dynamic loading. The experimental results also show that the resistance to tensile fracture of the steel fiber reinforced concrete for C100-mix is higher than those of C40-mix.

  10. Application of Bond-Slip in the Finite Element Analyses of Reinforced Concrete Shear Walls

    Directory of Open Access Journals (Sweden)

    İlker Kazaz

    2012-03-01

    Full Text Available Transfer of tensile forces from reinforcing steel into the surrounding concrete affects the behavior of reinforced concrete members. This transfer relies on the bond action between the steel and the concrete. Under monotonic loading the part of bond strength due to chemical adhesion is easily exhausted and bearing against the lugs is the primary load-transfer mechanism at loads near the ultimate. These stresses cause internal cracking of concrete at the steel-concrete interface. This paper deals with the finite element modeling of the bond-slip and its application due to internal cracking of the first layer of concrete surrounding the bar and the bending and/ or cracking of the small concrete teeth near the bar lugs. A previously proposed constitutive steel stress-bond slip relation by Mirza and Houde (1979 was used in finite element analysis of reinforced concrete shear wall specimens and the results were presented.

  11. Nonlinear analysis of the progressive collapse of reinforced concrete plane frames using a multilayered beam formulation

    Directory of Open Access Journals (Sweden)

    C. E. M. Oliveira

    Full Text Available This work investigates the response of two reinforced concrete (RC plane frames after the loss of a column and their potential resistance for progressive collapse. Nonlinear dynamic analysis is performed using a multilayered Euler/Bernoulli beam element, including elasto-viscoplastic effects. The material nonlinearity is represented using one-dimensional constitutive laws in the material layers, while geometrical nonlinearities are incorporated within a corotational beam formulation. The frames were designed in accordance with the minimum requirements proposed by the reinforced concrete design/building codes of Europe (fib [1-2], Eurocode 2 [3] and Brazil (NBR 6118 [4]. The load combinations considered for PC analysis follow the prescriptions of DoD [5]. The work verifies if the minimum requirements of the considered codes are sufficient for enforcing structural safety and robustness, and also points out the major differences in terms of progressive collapse potential of the corresponding designed structures.

  12. An Experimental Study of a Midbroken 2-Bay 6-Storey Reinforced Concrete Frame subject to Earthquakes

    DEFF Research Database (Denmark)

    Skjærbæk, P. S.; Taskin, B.; Kirkegaard, Poul Henning;

    1997-01-01

    A 2-bay, 6-storey model test reinforced concrete frame (scale 1:5) subjected to sequential earthquakes of increasing magnitude is considered in this paper. The frame was designed with a weak storey, in which the columns are weakened by using thinner and weaker reinforcement bars. The aim of the w......A 2-bay, 6-storey model test reinforced concrete frame (scale 1:5) subjected to sequential earthquakes of increasing magnitude is considered in this paper. The frame was designed with a weak storey, in which the columns are weakened by using thinner and weaker reinforcement bars. The aim...... of the work is to study global response to a damaging strong motion earthquake event of such buildings. Special emphasis is put on examining to what extent damage in the weak storey can be identified from global response measurements during an earthquake where the structure survives, and what level...

  13. Numerical-computational analysis of reinforced concrete structures considering the damage, fracture and failure criterion

    Directory of Open Access Journals (Sweden)

    L. A. F. de Souza

    Full Text Available The experimental results of testing structures or structural parts are limited and, sometimes, difficult to interpret. Thus, the development of mathematical-numerical models is needed to complement the experimental analysis and allow the generalization of results for different structures and types of loading. This article makes two computational studies of reinforced concrete structures problems found in the literature, using the Finite Element Method. In these analyses, the concrete is simulated with the damage classical model proposed by Mazars and the steel by a bilinear elastoplastic constitutive model. Numerical results show the validity of the application of constitutive models which consider the coupling of theories with the technique of finite element discretization in the simulation of linear and two-dimensional reinforced concrete structures.

  14. Crack elongation and its width of large depth reinforced concrete beams

    Institute of Scientific and Technical Information of China (English)

    GUAN Jun-feng; ZHAO Shun-bo; HUANG Cheng-kui

    2010-01-01

    In order to meet the requirement of structural inspection,the crack spacing and crack width at various heights in the tensile zone of six large depth reinforced concrete beams were measured under several loading levels of serviceability state.The effects of the depth of normal section beams on the crack spacing and crack width were analyzed,and the modified model is proposed for calculating the average crack spacing by thinking about the depth of normal section,the reinforcement arrangement and the effective reinforcement ratio.The relationships of crack widths at any position in the tensile zone and at the reinforcement level on the side surface of beam were studied.By theoretical and statistical analysis,a method is proposed to calculate the ratios of crack widths between any position and the reinforcement level on the side surface of large depth reinforced concrete beams.

  15. Damage detection of simply supported reinforced concrete beam by S transform

    Science.gov (United States)

    Liu, Ning; Xi, Jiaxin; Zhang, Xuebing; Liu, Zhenzhou

    2017-08-01

    Signal processing is the key component of vibration-based structural damage detection. The S transform is variable window of short time Fourier transform (STFT) or an extension of wavelet transform (WT). The goal of using S transform is to extract subtle changes in the vibration signals in order to detect and quantify the damage in the structure. This paper presents the concentrated load is applied to the simply supported reinforced concrete beam and adopting the stepwise loading method, the vibration signals of each loading and unloading state is obtained by using the hammer impact. Then the vibration data of the reinforced concrete beam pre-damage and post-damage is analysed by S transform. Experimental result shows the potential ability of S transform in identifying peak energy changes and multiple reflections with different loading force state.

  16. Evaluation of size dependent design shear strength of reinforced concrete beams without web reinforcement

    Indian Academy of Sciences (India)

    G Appa Rao; S S Injaganeri

    2011-06-01

    Analytical studies on the effect of depth of beam and several parameters on the shear strength of reinforced concrete beams are reported. A large data base available has been segregated and a nonlinear regression analysis (NLRA) has been performed for developing the refined design models for both, the cracking and the ultimate shear strengths of reinforced concrete (RC) beams without web reinforcement. The shear strength of RC beams is size dependent, which needs to be evaluated and incorporated in the appropriate size effect models. The proposed models are functions of compressive strength of concrete, percentage of flexural reinforcement and depth of beam. The structural brittleness of large size beams seems to be severe compared with highly ductile small size beams at a given quantity of flexural reinforcement. The proposed models have been validated with the existing popular models as well as with the design code provisions.

  17. Reinforced concrete in Catalonia (1898-1929: four companies and their relationship with architecture

    Directory of Open Access Journals (Sweden)

    R. Graus

    2017-06-01

    Full Text Available Between 1898 and 1929 various business initiatives that introduced reinforced concrete in its architecture developed in Catalonia. This article studies the following four companies: Anónima Claudio Duran - Construcciones Monier, Marial Hermanos - Sociedad Colectiva, Construcciones y Pavimentos, S. A. and Material y Obras, S. A. Only thorough knowledge of the production complexities that studies these companies, their technicians and works in all its complexity will allow us to assess how reinforced concrete transformed the construction sector, with new companies of a different productive scale. However, the depressed economic cycle of 1929-1952 weighed down any initiative and artificially lengthened what was left of traditional “Catalan construction”.

  18. Modeling of Normal Perforation of Reinforced Concrete Slabs by a Rigid Projectile

    Institute of Scientific and Technical Information of China (English)

    CHEN Xiaowei; LI Xiaoli

    2006-01-01

    An analytical model on the normal perforation of reinforced concrete slabs is constructed.The effect of reinforcing bars is further hybridized in a general three-stage model consisting of initial cratering,tunnelling and shear plugging.Besides three dimensionless numbers,i.e.,the impact function /,the geometry function of projectile N and the dimensionless thickness of concrete target χ,which are employed to predict the ballistic performance of perforation of concrete slabs,the reinforcement ratio ρs of concrete and the tensile strength fs of reinforcing bars are considered as the other main factors influencing the perforation process.Simpler solutions of ballistic performances of normal perforation of reinforced concrete slabs are formulated.Theoretical predictions agree well with individual published experimental data.

  19. Analysis of the Behaviour of Composite Steel and Steel Fiber Reinforced Concrete Slabs

    Directory of Open Access Journals (Sweden)

    Mindaugas Petkevičius

    2011-04-01

    Full Text Available There was a pending influence of steel fiber on the strength and stiffness of composite steel–concrete slabs under statical short–time load. Steel profiled sheeting and steel fiber reinforced concrete were used for specimens. Four composite slabs were made. Experimental investigations into the behaviour and influence of steel fiber reinforced concrete in composite slabs were conducted. Transverse, longitudinal, shear deformation and deflection of the slab were measured. The results indicated that the use of steel fiber in composite slabs was effective: strength was 20–24 % higher and the meanings of deflections under the action of the bending moment were 0,6MR (where MR is the bending moment at failure of the slabs and were 16–18 % lower for slabs with usual concrete. Article in Lithuanian

  20. REPAIR AND STRENGTHENING OF REINFORCED CONCRETE BEAMS USING FIBRE REINFORCED POLIMER (FRP MATERIALS

    Directory of Open Access Journals (Sweden)

    Nihat ÇETİNKAYA

    2004-03-01

    Full Text Available The use of Fibre Reinforced Polimer (FRP materials for the repair and strengthening of Reinforced Concrete structures has become widespread recently. FRP materials are being prefered because they have very high tensile strength, resistance to corrosion and they do not affect the use of the building during the repair and strengthening process. Four reinfoced concrete beams repaired and strengthened with FRP materials have been used in this study which were performed at Pamukkale University-Faculty of Engineering- Civil Engineering Department- Structural Engineering Laboratuary. The behaviour of the beams before and after repair and strengthening was compared by obtaining the load- displacement curves under static loading. In this study, it was observed that the repair and strengthening of reinforced concrete beams by using FRP materials had increased the load carrying capacity significantly.

  1. Flexural strengthening of Reinforced Concrete (RC) Beams Retrofitted with Corrugated Glass Fiber Reinforced Polymer (GFRP) Laminates

    Science.gov (United States)

    Aravind, N.; Samanta, Amiya K.; Roy, Dilip Kr. Singha; Thanikal, Joseph V.

    2015-01-01

    Strengthening the structural members of old buildings using advanced materials is a contemporary research in the field of repairs and rehabilitation. Many researchers used plain Glass Fiber Reinforced Polymer (GFRP) sheets for strengthening Reinforced Concrete (RC) beams. In this research work, rectangular corrugated GFRP laminates were used for strengthening RC beams to achieve higher flexural strength and load carrying capacity. Type and dimensions of corrugated profile were selected based on preliminary study using ANSYS software. A total of twenty one beams were tested to study the load carrying capacity of control specimens and beams strengthened with plain sheets and corrugated laminates using epoxy resin. This paper presents the experimental and theoretical study on flexural strengthening of Reinforced Concrete (RC) beams using corrugated GFRP laminates and the results are compared. Mathematical models were developed based on the experimental data and then the models were validated.

  2. Efficiency of fiber reinforced concrete application in structures subjected to dynamic effects

    Directory of Open Access Journals (Sweden)

    Morozov Valeriy Ivanovich

    2014-03-01

    Full Text Available Fiber reinforced concretes possess high strength under dynamic loadings, which include impact loads, thanks to their high structural viscosity. This is the reason for using them in difficult operating conditions, where increasing the performance characteristics and the structure durability is of prime importance, and the issues of the cost become less significant. Applying methods of disperse reinforcement is most challenging in case of subtle high-porous materials on mineral binders, for example foamed concrete. At the same time, the experiments conducted in Russia and abroad show, that also in other cases the concrete strength resistance several times increases as a result of disperse reinforcement. This doesn't depend on average density of the concrete and type of fiber used. In the article the fibre reinforced concrete impact resistance is analysed. Recommendations are given in regard to fibre concrete application in manufacture of monolithic floor units for industrial buildings and precast piles.

  3. Potential Effects of Corrosion Damage on the Performance of Reinforced Concrete Member

    Directory of Open Access Journals (Sweden)

    Mohd Noh Hamidun

    2016-01-01

    Full Text Available Corrosion of steel in reinforced concrete is one of the most serious issues for the owners. The main consequences of this phenomenon include loss of cross section of steel area, induced the expansive pressure which caused cracking of concrete, spalling and delaminating of the concrete cover. Thus, it reduces the bond strength between steel reinforcing bar and concrete, and deteriorates the strength of whole structure. In this study, a non-linear finite element analysis was conducted to investigate the potential effects of corrosion damage. A series of corroded reinforced concrete cylinder is used in the parametric study to assess the influence of different level of corrosion to the structural performance. As a result, a clear picture of corrosive expansion was investigated and the relationship between the expansive pressure and the degree of corrosion was identified to be the important factors of the structural deterioration.

  4. Influence of Tension Stiffening on the Flexural Stiffness of Reinforced Concrete Circular Sections

    Directory of Open Access Journals (Sweden)

    Francesco Morelli

    2017-06-01

    Full Text Available Within this paper, the assessment of tension stiffening effects on a reinforced concrete element with the circular sections subjected to axial and bending loads is presented. To this purpose, an enhancement of an analytical model already present within the actual technical literature is proposed. The accuracy of the enhanced method is assessed by comparing the experimental results carried out in past research and the numerical ones obtained by the model. Finally, a parametric study is executed in order to study the influence of axial compressive force on the flexural stiffness of reinforced concrete elements that are characterized by a circular section, comparing the secant stiffness evaluated at yielding and at maximum resistance, considering and not considering the effects of tension stiffness.

  5. Heavy vehicle simulator (HVS) evaluation of load transfer efficiency and continuously reinforced concrete inlays on the N3 near Pietermartizburg

    CSIR Research Space (South Africa)

    Du Plessis, L

    2006-07-01

    Full Text Available The paper addresses two different heavy Vehicle Simulator (HVS) studies conducted on concrete: Load transfer through aggregate interlock and the use of dowels and the evaluation of the performance of an in-service continuously reinforced concrete...

  6. Experimental and Analytical Investigations of Seismic Pounding of Adjacent 14-Story Reinforced Concrete Buildings Damaged in 1985 Mexico Earthquake

    National Research Council Canada - National Science Library

    Chujo, Takahiro; Yoshikado, Hiroshi; Sato, Yuichi; Naganuma, Kazuhiro; Kaneko, Yoshio

    2016-01-01

    Seismic pounding of a 14-story reinforced concrete building, Nuevo León, damaged in the 1985 Mexico Earthquake is investigated by means of dynamic finite element analyses and cyclic loading tests of columns specimens...

  7. Deflection Determination of Reinforced Concrete Support Poles for Overhead Transmission Lines

    Directory of Open Access Journals (Sweden)

    M. A. Korotkevich

    2011-01-01

    Full Text Available The paper contains values of torque magnification ratio while shifting vertical loads due to horizontal wind forces affecting on supports of overhead transmission lines of 35 kV and higher. These values pertain to various types of unified reinforced concrete conic and cylindrical supports while changing climatic conditions. The values make it possible to exclude rather complicated calculations in respect of support deflection in the case when there is uncertainty in initial data.

  8. Bending Moment Decrease of Reinforced Concrete Beam Supported by Additional CFRP

    Directory of Open Access Journals (Sweden)

    Mykolas Daugevičius

    2011-04-01

    Full Text Available The calculation method of reinforced concrete beam with additional CFRP composite is proposed in this article. This method estimates tangential angular concrete deformations in tensioned beam layers between steel and bonded carbon fiber reinforced polymer. The horizontal slip of CFRP composite reduce beam bending moment capacity. An additional coefficient to reduce CFRP resultant force is necessary for better precision of bending moment capacity. Also, various calculation methods of bending moment capacity are considered. Article in Lithuanian

  9. Effects of Shear Stirrup Details on Ultimate Capacity and Tensile Membrane Behavior of Reinforced Concrete Slabs

    Science.gov (United States)

    1985-08-01

    anticipation of the construction of 20,000 to 40,000 of the shelters, economical design requirements are very important. Because of high labor intensity... Derecho (Reference 35) stated that no data are available for one-way slabs tested under uniformly distributed load. During the same year that Iqbal and... Derecho reported their work (1969), *- Keenan (Reference 36) tested four laced reinforced concrete one-way slabs to failure under a uniformly

  10. Response Analysis for Steel Reinforced Concrete Frame Structures under Earthquake Load

    OpenAIRE

    Hua Wei; Jiye Zhang; Haijun Wang

    2013-01-01

    In order to understand the whole process of the steel reinforced concrete frame structure from elastic to elasto-plastic cracking gradually, damage until the collapse, the elasto-plastic finite element analysis theory and ETABS structural analysis software were used, then the spatial three-dimensional truss system model of frame structures was established. Based on the analysis of the elasto-plastic response for the frame structure under one-dimensional and two-dimensional earthquake load, th...

  11. Strength Design of Reinforced Concrete Hydraulic Structures; Report 3, T-Wall Design.

    Science.gov (United States)

    1982-01-01

    Concrete Reinforcing Steel Institute. 1978. CRSI Handbook, 3rd ed. Federation Internationale de la Precontrainte (FIP). 1974. "Recommen- dations for... concrete cover to the stirrups and main steel of a bridge floor beam that has been completely spalled off due to severe steel corrosion. 12. In this...Corrosion damage to a bridge floor beam C6 Tensile crack exposure tests by WES 13. Two series of reinforced concrete beams were made and exposed to

  12. Numerical modelling of large reinforced concrete specimens based on experimental tests from benchmark Concrack

    OpenAIRE

    2013-01-01

    Most infrastructures are reinforced concrete (RC) structures. And these structures have to be kept operational. For that the stackholders have to watch and observe the noticeable signs of degradation resulting from interactions between the environment and their constitutive materials. Of course, these interactions can reveal cracks which are the major worry with respect to durability and sustainability. If no maintenance or repair actions occur this durability could decrease until the service...

  13. Markov chain modeling of evolution of strains in reinforced concrete flexural beams

    Directory of Open Access Journals (Sweden)

    Anoop, M. B.

    2012-09-01

    Full Text Available From the analysis of experimentally observed variations in surface strains with loading in reinforced concrete beams, it is noted that there is a need to consider the evolution of strains (with loading as a stochastic process. Use of Markov Chains for modeling stochastic evolution of strains with loading in reinforced concrete flexural beams is studied in this paper. A simple, yet practically useful, bi-level homogeneous Gaussian Markov Chain (BLHGMC model is proposed for determining the state of strain in reinforced concrete beams. The BLHGMC model will be useful for predicting behavior/response of reinforced concrete beams leading to more rational design.A través del análisis de la evolución de la deformación superficial observada experimentalmente en vigas de hormigón armado al entrar en carga, se constata que dicho proceso debe considerarse estocástico. En este trabajo se estudia la utilización de cadenas de Markov para modelizar la evolución estocástica de la deformación de vigas flexotraccionadas. Se propone, para establecer el estado de deformación de estas, un modelo con distribución gaussiana tipo cadena de Markov homogénea de dos niveles (BLHGMC por sus siglas en inglés, cuyo empleo resulta sencillo y práctico. Se comprueba la utilidad del modelo BLHGMC para prever el comportamiento de estos elementos, lo que determina a su vez una mayor racionalidad a la hora de su cálculo y diseño

  14. Acoustic Emission Monitoring of Multicell Reinforced Concrete Box Girders Subjected to Torsion

    OpenAIRE

    Marya Bagherifaez; Arash Behnia; Abeer Aqeel Majeed; Chai Hwa Kian

    2014-01-01

    Reinforced concrete (RC) box girders are a common structural member for road bridges in modern construction. The hollow cross-section of a box girder is ideal in carrying eccentric loads or torques introduced by skew supports. This study employed acoustic emission (AE) monitoring on multicell RC box girder specimens subjected to laboratory-based torsion loading. Three multicell box girder specimens with different cross-sections were tested. The aim is to acquire AE analysis data indicative fo...

  15. Predicting the shear–flexural strength of slender reinforced concrete T and I shaped beams

    OpenAIRE

    Cladera Bohigas, Antoni; Marí Bernat, Antonio Ricardo; Ribas González, Carlos Rodrigo; Bairán García, Jesús Miguel; Oller Ibars, Eva

    2015-01-01

    A mechanical model previously developed by the authors for the prediction of the shear flexural strength of slender reinforced concrete beams with rectangular cross-section with or without stirrups has been extended to beams with T and I cross-sections. The effects of the section shape on each shear transfer action have been identified and incorporated into the corresponding equations. General expressions for strength verification and transverse reinforcement design have been derived. The con...

  16. Shear strengthening of reinforced concrete beams by means of vertical prestressed reinforcement

    OpenAIRE

    Santos Ferreira, Denise Carina; Bairán García, Jesús Miguel; Marí Bernat, Antonio Ricardo

    2016-01-01

    Strengthening reinforced concrete (RC) elements critical to shear with prestressed transversal reinforcement can be an efficient method to increase the shear resistance of structures, allowing the development of the full flexural capacity. However, research on the performance of this technique is very limited, and methods for designing the optimum amount of prestressed transversal reinforcement and assessing the retrofitted structure have not been produced yet. Nonlinear finite element models...

  17. Experimental Investigation and Analytical Modeling of Prefabricated Reinforced Concrete Sandwich Panels

    OpenAIRE

    BOURNAS DIONYSIOS; TORRISI Gonzalo; CRISAFULLI Francisco; Pavese, Alberto

    2012-01-01

    The behavior of prefabricated reinforced concrete sandwich panels (RCSPs) was investigated experimentally and analytically in this study. Initially, tests were carried out on single full-scale RCSPs with or without openings, reproducing the behavior of lateral resisting cantilever and fixed-end walls. The performance and failure mode of all panels tested revealed coupling between the flexure and shear response. However due to their well-detailed reinforcement, all panels exhibited a relativel...

  18. Corrosion inhibiting repair and rehabilitation treatment process for reinforced concrete structures

    OpenAIRE

    1994-01-01

    A repair and rehabilitation treatment process for reinforced concrete structures involves the removal of concrete from above rebar or other metal reinforcement material in the concrete structure. After removal of concrete, the metal reinforcement materials are saturated with corrosion inhibiting agents. Saturation is best achieved by multiple spray applications of the corrosion inhibitor. The cavity in the concrete structure with the treated rebar or other metal reinforcement materials is the...

  19. Evaluation of Concrete Consolidation: DSS-35 Antenna Reinforced Concrete Pedestal, Canberra Deep Space Communications Complex, Australia

    Science.gov (United States)

    Saldua, B. P.; Dodge, E. C.; Kolf, P. R.; Olson, C. A.

    2016-02-01

    Antenna structures for the Deep Space Network track spacecraft that are millions of miles away. Therefore, these structures have tight specifications for translation, rotation, and differential settlement. This article presents several nondestructive test methods that were used to evaluate, locate, and repair imperfections in the reinforced concrete pedestal that supports the DSS-35 antenna structure. These methods include: (1) impulse response (IR), (2) ultrasonic shear-wave tomography (MIRA), and (3) ground-penetrating radar (GPR).

  20. The effect of concrete strength and reinforcement on toughness of reinforced concrete beams

    OpenAIRE

    Carneiro, Joaquim A. O.; Jalali, Said; Teixeira, Vasco M. P.; Tomás, M.

    2005-01-01

    The objective pursued with this work includes the evaluating of the strength and the total energy absorption capacity (toughness) of reinforced concrete beams using different amounts of steel-bar reinforcement. The experimental campaign deals with the evaluation of the threshold load prior collapse, ultimate load and deformation, as well as the beam total energy absorption capacity, using a three point bending test. The beam half span displacement was measured using a displacement transducer,...

  1. Effect of Horizontal Tied Rebars on Precast Reinforced Concrete Core Walls

    OpenAIRE

    Nakachi, Tadaharu

    2013-01-01

    Multistory core walls installed in high-rise reinforced concrete buildings effectively reduce seismic vibration. On the other hand, precast core walls are considered effective for construction because they can be built more quickly than cast-in-place core walls. In this study, lateral loading tests were conducted on precast wall columns simulating the corner and the area near the corner of the L-shaped precast core wall. The specimen consisted of four square-section precast columns. The verti...

  2. METHOD OF DETERMINATION OF DIFFERENT STAGES OF CORROSION PROCESSES IN REINFORCED CONCRETE STRUCTURES ACCORDING TO SIGNALS AE

    Directory of Open Access Journals (Sweden)

    P. M. Stashuk

    2010-03-01

    Full Text Available The article describes the research of electrochemical corrosion of reinforcement concrete samples using the method of acoustic emission. The task of research was to identify patterns of acoustic emission signals depending on the mechanism of reinforcement corrosion. Тhe basic research results are outlined. As evaluation criteria for the selection of different stages of corrosion processes in reinforced concrete structures the usage of histograms of acoustic emission parameter Kр is proposed.

  3. Effects of edge beams on mechanic behavior under lateral load in reinforced concrete hollow slab-column structure

    Institute of Scientific and Technical Information of China (English)

    成洁筠; 杨建军; 唐小弟

    2008-01-01

    In order to get the formulae for calculating the equivalent frame width coefficient of reinforced concrete hollow slab-column structures with edge beam,the finite element structural program was used in the elastic analysis of reinforced concrete hollow slab-column structure with different dimensions to study internal relationship between effective beam width and the frame dimensions.In addition,the formulas for calculating the increasing coefficient of edge beam were also obtained.

  4. The Non-Destructive Test of Steel Corrosion in Reinforced Concrete Bridges Using a Micro-Magnetic Sensor

    OpenAIRE

    Hong Zhang; Leng Liao; Ruiqiang Zhao; Jianting Zhou; Mao Yang; Runchuan Xia

    2016-01-01

    This paper presents a non-destructive test method for steel corrosion in reinforced concrete bridges by using a 3-dimensional digital micro-magnetic sensor to detect and analyze the self-magnetic field leakage from corroded reinforced concrete. The setup of the magnetic scanning device and the measurement mode of the micro-magnetic sensor are introduced. The numerical analysis model is also built based on the linear magnetic charge theory. Compared to the self-magnetic field leakage data obta...

  5. Experimental and finite element analysis of bond-slip in reinforced concrete

    Directory of Open Access Journals (Sweden)

    A. R. V. WOLENSKI

    Full Text Available Abstract The modeling of reinforced concrete structures has taken advantage of the increasing progress on Computational Mechanics, in such way that complex phenomena, such as cracking and crushing, creep, reinforcement yielding, steel-concrete bond loss, can be modeled in a reasonable realistic way, using the proper set of numerical and computational resources. Among several options, the ones based on the Finite Element Method (FEM allow complex analysis simulations of reinforced concrete structures, including the interaction of different nonlinear effects. This paper deals with the nonlinear finite element analysis of the bond-slip between reinforcing steel and concrete, taking into account an experimental study previously performed. The FEM analysis presented uses a combination of resources where the material behavior of concrete is described by the Microplane Constitutive Model, and an embedded reinforcement model is used to represent steel inside the concrete and take into account the effect of bond-slip. The FEM models were created using the INSANE (INteractive Structural ANalysis Environment computational system, open source software that has a set of FEM tools for nonlinear analysis of reinforced concrete structures. The correlations between numerical-experimentals results and several parameters validate the proposed combination of resources and identifies the significance of various effects on the response.

  6. Experimental analysis of reinforced concrete beams strengthened in bending with carbon fiber reinforced polymer

    Directory of Open Access Journals (Sweden)

    M. M. VIEIRA

    Full Text Available The use of carbon fiber reinforced polymer (CFRP has been widely used for the reinforcement of concrete structures due to its practicality and versatility in application, low weight, high tensile strength and corrosion resistance. Some construction companies use CFRP in flexural strengthening of reinforced concrete beams, but without anchor systems. Therefore, the aim of this study is analyze, through an experimental program, the structural behavior of reinforced concrete beams flexural strengthened by CFRP without anchor fibers, varying steel reinforcement and the amount of carbon fibers reinforcement layers. Thus, two groups of reinforced concrete beams were produced with the same geometric feature but with different steel reinforcement. Each group had five beams: one that is not reinforced with CFRP (reference and other reinforced with two, three, four and five layers of carbon fibers. Beams were designed using a computational routine developed in MAPLE software and subsequently tested in 4-point points flexural test up to collapse. Experimental tests have confirmed the effectiveness of the reinforcement, ratifying that beams collapse at higher loads and lower deformation as the amount of fibers in the reinforcing layers increased. However, the increase in the number of layers did not provide a significant increase in the performance of strengthened beams, indicating that it was not possible to take full advantage of strengthening applied due to the occurrence of premature failure mode in the strengthened beams for pullout of the cover that could have been avoided through the use of a suitable anchoring system for CFRP.

  7. Experimental study on the seismic response of braced reinforced concrete frame with irregular columns

    Science.gov (United States)

    Xiao, Jianzhuang; Li, Jie; Chen, Jun

    2011-12-01

    A 15-storey K-braced reinforced concrete model frame with irregular columns, i.e., T-shaped, L-shaped, as well as +-shaped columns, was constructed and tested on the six-degree-of-freedom shaking table at the State Key Laboratory for Disaster Reduction in Civil Engineering in Tongji, China. Two types of earthquake records, El-Centro wave (south-north direction) and Shanghai artifi cial wave (SHAW) with various peak accelerations and principal-secondary sequences, were input and experimentally studied. Based on the shaking table tests and theoretical analysis, several observations can be made. The failure sequence of the model structure is brace→beam→column→joints, so that the design philosophy for several lines of defense has been achieved. Earthquake waves with different spectrums not only infl uence the magnitude and distribution of the earthquake force and the storey shear force, but also obviously affect the magnitude of the displacement response. The aftershock seismic response of previously damaged reinforced concrete braced frames with irregular columns possesses the equivalent elastic performance characteristic. Generally speaking, from the aspects of failure features and drift ratio, this type of reinforced concrete structure provides adequate earthquake resistance and can be promoted for use in China.

  8. Service-life prediction of reinforced concrete structures in subsurface environment

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Ki Jung; Jung, Hae Ryong; Park, Joo Wan [Korea Radioactive Waste Agency, Daejeon (Korea, Republic of)

    2016-03-15

    This paper focuses on the estimation of durability and service-life of reinforced concrete structures in Wolsong Low- and intermediate-level wastes Disposal Center (WLDC) in Korea. There are six disposal silos located in the saturated environment. The silo concrete is degraded due to reactions with groundwater and chemical attacks, and finally it will lose its properties as a transport barrier. The infiltration of sulfate and magnesium, leaching of potassium hydroxide, and chlorine induced corrosion are the most significant factors for degradation of reinforced concrete structure in underground environment. From the result of evaluation of the degradation time for each factor, the degradation rate of the reinforced concrete due to sulfate and magnesium is 1.308×10{sup -3} cm/yr, and it is estimated to take 48,000 years for full degradation while potassium hydroxide is leached in depth of less than 1.5 cm at 1,000 years after the initiation of degradation. In case of chlorine induced corrosion, it takes 1,648 years to initiate corrosion in the main reinforced bar and 2,288 years to reach the lifetime limit of the structural integrity, and thus it is evaluated as the most significant factor.

  9. Efficacy of Thermally Conditioned Sisal FRP Composite on the Shear Characteristics of Reinforced Concrete Beams

    Directory of Open Access Journals (Sweden)

    Tara Sen

    2013-01-01

    Full Text Available The development of commercially viable composites based on natural resources for a wide range of applications is on the rise. Efforts include new methods of production and the utilization of natural reinforcements to make biodegradable composites with lignocellulosic fibers, for various engineering applications. In this work, thermal conditioning of woven sisal fibre was carried out, followed by the development of woven sisal fibre reinforced polymer composite system, and its tensile and flexural behaviour was characterized. It was observed that thermal conditioning improved the tensile strength and the flexural strength of the woven sisal fibre composites, which were observed to bear superior values than those in the untreated ones. Then, the efficacy of woven sisal fibre reinforced polymer composite for shear strengthening of reinforced concrete beams was evaluated using two types of techniques: full and strip wrapping techniques. Detailed analysis of the load deflection behaviour and fracture study of reinforced concrete beams strengthened with woven sisal under shearing load were carried out, and it was concluded that woven sisal FRP strengthened beams, underwent very ductile nature of failure, without any delamination or debonding of sisal FRP, and also increased the shear strength and the first crack load of the reinforced concrete beams.

  10. Reinforced concrete bridges: effects due to corrosion and concrete young modulus variation

    Directory of Open Access Journals (Sweden)

    P. T. C. Mendes

    Full Text Available Most of the Brazilian bridges of federal road network are made of reinforced concrete and are more than 30 years old, with little information about the mechanical properties of their constitutive materials. Along the service life of these bridges much modification occurred on vehicles load and geometry and in design standard. Many of them show signs of concrete and steel deterioration and their stability conditions are unknown. With the aim of contributing to the structural evaluation of reinforced concrete bridges it was decided to analyze the stresses in reinforced concrete bridge sections to verify the effects due to reinforcement corrosion and variation of the concrete Young modulus on the stress distribution regarding several load patterns and cracking effects in a representative bridge of the Brazilian road network with different longitudinal reinforcement taxes and two concrete Young modulus, Ec and 0.5Ec, and with different percentage of reinforcement corrosion. The analysis considered two finite element models: frame and shell elements as well as solid elements. The results indicate that these variation effects are more significant in reinforcement bars than in concrete.

  11. EFFECT OF CORROSION ON BOND BEHAVIOR AND BENDING STRENGTH OF REINFORCED CONCRETE BEAMS

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    There is growing concern for corrosion damage in reinforced concrete structures with several decades' service. Pullout tests and beam tests were carried out to study the effect of reinforcement corrosion on the bond behavior and bending strength of reinforced concrete beams. The bond strength of plain bars and concrete initially increases with increasing corrosion, then declines. The turning point depends on the cracking of the concrete cover. The bond strength of deformed bars and concrete increases with corrosion up to a certain amount, but with progressive increase in corrosion, the bond strength decreases, and the cracking of the concrete cover seems to have no effect on the bond strength. On the basis of test data, the bond strength coefficient recommended here, which, together with the bond strength of uncorroded steel bars and concrete, can be used to easily calculate the bond strength of corroded steel bars and concrete. The bond strength coefficient proposed in this paper can be used to study the bond stress-slip relationship of corroded steel bars and concrete. The bending strength of corroded reinforced concrete beams declines with increasing reinforcement corrosion. Decreased bending strength of corroded RC beam is due to reduction in steel bar cross section, reduction of yield strength of steel bar, and reduction of bond capacity between steel bar and concrete.

  12. Fracture Formation Evaluation of Reinforced Concrete Structure Using Acoustic Emission Technique

    Directory of Open Access Journals (Sweden)

    Alireza Panjsetooni

    2013-01-01

    Full Text Available Acoustic emission (AE is an important nondestructive evaluation (NDE technique used in the field of structural engineering for both case local and global monitoring. In this study AE technique with a new approach was employed to investigate the process of fracture formation in reinforced concrete structure. A number of reinforced concrete (RC one story frames were tested under loading cycle and were simultaneously monitored using AE. The AE test data was analyzed using the relaxation ratio and calm and load ratio method. Also, the relaxation ratio was dominated with approaching load to 58% of the ultimate load. In addition three levels of damage using calm and load ratio were distinguished. The trend of relaxation ratio and calm and load ratio method during loading and unloading showed that these methods are strongly sensitive with cracks growth in RC frame specimens and were able to indicate the levels of damage. Also, results showed that AE can be considered as a viable method to predict the remaining service life of reinforced concrete. In addition, with respect to the results obtained from relaxation ratio and, load and calm ratio indicated, a new chart is proposed.

  13. Simulation of the Ill-Posed Problem of Reinforced Concrete Corrosion Detection Using Boundary Element Method

    Directory of Open Access Journals (Sweden)

    Syarizal Fonna

    2016-01-01

    Full Text Available Many studies have suggested that the corrosion detection of reinforced concrete (RC based on electrical potential on concrete surface was an ill-posed problem, and thus it may present an inaccurate interpretation of corrosion. However, it is difficult to prove the ill-posed problem of the RC corrosion detection by experiment. One promising technique is using a numerical method. The objective of this study is to simulate the ill-posed problem of RC corrosion detection based on electrical potential on a concrete surface using the Boundary Element Method (BEM. BEM simulates electrical potential within a concrete domain. In order to simulate the electrical potential, the domain is assumed to be governed by Laplace’s equation. The boundary conditions for the corrosion area and the noncorrosion area of rebar were selected from its polarization curve. A rectangular reinforced concrete model with a single rebar was chosen to be simulated using BEM. The numerical simulation results using BEM showed that the same electrical potential distribution on the concrete surface could be generated from different combinations of parameters. Corresponding to such a phenomenon, this problem can be categorized as an ill-posed problem since it has many solutions. Therefore, BEM successfully simulates the ill-posed problem of reinforced concrete corrosion detection.

  14. A state of the art review on reinforced concrete beams with openings retrofitted with FRP

    Science.gov (United States)

    Osman, Bashir H.; Wu, Erjun; Ji, Bohai; S Abdelgader, Abdeldime M.

    2016-09-01

    The use of externally bonded fiber reinforced polymer (FRP) sheets, strips or steel plates is a modern and convenient way for strengthening of reinforced concrete (RC) beams. Several researches have been carried out on reinforced concrete beams with web openings that strengthened using fiber reinforced polymer composite. Majority of researches focused on shear strengthening compared with flexural strengthening, while others studied the effect of openings on shear and flexural separately with various loading. This paper investigates the impact of more than sixty articles on opening reinforced concrete beams with and without strengthening by fiber reinforcement polymers FRP. Moreover, important practical issues, which are contributed in shear strengthening of beams with different strengthening techniques, such as steel plate and FRP laminate, and detailed with various design approaches are discussed. Furthermore, a simple technique of applying fiber reinforced polymer contributed with steel plate for strengthening the RC beams with openings under different load application is concluded. Directions for future research based on the existing gaps of the present works are presented.

  15. Experimental Study, Simulation and Model Predictions of Recycled PET Strip-Reinforced Concrete Flexion Members

    Directory of Open Access Journals (Sweden)

    F.J. Baldenebro-Lopez

    2014-07-01

    Full Text Available This study presents results from a theoretical-experimental program of beams partially pre-stressed made with continuous recycled PET strip-reinforced concrete (plain concrete strength of 20 MPa. These studies mainly attempted to determine the stripinfluence in altering the flexural strength at first and final crack. Also the load-deflection, ductility, energy absorption capacity of the beams are observed and the studies can be used in predicting the flexural behavior of longitudinally reinforced concrete. The model theory assumes that concrete has a tensile load capacity different from zero, characterized by a uniaxial tensile stress-strain diagram. The need for non-linear geometric and the material models imply the use of numerical methods such as the finite element method; so that, a finite element analysis of reinforced concrete beam with strips-reinforced plastic is performed. The obtained results were compared with computer analysis and experimental data to corroborate the validity of the suggested method, showing that the theory also predicts correctly the post-cracking creep deformation.

  16. Reinforced concrete structures loaded by snow avalanches : numerical and experimental approaches.

    Science.gov (United States)

    Ousset, I.; Bertrand, D.; Brun, M.; Limam, A.; Naaim, M.

    2012-04-01

    Today, due to the extension of occupied areas in mountainous regions, new strategies for risk mitigation have to be developed. In the framework of risk analysis, these latter have to take into account not only the natural hazard description but also the physical vulnerability of the exposed structures. From a civil engineering point of view, the dynamic behavior of column or portico was widely investigated especially in the case of reinforced concrete and steel. However, it is not the case of reinforced concrete walls for which only the in-plan dynamic behavior (shear behavior) has been studied in detail in the field of earthquake engineering. Therefore, the aim of this project is to study the behavior of reinforced concrete civil engineering structures submitted to out-of-plan dynamic loadings coming from snow avalanche interaction. Numerical simulations in 2D or 3D by the finite element method (FEM) are presented. The approach allows solving mechanical problems in dynamic condition involving none linearities (especially none linear materials). Thus, the structure mechanical response can be explored in controlled conditions. First, a reinforced concrete wall with a L-like shape is considered. The structure is supposed to represent a French defense structure dedicated to protect people against snow avalanches. Experimental pushover tests have been performed on a physical model. The experimental tests consisted to apply a uniform distribution of pressure until the total collapse of the wall. A 2D numerical model has been developed to simulate the mechanical response of the structure under quasi-static loading. Numerical simulations have been compared to experimental datas and results gave a better understanding of the failure mode of the wall. Moreover, the influence of several parameters (geometry and the mechanical properties) is also presented. Secondly, punching shear experimental tests have also been carried out. Reinforced concrete slabs simply supported have

  17. Shear punching studies on an impact loaded reinforced concrete slab

    Energy Technology Data Exchange (ETDEWEB)

    Saarenheimo, Arja, E-mail: Arja.saarenheimo@vtt.fi; Tuomala, Markku, E-mail: Markku.tuomala@professori.fi; Calonius, Kim, E-mail: Kim.calonius@vtt.fi

    2015-12-15

    A shear punching test series is being carried out at VTT by using as a target a two way simply supported concrete plate with a span of 2 m and a thickness of 25 cm. The mass of the impacting stainless steel missile-type projectile is 50 kg. The capabilities of different types of calculation methods in assessing local shear deformation and possible shear punching cone formation are studied. Numerical solutions are compared with experimental results of test called X3.

  18. Soft impact testing of a wall-floor-wall reinforced concrete structure

    Energy Technology Data Exchange (ETDEWEB)

    Vepsä, Ari, E-mail: ari.vepsa@vtt.fi; Calonius, Kim; Saarenheimo, Arja; Aatola, Seppo; Halonen, Matti

    2017-01-15

    Highlights: • A wall-floor-wall reinforced concrete structure was built. • The structure was subjected to three almost identical soft impact tests. • Response was measured with accelerometers, displacement sensors and strain gauges. • Modal tests was also carried out with the same structure in different conditions. • The results are meant to be used for validation of computational methods and models. - Abstract: Assessing the safety of the reactor building of a nuclear power plant against the crash of an airplane calls for valid computational tools such as finite element models and material constitutive models. Validation of such tools and models in turn calls for reliable and relevant experimental data. The problem is that such data is scarcely available. One of the aspects of such a crash is vibrations that are generated by the impact. These vibrations tend to propagate from the impact point to the internal parts of the building. If strong enough, these vibrations may cause malfunction of the safety-critical equipment inside the building. To enable validation of computational models for this type of behaviour, we have conducted a series of three tests with a wall-floor-wall reinforced concrete structure under soft impact loading. The response of the structure was measured with accelerometers, displacement sensors and strain gauges. In addition to impact tests, the structure was subjected to modal tests under different conditions. The tests yielded a wealth of useful data for validation of computational models and better understanding about shock induced vibration physics especially in reinforced concrete structures.

  19. Finite Element Simulation of GFRP Reinforced Concrete Beam Externally Strengthened With CFRP Plates

    Directory of Open Access Journals (Sweden)

    Salleh Norhafizah

    2017-01-01

    Full Text Available The construction technology now has become more and more advanced allowing the development of new technologies or material to replace the previous one and also solved some of the troubles confronted by construction experts. The Glass Fibre Reinforced Polymer (GFRP composite is an alternative to replace the current usage of steel as it is rust proof and stronger in terms of stiffness compared to steel. Furthermore, GFRP bars have a high strength-to-weight ratio, making them attractive as reinforcement for concrete structures. However, the tensile behavior of GFRP bars is characterized by a linear elastic stress–strain relationship up to failure and, therefore, concrete elements reinforced with GFRP reinforcement exhibit brittle failure without warning. Design codes encourage over-reinforced GFRP design since it is more progressive and leads to a less catastrophic failure with a higher degree of deformability. Moreover, because of GFRP low modulus of elasticity, GFRP reinforced concrete members exhibit larger deflections and wider cracks width than steel reinforced concrete. This aims of this paper is to developed 2D Finite Element (FE models that can accurately simulate the respond on an improvement in the deflection of GFRP reinforced concrete beam externally strengthened with CFRP plates on the tension part of beam. The prediction of flexural response according to RCCSA software was also discussed. It was observed that the predicted FE results are given similar result with the experimental measured test data. Base on this good agreement, a parametric study was the performed using the validation FE model to investigate the effect of flexural reinforcement ratio and arrangement of the beams strengthened with different regions of CFRP plates.

  20. Experimental investigation of reinforced concrete beams with and without CFRP wrapping

    Science.gov (United States)

    Venkatesha, K. V.; Dinesh, S. V.; Balaji Rao, K.; Bharatkumar, B. H.; Balasubramanian, S. R.; Iyer, Nagesh R.

    2012-11-01

    This paper presents the results of experimental investigations on six reinforced concrete beams, with three different shear span-to-depth ratios, which were tested under two-point loading. The aim of the work was to study the efficacy of Carbon Fibre Reinforced Polymer (CFRP) strips in enhancing shear capacity and/or changing the failure mode from brittle shear failure to ductile flexural failure. The results of the study indicate that while there is a marginal increase in first crack and ultimate loads, it is possible to achieve a change in the failure mode, and the monitored strain gauge data can be used to explain the failure pattern observed.

  1. Foundation Design for a High Bay Warehouse with a Steel Fibre Reinforced Concrete Slab

    DEFF Research Database (Denmark)

    Kasper, T.; Sørensen, Carsten Steen; Nielsen, J. B.

    2008-01-01

    concrete slabs, while a 69 x 77 m and 40 cm thick steel fibre reinforced concrete (SFRC) slab forms the inner part of the foundation. Steel fibre reinforcement has been chosen mainly due to approximately 15 % lower construction costs than a comparable solution with conventional rebar reinforcement......The high bay warehouse at the Carlsberg brewery in Fredericia, Denmark, is 40 m high and is founded with a 83 x 116 m foundation slab on clay till and sand layers. Due to the wind loads on the tall building, the edges of the foundation require 80 cm and 60 cm thick conventionally reinforced...

  2. Energy Dissipation Capacity of Reinforced Concrete Beams Strengthened with CFRP Strips

    Science.gov (United States)

    Hong, Sungnam; Park, Sun-Kyu

    2016-05-01

    Cyclic loading tests were performed to investigate the energy dissipation capacities of reinforced concrete (RC) beams strengthened with carbon-fiber-reinforced polymer (CFRP) strips. Four RC beams were manufactured and three-point loaded. Responses of the strengthened beams to the cyclic loadings were measured, including deflections at the center of their span and strains of the CFRP strips and reinforcing steel rebars. Based on test results, the energy dissipation capacity of the strengthened beams were evaluated in comparison with that of an unstrengthened control beam.

  3. Computational aspects of crack growth in sandwich plates from reinforced concrete and foam

    Science.gov (United States)

    Papakaliatakis, G.; Panoskaltsis, V. P.; Liontas, A.

    2012-12-01

    In this work we study the initiation and propagation of cracks in sandwich plates made from reinforced concrete in the boundaries and from a foam polymeric material in the core. A nonlinear finite element approach is followed. Concrete is modeled as an elastoplastic material with its tensile behavior and damage taken into account. Foam is modeled as a crushable, isotropic compressible material. We analyze slabs with a pre-existing macro crack at the position of the maximum bending moment and we study the macrocrack propagation, as well as the condition under which we have crack arrest.

  4. Active tendon control of reinforced concrete frame structures subjected to near-fault effects

    Science.gov (United States)

    Nigdeli, Sinan Melih; Boduroǧlu, M. Hasan

    2013-10-01

    A reinforced concrete (RC) frame structure was controlled with active tendons under the excitation of near-fault ground motions. Proportional Integral Derivative (PID) type controllers were used and the controller was tuned by using a numerical algorithm. In order to prevent brittle fracture of the structure, the aim of the control is to reduce maximum base shear force. The RC structure was investigated for different characteristic strengths of concrete and the approach is applicable for the structure with 14 MPa concrete strength or higher.

  5. Application of WST-method fore fracture testing of fibre-reinforced concrete

    DEFF Research Database (Denmark)

    Löfgren, Ingemar; Olesen, John Forbes; Flansbjer, Mathias

    ). The test results from each lab were analysed and a study of the variation was performed. From the study of the intra-lab variations, it is evident that the variations of the steel fibre-reinforced concrete properties are significant. The coefficient of variance for the splitting load was found to vary...... between 20 to 40%. The investigation of the inter-lab variation, based on an analysis of variance (ANOVA) indicated that there is no inter-lab variation. The test result can be said to be independent of the testing location and the equipment used (with or without CMOD-control). The conclusions that can...

  6. Experimental study on fire protection methods of reinforced concrete beams strengthened with carbon fiber reinforced polymer

    Institute of Scientific and Technical Information of China (English)

    HU Kexu; HE Guisheng; LU Fan

    2007-01-01

    In this paper,two reinforced concrete (RC) beams strengthened with carbon fiber reinforced polymer (CFRP)and attached with thick-painted fire resistant coating were tested for fire resistance following the standard fire testing procedures.The experimental results show that the specimen pasted with the insulated layer of 50 mm in thickness could resist fire for 2.5 h.It is also demonstrated that the steel wire mesh embedded in the insulated layer can effectively prevent it from cracking and eroding under firing.

  7. Environmental life cycle assessment comparison between two bridge types: reinforced concrete bridge and steel composite bridge

    DEFF Research Database (Denmark)

    Du, Guangli; Karoumi, Raid

    2013-01-01

    not been integrated into the decision-making process. This paper presents a systematic LCA method for quantifying the environmental impacts for bridges. The comparison study is performed between a reinforced concrete bridge and a steel bridge as an alternative design, with several key maintenance and EOL......The concept of sustainable construction has attracted an increased attention. Bridge infrastructures and their belonged construction activities consume considerable material and energy, which is responsible for large environmental burdens. However, the environmental assessment of bridges has...

  8. Application of WST-method fore fracture testing of fibre-reinforced concrete

    DEFF Research Database (Denmark)

    Löfgren, Ingemar; Olesen, John Forbes; Flansbjer, Mathias

    be drawn from this study are that: § the wedge-splitting test method is a suitable test method for assessment of fracture properties of steel fibre-reinforced concrete; § the test method is easy to handle and relatively fast to execute § the test can be run with CMOD-control or without, in a machine......To evaluate the reproducibility of the wedge-splitting test method and to provide guidelines, a round robin study was conducted in which three labs participated. The participating labs were: § DTU – the Technical University of Denmark, Department of Civil Engineering; § CTH – Chalmers University...

  9. Time reverse modeling of acoustic emissions in a reinforced concrete beam.

    Science.gov (United States)

    Kocur, Georg Karl; Saenger, Erik H; Grosse, Christian U; Vogel, Thomas

    2016-02-01

    The time reverse modeling (TRM) is applied for signal-based acoustic emission (AE) analysis of reinforced concrete (RC) specimens. TRM uses signals obtained from physical experiments as input. The signals are re-emitted numerically into a structure in a time-reversed manner, where the wavefronts interfere and appear as dominant concentrations of energy at the origin of the AE. The experimental and numerical results presented for selected AE signals confirm that TRM is capable of localizing AE activity in RC caused by concrete cracking. The accuracy of the TRM results is corroborated by three-dimensional crack distributions obtained from X-ray computed tomography images.

  10. Structural behavior of reinforced concrete slab rigid frame bridge with h-shaped steels

    OpenAIRE

    Fukada, Saiji; Kajikawa, Y.; Tokuno, M.

    2008-01-01

    The authors proposed a reinforced concrete slab bridge with H-shaped steels which has high load-carrying capacity in order to reduce the construction cost. Our past study clarified that H-shape steels without stud dowel and concrete could compose hybrid section and static load was equally distributed each H-shaped steel in elasticity stage. Considering the described above it is possible to design this type of bridge as composite. Moreover it clarified that the cyclically loaded this type brid...

  11. Polymer concrete for precast repair of continuously reinforced concrete pavement on IH 30, near Mt. Pleasant

    Science.gov (United States)

    Meyer, A. M.; McCullough, B. F.; Fowler, D. W.

    1981-08-01

    Two punchout repairs made in a continuously reinforced concrete pavement (CRCP) using precast portland cement panels are described. The two repairs, one 1.44 sq. ft., the other 36 sq. ft., were completed and opened to traffic in one afternoon. This technique provides a rapid method of repair that produces a repair that is structurally as good or better than the surrounding pavement. With a trained crew, the repair time can be reduced and thus reducing lane closure time. Since lane closure time is a critical consideration in high volume highways, this method is cost effective in those areas.

  12. Reliability and flexural behavior of triangular and T-reinforced concrete beams

    Science.gov (United States)

    Al-Ansari, Mohammed S.

    2015-12-01

    The paper studied the behavior of reinforced concrete triangular and T-beams. Three reinforced concrete beams were tested experimentally and analyzed analytically using the finite element method. Their reliability was also assessed using the reliability index approach. The results showed that the finite element vertical displacements compared well with those obtained experimentally. They also showed that the vertical displacements obtained using the finite element method were larger than those obtained experimentally. This is a strong indication that the finite element results were conservative and reliable. The results showed that the triangular beams exhibited higher ductility at failure than did the T-beam. The plastic deformations at failure of the triangular beams were higher than that of the T-beam. This is a strong indication of the higher ductility of the triangular beams compared to the T-beam. Triangular beams exhibited smaller cracks than did T-beams for equal areas of steel and concrete. The design moment strengths M c computed using the American Concrete Institute (ACI) design formulation were safe and close to those computed using experimental results. The experimental results validated the reliability analysis results, which stated that the triangular beams are more reliable than T-beams for equal areas of steel and concrete.

  13. Hybrid Reinforced Concrete Frame Building with Pumice Brick Masonry Infill under Static Lateral Loading

    Directory of Open Access Journals (Sweden)

    Akmaluddin

    2012-08-01

    Full Text Available The purpose of this study is to investigate the behaviour of hybrid reinforced concrete frame with pumice brick masonry infill under static lateral loading. The term hybrid herein is referred to the frame composed of precast block masonry unit and cast in-place reinforced concrete beams. Parameters considered in this study were frame opening representing doors and windows commonly used in the wall system. Six types of frame namely FS, FB, FDE, FDC, FWE and FWC designation for solid frame, bare frame, frame with door opening at edge, frame with door opening at centre, frame with window opening at edge and frame with window opening at centre respectively were considered. Test results indicated that the FS has a maximum lateral strength greater than that of FB. The lateral strength of FS was about 3.68 of FB. The frames with various openings have lateral strength nearly 2.3 of lateral strength of the bare frame, FB. Ductility factor of the frames varied from 2.4 to 4.92. The residual strength of the frame with openings were varies between 2.33 and 3.35 of the bare frame. The stiffness of the infilled frames with opening were varied from 3.56 to 3.67 of the bare frame. The presence of openings in the infilled frame did not affect the frame stiffness considerably.

  14. Improved Seismic Risk Assessment of Non-ductile Reinforced Concrete Buildings

    Science.gov (United States)

    Fuselier, Blaine Jacob

    Existing reinforced concrete (RC) buildings built to non-ductile specifications are highly susceptible to damage given lateral loads induced from earthquake ground motions. To explore the effects of these ground motions, non-linear finite element analyses are being used in research and practice to model representations of non-ductile RC buildings as well as conduct probabilistic analyses of their seismic fragility in as-built and retrofitted conditions. This study examines the influence of modeling fidelity on the response and fragility of non-ductile RC buildings, testing the role of explicitly capturing local failure in the finite element model as well as providing new insight into the probability of component damage levels given system level failure. Also, a survey is presented to assess the tagging decisions made during post-earthquake rapid evaluations of reinforced concrete buildings and compare these results to empirical data from past earthquake reconnaissance reports. The results of this study will provide insight into several key issues in seismic performance assessment for RC buildings.

  15. Demolition technique of high thin-wall hyperbolic reinforced concrete cool tower by directional controlled blasting

    Institute of Scientific and Technical Information of China (English)

    Luo Yong; Cui Xiaorong; Lu Hua

    2008-01-01

    Based on blasting demolition of high thin-wall hyperbolic reinforced concrete cool tower,by virtue of engi-neering practice of blasting the tube concrete structures,the analysis and research were made on the mechanism of cool tower collapse through selecting blasting parameters and selecting gap form,gap size and gap angle.The cool tower was twisted,collapsed directionally and broken weU according to the design requirements.The expected results and purpo-ses of blasting were obtained with no back blow,total blasted pile approximates to 4 ~ 5 m,no occurrence of flying stones and no damage to fixed buildings and equipment,the large-sized hyperbolic thin-wall reinforced concrete cool towers are twisted during blasting and it collapses well with good breaking.The test and measurement of blasting vibra-ting velocity was carried out during blasting and the measuring results are much less than critical values specified by Safety Regulations for Blasting.The study shows that gap form,gap size and gap angle are the key factors to cool tower collapse and will give beneficial references to related theoretical study and field application.

  16. Positioning of steel rods inclusions in reinforced concrete simulant by Compton backscattering

    Energy Technology Data Exchange (ETDEWEB)

    Boldo, Emerson M.; Prestes, Ana A.P.; Appoloni, Carlos R. [Universidade Estadual de Londrina (UEL), PR (Brazil). Dept. de Fisica. Lab. de Fisica Nuclear Aplicada

    2011-07-01

    Reinforced concrete is susceptible to a range of environmental degradation factors that can limit its service life. There has always been a need for test methods to measure, in situ, the properties of concrete for quality assurance and to evaluate the condition of existing structures. Compton scattering of gamma radiation is a nondestructive technique used for the detection of defects and inclusions in materials and it can be employed on reinforced concrete. The methodology allows for one-side inspection of large structures and can be implemented with a relatively inexpensive, portable apparatus. In this work, we used the Compton backscattering technique to measure both the size and depth of steel rod inclusions in plaster block samples. The samples were irradiated with gamma rays from a {phi}2 mm collimated {sup 241}Am (100 mCi) source, and the inelastically scattered photons were collected at an angle of 135 deg by a high-resolution CdTe semiconductor detector. Scanning was achieved by lateral movement of the sample blocks across the field of view of the source and detector in steps of 1 mm. The tests on plaster blocks with steel rod inclusions suggest that, for a low-energy and low-activity gamma source, beam attenuation has greater effects on the scattered intensity than does increased material density. Density contrast analysis allows determination of the size and depth of steel rods. Furthermore, the experimental results agree with theoretical data obtained through Monte Carlo simulation. (author)

  17. A Wireless Passive Sensing System for Displacement/Strain Measurement in Reinforced Concrete Members

    Science.gov (United States)

    Ozbey, Burak; Erturk, Vakur B.; Demir, Hilmi Volkan; Altintas, Ayhan; Kurc, Ozgur

    2016-01-01

    In this study, we show a wireless passive sensing system embedded in a reinforced concrete member successfully being employed for the measurement of relative displacement and strain in a simply supported beam experiment. The system utilizes electromagnetic coupling between the transceiver antenna located outside the beam, and the sensing probes placed on the reinforcing bar (rebar) surface inside the beam. The probes were designed in the form of a nested split-ring resonator, a metamaterial-based structure chosen for its compact size and high sensitivity/resolution, which is at µm/microstrains level. Experiments were performed in both the elastic and plastic deformation cases of steel rebars, and the sensing system was demonstrated to acquire telemetric data in both cases. The wireless measurement results from multiple probes are compared with the data obtained from the strain gages, and an excellent agreement is observed. A discrete time measurement where the system records data at different force levels is also shown. Practical issues regarding the placement of the sensors and accurate recording of data are discussed. The proposed sensing technology is demonstrated to be a good candidate for wireless structural health monitoring (SHM) of reinforced concrete members by its high sensitivity and wide dynamic range. PMID:27070615

  18. Compressive Behavior of Fiber-Reinforced Concrete with End-Hooked Steel Fibers

    Directory of Open Access Journals (Sweden)

    Seong-Cheol Lee

    2015-03-01

    Full Text Available In this paper, the compressive behavior of fiber-reinforced concrete with end-hooked steel fibers has been investigated through a uniaxial compression test in which the variables were concrete compressive strength, fiber volumetric ratio, and fiber aspect ratio (length to diameter. In order to minimize the effect of specimen size on fiber distribution, 48 cylinder specimens 150 mm in diameter and 300 mm in height were prepared and then subjected to uniaxial compression. From the test results, it was shown that steel fiber-reinforced concrete (SFRC specimens exhibited ductile behavior after reaching their compressive strength. It was also shown that the strain at the compressive strength generally increased along with an increase in the fiber volumetric ratio and fiber aspect ratio, while the elastic modulus decreased. With consideration for the effect of steel fibers, a model for the stress–strain relationship of SFRC under compression is proposed here. Simple formulae to predict the strain at the compressive strength and the elastic modulus of SFRC were developed as well. The proposed model and formulae will be useful for realistic predictions of the structural behavior of SFRC members or structures.

  19. Fatigue Strain and Damage Analysis of Concrete in Reinforced Concrete Beams under Constant Amplitude Fatigue Loading

    Directory of Open Access Journals (Sweden)

    Fangping Liu

    2016-01-01

    Full Text Available Concrete fatigue strain evolution plays a very important role in the evaluation of the material properties of concrete. To study fatigue strain and fatigue damage of concrete in reinforced concrete beams under constant amplitude bending fatigue loading, constant amplitude bending fatigue experiments with reinforced concrete beams with rectangular sections were first carried out in the laboratory. Then, by analyzing the shortcomings and limitations of existing fatigue strain evolution equations, the level-S nonlinear evolution model of fatigue strain was constructed, and the physical meaning of the parameters was discussed. Finally, the evolution of fatigue strain and fatigue damage of concrete in the compression zone of the experimental beam was analyzed based on the level-S nonlinear evolution model. The results show that, initially, fatigue strain grows rapidly. In the middle stages, fatigue strain is nearly a linear change. Because the experimental data for the third stage are relatively scarce, the evolution of the strain therefore degenerated into two phases. The model has strong adaptability and high accuracy and can reflect the evolution of fatigue strain. The fatigue damage evolution expression based on fatigue strain shows that fatigue strain and fatigue damage have similar variations, and, with the same load cycles, the greater the load level, the larger the damage, in line with the general rules of damage.

  20. Prediction of the behavior of reinforced concrete deep beams with web openings using the finite ele

    Directory of Open Access Journals (Sweden)

    Ashraf Ragab Mohamed

    2014-06-01

    Full Text Available The exact analysis of reinforced concrete deep beams is a complex problem and the presence of web openings aggravates the situation. However, no code provision exists for the analysis of deep beams with web opening. The code implemented strut and tie models are debatable and no unique solution using these models is available. In this study, the finite element method is utilized to study the behavior of reinforced concrete deep beams with and without web openings. Furthermore, the effect of the reinforcement distribution on the beam overall capacity has been studied and compared to the Egyptian code guidelines. The damaged plasticity model has been used for the analysis. Models of simply supported deep beams under 3 and 4-point bending and continuous deep beams with and without web openings have been analyzed. Model verification has shown good agreement to literature experimental work. Results of the parametric analysis have shown that web openings crossing the expected compression struts should be avoided, and the depth of the opening should not exceed 20% of the beam overall depth. The reinforcement distribution should be in the range of 0.1–0.2 beam depth for simply supported deep beams.

  1. A Wireless Passive Sensing System for Displacement/Strain Measurement in Reinforced Concrete Members

    Directory of Open Access Journals (Sweden)

    Burak Ozbey

    2016-04-01

    Full Text Available In this study, we show a wireless passive sensing system embedded in a reinforced concrete member successfully being employed for the measurement of relative displacement and strain in a simply supported beam experiment. The system utilizes electromagnetic coupling between the transceiver antenna located outside the beam, and the sensing probes placed on the reinforcing bar (rebar surface inside the beam. The probes were designed in the form of a nested split-ring resonator, a metamaterial-based structure chosen for its compact size and high sensitivity/resolution, which is at µm/microstrains level. Experiments were performed in both the elastic and plastic deformation cases of steel rebars, and the sensing system was demonstrated to acquire telemetric data in both cases. The wireless measurement results from multiple probes are compared with the data obtained from the strain gages, and an excellent agreement is observed. A discrete time measurement where the system records data at different force levels is also shown. Practical issues regarding the placement of the sensors and accurate recording of data are discussed. The proposed sensing technology is demonstrated to be a good candidate for wireless structural health monitoring (SHM of reinforced concrete members by its high sensitivity and wide dynamic range.

  2. Thermal Performance Analysis of Reinforced Concrete Floor Structure with Radiant Floor Heating System in Apartment Housing

    Directory of Open Access Journals (Sweden)

    Young-Sun Jeong

    2015-01-01

    Full Text Available The use of the resilient materials in the radiant floor heating systems of reinforced concrete floor in apartment housing is closely related to the reduction of the floor impact sound and the heating energy loss. This study examined the thermal conductivity of expanded polystyrene (EPS foam used for the resilient material in South Korea and analysed the thermal transfer of reinforced concrete floor structure according to the thermal conductivity of the resilient materials. 82 EPS specimens were used to measure the thermal conductivity. The measured apparent density of EPS resilient materials ranged between 9.5 and 63.0 kg/m3, and the thermal conductivity ranged between 0.030 and 0.046 W/(m·K. As the density of resilient materials made of expanded polystyrene foam increases, the thermal conductivity tends to proportionately decrease. To set up reasonable thermal insulation requirements for radiant heating floor systems, the thermal properties of floor structure according to thermal insulation materials must be determined. Heat transfer simulations were performed to analyze the surface temperature, heat loss, and heat flow of floor structure with radiant heating system. As the thermal conductivity of EPS resilient material increased 1.6 times, the heat loss was of 3.4% increase.

  3. Preparation and characterization of glass fibers - polymers (epoxy) bars (GFRP) reinforced concrete for structural applications

    Science.gov (United States)

    Alkjk, Saeed; Jabra, Rafee; Alkhater, Salem

    2016-06-01

    The paper presents some of the results from a large experimental program undertaken at the Department of Civil Engineering of Damascus University. The project aims to study the ability to reinforce and strengthen the concrete by bars from Epoxy polymer reinforced with glass fibers (GFRP) and compared with reinforce concrete by steel bars in terms of mechanical properties. Five diameters of GFRP bars, and steel bars (4mm, 6mm, 8mm, 10mm, 12mm) tested on tensile strength tests. The test shown that GFRP bars need tensile strength more than steel bars. The concrete beams measuring (15cm wide × 15cm deep × and 70cm long) reinforced by GFRP with 0.5 vol.% ratio, then the concrete beams reinforced by steel with 0.89 vol.% ratio. The concrete beams tested on deflection test. The test shown that beams which reinforced by GFRP has higher deflection resistance, than beams which reinforced by steel. Which give more advantage to reinforced concrete by GFRP.

  4. Dam safety review using non-destructive methods for reinforced concrete structure

    Energy Technology Data Exchange (ETDEWEB)

    Philibert, Alain; Saint-Pierre, Francois; Turcotte, Bernard [Le Groupe S.M. International Inc., Sherbrooke, (Canada)

    2010-07-01

    Dams built at the beginning of the twentieth century include concrete structures that were put in under rehabilitation works. In some cases, the details of the structures are not well documented. In other cases, concrete damage can be hidden under new layers of undamaged material. This requires that the dam safety review in a real investigation gather the information necessary for carrying out the hydraulic and stability studies required by the Dam Safety Act. This paper presented the process of dam safety review using non-destructive methods for reinforced concrete structures. Two reinforced concrete dams built in the 1900's, the Eustic dam on the Coaticook River and the Frontenac dam on the Magog River near Sherbrooke, were evaluated by S.M. International using non-destructive methods such as sonic and ground penetrating radar methods. The studies allowed mapping of concrete damage and provided geometric information on some non visible structure elements that were part of previous reinforcement operations.

  5. Nonstructural damages of reinforced concrete buildings due to 2015 Ranau earthquake

    Science.gov (United States)

    Adiyanto, Mohd Irwan; Majid, Taksiah A.; Nazri, Fadzli Mohamed

    2017-07-01

    On 15th June 2016 a moderate earthquake with magnitude Mw5.9 was occurred in Sabah, Malaysia. Specifically, the epicentre was located at 16 km northwest of Ranau. Less than two days after the first event, a reconnaissance mission took action to investigate the damages on buildings. Since the reinforced concrete buildings in Ranau were designed based on gravity and wind load only, a lot of minor to severe damages was occurred. This paper presents the damages on the nonstructural elements of reinforced concrete buildings due to Ranau earthquake. The assessment was conducted via in-situ field investigation covering the visual observation, taking photo, and interview with local resident. Based on in-situ field investigation, there was a lot of damages occurred on the nonstructural elements like the brick walls. Such damages cannot be neglected since it can cause injury and fatality to the victims. Therefore, it can be concluded that the installation of nonstructural elements should be reviewed for the sake of safety.

  6. Corrosion detection in steel-reinforced concrete using a spectroscopic technique

    Science.gov (United States)

    Garboczi, E. J.; Stutzman, P. E.; Wang, S.; Martys, N. S.; Hassan, A. M.; Duthinh, D.; Provenzano, V.; Chou, S. G.; Plusquellic, D. F.; Surek, J. T.; Kim, S.; McMichael, R. D.; Stiles, M. D.

    2014-02-01

    Detecting the early corrosion of steel that is embedded in reinforced concrete (rebar) is a goal that would greatly facilitate the inspection and measurement of corrosion in the US physical infrastructure. Since 2010, the National Institute of Standards and Technology (NIST) has been working on a large project to develop an electromagnetic (EM) probe that detects the specific corrosion products via spectroscopic means. Several principal iron corrosion products, such as hematite and goethite, are antiferromagnetic at field temperatures. At a given applied EM frequency, which depends on temperature, these compounds undergo a unique absorption resonance that identifies the presence of these particular iron corrosion products. The frequency of the resonances tends to be on the order of 100 GHz or higher, so transmitting EM waves through the cover concrete and back out again at a detectable level has been challenging. NIST has successfully detected these two iron corrosion products, and is developing equipment and methodologies that will be capable of penetrating the typical 50 mm of cover concrete in the field. The novel part of this project is the detection of specific compounds, rather than only geometrical changes in rebar cross-section. This method has the potential of providing an early-corrosion probe for steel in reinforced concrete, and for other applications where steel is covered by various layers and coatings.

  7. Computer-Aided Construction at Designing Reinforced Concrete Columns as Per Ec

    Directory of Open Access Journals (Sweden)

    Zielińska M.

    2015-02-01

    Full Text Available The article presents the authors’ computer program for designing and dimensioning columns in reinforced concrete structures taking into account phenomena affecting their behaviour and information referring to design as per EC. The computer program was developed with the use of C++ programming language. The program guides the user through particular dimensioning stages: from introducing basic data such as dimensions, concrete class, reinforcing steel class and forces affecting the column, through calculating the creep coefficient taking into account the impact of imperfection depending on the support scheme and also the number of mating members at load shit, buckling length, to generating the interaction curve graph. The final result of calculations provides two dependence points calculated as per methods of nominal stiffness and nominal curvature. The location of those points relative to the limit curve determines whether the column load capacity is assured or has been exceeded. The content of the study describes in detail the operation of the computer program and the methodology and phenomena which are indispensable at designing axially and eccentrically the compressed members of reinforced concrete structures as per the European standards.

  8. Positioning of steel rods inclusions in reinforced concrete simulant by Compton backscattering

    Energy Technology Data Exchange (ETDEWEB)

    Boldo, Emerson M.; Prestes, Ana A.P.; Appoloni, Carlos R. [Universidade Estadual de Londrina (UEL), PR (Brazil). Dept. de Fisica. Lab. de Fisica Nuclear Aplicada

    2011-07-01

    Reinforced concrete is susceptible to a range of environmental degradation factors that can limit its service life. There has always been a need for test methods to measure, in situ, the properties of concrete for quality assurance and to evaluate the condition of existing structures. Compton scattering of gamma radiation is a nondestructive technique used for the detection of defects and inclusions in materials and it can be employed on reinforced concrete. The methodology allows for one-side inspection of large structures and can be implemented with a relatively inexpensive, portable apparatus. In this work, we used the Compton backscattering technique to measure both the size and depth of steel rod inclusions in plaster block samples. The samples were irradiated with gamma rays from a {phi}2 mm collimated {sup 241}Am (100 mCi) source, and the inelastically scattered photons were collected at an angle of 135 deg by a high-resolution CdTe semiconductor detector. Scanning was achieved by lateral movement of the sample blocks across the field of view of the source and detector in steps of 1 mm. The tests on plaster blocks with steel rod inclusions suggest that, for a low-energy and low-activity gamma source, beam attenuation has greater effects on the scattered intensity than does increased material density. Density contrast analysis allows determination of the size and depth of steel rods. Furthermore, the experimental results agree with theoretical data obtained through Monte Carlo simulation. (author)

  9. The Vibration Based Fatigue Damage Assessment of Steel and Steel Fiber Reinforced Concrete (SFRC Composite Girder

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    Xu Chen

    2015-01-01

    Full Text Available The steel-concrete composite girder has been usually applied in the bridge and building structures, mostly consisting of concrete slab, steel girder, and shear connector. The current fatigue damage assessment for the composite girder is largely based on the strain values and concrete crack features, which is time consuming and not stable. Hence the vibration-based fatigue damage assessment has been considered in this study. In detail, a steel-steel fiber reinforced concrete (SFRC composite girder was tested. The steel fiber reinforced concrete is usually considered for dealing with the concrete cracks in engineering practice. The composite girder was 3.3m long and 0.45m high. The fatigue load and impact excitation were applied on the specimen sequentially. According to the test results, the concrete crack development and global stiffness degradation during the fatigue test were relatively slow due to the favourable performance of SFRC in tension. But on the other hand, the vibration features varied significantly during the fatigue damage development. Generally, it confirmed the feasibility of executing fatigue damage assessment of composite bridge based on vibration method.

  10. Evaluation and considerations about fundamental periods of damaged reinforced concrete buildings

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    R. Ditommaso

    2013-07-01

    Full Text Available The aim of this paper is an empirical estimation of the fundamental period of reinforced concrete buildings and its variation due to structural and non-structural damage. The 2009 L'Aquila earthquake has highlighted the mismatch between experimental data and code provisions value not only for undamaged buildings but also for the damaged ones. The 6 April 2009 L'Aquila earthquake provided the first opportunity in Italy to estimate the fundamental period of reinforced concrete (RC buildings after a strong seismic sequence. A total of 68 buildings with different characteristics, such as age, height and damage level, have been investigated by performing ambient vibration measurements that provided their fundamental translational period. Four different damage levels were considered according with the definitions by EMS 98 (European Macroseismic Scale, trying to regroup the estimated fundamental periods versus building heights according to damage. The fundamental period of RC buildings estimated for low damage level is equal to the previous relationship obtained in Italy and Europe for undamaged buildings, well below code provisions. When damage levels are higher, the fundamental periods increase, but again with values much lower than those provided by codes. Finally, the authors suggest a possible update of the code formula for the simplified estimation of the fundamental period of vibration for existing RC buildings, taking into account also the inelastic behaviour.

  11. Electrochemical Meaning of Cumulative Corrosion Rate for Reinforced Concrete in a Tropical Natural Marine Environment

    Directory of Open Access Journals (Sweden)

    Pedro Castro-Borges

    2017-01-01

    Full Text Available The objective of this paper is to discuss the meaning of cumulative corrosion rate (iCCR of reinforced concrete in a tropical marine microclimate of the Yucatan Peninsula identifying four stages that correspond to passivation, beginning of depassivation, breakdown and formation of subsequent corrosion layers, and nucleation and development of cracks. Sixty Portland cement concrete cylinders were exposed in a tropical marine environment at 50 m from the seashore. One-half of the samples had a reinforcing bar embedded at the center of the sample (corrosion measurements and the other half was made with plain concrete (chloride measurements. Five water/cement (w/c ratios and three times of curing (CT were tested representing the common practices of this region. The corrosion rate was monitored using the linear polarization resistance technique (Rp which enables calculating the apparent and cumulative corrosion rate. Representative results indicated that iCCR was effective not only to detect the beginning and duration of the reported stages but also to find the right influence of CT and w/c ratios on the corrosion performance of reinforced concrete.

  12. Experimental Investigation on Durability of Reinforced Concrete Beams in A Simulated Marine Environment

    Institute of Scientific and Technical Information of China (English)

    HE Shi-qin; GONG Jin-xin; ZHAO Guo-fan

    2005-01-01

    This paper presents some results from a comprehensive experimental program designed to determine the interaction between mechanical loading and corrosion of reinforcing steel, as well as their combined effect on serviceability and residual load- bearing capacity of reinforced concrete beams. Beam specimens with the size of 120mm×200mm×1700mm were subjected to four-point bending at various sustained loading levels (0%, 25%, 45%, and 65% of the ultimate load) during the corrosion test process. The marine tidal zone was simulated by alternating spraying and draining of 3.5% NaCl solution. An external direct current technique was used to accelerate the corrosion of the reinforcement. Residual flexural load-bearing capacity of the beams was evaluated at the end of the experiment. The results indicate that the loading has a significant effect on corrosion. Under simultaneous loading and accelerated corrosion conditions, the time-dependent deflection of the beams increases with the progressive corrosion of the reinforcement. The beams under high-level loading deteriorate more rapidly than those under low-level loading and without loading. As a result, the residual flexural capacity of the beams subjected to higher level loading was much lower than that of the beams subjected to lower level loading and in the absence of loading. The results suggest that, for a rational service-life prediction of reinforced concrete structures, the influence of the service load on the structural performance should be considered in combination with environmental conditions

  13. Strengthening of reinforced concrete circular columns using glass fibre reinforced polymers

    Directory of Open Access Journals (Sweden)

    Manish kumar Tiwari

    2014-04-01

    Full Text Available Seismic retrofitting of reinforced concrete members vulnerable to strong earthquakes is a great problem. It has long been recognized that confinement to concrete compression members not only increase the strength but improve ductility significantly. The present study focuses on the behavior of reinforced concrete specimens strengthened using glass fiber reinforced polymer (GFRP subjected to axial compressive loading. In this study specimen of circular cross section having length to diameter ratio of 2.0 and 0.96% longitudinal reinforcement were prepared and tested for 28 days compressive strength. The specimens were wrapped with 0,2,4,6 and 8 layers of GFRP outside the surface of the specimens as confinement. The test results showed that there is a significant increase in the strength of specimen with the increase of confinement layers on the specimen. The 28 days compressive strength of specimen wrapped with 8 layers of GRRP was increased by 47% as compared to the strength of specimen without any confinement.

  14. Probabilistic failure modelling of reinforced concrete structures subjected to chloride penetration

    Science.gov (United States)

    Nogueira, Caio Gorla; Leonel, Edson Denner; Coda, Humberto Breves

    2012-12-01

    Structural durability is an important criterion that must be evaluated for every type of structure. Concerning reinforced concrete members, chloride diffusion process is widely used to evaluate durability, especially when these structures are constructed in aggressive atmospheres. The chloride ingress triggers the corrosion of reinforcements; therefore, by modelling this phenomenon, the corrosion process can be better evaluated as well as the structural durability. The corrosion begins when a threshold level of chloride concentration is reached at the steel bars of reinforcements. Despite the robustness of several models proposed in literature, deterministic approaches fail to predict accurately the corrosion time initiation due the inherent randomness observed in this process. In this regard, structural durability can be more realistically represented using probabilistic approaches. This paper addresses the analyses of probabilistic corrosion time initiation in reinforced concrete structures exposed to chloride penetration. The chloride penetration is modelled using the Fick's diffusion law. This law simulates the chloride diffusion process considering time-dependent effects. The probability of failure is calculated using Monte Carlo simulation and the first order reliability method, with a direct coupling approach. Some examples are considered in order to study these phenomena. Moreover, a simplified method is proposed to determine optimal values for concrete cover.

  15. Model Experiment on Integral Seismic Behavior of Reinforced Concrete Frame with Split Columns

    Institute of Scientific and Technical Information of China (English)

    LI Zhongxian; JING Meng; HAO Yongchang; KANG Guyi

    2005-01-01

    Based on a series of previous studies, an experiment on the integral seismic behavior of a 1/3 scaled model of two-bay and three-story reinforced concrete frame with split columns at lower two stories is performed under cyclic loading. The original columns at lower two stories of the model frame are short columns and they are replaced by the split columns. The hysteresis curves between the horizontal cyclic load and the lateral displacement at the top of the model frame, indicate that under the cyclic loading, the model frame undergoes the process of cracking, yielding, and maximum loading before being destroyed at the ultimate load. They also indicate that the model frame has better ductility, and the ratio of the ultimate displacement to the yielding displacement, reaches 6.0. The yielding process of the model frame shows that for the frame with split columns, plastic hinges are generated at the ends of beams and then the columns begin yielding while the frame still possesses the bearing and deformation capacity. The design idea of directly changing the short column to long one in the reinforced concrete frame may be realized by replacing the short column with the split one.

  16. Corrosion behaviour of reinforced concrete: Laboratory experiments and archaeological analogues for long-term predictive modelling

    Energy Technology Data Exchange (ETDEWEB)

    L' Hostis, V. [CEA, DEN, DPC, SCCME, Laboratoire d' Etude du Comportement des Betons et des Argiles, F-91191 Gif-sur-Yvette (France)], E-mail: valerie.lhostis@cea.fr; Foct, F. [EDF R and D/MMC, Site des Renardieres, 77818 Moret-sur-Loing cedex (France); Dillmann, P. [CEA/CNRS Laboratoire Pierre Suee, 91191 Gif-sur-Yvette cedex (France); CNRS IRAMAT, UMR 5060 (France)

    2008-09-30

    In the context of the nuclear waste storage, reinforced concrete will be used for various purposes such as cell structures and some types of containers (e.g. for intermediate level wastes). These structures are required to be safe and reliable in varying environments for long periods of time (up to several hundred years). This paper presents a specific approach that is developed in France at CEA and EDF for the prediction of long-term behaviour of such structures. It discusses the experimental and theoretical approaches which have been developed. It is based on interactive studies dedicated to short term experimentations (corrosion and mechanical behaviour of structures), characterization and specific tests on archaeological analogues, both used to develop mechanistic understanding and modelling of corrosion and mechanical behaviour of reinforced concrete. Advantages and limits of these different and complementary aspects are presented and discussed. Moreover the prediction results of a specific mechanistic model have been confronted to real structures exposed to atmospheric conditions for many years.

  17. Compressive Behavior of Fiber-Reinforced Concrete with End-Hooked Steel Fibers.

    Science.gov (United States)

    Lee, Seong-Cheol; Oh, Joung-Hwan; Cho, Jae-Yeol

    2015-03-27

    In this paper, the compressive behavior of fiber-reinforced concrete with end-hooked steel fibers has been investigated through a uniaxial compression test in which the variables were concrete compressive strength, fiber volumetric ratio, and fiber aspect ratio (length to diameter). In order to minimize the effect of specimen size on fiber distribution, 48 cylinder specimens 150 mm in diameter and 300 mm in height were prepared and then subjected to uniaxial compression. From the test results, it was shown that steel fiber-reinforced concrete (SFRC) specimens exhibited ductile behavior after reaching their compressive strength. It was also shown that the strain at the compressive strength generally increased along with an increase in the fiber volumetric ratio and fiber aspect ratio, while the elastic modulus decreased. With consideration for the effect of steel fibers, a model for the stress-strain relationship of SFRC under compression is proposed here. Simple formulae to predict the strain at the compressive strength and the elastic modulus of SFRC were developed as well. The proposed model and formulae will be useful for realistic predictions of the structural behavior of SFRC members or structures.

  18. Preparation and characterization of glass fibers – polymers (epoxy bars (GFRP reinforced concrete for structural applications

    Directory of Open Access Journals (Sweden)

    Alkjk Saeed

    2016-06-01

    Full Text Available The paper presents some of the results from a large experimental program undertaken at the Department of Civil Engineering of Damascus University. The project aims to study the ability to reinforce and strengthen the concrete by bars from Epoxy polymer reinforced with glass fibers (GFRP and compared with reinforce concrete by steel bars in terms of mechanical properties. Five diameters of GFRP bars, and steel bars (4mm, 6mm, 8mm, 10mm, 12mm tested on tensile strength tests. The test shown that GFRP bars need tensile strength more than steel bars. The concrete beams measuring (15cm wide × 15cm deep × and 70cm long reinforced by GFRP with 0.5 vol.% ratio, then the concrete beams reinforced by steel with 0.89 vol.% ratio. The concrete beams tested on deflection test. The test shown that beams which reinforced by GFRP has higher deflection resistance, than beams which reinforced by steel. Which give more advantage to reinforced concrete by GFRP.

  19. The behaviour of reinforced concrete structure due to earthquake load using Time History analysis Method

    Science.gov (United States)

    Afifuddin, M.; Panjaitan, M. A. R.; Ayuna, D.

    2017-02-01

    Earthquakes are one of the most dangerous, destructive and unpredictable natural hazards, which can leave everything up to a few hundred kilometres in complete destruction in seconds. Indonesia has a unique position as an earthquake prone country. It is the place of the interaction for three tectonic plates, namely the Indo-Australian, Eurasian and Pacific plates. Banda Aceh is one of the cities that located in earthquake-prone areas. Due to the vulnerable conditions of Banda Aceh some efforts have been exerted to reduce these unfavourable conditions. Many aspects have been addressed, starting from community awareness up to engineering solutions. One of them is all buildings that build in the city should be designed as an earthquake resistant building. The objectives of this research are to observe the response of a reinforced concrete structure due to several types of earthquake load, and to see the performance of the structure after earthquake loads applied. After Tsunami in 2004 many building has been build, one of them is a hotel building located at simpang lima. The hotel is made of reinforced concrete with a height of 34.95 meters with a total area of 8872.5 m2 building. So far this building was the tallest building in Banda Aceh.

  20. Earthquake Response of Reinforced Concrete Building Retrofitted with Geopolymer Concrete and X-shaped Metallic Damper

    Science.gov (United States)

    Madheswaran, C. K.; Prakash vel, J.; Sathishkumar, K.; Rao, G. V. Rama

    2017-06-01

    A three-storey half scale reinforced concrete (RC) building is fixed with X-shaped metallic damper at the ground floor level, is designed and fabricated to study its seismic response characteristics. Experimental studies are carried out using the (4 m × 4 m) tri-axial shake-table facility to evaluate the seismic response of a retrofitted RC building with open ground storey (OGS) structure using yielding type X-shaped metallic dampers (also called as Added Damping and Stiffness-ADAS elements) and repairing the damaged ground storey columns using geopolymer concrete composites. This elasto-plastic device is normally incorporated within the frame structure between adjacent floors through chevron bracing, so that they efficiently enhance the overall energy dissipation ability of the seismically deficient frame structure under earthquake loading. Free vibration tests on RC building without and with yielding type X-shaped metallic damper is carried out. The natural frequencies and mode shapes of RC building without and with yielding type X-shaped metallic damper are determined. The retrofitted reinforced concrete building is subjected to earthquake excitations and the response from the structure is recorded. This work discusses the preparation of test specimen, experimental set-up, instrumentation, method of testing of RC building and the response of the structure. The metallic damper reduces the time period of the structure and displacement demands on the OGS columns of the structure. Nonlinear time history analysis is performed using structural analysis package, SAP2000.

  1. A Wireless Passive Sensing System for Displacement/Strain Measurement in Reinforced Concrete Members.

    Science.gov (United States)

    Ozbey, Burak; Erturk, Vakur B; Demir, Hilmi Volkan; Altintas, Ayhan; Kurc, Ozgur

    2016-04-08

    In this study, we show a wireless passive sensing system embedded in a reinforced concrete member successfully being employed for the measurement of relative displacement and strain in a simply supported beam experiment. The system utilizes electromagnetic coupling between the transceiver antenna located outside the beam, and the sensing probes placed on the reinforcing bar (rebar) surface inside the beam. The probes were designed in the form of a nested split-ring resonator, a metamaterial-based structure chosen for its compact size and high sensitivity/resolution, which is at µm/microstrains level. Experiments were performed in both the elastic and plastic deformation cases of steel rebars, and the sensing system was demonstrated to acquire telemetric data in both cases. The wireless measurement results from multiple probes are compared with the data obtained from the strain gages, and an excellent agreement is observed. A discrete time measurement where the system records data at different force levels is also shown. Practical issues regarding the placement of the sensors and accurate recording of data are discussed. The proposed sensing technology is demonstrated to be a good candidate for wireless structural health monitoring (SHM) of reinforced concrete members by its high sensitivity and wide dynamic range.

  2. Application of the wave finite element method to reinforced concrete structures with damage

    Science.gov (United States)

    El Masri, Evelyne; Ferguson, Neil; Waters, Timothy

    2016-09-01

    Vibration based methods are commonly deployed to detect structural damage using sensors placed remotely from potential damage sites. Whilst many such techniques are modal based there are advantages to adopting a wave approach, in which case it is essential to characterise wave propagation in the structure. The Wave Finite Element method (WFE) is an efficient approach to predicting the response of a composite waveguide using a conventional FE model of a just a short segment. The method has previously been applied to different structures such as laminated plates, thinwalled structures and fluid-filled pipes. In this paper, the WFE method is applied to a steel reinforced concrete beam. Dispersion curves and wave mode shapes are first presented from free wave solutions, and these are found to be insensitive to loss of thickness in a single reinforcing bar. A reinforced beam with localised damage is then considered by coupling an FE model of a short damaged segment into the WFE model of the undamaged beam. The fundamental bending, torsion and axial waves are unaffected by the damage but some higher order waves of the cross section are significantly reflected close to their cut-on frequencies. The potential of this approach for detecting corrosion and delamination in reinforced concrete beams will be investigated in future work.

  3. GEOMETRIC AND MATERIAL NONLINEAR ANALYSIS OF REINFORCED CONCRETE SLABS AT FIRE ENVIRONMENT

    Directory of Open Access Journals (Sweden)

    Ayad A. Abdul -Razzak

    2013-05-01

    Full Text Available In the present study a nonlinear finite element analysis is presented  to predict the fire resistance of reinforced concrete slabs at fire environment. An eight node layered degenerated shell element utilizing Mindlin/Reissner thick plate theory is employed. The proposed model considered cracking, crushing and yielding of concrete and steel at elevated temperatures. The layered approach is used to represent the steel reinforcement and discretize the concrete slab through the thickness. The reinforcement steel is represented as a smeared layer of equivalent thickness with uniaxial strength and rigidity properties.Geometric nonlinear analysis may play an important role in the behavior of reinforced concrete slabs at high temperature. Geometrical nonlinearity in the layered approach is considered in the mathematical model, which is based on the total Lagrangian approach taking into account Von Karman assumptions.Finally two examples for which experimental results are available are analyzed, using the proposed model .The comparison showed good agreement with experimental results. 

  4. Numerical Determination of Shear Strength of Steel Reinforced Concrete Column Strengthened by CFRP Sheets

    Institute of Scientific and Technical Information of China (English)

    王铁成; 余流; 王立军

    2003-01-01

    The earthquake-resistant property of reinforced concrete members depends on the interaction between reinforcing bars and surrounding concrete through bond to a large degree. In this paper a general system aimed at dealing with the failure analysis of reinforced concrete columns strengthened with carbon-fiber-reinforced plastic (CFRP) sheets including bond-slip of the anchored reinforcing bars at the foot of the columns is presented. It is based on the yield design theory with a mixed modeling of the structure, according to which the concrete material is treated as a classical two-dimensional continuum, whereas the longitudinal reinforcing bars are regarded as one-dimensional rods including bond-slip at the foot of the columns. In shear reinforced zones both the shear CFRP sheets and transverse reinforcing bars are incorporated in the analysis through a homogenization procedure and they are only in tension. The approach is then implemented numerically by means of the finite-element formulation. The numerical procedure produces accurate estimates for the loading-carrying capacity of the shear members taken as an illustrative application by correlation with the experimental results, so the proposed approach is valid.

  5. Behavior of one-way reinforced concrete slabs subjected to fire

    Directory of Open Access Journals (Sweden)

    Said M. Allam

    2013-12-01

    Full Text Available A finite difference analysis was performed to investigate the behavior of one-way reinforced concrete slabs exposed to fire. The objective of the study was to investigate the fire resistance and the fire risk after extinguishing the fire. Firstly, the fire resistance was obtained using the ISO834 standard fire without cooling phase. Secondly, the ISO834 parametric fire with cooling phase was applied to study the effect of cooling time. Accordingly, the critical time for cooling was identified and the corresponding failure time was calculated. Moreover, the maximum risk time which is the time between the fire extinguishing and the collapse of slab was obtained. Sixteen one-way reinforced concrete slabs were considered to study the effect of important parameters namely: the concrete cover thickness; the plaster; and the live load ratio. Equations for heat transfer through the slab thickness were used in the fire resistance calculations. Studying the cooling time revealed that the slabs are still prone to collapse although they were cooled before their fire resistance. Moreover, increasing the concrete cover thickness and the presence of plaster led to an increase in the maximum risk time. However, the variation in the live load ratio has almost no effect on such time.

  6. Dual purpose wheat production with different levels of nitrogen topdressing

    Directory of Open Access Journals (Sweden)

    Éderson Luis Henz

    2016-04-01

    Full Text Available Currently, the practice of Crop-Livestock Integration is stimulated as a way of increasing the generation of foreign exchange for Brazil. Integrated systems improve land use efficiency as well as preserve, recover and increment or soil fertility. The aim of this research was to evaluate how different doses of nitrogen fertilization can affect production and quality of dual purpose wheat submitted to grazing. The experimental designed was randomized block with five treatments (0, 75, 150, 225 and 300 Kg N ha-1, like ammonium nitrate and four repetitions. The forage yield, the percentage crude protein (P=.0001 and acid detergent insoluble protein (P=.0054 had a linear increased because of the nitrogen addition doses. The crude protein percentage changed the estimate of all soluble carbohydrates (P=.0001 and non-fibrous carbohydrates (P=.0186, but did not influence the, nitrogen detergent fiber corrected with ash and proteins percentage contributing for content cell. The crops production (P=.0001 and the number of kernels per ear (P=.0001 showed significantly difference because of the nitrogen additions dose, increasing the number of fertile flowers. The nitrogen topdressing alters forage production, the chemical composition and the production of dual purpose wheat grains subjected to grazing.

  7. Quantitative estimation of carbonation and chloride penetration in reinforced concrete by laser-induced breakdown spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Eto, Shuzo, E-mail: eto@criepi.denken.or.jp [Central Research Institute of Electric Power Industry, 2-6-1 Nagasaka, Yokosuka, Kanagawa 240-0196 (Japan); Matsuo, Toyofumi; Matsumura, Takuro; Fujii, Takashi [Central Research Institute of Electric Power Industry, 2-6-1 Nagasaka, Yokosuka, Kanagawa 240-0196 (Japan); Tanaka, Masayoshi Y. [Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, 2-6-1 Nagasaka, Yokosuka, Kanagawa 240-0196 (Japan)

    2014-11-01

    The penetration profile of chlorine in a reinforced concrete (RC) specimen was determined by laser-induced breakdown spectroscopy (LIBS). The concrete core was prepared from RC beams with cracking damage induced by bending load and salt water spraying. LIBS was performed using a specimen that was obtained by splitting the concrete core, and the line scan of laser pulses gave the two-dimensional emission intensity profiles of 100 × 80 mm{sup 2} within one hour. The two-dimensional profile of the emission intensity suggests that the presence of the crack had less effect on the emission intensity when the measurement interval was larger than the crack width. The chlorine emission spectrum was measured without using the buffer gas, which is usually used for chlorine measurement, by collinear double-pulse LIBS. The apparent diffusion coefficient, which is one of the most important parameters for chloride penetration in concrete, was estimated using the depth profile of chlorine emission intensity and Fick's law. The carbonation depth was estimated on the basis of the relationship between carbon and calcium emission intensities. When the carbon emission intensity was statistically higher than the calcium emission intensity at the measurement point, we determined that the point was carbonated. The estimation results were consistent with the spraying test results using phenolphthalein solution. These results suggest that the quantitative estimation by LIBS of carbonation depth and chloride penetration can be performed simultaneously. - Highlights: • We estimated the carbonation depth and the apparent diffusion coefficient of chlorine sodium in the reinforced concrete with cracking damage by LIBS. • Two-dimensional profile measurement of the emission intensity in each element was performed to visualize the chloride penetration and the carbonation in the reinforced concrete. • Apparent diffusion coefficient of chlorine and sodium can be estimated using the Fick

  8. Modification of strut effectiveness factor for reinforced concrete deep beams strengthened with CFRP laminates

    Directory of Open Access Journals (Sweden)

    Panjehpour, M.

    2014-05-01

    Full Text Available This paper proposes a method to modify the strut effectiveness factor in the strut-and-tie model for CFRP-strengthened reinforced concrete deep beams. Two groups of deep beams comprising six ordinary reinforced concrete deep beams and six CFRP-strengthened reinforced concrete deep beams were experimentally tested under the four-point bending configuration. The shear span-to-effective depth ratio of the beams in each group was 0.75, 1.00, 1.25, 1.50, 1.75, and 2.00. The theoretical principal tensile strain in CFRP-strengthened struts was modified based on a proposed empirical relationship, based on two ratios: the experimental to the theoretical value of principal tensile strain and the shear span-to-effective depth of deep beams.En este trabajo se propone un método en el que se modifica el factor de eficacia que se aplica a las bielas en el modelo de bielas y tirantes para vigas de canto de hormigón reforzadas con laminados CFRP (polímero reforzado con fibras de carbono. Mediante el ensayo a cuatro puntos se determina la resistencia a flexotracción de doce vigas de canto divididas en dos grupos de seis, las del primer grupo de hormigón armado normal y las del segundo de hormigón reforzado con laminados de CFRP. En ambos grupos cada una de las seis vigas se caracteriza por una relación luz de cortante-canto útil distinta, con valores utilizados de: 0.75, 1.00, 1.25, 1.50, 1.75, y 2.00. El valor teórico de la deformación principal por tracción de la biela reforzada con CFRP se modifica de acuerdo con la relación empírica propuesta en este trabajo. Esta se establece a partir de otras dos: la relación entre los valores experimental y teórico de la deformación por tracción principal y la relación luz de cortante-canto útil de las vigas de canto.

  9. Fundamental period of Italian reinforced concrete buildings: comparison between numerical, experimental and Italian code simplified values

    Science.gov (United States)

    Ditommaso, Rocco; Carlo Ponzo, Felice; Auletta, Gianluca; Iacovino, Chiara; Nigro, Antonella

    2015-04-01

    Aim of this study is a comparison among the fundamental period of reinforced concrete buildings evaluated using the simplified approach proposed by the Italian Seismic code (NTC 2008), numerical models and real values retrieved from an experimental campaign performed on several buildings located in Basilicata region (Italy). With the intention of proposing simplified relationships to evaluate the fundamental period of reinforced concrete buildings, scientists and engineers performed several numerical and experimental campaigns, on different structures all around the world, to calibrate different kind of formulas. Most of formulas retrieved from both numerical and experimental analyses provides vibration periods smaller than those suggested by the Italian seismic code. However, it is well known that the fundamental period of a structure play a key role in the correct evaluation of the spectral acceleration for seismic static analyses. Generally, simplified approaches impose the use of safety factors greater than those related to in depth nonlinear analyses with the aim to cover possible unexpected uncertainties. Using the simplified formula proposed by the Italian seismic code the fundamental period is quite higher than fundamental periods experimentally evaluated on real structures, with the consequence that the spectral acceleration adopted in the seismic static analysis may be significantly different than real spectral acceleration. This approach could produces a decreasing in safety factors obtained using linear and nonlinear seismic static analyses. Finally, the authors suggest a possible update of the Italian seismic code formula for the simplified estimation of the fundamental period of vibration of existing RC buildings, taking into account both elastic and inelastic structural behaviour and the interaction between structural and non-structural elements. Acknowledgements This study was partially funded by the Italian Civil Protection Department within the

  10. Effect of steel reinforcement with different degree of corrosion on degeneration of mechanical performance of reinforced concrete frame joints

    Directory of Open Access Journals (Sweden)

    Wu Xu

    2016-02-01

    Full Text Available Beam-column joints which shoulders high-level and vertical shearing effect that maintains balance of beam and column end is the major component influencing the performance of the whole framework. Post earthquake investigation suggests that collapse of frame structure is induced by failure of joints in most cases. Thus, beam-column joints must have strong bearing capacity and good ductility, and reinforced concrete structure just meets the above requirement. But corrosion caused by long time use of reinforced concrete framework will lead to degeneration of mechanical performance of joints. To find out the rule of effect of steel reinforcement with different corrosion rate on degeneration of bearing capacity of reinforced concrete framework joints, this study made a nonlinear numerical analysis on fifteen models without stirrup in the core area of reinforced concrete frame joints using displacement method considering axial load ratio of column end and constraint condition. This work aims to find out the key factor that influences mechanical performance of joints, thus to provide a basis for repair and reinforcement of degenerated framework joints.

  11. Influence of Freeze-Thaw Damage on the Steel Corrosion and Bond-Slip Behavior in the Reinforced Concrete

    Directory of Open Access Journals (Sweden)

    Fangzhi Zhu

    2016-01-01

    Full Text Available This paper mainly studies the behavior of steel corrosion in various reinforced concrete under freeze-thaw environment. The influence of thickness of concrete cover is also discussed. Additionally, the bond-slip behavior of the reinforced concrete after suffering the freeze-thaw damage and steel corrosion has also be presented. The results show that the freeze-thaw damage aggravates the steel corrosion in concrete, and the results become more obvious in the concrete after suffering serious freeze-thaw damage. Compared with the ordinary concrete, both air entrained concrete and waterproofing concrete possess better resistance to steel corrosion under the same freeze-thaw environment. Moreover, increasing the thicknesses of concrete cover is also an effective method of improving the resistance to steel corrosion. The bond-slip behavior of reinforced concrete with corroded steel decreases with the increase of freeze-thaw damage, especially for the concrete that suffered high freeze-thaw cycles. Moreover, there exists a good correlation between the parameters of bond-slip and freeze-thaw cycles. The steel corrosion and bond-slip behavior of reinforced concrete should be considered serious under freeze-thaw cycles environment, which significantly impact the durability and safety of concrete structure.

  12. Hybrid Effect Evaluation of Steel Fiber and Carbon Fiber on the Performance of the Fiber Reinforced Concrete

    Directory of Open Access Journals (Sweden)

    Weimin Song

    2016-08-01

    Full Text Available Fiber reinforcement is an important method to enhance the performance of concrete. In this study, the compressive test and impact test were conducted, and then the hybrid effect between steel fiber (SF and carbon fiber (CF was evaluated by employing the hybrid effect index. Compressive toughness and impact toughness of steel fiber reinforced concrete (SFRC, carbon fiber reinforced concrete (CFRC and hybrid fiber reinforced concrete (HFRC were explored at steel fiber volume fraction 0.5%, 1%, 1.5% and carbon fiber 0.1%, 0.2%, 0.3%. Results showed that the addition of steel fiber and carbon fiber can increase the compressive strength. SF, CF and the hybridization between them could increase the compressive toughness significantly. The impact test results showed that as the volume of fiber increased, the impact number of the first visible crack and the ultimate failure also increased. The improvement of toughness mainly lay in improving the crack resistance after the first crack. Based on the test results, the positive hybrid effect of steel fiber and carbon fiber existed in hybrid fiber reinforced concrete. The relationship between the compressive toughness and impact toughness was also explored.

  13. Nonlinear Analysis of the Failure of Nuclear Hermetic Reinforced Concrete Structure Due To Extreme Pressure and Temperature

    Directory of Open Access Journals (Sweden)

    Králik Juraj

    2016-12-01

    Full Text Available This paper describes the nonlinear analysis of the reinforced concrete hermetic containment under an accidental temperature. The scenario of the hard accident in NPP and the methodology of the calculation of the failure temperature using the safety assessment are presented. The experimental and project material properties are taken into account in the safety assessment.

  14. Labour-based construction, testing and monitoring of proof-of-concept ultrathin continuously reinforced concrete pavement technology demonstrators

    CSIR Research Space (South Africa)

    Dlamini, N

    2011-09-01

    Full Text Available presentation to the RRA board of directors that outlined the advantages of Ultrathin Continuously Reinforced Concrete Pavements (UTCRCP). From this presentation the board initiated a meeting between the members of the RRA namely SIRDC, CSIR and BOTEC. Aurecon...

  15. Performance of Reinforced Concrete Beam with Differently Positioned Replacement Zones of Block Infill under Low Impact Loads

    Directory of Open Access Journals (Sweden)

    Mokhatar Shahrul Niza

    2017-01-01

    Full Text Available This paper reveals a study performed on reinforced concrete with artificial aggregate concrete block infill composite beams to innovate a lightweight reinforced concrete utilizing polyethylene (PE waste materials, such as waste plastic bags. Six beam specimens of normal reinforced concrete (NRC and different block infill replacement zone positions RCAI (RZ1 beams containing 100% MAPEA with 50, 95, and 1,000 mm width, height, and length, respectively, were provided for the block infill, whereas RCAI (RZ2 with different block infill positions containing a 100% MAPEA with 50, 115, and 1000 mm width, height, and length were provided and tested under low impact load. The steel impactor with blunt nose dropped at 0.6 m height which equivalent to 3.5 m/s. The behaviors of the beams were studied relative to the impact force-time and displacement-time histories, the flexural/ bending cracks, and the impact failure. Results show that the overall failure modes of all the beam specimens were successfully recorded. In addition, the residual displacements of the RZ2 was almost same than those of the RZ1 and the significantly lower than those of the NRC. In the reinforced concrete beams, less stressed concrete near the neutral axis can be replaced by certain light weight material like waste plastic bags as modified artificial polyethylene aggregates to serve as an artificial aggregate.

  16. The influence of cracks on chloride-induced corrosion of reinforced concrete structures - development of the experimental set-up

    NARCIS (Netherlands)

    Blagojevic, A.; Koleva, D.A.; Walraven, J.C.

    2014-01-01

    Chloride-induced corrosion of steel reinforcement is one of the major threats to durability of reinforced concrete structures in aggressive environmental conditions. When the steel reinforcement starts to corrode, structures gradually lose integrity and service life is shortened. Cracks are inevitab

  17. Degradation processes of reinforced concretes by combined sulfate–phosphate attack

    Energy Technology Data Exchange (ETDEWEB)

    Secco, Michele, E-mail: michele.secco@unipd.it [Inter-Departmental Research Center for the Study of Cement Materials and Hydraulic Binders (CIRCe), University of Padova, Via Gradenigo 6, 35131 Padova (Italy); Department of Civil, Environmental and Architectural Engineering (ICEA), University of Padova, Via Marzolo 9, 35131 Padova (Italy); Lampronti, Giulio Isacco, E-mail: gil21@cam.ac.uk [Department of Earth Sciences, University of Cambridge, Downing Street, CB2 3EQ Cambridge (United Kingdom); Schlegel, Moritz-Caspar, E-mail: moritz-caspar.schlegel@helmholtz-berlin.de [BAM Federal Institute for Materials Research and Testing, Unter den Eichen 87, 12205 Berlin (Germany); Helmholtz-Zentrum Berlin fürMaterialien und Energie GmbH, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Maritan, Lara, E-mail: lara.maritan@unipd.it [Department of Geosciences, University of Padova, Via Gradenigo 6, 35131 Padova (Italy); Zorzi, Federico, E-mail: federico.zorzi@unipd.it [Department of Geosciences, University of Padova, Via Gradenigo 6, 35131 Padova (Italy)

    2015-02-15

    A novel form of alteration due to the interaction between hydrated cement phases and sulfate and phosphate-based pollutants is described, through the characterization of concrete samples from an industrial reinforced concrete building. Decalcification of the cement matrices was observed, with secondary sulfate and phosphate-based mineral formation, according to a marked mineralogical and textural zoning. Five alteration layers may be detected: the two outermost layers are characterized by the presence of gypsum–brushite solid solution phases associated with anhydrous calcium sulfates and phosphates, respectively, while a progressive increase in apatite and ammonium magnesium phosphates is observable in the three innermost layers, associated with specific apatite precursors (brushite, octacalcium phosphate and amorphous calcium phosphate, respectively). The heterogeneous microstructural development of secondary phases is related to the chemical, pH and thermal gradients in the attacked cementitious systems, caused by different sources of pollutants and the exposure to the sun's radiation.

  18. Flexural Behaviour Of Reinforced Concrete Beams Containing Expanded Glass As Lightweight Aggregates

    Science.gov (United States)

    Khatib, Jamal; Jefimiuk, Adrian; Khatib, Sammy

    2015-12-01

    The flexural properties of reinforced concrete beams containing expanded glass as a partial fine aggregate (sand) replacement are investigated. Four concrete mixes were employed to conduct this study. The fine aggregate was replaced with 0%, 25%, 50% and 100% (by volume) expanded glass. The results suggest that the incorporation of 50% expanded glass increased the workability of the concrete. The compressive strength was decreasing linearly with the increasing amount of expanded glass. The ductility of the concrete beam significantly improved with the incorporation of the expanded glass. However, the load-carrying capacity of the beam and load at which the first crack occurs was reduced. It was concluded that the inclusion of expanded glass in structural concrete applications is feasible.

  19. Use of Electrochemical Impedance Spectroscopy (EIS to monitoring the corrosion of reinforced concrete

    Directory of Open Access Journals (Sweden)

    D.V. RIBEIRO

    Full Text Available AbstractElectrochemical techniques are among the most commonly techniques used for the evaluation and study of corrosion in reinforced concrete, including electrochemical impedance spectroscopy (EIS. Electrochemical impedance spectroscopy (EIS is a powerful technique for characterizing a wide variety of electrochemical systems and for determining the contribution of electrode or electrolytic processes in these systems. The analysis of EIS results on samples of concrete is highly complex due to overlapping arcs from simultaneous phenomena and noise measurement, of course, associated with the heterogeneity of the samples and that complicate the analysis considerably. Thus, this paper proposes a new form of analysis based on the characteristic relaxation angular frequency, w, of each phenomenon and associating the typical capacitances and frequencies.

  20. Prediction of the Service Life of a Reinforced Concrete Column under Chloride Environment

    Directory of Open Access Journals (Sweden)

    Mohammad K. Alkam

    2015-01-01

    Full Text Available In the present investigation, service life of a reinforced concrete column exposed to chloride environment has been predicted. This study has been based on numerical simulation of chloride ion diffusion in a concrete column during its anticipated life span. The simulation process has included the concrete cover replacement whenever chloride ion concentration has reached the critical threshold value at the reinforcement surface. Repair scheduling of the concrete column under consideration has been discussed. Effects of the concrete cover thickness and the water cement ratio on the service life of the concrete column at hand have been presented. A new approach for arranging locations of reinforcement steel bars has been introduced. This approach is intended to prolong the service life of the concrete column under consideration against chloride induced corrosion.

  1. Prefabricated floor panels composed of fiber reinforced concrete and a steel substructure

    DEFF Research Database (Denmark)

    Lárusson, Lárus H.; Fischer, Gregor; Jönsson, Jeppe

    2013-01-01

    loading at the serviceability and ultimate limit states. The composite construction concept offers flexibility in the assembly process, the ability to adapt to various load and boundary requirements, and efficient utilization of material properties that result in a light weight prefabricated structural......This paper reports on a study on prefabricated composite and modular floor deck panels composed of relatively thin fiber reinforced concrete slabs connected to steel substructures. The study focuses on the design, manufacturing, structural improvements and behavior of the floor systems during...... detailing of these integrally cast deck panels and to modify them by providing individually cast anchor points in the precast ECC slab, which are subsequently used to attach a steel truss substructure.Full-scale experiments were carried out to verify the structural behavior of the integrally cast panels...

  2. Experimental analysis of reinforced concrete columns strengthened with Self-Compacting concrete

    Directory of Open Access Journals (Sweden)

    M. Y. M. Omar

    Full Text Available This paper presents the results of reinforced concrete columns strengthened by addition of a self-compacting concrete overlay at the compressed and at the tensioned face of the member, with and without addition of longitudinal steel bars. Eight columns were submit- ted to loading with an initial eccentricity of 60 mm . These columns had 120 mm x 250 mm of rectangular cross section, 2000 mm in length and four longitudinal reinforcement steel bars with 10 mm in diameter. Reference columns P1 and P2 were tested to failure without any type of rehabilitation. Columns P3 to P8 were loaded to a predefined load (close to the initial yield point of tension reinforce- ment, then unloaded and strengthened for a subsequent test until failure. Results showed that the method of rehabilitation used was effective, increasing the loading capacity of the strengthened pieces by 2 to 5 times the ultimate load of the reference column.

  3. An experimentally based analytical model for the shear capacity of FRP-strengthened reinforced concrete beams

    Science.gov (United States)

    Pellegrino, C.; Modena, C.

    2008-05-01

    This paper deals with the shear strengthening of Reinforced Concrete (RC) flexural members with externally bonded Fiber-Reinforced Polymers (FRPs). The interaction between an external FRP and an internal transverse steel reinforcement is not considered in actual code recommendations, but it strongly influences the efficiency of the shear strengthening rehabilitation technique and, as a consequence, the computation of interacting contributions to the nominal shear strength of beams. This circumstance is also discussed on the basis of the results of an experimental investigation of rectangular RC beams strengthened in shear with "U-jacketed" carbon FRP sheets. Based on experimental results of the present and other investigations, a new analytical model for describing the shear capacity of RC beams strengthened according to the most common schemes (side-bonded and "U-jacketed"), taking into account the interaction between steel and FRP shear strength contributions, is proposed.

  4. Moment redistribution in continuous reinforced concrete beams strengthened with carbon-fiber-reinforced polymer laminates

    Science.gov (United States)

    Aiello, M. A.; Valente, L.; Rizzo, A.

    2007-09-01

    The results of tests on continuous steel-fiber-reinforced concrete (RC) beams, with and without an external strengthening, are presented. The internal flexural steel reinforcement was designed so that to allow steel yielding before the collapse of the beams. To prevent the shear failure, steel stirrups were used. The tests also included two nonstrengthened control beams; the other specimens were strengthened with different configurations of externally bonded carbon-fiber-reinforced polymer (CFRP) laminates. In order to prevent the premature failure from delamination of the CFRP strengthening, a wrapping was also applied. The experimental results obtained show that it is possible to achieve a sufficient degree of moment redistribution if the strengthening configuration is chosen properly, confirming the results provided by two simple numerical models.

  5. Response Simulation of a Micro Reinforced Concrete Target Under Ballistic Impact

    Science.gov (United States)

    Mohan, V.; Rajasankar, J.; Iyer, N. R.

    2014-05-01

    The response of concrete structures subjected to impact loading has received extensive attention in both civil and military applications. Research on improving the shock resistance of concrete has led to the development of cementitious composites. Micro Reinforced Concrete (MRC), a type of cementitious composite, is a concrete matrix embedded with multilayered steel wire meshes. This paper presents 3D hydrocode simulations of MRC panels subjected to impact under a ballistic range. A finite element model based on Lagrange formulation is used to represent both a 300 mm × 300 mm × 100 mm target with 30 layers of wire mesh and a 5.56 × 45 mm projectile in simulations. Penetration depth and damage patterns of the MRC mesh cement composite panel are numerically compared with those of the field experiment. The results show a relatively good agreement.

  6. Computer aided seismic and fire retrofitting analysis of existing high rise reinforced concrete buildings

    CERN Document Server

    Hussain, Raja Rizwan; Hasan, Saeed

    2016-01-01

    This book details the analysis and design of high rise buildings for gravity and seismic analysis. It provides the knowledge structural engineers need to retrofit existing structures in order to meet safety requirements and better prevent potential damage from such disasters as earthquakes and fires. Coverage includes actual case studies of existing buildings, reviews of current knowledge for damages and their mitigation, protective design technologies, and analytical and computational techniques. This monograph also provides an experimental investigation on the properties of fiber reinforced concrete that consists of natural fibres like coconut coir and also steel fibres that are used for comparison in both Normal Strength Concrete (NSC) and High Strength Concrete (HSC). In addition, the authors examine the use of various repair techniques for damaged high rise buildings. The book will help upcoming structural design engineers learn the computer aided analysis and design of real existing high rise buildings ...

  7. Corrosion resistance of steel fibre reinforced concrete – a literature review

    DEFF Research Database (Denmark)

    Marcos Meson, Victor; Michel, Alexander; Solgaard, Anders

    2016-01-01

    the existence of a critical crack width, below 0.20 mm, where corrosion of carbon-steel fibres is not critical and the structural integrity of the exposed SFRC can be ensured over the long-term. A doctoral project investigating chloride-induced corrosion of steel fibres on cracked SFRC has been initiated......Steel fibre reinforced concrete (SFRC) is increasingly being used in the construction of prefabricated segmental linings for bored tunnels, since it entails simplified production processes and higher quality standards. However, international standards and guidelines are not consistent regarding...... the consideration of steel fibres for the structural verification of SFRC elements exposed to corrosive environments, hampering the development of civil infrastructure built of SFRC. In particular, the long-term effect of exposure to chlorides is in focus and under discussion. This paper reviews the existing...

  8. Consumption of carbon fiber plates in the reinforced concrete beams strengthened with CFPs

    Institute of Scientific and Technical Information of China (English)

    BU Liangtao; SONG Li; SHI Chuxian

    2007-01-01

    Four-point bending flexural tests were conducted to one full-size reinforced concrete (RC) beam and three full-size RC beams strengthened with carbon fiber plates (CFPs).The experimental results showed that the consumption of CFP had significant effects on failure modes and the flexural capacity.An analytical procedure,based on the limit failure ode and ductility,was presented to predict the applied area of CFP.An analytical program,based on Smith-Teng model and Cheng-Teng model,was provided to calculate the bonding length of CFP.The test results are used to validate the proposed procedure.The results are also applied to the design and construction of RC beam strengthened with CFP.

  9. Response Analysis for Steel Reinforced Concrete Frame Structures under Earthquake Load

    Directory of Open Access Journals (Sweden)

    Hua Wei

    2013-07-01

    Full Text Available In order to understand the whole process of the steel reinforced concrete frame structure from elastic to elasto-plastic cracking gradually, damage until the collapse, the elasto-plastic finite element analysis theory and ETABS structural analysis software were used, then the spatial three-dimensional truss system model of frame structures was established. Based on the analysis of the elasto-plastic response for the frame structure under one-dimensional and two-dimensional earthquake load, the interbedded displacement angle-time curve and horizontal displacement-time curve were obtained. Through the analysis of the model, the sequence of appearance of plastic hinges in the frame structure under earthquake load was cleared and the weak location of the frame structure was detected.

  10. Change of Electrochemical Property of Reinforced Concrete after Electrochemical Chloride Extraction

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The half cell potential (HCP) and corrosion current of reinforced concrete specimens doped with sodium chloride were determined after electrochemical chloride extraction (ECE). The experimental results show that when ECE treatment is removed, HCP becomes more negative and corrosion current becomes larger in comparison to those before ECE treatment, then HCP shifts positively and corrosion current decreases with time. After 30 days ECE treatment, the HCP of cored specimens turn to about -100 mV due to the existence of sufficient oxygen around the exposed steel bars, but for un-cored specimens, longer time, about two months,is to be taken. The non-homogeneous HCP distribution at different layers of the same specimen after ECE treatment might induce secondary corrosion of steels.

  11. Reliability Index for Reinforced Concrete Frames using Nonlinear Pushover and Dynamic Analysis

    Directory of Open Access Journals (Sweden)

    Ahmad A. Fallah

    2009-12-01

    Full Text Available In the conventional design and analysis methods affecting parameters loads, materials' strength, etc are not set as probable variables. Safety factors in the current Codes and Standards are usually obtained on the basis of judgment and experience, which may be improper or uneconomical. In technical literature, a method based on nonlinear static analysis is suggested to set Reliability Index on strength of structural systems. In this paper, a method based on Nonlinear Dynamic analysis with rising acceleration (or Incremental Dynamic Analysis is introduced, the results of which are compared with those of the previous (Static Pushover Analysis method and two concepts namely Redundancy Strength and Redundancy Variations are proposed as an index to these impacts. The Redundancy Variation Factor and Redundancy Strength Factor indices for reinforced concrete frames with varying number of bays and stories and different ductility potentials are computed and ultimately, Reliability Index is determined using these two indices.

  12. Strengthening of non-seismically detailed reinforced concrete beam–column joints using SIFCON blocks

    Indian Academy of Sciences (India)

    I S Misir; S Kahraman

    2013-02-01

    This article aims to propose a novel seismic strengthening technique for non-seismically detailed beam–column joints of existing reinforced concrete buildings, typical of the pre-1975 construction practice in Turkey. The technique is based on mounting pre-fabricated SIFCON composite corner and plate blocks on joints with anchorage rods. For the experimental part three 2/3 scale exterior beam–column joint specimens were tested under quasi-static cyclic loading. One of them was a control specimen with non-seismic details, and the remaining two with the same design properties were strengthened with composite blocks with different thickness and anchorage details. Results showed that the control specimen showed brittle shear failure at low drift levels, whereas in the strengthened specimens, plastic hinge formation moved away from column face allowing specimens to fail in flexure. The proposed technique greatly improved lateral strength, stiffness, energy dissipation, and ductility.

  13. Evaluation of Seismic Behaviors of Partially Deteriorated Reinforced Concrete Circular Columns Retrofitted with CFRP

    Directory of Open Access Journals (Sweden)

    Dongxu Hou

    2014-01-01

    Full Text Available Deficiency of the concrete strength in some regions of reinforced concrete (RC columns in practice may weaken the seismic behaviors of columns. Its effects on RC columns should be well understood. This paper aims to investigate the influences of deteriorated segment on the seismic behaviors of partially deteriorated RC columns and attempts to recover the seismic behaviors of partially deteriorated columns with Carbon Fiber Reinforced Polymer (CFRP composites. A finite element analysis was carried out to simulate the seismic behaviors of CFRP-confined partially deteriorated RC columns. The numerical results were verified by the laboratory tests of six specimens. Based on the finite element results, the failure location of partially deteriorated columns in an earthquake was predicted, and the effectiveness of CFRP retrofitted on partially deteriorated columns was evaluated.

  14. IDENTIFICATION OF OPTIMAL PARAMETERS OF REINFORCED CONCRETE STRUCTURES WITH ACCOUNT FOR THE PROBABILITY OF FAILURE

    Directory of Open Access Journals (Sweden)

    Filimonova Ekaterina Aleksandrovna

    2012-10-01

    The author suggests splitting the aforementioned parameters into the two groups, namely, natural parameters and value-related parameters that are introduced to assess the costs of development, transportation, construction and operation of a structure, as well as the costs of its potential failure. The author proposes a new improved methodology for the identification of the above parameters that ensures optimal solutions to non-linear objective functions accompanied by non-linear restrictions that are critical to the design of reinforced concrete structures. Any structural failure may be interpreted as the bounce of a random process associated with the surplus bearing capacity into the negative domain. Monte Carlo numerical methods make it possible to assess these bounces into the unacc eptable domain.

  15. Possible Collapse Mode for Slender Reinforced Concrete Plates Subjected to Blast Load

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xin; DU Xiuli; CHEN Zhen; ZENG Fanna

    2008-01-01

    This paper discusses the collapse mode of thin reinforced concrete (RC) plates subjected to blast load.To extend the well known plastic-mode method to analyze,not only perfectplastic plates,but also RC plates,it is needed to investigate the effect of material cracking on the collapse mode because the plate might have been cracked on both upper and lower surface before the plastic-mode fully develops,creating an unexpected type of collapse mode shape.A new failure mode is proposed and verified by numerical analysis in this paper.The new mode is a result of the material cracking and has an un-negligible effect on the reaction mechanism of the RC plate to the blast load.

  16. Highly Conductive Carbon Fiber Reinforced Concrete for Icing Prevention and Curing

    Directory of Open Access Journals (Sweden)

    Oscar Galao

    2016-04-01

    Full Text Available This paper aims to study the feasibility of highly conductive carbon fiber reinforced concrete (CFRC as a self-heating material for ice formation prevention and curing in pavements. Tests were carried out in lab ambient conditions at different fixed voltages and then introduced in a freezer at −15 °C. The specimens inside the freezer were exposed to different fixed voltages when reaching +5 °C for prevention of icing and when reaching the temperature inside the freezer, i.e., −15 °C, for curing of icing. Results show that this concrete could act as a heating element in pavements with risk of ice formation, consuming a reasonable amount of energy for both anti-icing (prevention and deicing (curing, which could turn into an environmentally friendly and cost-effective deicing method.

  17. International RILEM Workshop on Creep Behaviour in Cracked Sections of Fibre Reinforced Concrete

    CERN Document Server

    Llano-Torre, Aitor; Cavalaro, Sergio

    2017-01-01

    This is the first publication ever focusing strictly on the creep behaviour in cracked sections of Fibre Reinforced Concrete (FRC). These proceedings contain the latest scientific papers about new testing methodologies, results and conclusions of multiple experimental campaigns and recommendations about significant factors of long-term behaviour, experiences from more than ten years of creep testing and some reflections about future perspectives on this topic. This book is an essential reference for all researchers of creep behaviour on FRC. This volume is the result of the efforts of the RILEM TC 261-CCF, that has been working since 2014 to develop standardized methodologies and guidelines to compare results from different laboratories and get a better understanding of the significant parameters related to creep of FRC.

  18. Influence of Characteristics on Bending Strength of Layered Steel Fiber Reinforced Concrete

    Institute of Scientific and Technical Information of China (English)

    DAI Shao-bin; SONG Ming-hai; HUANG Jun

    2005-01-01

    The influence of two main characteristics of steel fiber, the aspect ratio (Df) and volume fraction (pf), on the bending strength of Layered Steel Fiber Reinforced Concrete (LSFRC) is investigated by using orthogonal test. Via the variance analysis on the experimental results and trend analysis on the two characteristics, Df is found significantly related to the bending strength of LSFRC. The influence ratio is 63.3%. The bending strength of LSFRC increases if Df increases, makes better when Df reaches 100. ρf has ordinary influence on the bending strength of LSFRC. The influence ratio is 29.2%. Other characteristics, such as the shape of steel fiber and the mix proportion, have less influence. The best ρf contributing to the bending strength of LSFRC is 1.5 %. If pf is greater than 1.5 %, it has negative influence on the bending strength of LSFRC. So, pf makes a limited contribution to the bending strength of LSFRC.

  19. Detection and monitoring of flexural cracks in reinforced concrete beams using mounted smart aggregate transducers

    Science.gov (United States)

    Taghavipour, S.; Kharkovsky, S.; Kang, W.-H.; Samali, B.; Mirza, O.

    2017-10-01

    Previous studies have successfully demonstrated the capability and reliability of the use of Smart Aggregate (SA) transducers to monitor reinforced concrete (RC) structures. However, they mainly focused on the applications of embedded SAs to new structural members, while no major attention was paid to the monitoring of existing RC members using externally mounted SAs. In this paper, a mounted SA-based approach is proposed for a real-time health monitoring of existing RC beams. The proposed approach is verified through monitoring of RC beams under flexural loading, on each of which SA transducers are mounted as an actuator and sensors. The experimental results show that the proposed SA-based approach effectively evaluates the cracking status of RC beams in terms of the peak of power spectral density and damage indexes obtained at multiple sensor locations. It is also shown that the proposed sensor system can also capture a precautionary signal for major cracking.

  20. 3D Nonlinear Numerical Simulation of Intact and Debonded Reinforced Concrete Beams

    Institute of Scientific and Technical Information of China (English)

    Chen Quan(陈权); Marcus L.

    2004-01-01

    To study the behaviour of reinforced concrete (RC) structures with sections of concrete removed and the reinforcement exposed, 3D nonlinear numerical analysis was performed upon both intact and debonded RC beams by using finite element techniques. The deformational characteristics and the ultimate loads were obtained through numerical models, as well as crack and stress distributions. The failure modes can also be deduced from computational results. Compared with intact beams, the normal assumptions of plane section behaviour is not hold true and the patterns of stress and strain are different in debonded RC beams. The numerical results show good consistency with experimental data. This kind of numerical simulation is a supplement to existing codes.

  1. Flexural retrofitting of reinforced concrete structures using Green Natural Fiber Reinforced Polymer plates

    Science.gov (United States)

    Cervantes, Ignacio

    An experimental study will be carried out to determine the suitability of Green Natural Fiber Reinforced Polymer plates (GNFRP) manufactured with hemp fibers, with the purpose of using them as structural materials for the flexural strengthening of reinforced concrete (RC) beams. Four identical RC beams, 96 inches long, are tested for the investigation, three control beams and one test beam. The first three beams are used as references; one unreinforced, one with one layer of Carbon Fiber Reinforced Polymer (CFRP), one with two layers of CFRP, and one with n layers of the proposed, environmental-friendly, GNFRP plates. The goal is to determine the number of GNFRP layers needed to match the strength reached with one layer of CFRP and once matched, assess if the system is less expensive than CFRP strengthening, if this is the case, this strengthening system could be an alternative to the currently used, expensive CFRP systems.

  2. Post-cracking Behaviour and Fracture Energy of Synthetic Fibre Reinforced Concrete

    Directory of Open Access Journals (Sweden)

    Marta KOSIOR-KAZBERUK

    2016-11-01

    Full Text Available The paper reports the results of experimental programme focused on the effect of various synthetic fibres on fracture properties and ductility of concrete. The fracture energy was assessed on beams with initial notches in three-point bend test. The incorporation of synthetic fibres had a slight effect on mechanical properties of concrete but, at the same time, it had a significant influence on the fracture energy by modification of post-cracking behaviour of concrete. It was found that the modern synthetic fibres might be able to impart significant toughness and ductility to concrete. However, the beneficial effect of fibres depends on their length and flexibility. The analysis of load-deflection curves obtained made it possible to fit the simple function, describing the post-peak behaviour of fibre reinforced concrete, which can be useful for the calculation of GF value.DOI: http://dx.doi.org/10.5755/j01.ms.22.4.13246

  3. Reinforced concrete in Louis Kahn’s National Assembly, Dhaka: Modernity and modernism in Bangladeshi architecture

    Directory of Open Access Journals (Sweden)

    Kathleen James-Chakraborty

    2014-06-01

    Full Text Available Louis Kahn is often credited with having in his National Assembly in Dhaka (1962–1983 introduced modern architecture to Bangladesh. In fact at least as technologically advanced construction as any he employed was already in use there. Nor was he the first to use a sophisticated abstract esthetic in what was from 1947 to 1971 East Pakistan. The importance and originality of the National Assembly instead resides in the care with which he built in reinforced concrete and the forms into which he required that it be cast. These were esthetic decisions rooted in a particular theoretical position; they were located outside established modernist practice of the time in both South Asia and the United States. Indeed operating at such a great remove from home may have heightened Kahn’s authority to implement these forms even as it substantially complicated their execution.

  4. Bond slip model in cylindrical reinforced concrete elements confined with stirrups

    Science.gov (United States)

    Coccia, Simona; Di Maggio, Erica; Rinaldi, Zila

    2015-12-01

    An analytical model able to evaluate the bond-slip law of confined reinforced concrete elements is developed and presented in this paper. The model is based on the studies developed by Tepfers and by den Uijl and Bigaj on the thick-walled cylinder model and extended to the case of the presence of transverse reinforcement. The bond strength and the considered failure modes (splitting or pull-out failure) are expressed as a function of the geometrical (concrete cover and transverse reinforcement) and mechanical (concrete strength) parameters of the element. The application of the proposed methodology allows to forecast the failure mode, and equations for the bond-slip law are finally proposed for a range of steel strain lower than the yielding one.

  5. Performance based seismic qualification of reinforced concrete nuclear materials processing facilities

    Energy Technology Data Exchange (ETDEWEB)

    Mertz, G.E.; Loceff, F.; Houston, T.; Rauls, G. [Westinghouse Savannah River Company, Aiken, SC (United States); Mulliken, J. [LPA Group Inc., SC (United States)

    1997-09-01

    A seismic qualification of a reinforced concrete nuclear materials processing facility using performance based acceptance criteria is presented. Performance goals are defined in terms of a minimum annual seismic failure frequency. Pushover analyses are used to determine the building`s ultimate capacity and relate the capacity to roof drift and joint rotation. Nonlinear dynamic analyses are used to quantify the building`s drift using a suite of ground motion intensities representing varying soil conditions and levels of seismic hazard. A correlation between joint rotation and building drift to damage state is developed from experimental data. The damage state and seismic hazard are convolved to determine annual seismic failure frequency. The results of this rigorous approach is compared to those using equivalent force methods and pushover techniques recommended by ATC-19 and FEMA-273.

  6. Influence of Excitation on Dynamic System Identification for a Multi-Span Reinforced Concrete Bridge

    Directory of Open Access Journals (Sweden)

    M. Alwash

    2009-01-01

    Full Text Available In vibration-based damage detection, changes to structural modal properties are tracked over time in order to infer the current state of damage or deterioration. As such, the ability to obtain reliable estimates of modal parameters, particularly natural frequencies and mode shapes, is of critical importance. In the present study, the influence of the dynamic excitation source on the accuracy and statistical uncertainty of modal property estimates for a three span reinforced concrete bridge was investigated experimentally and numerically. Comparisons were made between the dynamic responses due to vehicle loading, harmonic and random forcing, impact, and environmental excitation. It was demonstrated that natural frequencies and mode shapes extracted from the free vibration response following vehicle and random loading events were of higher quality than corresponding values determined during the forcing phase of those events. Harmonic excitation at resonant frequencies and impact were also found to produce statistically reliable results.

  7. Assessment of Reinforced Concrete Surface Breaking Crack Using Rayleigh Wave Measurement.

    Science.gov (United States)

    Lee, Foo Wei; Chai, Hwa Kian; Lim, Kok Sing

    2016-03-05

    An improved single sided Rayleigh wave (R-wave) measurement was suggested to characterize surface breaking crack in steel reinforced concrete structures. Numerical simulations were performed to clarify the behavior of R-waves interacting with surface breaking crack with different depths and degrees of inclinations. Through analysis of simulation results, correlations between R-wave parameters of interest and crack characteristics (depth and degree of inclination) were obtained, which were then validated by experimental measurement of concrete specimens instigated with vertical and inclined artificial cracks of different depths. Wave parameters including velocity and amplitude attenuation for each case were studied. The correlations allowed us to estimate the depth and inclination of cracks measured experimentally with acceptable discrepancies, particularly for cracks which are relatively shallow and when the crack depth is smaller than the wavelength.

  8. Structural Response to Blast Loading: The Effects of Corrosion on Reinforced Concrete Structures

    Directory of Open Access Journals (Sweden)

    Hakan Yalciner

    2014-01-01

    Full Text Available Structural blast design has become a necessary part of the design with increasing terrorist attacks. Terrorist attacks are not the one to make the structures important against blast loading where other explosions such as high gas explosions also take an important place in structural safety. The main objective of this study was to verify the structural performance levels under the impact of different blast loading scenarios. The blast loads were represented by using triangular pulse for single degree of freedom system. The effect of blast load on both corroded and uncorroded reinforced concrete buildings was examined for different explosion distances. Modified plastic hinge properties were used to ensure the effects of corrosion. The results indicated that explosion distance and concrete strength were key parameters to define the performance of the structures against blast loading.

  9. The strut-and-tie models in reinforced concrete structures analysed by a numerical technique

    Directory of Open Access Journals (Sweden)

    V. S. Almeida

    Full Text Available The strut-and-tie models are appropriate to design and to detail certain types of structural elements in reinforced concrete and in regions of stress concentrations, called "D" regions. This is a good model representation of the structural behavior and mechanism. The numerical techniques presented herein are used to identify stress regions which represent the strut-and-tie elements and to quantify their respective efforts. Elastic linear plane problems are analyzed using strut-and-tie models by coupling the classical evolutionary structural optimization, ESO, and a new variant called SESO - Smoothing ESO, for finite element formulation. The SESO method is based on the procedure of gradual reduction of stiffness contribution of the inefficient elements at lower stress until it no longer has any influence. Optimal topologies of strut-and-tie models are presented in several instances with good settings comparing with other pioneer works allowing the design of reinforcement for structural elements.

  10. Experimental and analytical behavior of strengthened reinforced concrete columns with steel angles and strips

    Science.gov (United States)

    Khalifa, Essam S.; Al-Tersawy, Sherif H.

    2014-06-01

    The need of strengthening reinforced concrete columns, due to loss of strength and/or stiffness, is an essential requirement due to variation of the loads and environmental conditions applied on these columns. Steel jackets around the reinforced concrete (RC) columns are usually made by means of steel plates covering all over the column surface area. For the value of engineering purposes, another technique was developed using steel angles at the corners of the RC columns connected with discrete steel strips. In this paper, an experimental program is designed to evaluate the improvement in load-carrying capacity, stiffness and ductility of strengthened RC columns, concomitant with steel angles and strips. Despite of prevailing a substantially increased loading capacity and strength a pronounced enhancement in ductility and stiffness has been reported. A need for experimental test results with low value of concrete strength to mimic the local old-age structures condition that required strengthening in local countries. Seven columns specimens are tested to evaluate the strength improvement provided by steel strengthening of columns. The method of strengthened steel angles with strips is compared with another strengthening technique. This technique includes connected and unconnected steel-casing specimens. The observed experimental results describe load-shortening curves, horizontal strains in stirrups and steel strips, as well as description of failure mode. The extra-confinement pressure, due to existence of steel cage, of the strengthened RC column can be also observed from experimental results. The code provisions that predict the load-carrying capacity of the strengthened RC composite column has a discrepancy in the results. For this reason, an analytical model is developed in this paper to compare the code limit with experimental observed results. The proposed model accounts for the composite action for concrete confinement and enhancement of the local buckling

  11. Calculation of dynamic load impact on reinforced concrete arches in the ground

    Directory of Open Access Journals (Sweden)

    Barbashev Nikita Petrovich

    2016-01-01

    Full Text Available Concrete arches are widely used in the construction of underground facilities. The analysis of their work under dynamic loads (blasting, shock, seismic will improve the efficiency of design and application. The article addresses the problems of calculation of reinforced concrete arches in the ground in terms of the action of dynamic load - compression wave. The calculation is made basing on the decision of a closed system of equations that allows performing the calculation of elastic-plastic curved concrete structures under dynamic loads. Keeping in mind the properties of elastic-plastic reinforcement and concrete in the process of design variations, σ-ε diagrams are variable. The calculation is performed by the direct solution of differential equations in partial derivatives. The result is based on a system of ordinary differential equations of the second order (expressing the transverse and longitudinal oscillations of the structure and the system of algebraic equations (continuity condition of deformation. The computer program calculated three-hinged reinforced concrete arches. The structural calculations were produced by selection of the load based on the criteria of reaching the first limit state: ultimate strain of compressed concrete; ultimate strain tensile reinforcement; the ultimate deformation of the structure. The authors defined all the characteristics of the stress-strain state of the structure. The presented graphs show the change of bending moment and shear force in time for the most loaded section of the arch, the dependence of stresses and strains in concrete and reinforcement, stress changes in time for the cross-sectional height. The peculiarity of the problem is that the action of the load provokes the related dynamic forces - bending moment and longitudinal force. The calculations allowed estimating the carrying capacity of the structure using the criteria of settlement limit states. The decisive criterion was the

  12. Steel fiber reinforced concrete pipes: part 1: technological analysis of the mechanical behavior

    Directory of Open Access Journals (Sweden)

    A. D. de Figueiredo

    Full Text Available This paper is the first part of an extensive work focusing the technological development of steel fiber reinforced concrete pipes (FRCP. Here is presented and discussed the experimental campaign focusing the test procedure and the mechanical behavior obtained for each of the dosages of fiber used. In the second part ("Steel fiber reinforced concrete pipes. Part 2: Numerical model to simulate the crushing test", the aspects of FRCP numerical modeling are presented and analyzed using the same experimental results in order to be validated. This study was carried out trying to reduce some uncertainties related to FRCP performance and provide a better condition to the use of these components. In this respect, an experimental study was carried out using sewage concrete pipes in full scale as specimens. The diameter of the specimens was 600 mm, and they had a length of 2500 mm. The pipes were reinforced with traditional bars and different contents of steel fibers in order to compare their performance through the crushing test. Two test procedures were used in that sense. In the 1st Series, the diameter displacement was monitored by the use of two LVDTs positioned at both extremities of the pipes. In the 2nd Series, just one LVDT is positioned at the spigot. The results shown a more rigidity response of the pipe during tests when the displacements were measured at the enlarged section of the socket. The fiber reinforcement was very effective, especially when low level of displacement was imposed to the FRCP. At this condition, the steel fibers showed an equivalent performance to superior class pipes made with traditional reinforced. The fiber content of 40 kg/m3 provided a hardening behavior for the FRCP, and could be considered as equivalent to the critical volume in this condition.

  13. Uncertainties Concerning the Free Vibration of Inhomogeneous Orthotropic Reinforced Concrete Plates

    Science.gov (United States)

    Shahsavar, Vahid Lal; Tofighi, Samira

    2014-09-01

    Analyzing nearly collapsed and broken structures gives good insights into possible architectural and engineering design mistakes and faults in the detailing and mismanagement of a construction by building contractors. Harmful vibration effects of construction operations occur frequently. The background reviews have demonstrated that the problem of the vibration serviceability of long-span concrete floors in buildings is complex and interdisciplinary in nature. In public buildings, floor vibration control is required in order to meet Serviceability Limit States that ensure the comfort of the users of a building. In industrial buildings, machines are often placed on floors. Machines generate vibrations of various frequencies, which are transferred to supporting constructions. Precision machines require a stable floor with defined and known dynamic characteristics. In recent years there has been increasing interest in the motion of elastic bodies whose material properties (density, elastic moduli, etc.) are not constant, but vary with their position, perhaps in a random manner. Concrete is a non-homogeneous and anisotropic material. Modeling the mechanical behavior of reinforced concrete (RC) is still one of the most difficult challenges in the field of structural engineering. One of several methods for determining the dynamic modulus of the elasticity of engineering materials is the vibration frequency procedure. In this method, the required variables except for the modulus of elasticity are accurately and certainly determined. In this research, the uncertainly analysis of the free vibration of inhomogeneous orthotropic reinforced concrete plates has been investigated. Due to the numerous outputs obtained, the software package has been written in Matlab, and an analysis of the data and drawing related charts has been done.

  14. Numerical Evaluation Of Shape Memory Alloy Recentering Braces In Reinforced Concrete Buildings Subjected To Seismic Loading

    Science.gov (United States)

    Charles, Winsbert Curt

    Seismic protective techniques utilizing specialized energy dissipation devices within the lateral resisting frames have been successfully used to limit inelastic deformation in reinforced concrete buildings by increasing damping and/or altering the stiffness of these structures. However, there is a need to investigate and develop systems with self-centering capabilities; systems that are able to assist in returning a structure to its original position after an earthquake. In this project, the efficacy of a shape memory alloy (SMA) based device, as a structural recentering device is evaluated through numerical analysis using the OpenSees framework. OpenSees is a software framework for simulating the seismic response of structural and geotechnical systems. OpenSees has been developed as the computational platform for research in performance-based earthquake engineering at the Pacific Earthquake Engineering Research Center (PEER). A non-ductile reinforced concrete building, which is modelled using OpenSees and verified with available experimental data is used for the analysis in this study. The model is fitted with Tension/Compression (TC) SMA devices. The performance of the SMA recentering device is evaluated for a set of near-field and far-field ground motions. Critical performance measures of the analysis include residual displacements, interstory drift and acceleration (horizontal and vertical) for different types of ground motions. The results show that the TC device's performance is unaffected by the type of ground motion. The analysis also shows that the inclusion of the device in the lateral force resisting system of the building resulted in a 50% decrease in peak horizontal displacement, and inter-story drift elimination of residual deformations, acceleration was increased up to 110%.

  15. Improvement of impact-resistance of a nuclear containment building using fiber reinforced concrete

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Se-Jin, E-mail: conc@ajou.ac.kr [Ajou University, 206, World cup-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do 16499 (Korea, Republic of); Jin, Byeong-Moo [DAEWOO E& C, Institute of Construction Technology, 20, Suil-ro 123beon-gil, Jangan-gu, Suwon-si, Gyeonggi-do 16297 (Korea, Republic of)

    2016-08-01

    Highlights: • Impact-resistance of a structure can be improved by fiber reinforced concrete (FRC). • Material modeling of FRC is incorporated into finite element analysis of a structure. • A new index for impact-resistance is proposed based on plastic dissipation energy. • A nuclear power plant made of FRC shows improved resistance against aircraft crashes. - Abstract: Since the act of terrorism that occurred in the USA on September 11, 2001, the protection of nuclear power plants against large commercial aircraft crashes has been an emerging issue. Besides the verification of the safety of nuclear power plants in operation or in design, efficient methods for improving the impact-resistance of these structures have been investigated. Fiber reinforced concrete (FRC) has been generally accepted as an effective material for this purpose. In particular, FRC has been developed to improve the tensile behavior of concrete such as tensile strength, ductility and toughness. One of the main fields of application of FRC can be found in blast-protective or blast-resistant concrete structures. It is expected, therefore, that safety-related structures in a nuclear power plant can also be effectively protected from external blast, aircraft crash, etc. by applying FRC. In order to analytically verify the effect on structural behavior of applying FRC, the particular material properties of FRC should be incorporated into the material modeling of a structural analysis program. This study investigates the mathematical modeling of FRC, which represents various aspects of material behavior. Two numerical examples are provided to show the improved impact-resistance of a nuclear containment building that is expected when applying FRC in comparison with ordinary concrete. The analysis results show that the displacement decreases by 43–67% while the impact-resistance increases by 40–82%, depending on a fiber type.

  16. Uncertainties Concerning the Free Vibration of Inhomogeneous Orthotropic Reinforced Concrete Plates

    Directory of Open Access Journals (Sweden)

    Shahsavar Vahid Lal

    2014-09-01

    Full Text Available Analyzing nearly collapsed and broken structures gives good insights into possible architectural and engineering design mistakes and faults in the detailing and mismanagement of a construction by building contractors. Harmful vibration effects of construction operations occur frequently. The background reviews have demonstrated that the problem of the vibration serviceability of long-span concrete floors in buildings is complex and interdisciplinary in nature. In public buildings, floor vibration control is required in order to meet Serviceability Limit States that ensure the comfort of the users of a building. In industrial buildings, machines are often placed on floors. Machines generate vibrations of various frequencies, which are transferred to supporting constructions. Precision machines require a stable floor with defined and known dynamic characteristics. In recent years there has been increasing interest in the motion of elastic bodies whose material properties (density, elastic moduli, etc. are not constant, but vary with their position, perhaps in a random manner. Concrete is a non-homogeneous and anisotropic material. Modeling the mechanical behavior of reinforced concrete (RC is still one of the most difficult challenges in the field of structural engineering. One of several methods for determining the dynamic modulus of the elasticity of engineering materials is the vibration frequency procedure. In this method, the required variables except for the modulus of elasticity are accurately and certainly determined. In this research, the uncertainly analysis of the free vibration of inhomogeneous orthotropic reinforced concrete plates has been investigated. Due to the numerous outputs obtained, the software package has been written in Matlab, and an analysis of the data and drawing related charts has been done.

  17. Seismic fragility analysis of lap-spliced reinforced concrete columns retrofitted by SMA wire jackets

    Science.gov (United States)

    Choi, Eunsoo; Park, Sun-Hee; Chung, Young-Soo; Kim, Hee Sun

    2013-08-01

    The aim of this study is to provide seismic fragility curves of reinforced concrete columns retrofitted by shape memory alloy wire jackets and thus assess the seismic performance of the columns against earthquakes, comparing them with reinforced concrete columns with lap-spliced and continuous reinforcement. For that purpose, this study first developed analytical models of the experimental results of the three types of columns, (1) lap-spliced reinforcement, (2) continuous reinforcement and (3) lap-spliced reinforcement and retrofitted by SMA wire jackets, using the OpenSEES program, which is oriented to nonlinear dynamic analysis. Then, a suite of ten recorded ground motions was used to conduct dynamic analyses of the analytical models with scaling of the peak ground acceleration from 0.1g to 1.0g in steps of 0.1g. From the static experimental tests, the column retrofitted with SMA wire jackets had a larger displacement ductility by a factor of 2.3 times that of the lap-spliced column, which was 6% larger compared with the ductility of the continuous reinforcement column. From the fragility analyses, the SMA wire jacketed column had median values of 0.162g and 0.567g for yield and collapse, respectively. For the yield damage state, the SMA wire jacketed column had a median value similar to the continuous reinforcement column. However, for the complete damage state, the SMA wire jacketed column showed a 1.33 times larger median value than the continuously reinforcement column.

  18. Behavior of Low Grade Steel Fiber Reinforced Concrete Made with Fresh and Recycled Brick Aggregates

    Directory of Open Access Journals (Sweden)

    Md. Shariful Islam

    2017-01-01

    Full Text Available In recent years, recycled aggregates from construction and demolition waste (CDW have been widely accepted in construction sectors as the replacement of coarse aggregate in order to minimize the excessive use of natural resources. In this paper, an experimental investigation is carried out to observe the influence of low grade steel fiber reinforcements on the stress-strain behavior of concrete made with recycled and fresh brick aggregates. In addition, compressive strength by destructive and nondestructive tests, splitting tensile strength, and Young’s modulus are determined. Hooked end steel wires with 50 mm of length and an aspect ratio of 55.6 are used as fiber reinforcements in a volume fraction of 0% (control case, 0.50%, and 1.00% in concrete mixes. The same gradation of aggregates and water-cement ratio (w/c=0.44 were used to assess the effect of steel fiber in all these concrete mixes. All tests were conducted at 7, 14, and 28 days to perceive the effect of age on different mechanical properties. The experimental results show that around 10%~15% and 40%~60% increase in 28 days compressive strength and tensile strength of steel fiber reinforced concrete, respectively, compared to those of the control case. It is observed that the effect of addition of 1% fiber on the concrete compressive strength is little compared to that of 0.5% steel fiber addition. On the other hand, strain of concrete at failure of steel fiber reinforced concrete has increased almost twice compared to the control case. A simple analytical model is also proposed to generate the ascending portions of the stress-strain curve of concrete. There exists a good correlation between the experimental results and the analytical model. A relatively ductile failure is observed for the concrete made with low grade steel fibers.

  19. Use of response envelopes for seismic margin assessment of reinforced concrete walls and slabs

    Energy Technology Data Exchange (ETDEWEB)

    Ile, Nicolas; Frau, Alberto, E-mail: alberto.frau@cea.fr

    2017-04-01

    Highlights: • Proposal of a method for application of the elliptical envelope to RC shell elements. • Proposal of new algorithms for the seismic margin evaluation for RC shell elements. • Verification of a RC wall 3D structure, using the proposed assessment approach. - Abstract: Seismic safety evaluations of existing nuclear facilities are usually based on the assumption of structural linearity. For the design basis earthquake (DBE), it is reasonable to apply a conventional evaluation of the seismic safety of building structures and carry out a linear elastic analysis to assess the load effects on structural elements. Estimating the seismic capacity of a structural element requires an estimation of the critical combination of responses acting in this structural element and compare this combination with the capacity of the element. By exploiting the response-spectrum-based procedure for predicting the response envelopes in linear structures formulated by Menun and Der Kiureghian (2000a), algorithms are developed for the seismic margin assessment of reinforced concrete shell finite elements. These algorithms facilitate the comparison of the response-spectrum-based envelopes to prescribed capacity surfaces for the purpose of assessing the safety margin of this kind of structures. The practical application of elliptical response envelopes in case of shell finite elements is based on the use of layer models such as those developed by Marti (1990), which transfer the generalized stress field to three layers under the assumption that the two outer layers carry membrane forces and the internal layer carries only the out-of-plane shears. The utility of the assessment approach is discussed with reference to a case study of a 3D structure made of reinforced concrete walls.

  20. THE STRENGTH OF REINFORCED CONCRETE BEAM ELEMENTS UNDER CYCLIC ALTERNATING LOADING AND LOW CYCLE LOAD OF CONSTANT SIGN

    Directory of Open Access Journals (Sweden)

    Semina Yuliya Anatol'evna

    2015-09-01

    Full Text Available The behavior of reinforced concrete elements under some types of cyclic loads is described in the paper. The main aim of the investigations is research of the stress-strain state and strength of the inclined sections of reinforced concrete beam elements in conditions of systemic impact of constructive factors and the factor of external influence. To spotlight the problem of cyclic loadings three series of tests were conducted by the author. Firstly, the analysis of the tests showed that especially cyclic alternating loading reduces the bearing capacity of reinforced concrete beams and their crack resistance by 20 % due to the fatigue of concrete and reinforcement. Thus the change of load sign creates serious changes of stress-strain state of reinforced concrete beam elements. Low cycle loads of constant sign effect the behavior of the constructions not so adversely. Secondly, based on the experimental data mathematical models of elements’ strength were obtained. These models allow evaluating the impact of each factor on the output parameter not only separately, but also in interaction with each other. Furthermore, the material spotlighted by the author describes stress-strain state of the investigated elements, cracking mechanism, changes of deflection values, the influence of mode cyclic loading during the tests. Since the data on the subject are useful and important to building practice, the ultimate aim of the tests will be working out for improvement of nonlinear calculation models of span reinforced concrete constructions taking into account the impact of these loads, and also there will be the development of engineering calculation techniques of their strength, crack resistance and deformability.

  1. Production indices for dual purpose cattle in central Brazil

    Directory of Open Access Journals (Sweden)

    Concepta McManus

    2011-07-01

    Full Text Available This study examined the effects of crossbreeding low genetic potential cows of Bos indicus origin characterized by Gyr crossed with Holstein-Friesian and Simmental bulls to produce animals in a low input dual purpose system. The farm is situated near Brasilia, in the savannah region of Brazil. The climate of the region is classified as Aw by Köppen. Data was available on 1580 calvings and completed lactations of cows with three genetic types: Gyr, Holstein-Friesian × Gyr and Simmental × Gyr. The bulls ran with the cows all year round and the diet comprised of pasture (mainly Brachiaria and Andropogon during the summer (rainy season and milled sugar cane with added urea during the winter (dry season. A mineral salt mixture was available ad libitum. Data was analysed using Statistical Analysis System. The results show that, under low input management conditions, the crossbred cows produce approximately twice the volume of milk per lactation, calve at a younger age and have a shorter open period, but there are no significant differences between crosses for growth rates of the calves or body condition of the cows. In this system, crossbred cows had production higher indices than zebu cattle. The best indices were found for cows calving in the rainy season (September to December and thinner cows (with body condition 3-5 on a scale of 9.

  2. Experimental investigation of the relation between damage at the concrete-steel interface and initiation of reinforcement corrosion in plain and fibre reinforced concrete

    DEFF Research Database (Denmark)

    Michel, Alexander; Solgaard, Anders Ole Stubbe; Pease, Bradley Justin;

    2013-01-01

    Cracks in covering concrete are known to hasten initiation of steel corrosion in reinforced concrete structures. To minimise the impact of cracks on the deterioration of reinforced concrete structures, current approaches in (inter)national design codes often limit the concrete surface crack width....... Recent investigations however, indicate that the concrete-reinforcement interfacial condition is a more fundamental criterion related to reinforcement corrosion. This work investigates the relation between macroscopic damage at the concrete-steel interface and corrosion initiation of reinforcement...... embedded in plain and fibre reinforced concrete. Comparisons of experimental and numerical results indicate a strong correlation between corrosion initiation and interfacial condition....

  3. Influence of transverse reinforcement on perforation resistance of reinforced concrete slabs under hard missile impact

    Energy Technology Data Exchange (ETDEWEB)

    Orbovic, Nebojsa, E-mail: nebojsa.orbovic@cnsc-ccsn.gc.ca; Sagals, Genadijs; Blahoianu, Andrei

    2015-12-15

    This paper describes the work conducted by the Canadian Nuclear Safety Commission (CNSC) related to the influence of transverse reinforcement on perforation capacity of reinforced concrete (RC) slabs under “hard” missile impact (impact with negligible missile deformations). The paper presents the results of three tests on reinforced concrete slabs conducted at VTT Technical Research Centre (Finland), along with the numerical simulations as well as a discussion of the current code provisions related to impactive loading. Transverse reinforcement is widely used for improving the shear and punching strength of concrete structures. However, the effect of this reinforcement on the perforation resistance under localized missile impact is still unclear. The goal of this paper is to fill the gap in the current literature related to this topic. Based on similar tests designed by the authors with missile velocity below perforation velocity, it was expected that transverse reinforcement would improve the perforation resistance. Three slabs were tested under almost identical conditions with the only difference being the transverse reinforcement. One slab was designed without transverse reinforcement, the second one with the transverse reinforcement in form of conventional stirrups with hooks and the third one with the transverse reinforcement in form of T-headed bars. Although the transverse reinforcement reduced the overall damage of the slabs (the rear face scabbing), the conclusion from the tests is that the transverse reinforcement does not have important influence on perforation capacity of concrete slabs under rigid missile impact. The slab with T-headed bars presented a slight improvement compared to the baseline specimen without transverse reinforcement. The slab with conventional stirrups presented slightly lower perforation capacity (higher residual missile velocity) than the slab without transverse reinforcement. In conclusion, the performed tests show slightly

  4. Seismic Performance Evaluation of Reinforced Concrete Moment Resisting Frames with Various Ductility in Low Seismic Zone

    Directory of Open Access Journals (Sweden)

    N. Choopool

    2011-01-01

    Full Text Available Problem statement: Bangkok, the capital of Thailand, is at moderate risk for distant earthquake due to the ability of soft soil to amplify ground motion about 3-4 times although it locates in low seismic zone. In addition, before the enforcement of seismic loading for buildings in the Ministerial Law in 2007, many existing reinforced concrete buildings in Bangkok may have been designed without consideration for seismic loading and did not incorporate the special detailing provisions that required for ductile concrete frames. Now, guidelines for seismic loading of buildings of Thailand (DPT 1302-52 have been recently improved by adopting ASCE7-05. Approach: This study is focused on the effects of the new guidelines on cost estimates and the seismic performance of a nine-story reinforced concrete apartment building with various ductility by the nonlinear static and nonlinear dynamic analyses compared with a Gravity Load Designed (GLD building. Five selected ground motion records are investigated in the analyses. In order to examine the influence of design ductility classes, the seismic forces on moment resisting frame buildings are defined according to the newly proposed seismic specifications of Thailand with ductility from 8, 5 and 3, corresponding to Special Ductile (SDF, Intermediate Ductile (IDF and Ordinary Ductile (ODF frames, respectively. The various frames are assumed to have collapsed if the local drift exceed of 3, 2.5, 2 and 1% for SDF, IDF, ODF and GLD, respectively. Results: SDF is more ductile than that of ODF, however, the strength of SDF is less than ODF. For inelastic designs, SDF decreases stiffness and increases deflection of structures. As for the effect on cost estimates, ODF is the most expensive among ODF, IDF and SDF. Costs of SDF and IDF in Bangkok are quite similar. The study found that the average PGAs for the failure state for SDF, IDF, ODF and GLD are 0.76, 0.60, 0.50 and 0.29g, respectively. Moreover, for the

  5. Mitigation of chloride and sulfate based corrosion in reinforced concrete via electrokinetic nanoparticle treatment

    Science.gov (United States)

    Kupwade-Patil, Kunal

    Concrete is a porous material which is susceptible to the migration of highly deleterious species such as chlorides and sulfates. Various external sources, including sea salt spray, direct seawater wetting, deicing salts and chlorides can contaminate reinforced concrete. Chlorides diffuse into the capillary pores of concrete and come into contact with the reinforcement. When chloride concentration at the reinforcement exceeds a threshold level it breaks down the passive oxide layer, leading to chloride induced corrosion. The application of electrokinetics using positively charged nanoparticles for corrosion protection in reinforced concrete structures is an emerging technology. This technique involves the principle of electrophoretic migration of nanoparticles to hinder chloride diffusion in the concrete. The return of chlorides is inhibited by the electrodeposited assembly of the nanoparticles at the reinforcement interface. This work examined the nanoparticle treatment impact on chloride and sulfate induced corrosion in concrete. Electrokinetic Nanoparticle (EN) treatments were conducted on reinforced cylindrical concrete, rectangular ASTM G109 specimens that simulate a bridge deck and full scale beam specimens. EN treatment to mitigate external sulfate attack in concrete was performed on cylindrical concrete specimens. Corrosion results indicated lower corrosion potentials and rates as compared to the untreated specimens. Scanning electron microscopy (SEM) showed a dense microstructure within the EN treated specimens. Chemical analysis (Raman spectroscopy, X ray-diffraction, and Fourier transform infrared spectroscopy FTIR) showed the presence of strength enhancing phases such as calcium aluminate hydrate (C-A-H) and increased amounts of calcium silicate hydrate (C-S-H) within the EN treated specimens. Strength and porosity results showed an increase in strength and a reduction in porosity among the EN treated specimens. EN treatment acted as a protective

  6. Comparative Evaluation Of Reinforced Concrete, Steel And Composite Structures Under The Effect Of Static And Dynamic Loads

    Directory of Open Access Journals (Sweden)

    Zafar Mujawar

    2015-01-01

    Full Text Available Steel-concrete composite construction has gained wide acceptance all over the world as an alternative for pure steel and pure concrete construction. However this approach is a new concept for construction industry. R.C.C are no longer economical because of their increased dead load, hazardous formwork. The present study deals with comparison of reinforced concrete, steel and composite structures under the effect of static and dynamic loads. The results of this work show that composite structures are best suited for high rise buildings compared to that of steel and reinforced concrete structures. Response spectrum method is used for comparison of three structures with the help of ETABS software.

  7. RCP 钢筋混凝土管检测技术%On testing technique of RCP reinforced concrete pipes

    Institute of Scientific and Technical Information of China (English)

    焦利敏

    2016-01-01

    The paper introduces the testing programs of RCP reinforced concrete pipes,illustrates its testing points from the outline quality,geo-metric dimensioning,compressive strength,and internal water pressure,and points out the test evaluation for the reinforced concrete pipes,so as to be meaningful for the improvement of the drainage pipe quality.%介绍了 RCP 钢筋混凝土管的检测项目,从外观质量、几何尺寸、抗压强度、内水压力等方面,阐述了 RCP 钢筋混凝土管的检测要点,指出钢筋混凝土管的检测评定,对于提高排水管的质量有重要意义。

  8. Application of global elements to a reinforced concrete structure; Application des elements globaux a une structure en beton arme

    Energy Technology Data Exchange (ETDEWEB)

    Morand, O

    1994-07-01

    The dimensioning of nuclear facilities requires to take into account the possible risk of earthquakes. However such installations are generally complex structures with reinforced concrete poles, walls, beams and porches. In this study, a seismic analysis of such a structure is proposed. The use of the Castem 2000 global element code was attempted to dynamically simulate the behaviour of the reinforced concrete elements. However, no suitable modeling has been found for the storeys, the functioning of which being dominated by carrying walls. Concerning the porch-type storeys, monotonous static loads were simulated and provided information on the local and global behaviour of these structures. Thus, representative global elements could be realized for these structures. Results obtained are satisfactory for these storeys which essentially undergo a bending deformation. (J.S.)

  9. Study of the Corrosion of Reinforced Concrete%基于钢筋混凝土腐蚀的研究

    Institute of Scientific and Technical Information of China (English)

    谢振阳; 张智慧

    2014-01-01

    在混凝土中,最能影响其耐久性的因素就是钢筋的腐蚀。本文通过对某工程的钢筋混凝土结构腐蚀进行研究,介绍了钢筋混凝土结构的防腐问题,提出一系列切实可行的处理方法。%In concrete, corrosion is the main factor which affects its durability. This paper studies the corrosion of reinforced concrete structure of a certain project, introduces the problem of corrosion of reinforced concrete structure, and puts forward a series of feasible treatment method.

  10. The influence of self-compacting steel fibre reinforced concrete infill on the flexure strength and ductility of masonry walls

    OpenAIRE

    Oliveira, Luiz António Pereira de; Bernardo, Luís Filipe Almeida

    2010-01-01

    This paper presents an experimental study on the influence of longitudinal reinforcement ratio and steel fibre volume in self-compacting concrete infill on the strength and ductility of reinforced masonry walls subjected to flexure. Flexure tests were performed as four-point bending tests on twelve walls. The analysis of the concrete infill contribution to the walls capacity is made considering recent recommendations for steel fibre reinforced concrete design. A ductility...

  11. Design Criteria for Deflection Capacity of conventionally Reinforced Concrete Slabs. Phase I. State-of-the-Art Report.

    Science.gov (United States)

    1980-10-01

    Stopping- off bars, however, will effect some economy. -74- 3 in. 1.3in 3im. (6in) (12 in) spoc "’ sm.iar to S2 4.5 in ISin. U99 et al. On Son-urtro renocmn...rcordeis, A.C., "Finite Element Analysis of Reinforced Concrete Strkc’- tures," Fratelli Presenti Specialty Course on Reariforce6 Concrete Construction

  12. Comparative Evaluation Of Reinforced Concrete, Steel And Composite Structures Under The Effect Of Static And Dynamic Loads

    OpenAIRE

    Zafar Mujawar; Prakarsh Sangave

    2015-01-01

    Steel-concrete composite construction has gained wide acceptance all over the world as an alternative for pure steel and pure concrete construction. However this approach is a new concept for construction industry. R.C.C are no longer economical because of their increased dead load, hazardous formwork. The present study deals with comparison of reinforced concrete, steel and composite structures under the effect of static and dynamic loads. The results of this work show that compo...

  13. Seismic capacity of a reinforced concrete frame structure without seismic detailing and limited ductility seismic design in moderate seismicity

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J. K.; Kim, I. H. [Seoul National Univ., Seoul (Korea, Republic of)

    1999-10-01

    A four-story reinforced concrete frame building model is designed for the gravity loads only. Static nonlinear pushover analyses are performed in two orthogonal horizontal directions. The overall capacity curves are converted into ADRS spectra and compared with demand spectra. At several points the deformed shape, moment and shear distribution are calculated. Based on these results limited ductility seismic design concept is proposed as an alternative seismic design approach in moderate seismicity resign.

  14. EI Scale: an environmental impact assessment scale related to the construction materials used in the reinforced concrete

    OpenAIRE

    Gilson Morales; Antonio Edésio Jungles; Sheila Elisa Scheidemantel Klein; Juliana Guarda

    2010-01-01

    This study aimed to create EI Scal, an environmental impact assessment scal, related to construction materials used in the reinforced concrete structure production. The main reason for that was based on the need to classify the environmental impact levels through indicators to assess the damage level process. The scale allowed converting information to estimate the environmental impact caused. Indicators were defined trough the requirements and classification criteria of impact aspects consid...

  15. Modeling the Time-to Corrosion Cracking of the Cover Concrete in Chloride Contaminated Reinforced Concrete Structures

    OpenAIRE

    Liu, Youping

    1996-01-01

    Significant factors on steel corrosion in chloride contaminated reinforced concrete and time-to-corrosion cracking were investigated in this study. Sixty specimens were designed with seven admixed chloride contents, three concrete cover depths, two reinforcing steel bar diameters, two exposure conditions, and a typical concrete with water to cement ratio of 0.45. Corrosion current density (corrosion rate), corrosion potential, ohmic resistance of concrete and temperature were measured monthly...

  16. An application of asymmetrical glass fibre-reinforced plastics for the manufacture of curved fibre reinforced concrete

    OpenAIRE

    Funke, Henrik; Gelbrich, Sandra; Ulke-Winter , Lars; Kroll, Lothar; Petzoldt, Carolin

    2015-01-01

    There was developed a novel technological and constructive approach for the low-cost production of curved freeform formworks, which allow the production of single and double-curved fibre reinforced concrete. The scheduled approach was based on a flexible, asymmetrical multi-layered formwork system, which consists of glass-fibre reinforced plastic (GFRP). By using of the unusual anisotropic structural behavior, these GFRP formwork elements permitted a specific adjustment of defined curvature. ...

  17. Development and Evaluation of Cement-Based Materials for Repair of Corrosion-Damaged Reinforced Concrete Slabs

    OpenAIRE

    Liu, Rongtang; Olek, J.

    2001-01-01

    In this study, the results of an extensive laboratory investigation conducted to evaluate the properties of concrete mixes used as patching materials to repair reinforced concrete slabs damaged by corrosion are reported. Seven special concrete mixes containing various combinations of chemical or mineral admixtures were developed and used as a patching material to improve the durability of the repaired slabs. Physical and mechanical properties of these mixes, such as compressive strength, stat...

  18. Estimating displacement demand in reinforced concrete frames using some failure criteria

    Science.gov (United States)

    Monavari, Benyamin; Massumi, Ali

    2012-12-01

    Under seismic loads on structures, the maximum drift without total collapse is called target displacement. Most of low- and medium-rise building structures are seismically designed using equivalent static method. In equivalent static method, design forces are obtained from elastic spectra which are reduced using response modification factor. This coefficient represents the structures' inelastic performance and indicates strength and hidden ductility of structures in inelastic phase. The ultimate deformation of the structure to its deformation in yielding is called ductility coefficient which expresses the inelastic deformation capacity of structures. The larger this coefficient, the higher the level of energy absorption and the more the formation of plastic joints, so accurate determination of yielding points and ultimate displacements are very important. In this paper some failure criteria are used to estimate seismic demands for buildings. To investigate these criteria, pushover analysis is done on reinforced concrete frame buildings. Using a combination of these criteria will lead to displacements that are closed to the target displacement presented in FEMA-356.

  19. Flexural behavior of reinforced concrete beams: Comparative analysis between high-performance concrete and ordinary concrete

    Directory of Open Access Journals (Sweden)

    Hamrat Mostefa

    2014-04-01

    Full Text Available This paper presents an experimental study on the flexural strength of reinforced concrete beams made with high performance concrete (HPC and ordinary concrete (OC. We are carried an experimental campaign aimed comes in three points: 1- the study of the law of behavior of the two materials (OC and HPC, 2- the influence of the compressive strength of concrete and the rate of longitudinal reinforcement on the loaddeflection behavior and ductility index, 3- comparative analysis (ACI318, Eurocode 2 and BS8110 against the crack opening. Test results showed that the capacity of the beams in HPC is higher (6% to 20 % than the beams in OC. The use of HPC is more efficient than the OC to delay the first cracking. The average value of the ductility index for the beams in HPC is 1.30 times those beams in OC. The formula for calculating the crack opening derived of the Eurocode 2 gives the best prediction the crack width of beams (for both types of concrete.

  20. Strength Modeling of Reinforced Concrete Beam with Externally Bonded FRP Reinforcement

    Directory of Open Access Journals (Sweden)

    N. Pannirselvam

    2008-01-01

    Full Text Available This research study presents the evaluation of the structural behaviour of reinforced concrete beams with externally bonded Fibre Reinforced Polymer (FRP reinforcements. Three different steel ratios with two different Glass Fibre Reinforced Polymer (GFRP types and two different thicknesses in each type of GFRP were used. Totally fifteen rectangular beams of 3 m length were cast. Three rectangular beams were used as reference beam (Control Beams and the remaining were fixed with GFRP laminates on the soffit of the rectangular beam. The variables considered for the study includes longitudinal steel ratio, type of GFRP laminates, thickness of GFRP laminates and composite ratios. Flexural test, using simple beam with third-point loading was adopted to study the performance of FRP plated beams interms flexural strength, deflection, ductility and was compared with the unplated beams. The test results show that the beams strengthened with GFRP laminates exhibit better performance. The flexural strength and ductility increase with increase in thickness of GFRP plate. The increase in first crack loads was up to 88.89% for 3 mm thick WRGFRP plates and 100.00% for 5 mm WRGFRP plated beams and increase in ductility interms of energy and deflection was found to be 56.01 and 64.69% respectively with 5 mm thick GFRP plated beam. Strength models were developed for predicting the flexural strength (ultimate load, service load and ductility of FRP beams. The strength model developed give prediction matching the measurements.

  1. Nonlinear fracture mechanics investigation on the ductility of reinforced concrete beams

    Directory of Open Access Journals (Sweden)

    A. Carpinteri

    Full Text Available In the present paper, a numerical algorithm based on the finite element method is proposed for the prediction of the mechanical response of reinforced concrete (RC beams under bending loading. The main novelty of such an approach is the introduction of the Overlapping Crack Model, based on nonlinear fracture mechanics concepts, to describe concrete crushing. According to this model, the concrete dam- age in compression is represented by means of a fictitious interpenetration. The larger is the interpenetration, the lower are the transferred forces across the damaged zone. The well-known Cohesive Crack Model in tension and an elastic-perfectly plastic stress versus crack opening displacement relationship describing the steel reinforcement behavior are also integrated into the numerical algorithm. The application of the proposed Cohesive-Overlapping Crack Model to the assessment of the minimum reinforcement amount neces- sary to prevent unstable tensile crack propagation and to the evaluation of the rotational capacity of plastic hinges, permits to predict the size-scale effects evidenced by several experimental programs available in the literature. According to the obtained numerical results, new practical design formulae and diagrams are proposed for the improvement of the current code provisions which usually disregard the size effects.

  2. Investigation of Ductility Reduction Factor in Seismic Rehabilitation of Existing Reinforced Concrete School Buildings

    Directory of Open Access Journals (Sweden)

    O. Gorgulu

    2015-02-01

    Full Text Available Converting existing Reinforced Concrete (RC frames into RC infill walls is one of the most efficient seismic strengthening technique due to its simplicity in application providing high rigidity, stability and strength in structures. On the other hand, this method affects the seismic behavior of existing RC structure in terms of the energy dissipation capacity or in other words, ductility reduction factor, Rμ. This research is an attempt to investigate the RC infill wall ratio effect on ductility reduction factor in terms of the seismic rehabilitation of the typical RC school buildings. For this purpose, nonlinear static pushover analyses are conducted for existing 3 and 5 story RC school buildings which were rehabilitated with different RC infill wall ratio. Numerical analyses are carried out by using the fiber element based modeling approach in the software, Perform-3D. Based on these analytical results, correlation between the ductility reduction factor and the RC infill wall ratio is obtained for the seismic rehabilitation of the RC school buildings. In addition, two mathematical expressions for the variation of the ductility reduction factor with RC infill wall ratios are proposed in terms of the preliminary seismic rehabilitation assessment of the existing RC school buildings.

  3. Behavior of Reinforced Concrete Frames In-Filled with Lightweight Materials Under Seismic Loads

    Directory of Open Access Journals (Sweden)

    Iswandi Imran

    2009-01-01

    Full Text Available This paper presents an experimental and analytical research conducted to study the in-plane behavior of reinforced concrete (R/C frames in-filled with lightweight materials. The tests were performed on two single bay, single story in-filled frame specimens with ½ scale models. One of the test specimens was in-filled with lightweight materials, i.e. autoclaved aerated concrete (AAC blocks, and the other, used as the comparison, was in-filled with clay brick materials. The loading used in the tests was in the form of cyclic in-plane lateral loads, simulating earthquake forces. Behavior of the frame structures was evaluated through the observed strength and deformation characteristics, the measured hysteretic energy dissipation capacity and the measured ductility. The experimental results show that the R/C frame in-filled with AAC blocks exhibited better performance under in-plane lateral loads than that in-filled with conventional clay bricks. In the analytical work, the performance of some analytical models available in the literature was evaluated in simulating the experimental results

  4. Assessment of Methods for Development of Confinement Model of Low Strength Reinforced Concrete Columns: A Review

    Directory of Open Access Journals (Sweden)

    Asif Ali

    2016-10-01

    Full Text Available Reinforced Concrete is composed of concrete and steel, where compressive strength of concrete and tensile strength of steel are utilized to achieve the required member strength. The high tensile property of steel is thus used to confine and increase compressive strength and ductility of RC columns. Confined concrete is defined as concrete that is restrained laterally by any internal or external means i.e. reinforcement consisting of steel stirrups or spirals, Fiber Reinforced Polymer (FRP, Circular Concrete Filled Steel Tube, RC shell jacketing etc. An appropriate amount of confinement increases the strength, ductility and energy dissipation capacity of RC members. This paper focuses on finding out strength and ductility enhancement of low strength RC columns by reinforcement using existing confinement models. Confinement models are stress-strain curves developed for concrete compression member under uniaxial or dynamic loading, confined with transverse reinforcement. Different models along with their experimental validations are discussed in this paper to get state of the art knowledge of confinement studies possible for low strength concrete. The models recommended from this study are used to evaluate existing structures made with low strength concrete

  5. Predicting Nonlinear Behavior and Stress-Strain Relationship of Rectangular Confined Reinforced Concrete Columns with ANSYS

    Directory of Open Access Journals (Sweden)

    A. Tata

    2009-01-01

    Full Text Available This paper presents a nonlinear finite element modeling and analysis of rectangular normal-strength reinforced concrete columns confined with transverse steel under axial compressive loading. In this study, the columns were modeled as discrete elements using ANSYS nonlinear finite element software. Concrete was modeled with 8-noded SOLID65 elements that can translate either in the x-, y-, or z-axis directions from ANSYS element library. Longitudinal and transverse steels were modeled as discrete elements using 3D-LINK8 bar elements available in the ANSYS element library. The nonlinear constitutive law of each material was also implemented in the model. The results indicate that the stress-strain relationships obtained from the analytical model using ANSYS are in good agreement with the experimental data. This has been confirmed with the insignificant difference between the analytical and experimental, i.e. 5.65 and 2.80 percent for the peak stress and the strain at the peak stress, respectively. The comparison shows that the ANSYS nonlinear finite element program is capable of modeling and predicting the actual nonlinear behavior of confined concrete column under axial loading. The actual stress-strain relationship, the strength gain and ductility improvement have also been confirmed to be satisfactorily.

  6. Effect of Neutron Radiation on Moment-Curvature Response of Reinforced Concrete Beam

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Taehyun; Kim, Jun Yeon; Cho, Mansoon; Wu, Sangik [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Park, Kyoungsoo [Yonsei Univ., Seoul (Korea, Republic of)

    2014-05-15

    Reinforced concrete (RC) is a composite material in which concrete resists compression and steel bars as reinforcement are embedded in tensile regions to counteract the concrete's relative low tensile strength and ductility. RC is commonly used as a biological shield and as a load carrying support for a reactor vessel and, if any, changes in the mechanical properties can be particular significant for long-term irradiation. The highlights can be considered as the most critical due to its load bearing in the RC design. This study investigated the moment-curvature response of an RC beam with incremental neutron radiation. The RC structure close to the reactor vessel was considered as the most critical in estimating that the total fluence for 40 years becomes about 10{sup 14} to 10{sup 18} n/cm{sup 2}. The moment-curvature response of an RC beam was investigated with the maximum neutron fluence up to 10{sup 19} n/cm{sup 2} and it shows twice the increase in ultimate strength, which is mainly contributed from the increased yield stress of mild steel. The RC beam response became so brittle that it may fail without large deformation as a warning. The same observation can be equally applied to other RC designs such as the column, slab, and foundation.

  7. Strength and behavior in shear of reinforced concrete deep beams under dynamic loading conditions

    Energy Technology Data Exchange (ETDEWEB)

    Adhikary, Satadru Das [School of Civil and Environmental Engineering, Nanyang Technological University, 639798 (Singapore); Li, Bing, E-mail: cbli@ntu.edu.sg [School of Civil and Environmental Engineering, Nanyang Technological University, 639798 (Singapore); Fujikake, Kazunori [Department of Civil and Environmental Engineering, National Defense Academy, Yokosuka 239 8686 (Japan)

    2013-06-15

    Highlights: ► Effects of wider range of loading rates on dynamic shear behavior of RC deep beams. ► Experimental investigation of RC deep beam with and without shear reinforcements. ► Verification of experimental results with truss model and FE simulation results. ► Empirical equations are proposed to predict the dynamic increase factor of maximum resistance. -- Abstract: Research on reinforced concrete (RC) deep beams has seen considerable headway over the past three decades; however, information on the dynamic shear strength and behavior of RC deep beams under varying rates of loads remains limited. This paper describes the experimental results of 24 RC deep beams with and without shear reinforcements under varying rates of concentrated loading. Results obtained serve as useful data on shear resistance, failure patterns and strain rates corresponding to varying loading rates. An analytical truss model approach proves its efficacy in predicting the dynamic shear resistance under varying loading rates. Furthermore, three-dimensional nonlinear finite element (FE) model is described and the simulation results are verified with the experimental results. A parametric study is then conducted to investigate the influence of longitudinal reinforcement ratio, transverse reinforcement ratio and shear span to effective depth ratio on shear behavior. Subsequently, two empirical equations were proposed by integrating the various parameters to assess the dynamic increase factor (DIF) of maximum resistance under varying rates of concentrated loading.

  8. Combined Transverse Steel-External FRP Confinement Model for Rectangular Reinforced Concrete Columns

    Directory of Open Access Journals (Sweden)

    Ahmed Al-Rahmani

    2016-02-01

    Full Text Available Recently, the need to increase the strength of reinforced concrete members has become a subject that civil engineers are interested in tackling. Of the many proposed solutions, fiber-reinforced polymer (FRP materials have attracted attention due to their superior properties, such as high strength-to-weight ratio, high energy absorption and excellent corrosion resistance. FRP wrapping of concrete columns is done to enhance the ultimate strength due to the confinement effect, which is normally induced by steel ties. The existence of the two confinement systems changes the nature of the problem, thus necessitating specialized nonlinear analysis to obtain the column’s ultimate capacity. Existing research focused on a single confinement system. Furthermore, very limited research on rectangular sections was found in the literature. In this work, a model to estimate the combined behavior of the two systems in rectangular columns is proposed. The calculation of the effective lateral pressure is based on the Lam and Teng model and the Mander model for FRP wraps and steel ties, respectively. The model then generates stress-strain diagrams for both the concrete core and the cover. The model was developed for the analysis in extreme load events, where all possible contributions to the column’s ultimate capacity should be accounted for without any margin of safety. The model was validated against experiments, and the results obtained showed good agreement with almost all of the available experimental data.

  9. A Modified Model for Deflection Calculation of Reinforced Concrete Beam with Deformed GFRP Rebar

    Directory of Open Access Journals (Sweden)

    Minkwan Ju

    2016-01-01

    Full Text Available The authors carried out experimental and analytical research to evaluate the flexural capacity and the moment-deflection relationship of concrete beams reinforced with GFRP bars. The proposed model to predict the effective moment of inertia for R/C beam with GFRP bars was developed empirically, based on Branson’s equation to have better accuracy and a familiar approach to a structural engineer. For better prediction of the moment-deflection relationship until the ultimate strength is reached, a nonlinear parameter (k was also considered. This parameter was introduced to reduce the effect of the cracked moment of inertia for the reinforced concrete member, including a lower reinforcement ratio and modulus of elasticity of the GFRP bar. In a comparative study using six equations suggested by others, the proposed model showed better agreement with the experimental test results. It was confirmed that the empirical modification based on Branson’s equation was valid for predicting the effective moment of inertia of R/C beams with GFRP bar in this study. To evaluate the generality of the proposed model, a comparative study using previous test results from the literature and the results from this study was carried out. It was found that the proposed model had better accuracy and was a familiar approach to structural engineers to predict and evaluate the deflection behavior.

  10. Average Frequency – RA Value for Reinforced Concrete Beam Strengthened with Carbon Fibre Sheet

    Directory of Open Access Journals (Sweden)

    Mohamad M. Z.

    2016-01-01

    Full Text Available Acoustic Emission (AE is one of the tools that can be used to detect the crack and to classify the type of the crack of reinforced concrete (RC structure. Dislocation or movement of the material inside the RC may release the transient elastic wave. In this situation, AE plays important role whereby it can be used to capture the transient elastic wave and convert it into AE parameters such as amplitude, count, rise time and duration. Certain parameter can be used directly to evaluate the crack behavior. But in certain cases, the AE parameter needs to add and calculate by using related formula in order to observe the behavior of the crack. Using analysis of average frequency and RA value, the crack can be classified into tensile or shear cracks. In this study, seven phases of increasing static load were used to observe the crack behavior. The beams were tested in two conditions. For the first condition, the beams were tested in original stated without strengthened with carbon fibre sheet (CFS at the bottom of the beam or called as tension part of the beam. For the second condition, the beams were strengthened with CFS at the tension part of the beam. It was found that, beam wrapped with CFS enhanced the strength of the beams in term of maximum ultimate load. Based on the relationship between average frequency (AF and RA value, the cracks of the beams can be classified.

  11. Study of a reinforced concrete beam strengthened using a combination of SMA wire and CFRP plate

    Science.gov (United States)

    Liu, Zhi-qiang; Li, Hui

    2006-03-01

    Traditional methods used for strengthening of reinforced concrete (RC) structures, such as bonding of steel plates, suffer from inherent disadvantages. In recent years, strengthening of RC structures using carbon fiber reinforced polymer (CFRP) plates has attracted considerable attentions around the world. Most existing research on CFRP plate bonding for flexural strengthening of RC beams has been carried out for the strength enhancement. However, little research is focused on effect of residual deformations on the strengthening. The residual deformations have an important effect on the strengthening by CFRP plates. There exists a very significant challenge how the residual deformations are reduced. Shape memory alloy (SMA) has showed outstanding functional properties as an actuator. It is a possibility that SMA can be used to reduce the residual deformation and make cracks of concrete close by imposing the recovery forces on the concrete in the tensile zone. It is only an emergency damage repair since the SMA wires need to be heated continuously. So, an innovative method of a RC beam strengthened by CFRP plates in combination with SMA wires was first investigated experimentally in this paper. In addition, the nonlinear finite element software of ABAQUS was employed to further simulate the behavior of RC beams strengthened through the new strengthening method. It can be found that this is an excellent and effective strengthening method.

  12. Near Surface Mounted Composites for Flexural Strengthening of Reinforced Concrete Beams

    Directory of Open Access Journals (Sweden)

    Md. Akter Hosen

    2016-03-01

    Full Text Available Existing structural components require strengthening after a certain period of time due to increases in service loads, errors in design, mechanical damage, and the need to extend the service period. Externally-bonded reinforcement (EBR and near-surface mounted (NSM reinforcement are two preferred strengthening approach. This paper presents a NSM technique incorporating NSM composites, namely steel and carbon fiber-reinforced polymer (CFRP bars, as reinforcement. Experimental and analytical studies carried out to explore the performance of reinforced concrete (RC members strengthened with the NSM composites. Analytical models were developed in predicting the maximum crack spacing and width, concrete cover separation failure loads, and deflection. A four-point bending test was applied on beams strengthened with different types and ratios of NSM reinforcement. The failure characteristics, yield, and ultimate capacities, deflection, strain, and cracking behavior of the beams were evaluated based on the experimental output. The test results indicate an increase in the cracking load of 69% and an increase in the ultimate load of 92% compared with the control beam. The predicted result from the analytical model shows good agreement with the experimental result, which ensures the competent implementation of the present NSM-steel and CFRP technique.

  13. Strengthening an in-service reinforcement concrete bridge with prestressed CFRP bars

    Institute of Scientific and Technical Information of China (English)

    Hai-long WANG; Wei-liang JIN; David J.CLELAND; Ai-hui ZHANG

    2009-01-01

    Carbon fiber reinforced polymer(CFRP)bars were prestressed for the structural strengthening of 8 T-shaped rein-forced concrete (RC)beams of a 21-year-old bridge in China.The ultimate bearing capacity of the existing bridge after retrofit was discussed on the basis of concrete structures theory.The flexural strengths of RC beams strengthened with CFRP bars were controlled by the failure of concrete in compression and a prestressing method was applied in the retrofit.The field construction processes of strengthening with CFRP bars-including grouting cracks,cutting groove,grouting epoxy and embedding CFRP bars,surface treating,banding with the U-type CFRP sheets,releasing external prestressed steel tendons-were introduced in detail.In order to evaluate the effectiveness of this strengthening method,field tests using vehicles as live load were applied before and after the retrofit.The test results of deflection and concrete strain of the T-shaped beams with and without strengthening show that the capacity of the repaired bridge,including the bending strength and stiffness,is enhanced.The measurements of crack width also indicate that this strengthening method can enhance the durability of bridges.Therefore,the proposed strengthening technology is feasible and effective.

  14. Seismic Behavior of Steel Off-Diagonal Bracing System (ODBS Utilized in Reinforced Concrete Frame

    Directory of Open Access Journals (Sweden)

    Keyvan Ramin

    2014-01-01

    Full Text Available The introduction of an eccentricity in this system results in a geometric nonlinearity behavior. The midpoint of the diagonal member is connected to the corner joint using a brace member with a relatively low stiffness, thus forming a three-member bracing system in each braced panel. An iterative method of analysis has been developed to study the nonlinear load-deflection behavior of ODBS. The results indicate that the load-deflection behavior of this system follows a nonlinear stiffness-hardening pattern with two yielding points, which reflect the tensile failure of different bracings; the present study aims to investigate the efficiency of applying off-diagonal steel braces to reinforced concrete frames. To achieve this, three types of 2-story, 6-story, and 15-story structures without and with X-bracing and off-center bracing systems were modeled using SAP2000 software, and for micromodeling ANSYS software was used to achieve finite element results for an exact comparison between various retrofitting systems. The results showed that the structures strengthened by toggle bracing system revealed better behavior for low oscillation periods. Moreover, this type of bracing system is quite suitable for 10-story structures but not for higher ones. Its main problem, which requires special contrivances to solve, is the existence of a soft ground floor.

  15. Seismic retrofitting of reinforced concrete frame structures using GFRP-tube-confined-concrete composite braces

    Science.gov (United States)

    Moghaddasi B., Nasim S.; Zhang, Yunfeng; Hu, Xiaobin

    2012-03-01

    This paper presents a new type of structural bracing intended for seismic retrofitting use in framed structures. This special composite brace, termed glass-fiber-reinforced-polymer (GFRP)-tube-confined-concrete composite brace, is comprised of concrete confined by a GFRP tube and an inner steel core for energy dissipation. Together with a contribution from the GFRP-tube confined concrete, the composite brace shows a substantially increased stiffness to control story drift, which is often a preferred feature in seismic retrofitting. An analysis model is established and implemented in a general finite element analysis program — OpenSees, for simulating the load-displacement behavior of the composite brace. Using this model, a parametric study of the hysteretic behavior (energy dissipation, stiffness, ductility and strength) of the composite brace was conducted under static cyclic loading and it was found that the area ratio of steel core to concrete has the greatest influence among all the parameters considered. To demonstrate the application of the composite brace in seismic retrofitting, a three-story nonductile reinforced concrete (RC) frame structure was retrofitted with the composite braces. Pushover analysis and nonlinear time-history analyses of the retrofitted RC frame structure was performed by employing a suite of 20 strong ground motion earthquake records. The analysis results show that the composite braces can effectively reduce the peak seismic responses of the RC frame structure without significantly increasing the base shear demand.

  16. Probabilistic Lifetime Assessment of Marine Reinforced Concrete with Steel Corrosion and Cover Cracking

    Institute of Scientific and Technical Information of China (English)

    LU Chun-hua; JIN Wei-liang; LIU Rong-gui

    2011-01-01

    In order to study the durability behavior of marine reinforced concrete structure suffering from chloride attack, the structural service life is assumed to be divided into three critical stages, which can be characterized by steel corrosion and cover cracking. For each stage, a calculated model used to predict the lifetime is developed. Based on the definition of durability limit state, a probabilistic lifetime model and its time-dependent reliability analytical method are proposed considering the random natures of influencing factors. Then, the probabilistic lifetime prediction models are applied to a bridge pier located in the Hangzhou Bay with Monte Carlo simulation. It is found that the time to corrosion initiation to follows a lognonnal distribution, while that the time from corrosion initiation to cover cracking t and the time for crack to develop from hairline crack to a limit crack width t can be described by Weibull distributions. With the permitted failure probability of 5.0%, it is also observed that the structural durability lifetime mainly depends on the durability life to and that the percentage of participation of tbe life t to the total service life grows from 61.5% to 83.6% when the cover thickness increases from 40 mm to 80 mm. Therefore, for any part of the marine RC bridge, the lifetime predictions and maintenance efforts should also be directed toward controlling the stage of corrosion initiation induced by chloride ion.

  17. Performance evaluation of corrosion-affected reinforced concrete bridge girders using Markov chains with fuzzy states

    Indian Academy of Sciences (India)

    M B ANOOP; K BALAJI RAO

    2016-08-01

    A methodology for performance evaluation of reinforced concrete bridge girders in corrosive environments is proposed. The methodology uses the concept of performability and considers both serviceability- and ultimate-limit states. The serviceability limit states are defined based on the degree of cracking (characterized by crack width) in the girder due to chloride induced corrosion of reinforcement, and the ultimate limit states are defined based on the flexural load carrying capacity of the girder (characterized in terms of rating factor using the load and resistance factor rating method). The condition of the bridge girder is specified by the assignment of a condition state from a set of predefined condition states. Generally, the classification of condition states is linguistic, while the condition states are considered to be mutually exclusive and collectivelyexhaustive. In the present study, the condition states of the bridge girder are also represented by fuzzy sets to consider the ambiguities arising due to the linguistic classification of condition states. A non-homogeneous Markov chain (MC) model is used for modeling the condition state evolution of the bridge girder with time. The usefulness of the proposed methodology is demonstrated through a case study of a severely distressed beam of the Rocky Point Viaduct. The results obtained using the proposed approach are compared with those obtained using conventional MC model. It is noted that the use of MC with fuzzy states leads to conservative decision making for the problem considered in the case study.

  18. THEORETICAL MODEL ON INTERFACE FAILURE MECHANISM OF REINFORCED CONCRETE CONTINUOUS BEAM STRENGTHENED BY FRP

    Institute of Scientific and Technical Information of China (English)

    Hong Yuan; Zifeng Lin

    2009-01-01

    Fiber reinforced polymer (FRP) composites are increasingly being used for the re-pair and strengthening of deteriorated concrete structural components through adhesive bonding of prefabricated strips/plates and the wet lay-up of fabric. Interracial bond failure modes have at-tracted the attention of researchers because of the importance. The objective of the present study is to analyse the interface failure mechanism of reinforced concrete continuous beam strength-ened by FRP. An analytical solution has been firstly presented to predict the entire debonding process of the model. The realistic bi-linear bond-slip interfacial law was adopted to study this problem. The crack propagation process of the loaded model was divided into four stages (elastic, elastic-softening, elastic-softening-debonded and softening-debonded stage). Among them, elastic-softening-debonded stage has four sub-stages. The equations are solved by adding suitable stress and displacement boundary conditions. Finally, critical value of bond length is determined to make the failure mechanism in the paper effective by solving the simultaneously linear algebraic equations. The interaction between the upper and lower FRP plates can be neglected if axial stiffness ratio of the concrete-to-plate prism is large enough.

  19. Numerical Methods Application for Reinforced Concrete Elements-Theoretical Approach for Direct Stiffness Matrix Method

    Directory of Open Access Journals (Sweden)

    Sergiu Ciprian Catinas

    2015-07-01

    Full Text Available A detailed theoretical and practical investigation of the reinforced concrete elements is due to recent techniques and method that are implemented in the construction market. More over a theoretical study is a demand for a better and faster approach nowadays due to rapid development of the calculus technique. The paper above will present a study for implementing in a static calculus the direct stiffness matrix method in order capable to address phenomena related to different stages of loading, rapid change of cross section area and physical properties. The method is a demand due to the fact that in our days the FEM (Finite Element Method is the only alternative to such a calculus and FEM are considered as expensive methods from the time and calculus resources point of view. The main goal in such a method is to create the moment-curvature diagram in the cross section that is analyzed. The paper above will express some of the most important techniques and new ideas as well in order to create the moment curvature graphic in the cross sections considered.

  20. Flexural and Thermal Properties of Novel Energy Conservation Slotted Reinforced Concrete Beams

    Directory of Open Access Journals (Sweden)

    Gao Ma

    2016-01-01

    Full Text Available Conventional solid reinforced concrete (RC beams were modified to slotted beams for consideration as thermal insulation structural components. The slotted beam consisted of an outer and an inner beam, respectively, with a slot located near the middle of the beam along its width direction for filling thermal insulation material. Flexural and thermal behavior of the slotted beams were investigated. Three RC reference solid beams and six slotted beams were fabricated and tested under four-point bending tests. The test results indicated that the failure mode of both slotted beams and the solid beams was flexural failure. However, the damage process of the slotted beams was different from that of the solid beams at the final loading stage. The moment curvature analysis indicated that the tensile reinforcement ratio of the outer and inner beams had an important effect on the flexural behavior, especially the ductility of the slotted beams. Thermal study indicated that the heat transfer coefficient of the slotted beam was greatly reduced and the thermal inertia factor increased a lot, compared with the solid beam. In addition, FE simulation results showed that a new frame structure using slotted beams exhibited obvious and attractive thermal insulation property.

  1. Evaluation of the resistance to progressive collapse of monolithic reinforced concrete frame buildingswith separate amplified floors

    Directory of Open Access Journals (Sweden)

    Domarova Ekaterina Vladimirovna

    2014-02-01

    Full Text Available In the article the authors propose a simplified method of dynamic analysis of the resistance to progressive collapse of a fragment of the building bearing system with amplified floors. This method is based on representing the building bearing system as a dynamic model with a denumerable number of degrees of freedom, in which the resistance of the system is provided mainly by the behavior of the columns. The degrees of freedom number is determined by the number of floors «hanging» to amplified floors. Thecontribution of slabs in the total system resistance is not taken into account. Stress-strain state of the columns is determined by the non-linear resistance diagram, including three stages: elastic, elastic with cracks and plastic stage connected with plastic yield in the steel of the columns. The criterion of sustainability to the progressive collapse is relative strain of steel of the undestroyed columns. A numerical example of the calculation of the building resistance to progressive collapse in case of sudden destruction of one vertical element based on proposed theoretical method is offered. A model with two numbers of degrees was considered. The suggested method allows estimating the strength, deformability and stability of monolithic reinforced concrete frame buildings with separate amplified floors. In the future it is intended to complicate the model by the accounting for the influence of deformation and constructive solution of the slabs on the stiffness characteristics of the model as a system with a finite number of degrees of freedom.

  2. Primer on Durability of Nuclear Power Plant Reinforced Concrete Structures - A Review of Pertinent Factors

    Energy Technology Data Exchange (ETDEWEB)

    Naus, Dan J [ORNL

    2007-02-01

    The objective of this study was to provide a primer on the environmental effects that can affect the durability of nuclear power plant concrete structures. As concrete ages, changes in its properties will occur as a result of continuing microstructural changes (i.e., slow hydration, crystallization of amorphous constituents, and reactions between cement paste and aggregates), as well as environmental influences. These changes do not have to be detrimental to the point that concrete will not be able to meet its performance requirements. Concrete, however, can suffer undesirable changes with time because of improper specifications, a violation of specifications, or adverse performance of its cement paste matrix or aggregate constituents under either physical or chemical attack. Contained in this report is a discussion on concrete durability and the relationship between durability and performance, a review of the historical perspective related to concrete and longevity, a description of the basic materials that comprise reinforced concrete, and information on the environmental factors that can affect the performance of nuclear power plant concrete structures. Commentary is provided on the importance of an aging management program.

  3. EFFECTS OF COLUMN FAILURES ON THE INTERNAL FORCES OF ORTHOGONAL REINFORCED CONCRETE BUILDING FRAMES

    Directory of Open Access Journals (Sweden)

    Nilay KAYA

    2006-02-01

    Full Text Available In this study, the effects of column failures which may take place due to the special causes such as blast, vehicle impact, insufficient or deficient design, on the internal forces of orthogonal reinforced concrete building frames have been investigated. Calculations have been performed with SAP2000 structural analysis program, under static conditions. For a typical frame system, firstly, various column failure scenarios have been considered for uninfilled case and internal forces have been calculated and compared with those in the intact case. Then, similar calculations have been implemented for the case of presence of infill walls. The results of analyses have shown that the effects of column failures had condensed on the neighbor columns and beams of orthogonal frames on which the columns had been failed. Moreover, it has been determined that, while the bending moment capacities of the connected beams to the failed columns had exceeded in the bare frames, in the masonry infilled frames, walls give substantial support to the structural elements of the building, and capacities of the beams had not exceeded.

  4. Improved design of special boundary elements for T-shaped reinforced concrete walls

    Science.gov (United States)

    Ji, Xiaodong; Liu, Dan; Qian, Jiaru

    2017-01-01

    This study examines the design provisions of the Chinese GB 50011-2010 code for seismic design of buildings for the special boundary elements of T-shaped reinforced concrete walls and proposes an improved design method. Comparison of the design provisions of the GB 50011-2010 code and those of the American code ACI 318-14 indicates a possible deficiency in the T-shaped wall design provisions in GB 50011-2010. A case study of a typical T-shaped wall designed in accordance with GB 50011-2010 also indicates the insufficient extent of the boundary element at the non-flange end and overly conservative design of the flange end boundary element. Improved designs for special boundary elements of T-shaped walls are developed using a displacement-based method. The proposed design formulas produce a longer boundary element at the non-flange end and a shorter boundary element at the flange end, relative to those of the GB 50011-2010 provisions. Extensive numerical analysis indicates that T-shaped walls designed using the proposed formulas develop inelastic drift of 0.01 for both cases of the flange in compression and in tension.

  5. Theoretical and numerical analysis of reinforced concrete beams with confinement reinforcement

    Directory of Open Access Journals (Sweden)

    R. G. Delalibera

    Full Text Available This paper discusses the use of confinement in over-reinforced concrete beams. This reinforcement consists of square stirrups, placed in the compression zone of the beam cross-section, in order to improve its ductility. A parametric numerical study is initially performed, using a finite element computational program that considers the material nonlinearities and the confinement effect. To investigate the influence of the transverse reinforcing ratio on the beam ductility, an experimental program was also conducted. Four over-reinforced beams were tested; three beam specimens with additional transverse reinforcement to confine the beams, and one without it. All specimens were fabricated with a concrete designed for a compressive strength of 25 MPa. The experimental results show that the post-peak ductility factor is proportional to the confining reinforcement ratio, however the same is not observed for the pre-peak ductility factor, which varied randomly with changes in the confining reinforcement ratio. It was also observed from the experiments that the confinement effect tends to be smaller close to the beam neutral axis.

  6. Multifunctional Cement Composites Strain and Damage Sensors Applied on Reinforced Concrete (RC Structural Elements

    Directory of Open Access Journals (Sweden)

    Pedro Garcés

    2013-03-01

    Full Text Available In this research, strain-sensing and damage-sensing functional properties of cement composites have been studied on a conventional reinforced concrete (RC beam. Carbon nanofiber (CNFCC and fiber (CFCC cement composites were used as sensors on a 4 m long RC beam. Different casting conditions (in situ or attached, service location (under tension or compression and electrical contacts (embedded or superficial were compared. Both CNFCC and CFCC were suitable as strain sensors in reversible (elastic sensing condition testing. CNFCC showed higher sensitivities (gage factor up to 191.8, while CFCC only reached gage factors values of 178.9 (tension or 49.5 (compression. Furthermore, damage-sensing tests were run, increasing the applied load progressively up to the RC beam failure. In these conditions, CNFCC sensors were also strain sensitive, but no damage sensing mechanism was detected for the strain levels achieved during the tests. Hence, these cement composites could act as strain sensors, even for severe damaged structures near to their collapse.

  7. Shear strengthening of pre-damaged reinforced concrete beams with carbon fiber reinforced polymer sheet strips

    Institute of Scientific and Technical Information of China (English)

    Feras ALZOUBI; ZHANG Qi; LI Zheng-liang

    2007-01-01

    This paper presents the results of an experimental investigation on the response of pre-damaged reinforced concrete (RC) beam strengthened in shear using applied-epoxy unidirectional carbon fiber reinforced polymer (CFRP) sheet. The reasearch included four test rectangular simply supported RC beams in shear capacity. One is the control beam, two RC beams are damaged to a predetermined degree from ultimate shear capacity of the control beam, and the last beam is left without pre-damaged and then strengthened with using externally bonded carbon fiber reinforced polymer to upgrade their shear capacity. We focused on the damage degree to beams during strengthening, therefore, only the beams with side-bonded CFRPs strips and horizontal anchored strips were used. The results show the feasibility of using CFRPs to restore or increase the load-carrying capacity in the shear of damaged RC beams. The failure mode of all the CFRP-strengthened beams is debonding of CFRP vertical strips. Two prediction available models in ACI-440 and fib European code were compared with the experimental results.

  8. Behavior of FRP Bars-Reinforced Concrete Slabs under Temperature and Sustained Load Effects

    Directory of Open Access Journals (Sweden)

    Hizia Bellakehal

    2014-03-01

    Full Text Available The large temperature variation has a harmful effect on concrete structures reinforced with fiber reinforced polymer (FRP bars. This is due to the significant difference between transverse coefficient of thermal expansion of these bars and that of the hardened concrete. This difference generates a radial pressure at the FRP bar/concrete interface, and may cause splitting cracks within concrete. This paper presents results of an experimental and analytical study carried out on FRP-reinforced concrete slabs subjected, simultaneously, to thermal and mechanical loads. The analytical model based on the theory of linear elasticity consists to evaluate combined effects of thermal and mechanical loads on the transverse expansion of FRP bars. Parameters studied in this investigation are the concrete cover thickness, FRP bar diameter, and the temperature variation. The thermal cycles were varied from −30 to +60 °C. Comparisons between analytical and experimental results show that transverse strains predicted from the proposed model are in good correlation with experimental results.

  9. Progressive collapse resisting capacity of reinforced concrete load bearing wall structures

    Institute of Scientific and Technical Information of China (English)

    Alireza Rahai; Alireza Shahin; Farzad Hatami

    2015-01-01

    Reinforced concrete (RC) load bearing wall is widely used in high-rise and mid-rise buildings. Due to the number of walls in plan and reduction in lateral force portion, this system is not only stronger against earthquakes, but also more economical. The effect of progressive collapse caused by removal of load bearing elements, in various positions in plan and stories of the RC load bearing wall system was evaluated by nonlinear dynamic and static analyses. For this purpose, three-dimensional model of 10-story structure was selected. The analysis results indicated stability, strength and stiffness of the RC load-bearing wall system against progressive collapse. It was observed that the most critical condition for removal of load bearing walls was the instantaneous removal of the surrounding walls located at the corners of the building where the sections of the load bearing elements were changed. In this case, the maximum vertical displacement was limited to 6.3 mm and the structure failed after applying the load of 10 times the axial load bored by removed elements. Comparison between the results of the nonlinear dynamic and static analyses demonstrated that the “load factor” parameter was a reasonable criterion to evaluate the progressive collapse potential of the structure.

  10. Analytical Prediction of the Seismic Response of a Reinforced Concrete Containment Vessel

    Energy Technology Data Exchange (ETDEWEB)

    James, R.J.; Rashid, Y.R.; Cherry, J.L.; Chokshi, N.; Tsurumaki, S.

    1999-03-19

    Under the sponsorship of the Ministry of International Trade and Industry (MITI) of Japan, the Nuclear Power Engineering Corporation (NUPEC) is investigating the seismic behavior of a Reinforced Concrete Containment Vessel (RCCV) through scale-model testing using the high-performance shaking table at the Tadotsu Engineering Laboratory. A series of tests representing design-level seismic ground motions was initially conducted to gather valuable experimental measurements for use in design verification. Additional tests will be conducted with increasing amplifications of the seismic input until a structural failure of the test model occurs. In a cooperative program with NUPEC, the US Nuclear Regulatory Commission (USNRC), through Sandia National Laboratories (SNL), is conducting analytical research on the seismic behavior of RCCV structures. As part of this program, pretest analytical predictions of the model tests are being performed. The dynamic time-history analysis utilizes a highly detailed concrete constitutive model applied to a three-dimensional finite element representation of the test structure. This paper describes the details of the analysis model and provides analysis results.

  11. Development of Genetic Algorithm Based Macro Mechanical Model for Steel Fibre Reinforced Concrete

    Directory of Open Access Journals (Sweden)

    Gopala Krishna Sastry, K, V.S ,

    2014-01-01

    Full Text Available This paper presents the applicability of hybrid networks that combine Artificial Neural Network (ANN and Genetic Algorithm (GA for predicting the strength properties of Steel Fibre Reinforced concrete (SFRC with different water-cement ratio (0.4,0.45,0.5,0.55, aggregate-cement ratio (3,4,5, % of fibres (0.75,1.0,1.5 and aspect ratio of fibres (40,50,60 as input vectors. Strength properties of SFRC such as compressive strength, flexural strength, split tensile strength and compaction factor are considered as output vector. The network has been trained with data obtained from experimental work. The hybrid neural network model learned the relation between input and output vectors in 1900 iterations. After successful learning GA based BPN model predicted the strength characteristics satisfying all the constrains with an accuracy of about 95%.The various stages involved in the development of genetic algorithm based neural network model are addressed at length in this paper.

  12. Nonlinear seismic response analysis of reinforced concrete tube in tube structure

    Institute of Scientific and Technical Information of China (English)

    WANG Hai-bo; SHEN Pu-sheng

    2005-01-01

    Super-highly reinforced concrete tube in tube structure is a developing structure system of high-rise building. The more reasonable derivation process of the multi-vertical-line-element model stiffness matrix is given.On the premise of pointing out the problems of present multi-spring element model, combined with present multivertical-line-element model for analyzing on shear wall, the model is expanded to spatial one, and the stiffness matrix of which is derived. Combined with hysteretic axial model and hysteretic shear model, it is suitable for columns,wall limbs and beams with all kinds of section form. Some examples are calculated and compared with test results,which shows that the models have relatively good accuracy. On the base of the experimental phenomenon and failure mechanism for tube in tube structure specimen, nonlinear seismic responses analysis program on the basis of the advantaged element model for tube in tube structure is developed. Calculation results are in good agreement with those of the pseudo-dynamic tests and the failure mechanism can be well reflected.

  13. Experimental Research of Reinforced Concrete Buildings Struck by Debris Flow in Mountain Areas of Western China

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yu; WEI Fangqiang; WANG Qing

    2007-01-01

    It's very important to simulate impact load of debris flow effectively and to investigate dynamic response of architectures under dynamic impact of debris flow, which are necessary to design disaster mitigation construction. Firstly, reinforced concrete domestic architectures in mountain areas of western China had been chosen as main architecture style. The bearing load style and the destructed shape of reinforced framed construction impacted by discontinuous viscous debris flow were studied systematically. Secondly, Jiangjia Ravine debris flow valley in Yunnan Province, China had been chosen as research region. Utilizing based data from fieldwork and practical survey, the authors simulated and calculated theoretically impact force of discontinuous viscous debris flow. Thirdly, an impact data collecting system (IMHE IDCS) was designed and developed to fulfill designed simulation experiments. Finally, a series of impact test of researched structure models had been fulfilled. During experiment, the destructed shape and course of models were observed and the dynamic displacement data and main natural frequency data of models were collected and analyzed.

  14. Qualitative and Quantitative Seismic Evaluation of Reinforced Concrete Structures in Petrochemical Plant

    Directory of Open Access Journals (Sweden)

    Fariborz Nateghi-A.

    2010-12-01

    Full Text Available In this paper the seismic evaluation of reinforced concrete structures in petrochemical facilities under sever conditions such as high pressure, high temperature and corrosive environment is studied. These structures were designed and constructed during 1976-78. The evaluation procedure is basically performed in two phases namely; a qualitative and b quantitative methods. In the qualitative evaluation, all possible documentations including drawings, specifications, structural calculations, new additions and test results were studied. Collected data then was summarized in an evaluation checklist. When the needed requirements did not meet the specified entries, more detailed and quantitative analysis were performed and utilized in this study. Quantitative and numerical study was performed using finite element modeling under sever loading combinations. Based on the results of this evaluation, some important RC structures in this plant were highly vulnerable to seismic forces which required immediate attention. The methodology used and results obtained can be generalized and adapted for similar facilities. This paper will present details, procedure and conclusions obtained.

  15. Analysis of Three Dimensional Horizontal Reinforced Concrete Curved Beam Using Ansys

    Directory of Open Access Journals (Sweden)

    T. Subramani

    2014-06-01

    Full Text Available Reinforced concrete horizontally curved beams are extensively used in many fields, such as in the construction of modern highway intersections, elevated freeways, the rounded corners of buildings, circular balconies,….etc. In some of these cases, large depths are needed for curved beams in order to resist high loads or to fulfill some aesthetic purposes. The analytical analysis of such members is very complex due to the fact that those members are subjected to combined action of bending, shear and torsion. Furthermore, non homogeneous nature of the materials involved contributes to the complexity of the problem. Therefore, it becomes necessary to employ numerical analysis procedures, such as the finite element method, to satisfy the safety and the economy requirements.A horizontally curved beam, loaded transversely to its plane, is subjected to torsion in addition to bending and shear. Furthermore, in deep beam the plane section does not remain plane after bending because of high stresses and warping occurs. Therefore, special features of analysis and design for horizontally curved deep beams is necessary to include the effect of above mentioned factors. Several methods of collapse analysis (Khalifa 1972, Jordaan et al. 1974, Badawy et al. 1977, Hsu et al.

  16. PREDICTION OF MAXIMUM CREEP STRAIN OF HIGH PERFORMANCE STEEL FIBER REINFORCED CONCRETE

    Directory of Open Access Journals (Sweden)

    Mishina Alexandra Vasil'evna

    2012-12-01

    Full Text Available The strongest research potential is demonstrated by the areas of application of high performance steel fiber reinforced concrete (HPSFRC. The research of its rheological characteristics is very important for the purposes of understanding its behaviour. This article is an overview of an experimental study of UHSSFRC. The study was carried out in the form of lasting creep tests of HPSFRC prism specimen, loaded by stresses of varied intensity. The loading was performed at different ages: 7, 14, 28 and 90 days after concreting. The stress intensity was 0.3 and 0.6 Rb; it was identified on the basis of short-term crush tests of similar prism-shaped specimen, performed on the same day. As a result, values of ultimate creep strains and ultimate specific creep of HPSFRC were identified. The data was used to construct an experimental diagramme of the ultimate specific creep on the basis of the HPSFRC loading age if exposed to various stresses. The research has resulted in the identification of a theoretical relationship that may serve as the basis for the high-precision projection of the pattern of changes in the ultimate specific creep of HPSFRC, depending on the age of loading and the stress intensity.

  17. In-Plane Behaviour of a Reinforcement Concrete Frame with a Dry Stack Masonry Panel

    Directory of Open Access Journals (Sweden)

    Kun Lin

    2016-02-01

    Full Text Available In order to improve the energy dissipation of the masonry infilled frame structure while decreasing the stiffening and strengthening effects of the infill panels, a new dry stacked panel (DSP semi-interlocking masonry (SIM infill panel has been developed. In this paper, the material properties of DSP and a traditional unreinforced masonry (URM panel have been evaluated experimentally. A series of cyclic tests were performed to investigate the cyclic behaviour of the reinforcement concrete (RC frame with different infill panels. The failure modes, damage evolution, hysteretic behaviour, stiffness degradation and energy dissipation were compared and analysed. We concluded that DSP is capable of significantly improving the seismic energy dissipation due to its hysteretic behaviour when the frame is in elastic stage without increasing the stiffness of the frame. Therefore, DSP or SIM panels can be considered as frictional dampers. Based on the experimental results, the influence of DSP was examined. Using the parallel model, the hysteretic loops of DSP subjected to different load cases were achieved. The typical full hysteretic loop for DSP could be divided into three distinct stages of behaviour: packing stage, constant friction stage and equivalent strut stage. The connection between the panel and the frame had a great effect on the transferring of different mechanical stages. The constant friction stage was verified to provide substantial energy dissipation and benefits to the ductility of the structure, which, therefore, is suggested to be prolonged in reality.

  18. Structural Engineering Properties of Fibre Reinforced Concrete Based On Recycled Glass Fibre Polymer (GFRP

    Directory of Open Access Journals (Sweden)

    Adetiloye A

    2015-04-01

    Full Text Available Glass fibre reinforced plastics (GFRP based on resin recovered from recycling plastic waste has been shown to possess mechanical properties satisfying normative requirements. This paper investigates the flexural behavior of concrete beams reinforced with GFRP produced from resin recovered from recycled plastic wastes. A total of twelve of beams of sizes 150 ×150 ×900mm and 100 × 100 × 500mm reinforced with GFRP made from recycled glass fibre reinforced polymer was tested. The flexural test results yielded lower ultimate load, lower stiffness and larger deflections at the same load when compared with the control steel reinforced beam. However, the ultimate flexural strength of beams, reinforced with GFRP from recycled resin was at least four times higher than that of the control unreinforced beam. This is in agreement, quantitatively and qualitatively, with the trend of these parameters in GFRP reinforced concrete based on virgin resins. The results therefore confirm the applicability for structural uses of GFRP reinforcement made from recycled plastic waste, with the accompanying benefits of wealth creation, value addition and environmental sustainability.

  19. Simulation of reinforced concrete short shear wall subjected to cyclic loading

    Energy Technology Data Exchange (ETDEWEB)

    Parulekar, Y.M., E-mail: yogitap@barc.gov.in [Bhabha Atomic Research Centre (India); Reddy, G.R., E-mail: rssred@barc.gov.in [Bhabha Atomic Research Centre (India); Vaze, K.K. [Reactor Design and Development Group, Bhabha Atomic Research Centre (India); Pegon, P. [Joint Research Centre, Ispra (Italy); Wenzel, H. [Vienna Consulting Engineers, Vienna (Austria)

    2014-04-01

    Highlights: • Prediction of the capacity of squat shear wall using tests and analysis. • Modification of model of concrete in the softening part. • Pushover analysis using softened truss theory and FE analysis is performed. • Modified concrete model gives reasonable accurate peak load and displacement. • The ductility, ultimate load and also crack pattern can be accurately predicted. - Abstract: This paper addresses the strength and deformation capacity of stiff squat shear wall subjected to monotonic and pseudo-static cyclic loading using experiments and analysis. Reinforced concrete squat shear walls offer great potential for lateral load resistance and the failure mode of these shear walls is brittle shear mode. Shear strength of these shear walls depend strongly on softening of concrete struts in principal compression direction due to principal tension in other direction. In this work simulation of the behavior of a squat shear wall is accurately predicted by finite element modeling by incorporating the appropriate softening model in the program. Modification of model of concrete in the softening part is suggested and reduction factor given by Vecchio et al. (1994) is used in the model. The accuracy of modeling is confirmed by comparing the simulated response with experimental one. The crack pattern generated from the 3D model is compared with that obtained from experiments. The load deflection for monotonic loads is also obtained using softened truss theory and compared with experimental one.

  20. Review of Physical Based Monitoring Techniques for Condition Assessment of Corrosion in Reinforced Concrete

    Directory of Open Access Journals (Sweden)

    Ying Lei

    2013-01-01

    Full Text Available Monitoring the condition of steel corrosion in reinforced concrete (RC is imperative for structural durability. In the past decades, many electrochemistry based techniques have been developed for monitoring steel corrosion. However, these electrochemistry techniques can only assess steel corrosion through monitoring the surrounding concrete medium. As alternative tools, some physical based techniques have been proposed for accurate condition assessment of steel corrosion through direct measurements on embedded steels. In this paper, some physical based monitoring techniques developed in the last decade for condition assessment of steel corrosion in RC are reviewed. In particular, techniques based on ultrasonic guided wave (UGW and Fiber Bragg grating (FBG are emphasized. UGW based technique is first reviewed, including important characters of UGW, corrosion monitoring mechanism and feature extraction, monitoring corrosion induced deboning, pitting, interface roughness, and influence factors. Subsequently, FBG for monitoring corrosion in RC is reviewed. The studies and application of the FBG based corrosion sensor developed by the authors are presented. Other physical techniques for monitoring corrosion in RC are also introduced. Finally, the challenges and future trends in the development of physical based monitoring techniques for condition assessment of steel corrosion in RC are put forward.

  1. A Study on the Bond Behavior of Corroded Reinforced Concrete Containing Recycled Aggregates

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    Haifeng Yang

    2015-01-01

    Full Text Available This paper investigated bond-slip characteristics of chloride-induced corroded reinforced concrete incorporating different levels of recycled concrete aggregates (RCA. Pullout tests were adopted to evaluate the bonding and debonding behaviors of the embedded rebar experiencing different corrosion levels. Both high- and low-strength concrete were considered. Bond-slip curves were recorded to determine the influences of rebar corrosion levels and RCA replacements on the bond strength and debonding energy of the specimens. Test results indicate that increasing rebar corrosion level gradually weakens the antisliding ability of reinforced recycled aggregate concrete (RAC except for a small level corrosion and the degradation rate of ultimate bond strength increases with a decrease of compressive strength at 0.5% rebar corrosion. The results also demonstrate that the ultimate bond strength of reinforced RAC slightly decreases with an increase of RCA replacement. However, the relative bond strength between uncorroded rebar and RAC is little affected by RCA content, while it decreases with an increase of RCA replacement in high-strength specimens after rebar corrosion. The debonding energy between deformed rebar and RAC is found decreasing with the increment of the rebar corrosion level and increasing with an increase of RAC content.

  2. An Experimental Study on Strengthening of Reinforced Concrete Flexural Members using Steel Wire Mesh

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    Al Saadi Hamza Salim Mohammed

    2017-01-01

    Full Text Available One of the major challenges and contemporary research in the field of structural engineering is strengthening of existing structural elements using readily available materials in the market. Several investigations were conducted on strengthening of various structural components using traditional and advanced materials. Many researchers tried to enhance the reinforced concrete (RC beams strength using steel plate, Glass and Carbon Fibre Reinforced Polymers (GFRP & CFRP. For the reason that high weight to the strength ratio and compatibility in strength between FRP composites and steel bars, steel plates and GFRP and CFRP composites are not used for strengthening works practically. Hence, in this present work the suitability of using wire mesh for the purpose of strengthening the RC flexural members is studied by conducting experimental works. New technique of strengthening system using wire mesh with a view to improve sectional properties and subsequently flexural strength of RC beams is adopted in this work. The results for experimental and theoretical analysis were compared and found that good correlation exists between them. The experimental results indicate that RC beams strengthened with steel wire mesh are easy technique for strengthening of existing flexural members.

  3. Acoustic emission monitoring of multicell reinforced concrete box girders subjected to torsion.

    Science.gov (United States)

    Bagherifaez, Marya; Behnia, Arash; Majeed, Abeer Aqeel; Hwa Kian, Chai

    2014-01-01

    Reinforced concrete (RC) box girders are a common structural member for road bridges in modern construction. The hollow cross-section of a box girder is ideal in carrying eccentric loads or torques introduced by skew supports. This study employed acoustic emission (AE) monitoring on multicell RC box girder specimens subjected to laboratory-based torsion loading. Three multicell box girder specimens with different cross-sections were tested. The aim is to acquire AE analysis data indicative for characterizing torsion fracture in the box girders. It was demonstrated through appropriate parametric analysis that the AE technique could be utilized to effectively classify fracture developed in the specimens for describing their mechanical behavior under torsion. AE events localization was presented to illustrate the trend of crack and damage propagation in different stages of fracture. It could be observed that spiral-like patterns of crack were captured through AE damage localization system and damage was quantified successfully in different stages of fracture by using smoothed b-value analysis.

  4. Acoustic Emission Monitoring of Multicell Reinforced Concrete Box Girders Subjected to Torsion

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    Marya Bagherifaez

    2014-01-01

    Full Text Available Reinforced concrete (RC box girders are a common structural member for road bridges in modern construction. The hollow cross-section of a box girder is ideal in carrying eccentric loads or torques introduced by skew supports. This study employed acoustic emission (AE monitoring on multicell RC box girder specimens subjected to laboratory-based torsion loading. Three multicell box girder specimens with different cross-sections were tested. The aim is to acquire AE analysis data indicative for characterizing torsion fracture in the box girders. It was demonstrated through appropriate parametric analysis that the AE technique could be utilized to effectively classify fracture developed in the specimens for describing their mechanical behavior under torsion. AE events localization was presented to illustrate the trend of crack and damage propagation in different stages of fracture. It could be observed that spiral-like patterns of crack were captured through AE damage localization system and damage was quantified successfully in different stages of fracture by using smoothed b-value analysis.

  5. Effect of the selected seismic energy dissipation capacity on the materials quantity for reinforced concrete walls

    Directory of Open Access Journals (Sweden)

    José Miguel Benjumea Royero

    2017-02-01

    Full Text Available Context: Regarding their design of reinforced concrete structural walls, the Colombian seismic design building code allows the engineer to select one of the three seismic energy dissipation capacity (ordinary, moderate, and special depending on the seismic hazard of the site. Despite this, it is a common practice to choose the minor requirement for the site because it is thought that selecting a higher requirement will lead to larger structural materials amounts and, therefore, cost increments.  Method: In this work, an analytical study was performed in order to determine the effect of the selected energy dissipation capacity on the quantity of materials and ductility displacement capacity of R/C walls. The study was done for a region with low seismic hazard, mainly because this permitted to explore and compare the use of the three seismic energy dissipations capacities. The effect of different parameters such as the wall total height and thickness, the tributary loaded area, and the minimum volumetric steel ratio were studied. Results: The total amount of steel required for the walls with moderate and special energy dissipation capacity corresponds, on average, to 77% and 89%, respectively, of the quantity required for walls with minimum capacity. Conclusions: it is possible to achieve reductions in the total steel required weight when adopting either moderated or special seismic energy dissipation instead of the minimum capacity.  Additionally, a significant increment in the seismic ductility displacements capacity of the wall was obtained.

  6. Self-immunity microcapsules for corrosion protection of steel bar in reinforced concrete

    Science.gov (United States)

    Wang, Yanshuai; Fang, Guohao; Ding, Weijian; Han, Ningxu; Xing, Feng; Dong, Biqin

    2015-12-01

    A novel microcapsule-based self-immunity system for reinforced concrete is proposed. Its feasibility for hindering the corrosion of steel rebar by means of lifting the threshold value of [Cl-]/[OH-] is discussed. Precisely controlled release behavior enables corrosion protection in the case of depassivation. The release process is characterized over a designated range of pH values, and its release characteristics of the microcapsules, triggered by decreasing pH value, are captured by observing that the core crystals are released when exposed to a signal (stimulus). The aim of corrosion protection of steel bar is achieved through the constantly-stabilized passive film, and its stability is promoted using continuous calcium hydroxide released from the microcapsule, restoring alkaline conditions. The test results exhibited that the release process of the microcapsules is a function of time. Moreover, the release rate of core materials could interact with environmental pH value, in which the release rate is found to increase remarkably with decreasing pH value, but is inhibited by high pH levels.

  7. Flexural Strength Evaluation of Reinforced Concrete Members with Ultra High Performance Concrete

    Directory of Open Access Journals (Sweden)

    Baek-Il Bae

    2016-01-01

    Full Text Available Flexural strength evaluation models for steel fiber reinforced ultra high strength concrete were suggested and evaluated with test results. Suggested flexural strength models were composed of compression stress blocks and tension stress blocks. Rectangular stress block, triangular stress block, and real distribution shape of stress were used on compression side. Under tension, rectangular stress block distributed to whole area of tension side and partial area of tension side was used. The last model for tension side is realistic stress distribution. All these models were verified with test result which was carried out in this study. Test was conducted by four-point loading with 2,000 kN actuator for slender beam specimen. Additional verifications were carried out with previous researches on flexural strength of steel fiber reinforced concrete or ultra high strength concrete. Total of 21 test specimens were evaluated. As a result of comparison for flexural strength of section, neutral axis depth at ultimate state, models with triangular compression stress block, and strain-softening type tension stress block can be used as exact solution for ultra high performance concrete. For the conservative and convenient design of section, modified rectangular stress block model can be used with strain softening type tension stress block.

  8. Organic substances as inhibitors for chloride-induced corrosion in reinforced concrete

    Energy Technology Data Exchange (ETDEWEB)

    Ormellese, M.; Bolzoni, F.; Lazzari, L.; Brenna, A.; Pedeferri, M. [Department Chemistry, Material and Chemical Engineering, Politecnico di Milano (Italy)

    2011-02-15

    Corrosion inhibitors are used to prevent chloride-induced corrosion in reinforced concrete structures. Since performance of commercial organic inhibitors is only partially satisfactory, a 7-year long research has been carried out in order to set-up a new organic inhibitive mixture, able to prevent chlorides-induced corrosion. A first screening, by means of potentiodynamic polarisation test in alkaline synthetic pore solution, was performed on 80 organic compounds, mainly primary and tertiary amines, aminoalcohols, carboxylates compounds and aminoacids, in order to select the best inhibiting substances. The nine best inhibitive organic substances were selected for long-term tests: 2 amines (dimethylethanolamine and triethylentetramine), 4 aminoacids (aspartate, asparagine, glutamate and glutamine) and 3 carboxylates compounds (tartrate, benzoate and EDTA). Potentiostatic polarisation and free corrosion tests in synthetic pore solution were performed, as well as tests in concrete exposed to accelerated chlorides penetration. Five years of tests allow estimating the efficiency of the substances in preventing chlorides-induced corrosion, in term of influence on chlorides penetration and on critical chlorides threshold. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  9. Covercrete with hybrid functions - A novel approach to durable reinforced concrete structures

    Energy Technology Data Exchange (ETDEWEB)

    Tang, L.; Zhang, E.Q. [Chalmers University of Technology, SE-412 96 Gothenburg (Sweden); Fu, Y. [KTH Royal Institute of Technology, SE-106 91 Stockholm (Sweden); Schouenborg, B.; Lindqvist, J.E. [CBI Swedish Cement and Concrete Research Institute, c/o SP, Box 857, SE-501 15 Boraas (Sweden)

    2012-12-15

    Due to the corrosion of steel in reinforced concrete structures, the concrete with low water-cement ratio (w/c), high cement content, and large cover thickness is conventionally used for prolonging the passivation period of steel. Obviously, this conventional approach to durable concrete structures is at the sacrifice of more CO{sub 2} emission and natural resources through consuming higher amount of cement and more constituent materials, which is against sustainability. By placing an economically affordable conductive mesh made of carbon fiber or conductive polymer fiber in the near surface zone of concrete acting as anode we can build up a cathodic prevention system with intermittent low current density supplied by, e.g., the solar cells. In such a way, the aggressive negative ions such as Cl{sup -}, CO{sub 3}{sup 2-}, and SO{sub 4}{sup 2-} can be stopped near the cathodic (steel) zone. Thus the reinforcement steel is prevented from corrosion even in the concrete with relatively high w/c and small cover thickness. This conductive mesh functions not only as electrode, but also as surface reinforcement to prevent concrete surface from cracking. Therefore, this new type of covercrete has hybrid functions. This paper presents the theoretical analysis of feasibility of this approach and discusses the potential durability problems and possible solutions to the potential problems. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  10. Performance of Hybrid Reinforced Concrete Beam Column Joint: A Critical Review

    Directory of Open Access Journals (Sweden)

    Md Rashedul Kabir

    2016-04-01

    Full Text Available Large residual strain in reinforced concrete structures after a seismic event is a major concern for structural safety and serviceability. Alternative reinforcement materials like fiber-reinforced polymer (FRP have been widely used to mitigate corrosion problems associated with steel. Low modulus of elasticity and brittle behavior compared to steel has made the use of FRP unsuitable in seismic resistant strictures. A combination of steel-FRP reinforcement configuration can address the problem of corrosion. Therefore, introducing a material that shows strong post elastic behavior without any decay due to corrosion is in demand. Shape memory alloy (SMA, a novel material, is highly corrosion resistive and shows super elastic property. Coupling SMA with FRP or steel in the plastic hinge region allows the structure to undergo large deformations, but regains its original shape upon unloading. In this study, the performance characteristics of four previously tested beam-column joints reinforced with different configurations (steel, SMA/steel, glass fiber reinforced polymer (GFRP and SMA/FRP are compared to assess their capacity to endure extreme loading. Experimental results are scrutinized to compare the behavior of these specimens in terms of load-story drift and energy dissipation capacity. SMA/FRP and SMA/Steel couples have been found to be an acceptable approach to reduce residual deformation in beam-column joints with adequate energy dissipation capacity. However, SMA/FRP is superior to SMA/Steel concerning to the corrosion issue in steel.

  11. Long-Term Flexural Behaviors of GFRP Reinforced Concrete Beams Exposed to Accelerated Aging Exposure Conditions

    Directory of Open Access Journals (Sweden)

    Yeonho Park

    2014-06-01

    Full Text Available This study investigates the impact of accelerated aging conditions on the long-term flexural behavior and ductility of reinforced concrete (RC members with glass fiber-reinforced polymer (GFRP bars (RC-GFRP specimen and steel bars (RC-steel specimen. A total of thirty six specimens were designed with different amounts of reinforcement with three types of reinforcing bars (i.e., helically wrapped GFRP, sand-coated surface GFRP and steel. Eighteen specimens were subjected to sustained loads and accelerated aging conditions (i.e., 47 °C and 80% relative humidity in a chamber. The flexural behavior of specimens under 300-day exposure was compared to that of the companion specimens without experiencing accelerated aging conditions. Results indicate that the accelerated aging conditions reduced flexural capacity in not only RC-steel, but also RC-GFRP specimens, with different rates of reduction. Different types of GFRP reinforcement exhibited different rates of degradation of the flexural capacity when embedded in concrete under the same exposure conditions. Several existing models were compared with experimental results for predicting the deflection and deformability index for specimens. Bischoff and Gross’s model exhibited an excellent prediction of the time-dependent deflections. Except for the deformability index proposed by Jaeger, there was no general trend related to the aging duration. This study recommends the need for further investigation on the prediction of the deformability index.

  12. Enhancement of shear strength and ductility for reinforced concrete wide beams due to web reinforcement

    Directory of Open Access Journals (Sweden)

    M. Said

    2013-12-01

    Full Text Available The shear behavior of reinforced concrete wide beams was investigated. The experimental program consisted of nine beams of 29 MPa concrete strength tested with a shear span-depth ratio equal to 3.0. One of the tested beams had no web reinforcement as a control specimen. The flexure mode of failure was secured for all of the specimens to allow for shear mode of failure. The key parameters covered in this investigation are the effect of the existence, spacing, amount and yield stress of the vertical stirrups on the shear capacity and ductility of the tested wide beams. The study shows that the contribution of web reinforcement to the shear capacity is significant and directly proportional to the amount and spacing of the shear reinforcement. The increase in the shear capacity ranged from 32% to 132% for the range of the tested beams compared with the control beam. High grade steel was more effective in the contribution of the shear strength of wide beams. Also, test results demonstrate that the shear reinforcement significantly enhances the ductility of the wide beams. In addition, shear resistances at failure recorded in this study are compared to the analytical strengths calculated according to the current Egyptian Code and the available international codes. The current study highlights the need to include the contribution of shear reinforcement in the Egyptian Code requirements for shear capacity of wide beams.

  13. Dynamic Mechanical Behaviour of Ultra-high Performance Fiber Reinforced Concretes

    Institute of Scientific and Technical Information of China (English)

    LAI Jianzhong; SUN Wei

    2008-01-01

    Ultra-high performance fiber reinforced concretes (UHPFRC) were prepared by replacing 60% of cement with ultra-fine industrial waste powder.The dynamic mechanical behaviour of UHPFRC with different fiber volume fraction was researched on repeated compressive impact in four kinds of impact modes through split Hopkinson pressure bar (SHPB).The experimental results show that the peak stress and elastic modulus decrease and the strain rate and peak strain increase gradually with the increasing of impact times.The initial material damage increases and the peak stress of the specimen decreases from the second impact with the increasing of the initial incident wave.Standard strength on repeated impact is defined to compare the ability of resistance against repeated impact among different materials.The rate of reduction of standard strength is decreased by fiber reinforcement under repeated impact.The material damage is reduced and the ability of repeated impact resistance of UHPFRC is improved with the increasing of fiber volume fraction.

  14. Hysteretic behavior of special shaped columns composed of steel and reinforced concrete (SRC)

    Science.gov (United States)

    Chen, Zongping; Xu, Jinjun; Xue, Jianyang

    2015-06-01

    This paper describes a series of experimental investigations on seventeen specimens of steel reinforced concrete special shaped (SRCSS) columns under low cyclic reversed loading using parallel crosshead equipment. Nine T-shaped SRC columns, four L-shaped SRC columns and four +-shaped SRC columns were tested to examine the effects of shape steel configuration, loading angle, axial compressive ratio and shear-span ratio on the behavior (strength, stiffness, energy dissipation, ductility, etc.) of SRCSS column specimens. The failure modes and hysteretic performance of all the specimens were obtained in the tests. Test results demonstrate that the shear-span ratio is the main parameter affecting the failure modes of SRCSS columns. The specimens with small shear-span ratio are prone to shear failure, and the primary failure planes in SRCSS columns are parallel to the loading direction. As a result, there is a symmetry between positive and negative loading directions in the hysteretic curves of the SRCSS columns. The majority of displacement ductility coefficients for all the specimens are over 3.0, so that the SRCSS columns demonstrate a better deformation capacity. In addition, the equivalent viscous damping coefficients of all the specimens are greater than 0.2, indicating that the seismic behavior of SRCSS columns is adequate. Finally, the superposition theory was used to calculate the limits of axial compressive ratio for the specimens, and it is found that the test axial compressive ratio is close to or smaller than the calculated axial compressive ratio limit.

  15. Experimental study of bond-slip performance of corroded reinforced concrete under cyclic loading

    Directory of Open Access Journals (Sweden)

    Haijun Zhou

    2015-03-01

    Full Text Available Reinforced concrete structures exposed to marine environment often sustain high levels of chloride-induced reinforcement corrosion, which causes reinforcement corrosion and resulting in degraded performance under cyclic service loading. This article studied the dynamic bond performance between corroded reinforcing and concrete under force controlled loading. Tests were carried out to evaluate the cyclic bond-slip degradation with different reinforcement corrosion levels. A series of 30 specimens with various corrosion levels of rebar and stirrup were made. The specimen was cast as concrete cube with the dimension of 200 mm, and a steel rebar was centrally embedded with two stirrups around. The embedded steel rebar and stirrups were corroded using an electrochemical accelerated corrosion technique. The corrosion crack opening width and length were recorded after completion of artificial corrosion. Then, cyclic loading test was carried out; three different force levels of 24, 36, and 48 kN were adopted. The effects of reinforcement corrosion rate on crack opening, maximum slip, energy dissipation, and unloading stiffness were discussed in detail. It was found that both reinforcement corrosion rate and crack opening would have significant effects on cyclic bond performance. Further studies are urgently needed to quantify these effects to the cyclic bond performance.

  16. The performance analysis of distributed Brillouin corrosion sensors for steel reinforced concrete structures.

    Science.gov (United States)

    Wei, Heming; Zhao, Xuefeng; Kong, Xianglong; Zhang, Pinglei; Cui, Yanjun; Sun, Changsen

    2013-12-27

    The Brillouin optical time-domain analysis (BOTDA)-based optical fiber method has been proposed to measure strain variations caused by corrosion expansion. Spatial resolutions of 1 m can be achieved with this kind of Brillouin sensor for detecting the distributed strain. However, when the sensing fiber is wound around the steel rebar in a number of circles in a range of several meters, this spatial resolution still has limitations for corrosion monitoring. Here, we employed a low-coherent fiber-optic strain sensor (LCFS) to survey the performance of Brillouin sensors based on the fact that the deformation measured by the LCFS equals the integral of the strains obtained from Brillouin sensors. An electrochemical accelerated corrosion experiment was carried out and the corrosion expansion was monitored by both BOTDA and the LCFS. Results demonstrated that the BOTDA can only measure the expansion strain of about 1,000 με, which was generated by the 18 mm steel rebar corrosion, but, the LCFS had high sensitivity from the beginning of corrosion to the destruction of the structure, and no obvious difference in expansion speed was observed during the acceleration stage of the corrosion developed in the reinforced concrete (RC) specimens. These results proved that the BOTDA method could only be employed to monitor the corrosion inside the structure in the early stage.

  17. Air-coupled impact-echo damage detection in reinforced concrete using wavelet transforms

    Science.gov (United States)

    Epp, Tyler; Cha, Young-Jin

    2017-02-01

    Internal damage detection of reinforced concrete (RC) structures is a challenging field that has garnered increasing attention over the past decades due to a decline in the state of infrastructure in North America. As a nondestructive testing mode, the impact-echo method is currently a promising approach. However, it requires intensive testing to cover large-scale civil RC structures with point-by-point inspection. In order to partially overcome this limitation, this study proposes a new impact-echo analysis method using wavelet transforms with dual microphones with 20 kHz resolution to improve damage detection capability. The signals recorded from the microphones are processed to recover spectral data that are further analyzed using percentage of energy information to determine the condition of the specimen and detect in situ damages. In order to validate the performance of the proposed method, the results from traditional signal processing using FFT and wavelet transforms are compared. The proposed wavelet transform based approach showed better accuracy when covering broader areas, which can contribute to reduce testing time significantly when monitoring large-scale civil RC structures.

  18. Galvanic metallized zinc cathodic protection systems for a carbonated reinforced concrete structure

    Energy Technology Data Exchange (ETDEWEB)

    Sitton, I.; Costa, J.E. [Corrosion Restoration Technologies, Inc., Jupiter, FL (United States); Powers, R.G. [Florida Dept. of Transportation, Gainesville, FL (United States). Materials Office

    1998-12-31

    A corrosion assessment survey was conducted with the objective of facilitating the selection of repair methods for the corrosion control of two reinforced concrete structures. The work completed during the evaluation consisted of visual inspections, depth of cover determinations, concrete resistivity measurements, chloride analyses, carbonation depth measurements, and cathodic protection feasibility tests. Results from preliminary field-testing indicated that these 75+ year old historically significant structures both exhibited widespread corrosion distress throughout most of the substructure components due to carbonation of the concrete matrix. These areas were generally associated with shallow concrete cover over the steel reinforcement. Consequently, the concrete resistivity values measured at the two structures were high in comparison to resistivity values observed in various other Florida locations. Tests to assess the prospect of using cathodic protection (CP) as a means of controlling the state of corrosion were preformed using a series of zinc foil anodes with an ionically conductive adhesive backing. Results from the CP tests indicated that although anode current outputs were low, the steel was cathodically protected due to a rapid high potential shift observed. Based on the field results and an economic analysis, the use of a sacrificial metallized zinc CP system, applied directly unto the spalled areas, emerged as the leading restoration option.

  19. Sensitivity Analysis of Corrosion Rate Prediction Models Utilized for Reinforced Concrete Affected by Chloride

    Science.gov (United States)

    Siamphukdee, Kanjana; Collins, Frank; Zou, Roger

    2013-06-01

    Chloride-induced reinforcement corrosion is one of the major causes of premature deterioration in reinforced concrete (RC) structures. Given the high maintenance and replacement costs, accurate modeling of RC deterioration is indispensable for ensuring the optimal allocation of limited economic resources. Since corrosion rate is one of the major factors influencing the rate of deterioration, many predictive models exist. However, because the existing models use very different sets of input parameters, the choice of model for RC deterioration is made difficult. Although the factors affecting corrosion rate are frequently reported in the literature, there is no published quantitative study on the sensitivity of predicted corrosion rate to the various input parameters. This paper presents the results of the sensitivity analysis of the input parameters for nine selected corrosion rate prediction models. Three different methods of analysis are used to determine and compare the sensitivity of corrosion rate to various input parameters: (i) univariate regression analysis, (ii) multivariate regression analysis, and (iii) sensitivity index. The results from the analysis have quantitatively verified that the corrosion rate of steel reinforcement bars in RC structures is highly sensitive to corrosion duration time, concrete resistivity, and concrete chloride content. These important findings establish that future empirical models for predicting corrosion rate of RC should carefully consider and incorporate these input parameters.

  20. Detecting the Resistivity Distribution of Carbon Fiber Reinforced Concrete by Electrical Resistance Tomography Method

    Institute of Scientific and Technical Information of China (English)

    Xu Dongliang; Li Zhuoqiu; Song Xianhui; Lü Yong

    2006-01-01

    According to the principle of electrical resistance tomography (ERT), the resistivity distribution of the carbon fiber reinforced concrete (CFRC) in the sensing field can be measured by injecting exciting current and measuring the voltage on the sensor electrode arrays installed on the surface of the object Therefore, measurement of the resistivity distribution of CFRC is divided into first measuring the boundary conditions and then inversely computing the resistivity distribution. To reach this goal, an ERT system was constructed, which is composed of a sensor array unit, a data acquisition unit and an image reconstruction unit. Simulations of static ERT was performed on set-ups with many objects spread in a homogeneous background, and a simulation of dynamic ERT was also done on a rectangular board, the resistivity of which was changed within a small domain of it. Then, the resistivity distribution of a CFRC sample with a circlar hole as the target was detected by the ERT system. Simulation and experimental results show that the reconstructed ERT image reflects the resistivity distribution or the resistivity change of CFRC structure well. Especially, a small change in resistivity can be identified from the reconstructed images in the simulation of dynamic ERT images.

  1. Nonlinear Analysis of External Prestressed Reinforced Concrete Beams with BFRP and CFRP

    Directory of Open Access Journals (Sweden)

    Haleem K. Hussain

    2017-05-01

    Full Text Available The traditional strengthening methods for concrete structure (girders, beams, columns…. consuming time and could be an economical, a new modern repair methods using the Carbon Fiber Reinforced Polymers (CFRP and Basalt Fiber Reinforced Polymer (BFRP as a laminate strips or bars,and considered a competitive solution that will increase the life-cycle of repaired structures. This study investigated the strengthen reinforced concrete girder. Nonlinear analysis have been adopted to the models using FEM analysis (ANSYS to simulate the theoretical results compared with experimental results.Using finite element packages, more efficient and better analyses can be made to fully understand the response of individual structural components and their contribution to a structure as a whole.Three type of material are used in this study as an external prestressed wire (steel, CFRP and BFRP. The prestressed beam is modeled as simply supported beam with two concentrated point load. The results showed that all tested strengthening beam increased the load carryingcapacity of the beams depend on prestressing force. Obtained Result was compared for different type of beam.This study also was enlarged to include using CFRP and BFRPbarwhich are light weight and moredurable, lead to ease of handling and maintenance. The research conducted analytical work to evaluate the effectiveness of concrete beams reinforced normally by the use of CFRP and BFRP bars. The results showed a significant gain in the beam’s ultimate capacities using CFRP bars comparing with beam reinforced with BFRP bar and reference beam

  2. DRIVEN POLYSTRONG REINFORCED CONCRETE PILES AND NEW DESIGN OF PILE CAPS

    Directory of Open Access Journals (Sweden)

    I. I. Bekbasarov

    2015-01-01

    Full Text Available The paper presents constructional and technological features for manufacturing driven piles with variable strength of pile shaft. Economical efficiency of their production has been shown in the paper. The paper provides a pile cap design that ensures perception of hammer impacts with the help of lateral edges of the pile cap. Driven reinforced concrete piles which are manufactured from three shaft sections having various strength have been proposed in the paper. Material strength (concrete grade and diameter of bars and length of shaft sections are given on a case by case basis in accordance with nature and rate of stresses in piles during their driving process. Manufacturing of polystrong piles provides an opportunity to select them for a particular construction site with due account of their preservation during driving process.A pile cap has been developed that as opposed to existing analogous designs makes it possible to transmit impact efforts from a hammer to the pile through lateral surface of its head part. The pile cap provides the possibility to increase an area for perception of hammer impact efforts by the pile and in doing so it is possible significantly to reduce a damage risk and destruction of pile concrete during its driving. Application of polystrong piles and their driving with the help of new pile cap are considered as a basis for defect-free and resource-saving technology for pile foundations in the construction.

  3. Acoustic emission evaluation of reinforced concrete bridge beam with graphite composite laminate

    Science.gov (United States)

    Johnson, Dan E.; Shen, H. Warren; Finlayson, Richard D.

    2001-07-01

    A test was recently conducted on August 1, 2000 at the FHwA Non-Destructive Evaluation Validation Center, sponsored by The New York State DOT, to evaluate a graphite composite laminate as an effective form of retrofit for reinforced concrete bridge beam. One portion of this testing utilized Acoustic Emission Monitoring for Evaluation of the beam under test. Loading was applied to this beam using a two-point loading scheme at FHwA's facility. This load was applied in several incremental loadings until the failure of the graphite composite laminate took place. Each loading culminated by either visual crack location or large audible emissions from the beam. Between tests external cracks were located visually and highlighted and the graphite epoxy was checked for delamination. Acoustic Emission data was collected to locate cracking areas of the structure during the loading cycles. To collect this Acoustic Emission data, FHwA and NYSDOT utilized a Local Area Monitor, an Acoustic Emission instrument developed in a cooperative effort between FHwA and Physical Acoustics Corporation. Eight Acoustic Emission sensors were attached to the structure, with four on each side, in a symmetrical fashion. As testing progressed and culminated with beam failure, Acoustic Emission data was gathered and correlated against time and test load. This paper will discuss the analysis of this test data.

  4. Application of digital image correlation method for analysing crack variation of reinforced concrete beams

    Indian Academy of Sciences (India)

    Ming-Hsiang Shih; Wen-Pei Sung

    2013-08-01

    The Digital Image Correlation (DIC) method is a fast-growing emerging technology that provides a low-cost method for measuring the strain of an object. In this study, the feasibility of using this method to observe cracks developed in reinforced concrete beams will be explored so that a practical application can be proposed. The DIC method has been applied for analysing the field of surface displacement and strain; it is not applicable for measuring non-continuous field of displacement. However, if a singular point (i.e., crack points) can be considered as the area of concentrated strain by imitating the treatment of micro-cracks using the finite element method, the region of concentrated strain field based on analyses of digital images can be applied for determining the locations of cracks. Laboratory results show that cracks developed in reinforced cement beams can be observed with a good precision using the von Mises strain field, and that smaller grids lead to clearer crack images. In addition to identifying visible cracks, the DIC image analysis will enable researchers to identify minute cracks that are not visible to naked eyes. Additionally, the DIC method has more accuracy and precision than visual observation for analysing crack loadings so that earlier warnings can be realized before cracks develop in the specimen.

  5. Elastomeric Polymers for Retrofitting of Reinforced Concrete Structures against the Explosive Effects of Blast

    Directory of Open Access Journals (Sweden)

    S. N. Raman

    2012-01-01

    Full Text Available The main distinction of blast load from other types of dynamic loadings is its impulsive nature, where the loads usually act for a very short duration but transmit very high impulsive pressures. This paper presents an overview of the present retrofitting techniques in use to enhance the capacity of structural elements to withstand the effects of blast loads, and introduces an alternative retrofitting approach by utilizing polymer coatings. The authors have demonstrated the positive effects of this approach by conducting a numerical investigation on the behavior of an unretrofitted reinforced concrete panel subjected to the blast load from a 2 kg charge at 1.6 m stand-off distance, and subsequently comparing its performance with several polymer coated panels. The analysis was performed by using an explicit nonlinear finite element (FE code. The results demonstrate the contributions of this technique in terms of panel displacement control and energy dissipation. Considering that the polymer coating can also act as a protective layer in improving the durability of structural materials, this technique can also be optimized favorably to enhance the overall sustainability of structures.

  6. Refinement of Strut-and-Tie Model for Reinforced Concrete Deep Beams.

    Directory of Open Access Journals (Sweden)

    Mohammad Panjehpour

    Full Text Available Deep beams are commonly used in tall buildings, offshore structures, and foundations. According to many codes and standards, strut-and-tie model (STM is recommended as a rational approach for deep beam analyses. This research focuses on the STM recommended by ACI 318-11 and AASHTO LRFD and uses experimental results to modify the strut effectiveness factor in STM for reinforced concrete (RC deep beams. This study aims to refine STM through the strut effectiveness factor and increase result accuracy. Six RC deep beams with different shear span to effective-depth ratios (a/d of 0.75, 1.00, 1.25, 1.50, 1.75, and 2.00 were experimentally tested under a four-point bending set-up. The ultimate shear strength of deep beams obtained from non-linear finite element modeling and STM recommended by ACI 318-11 as well as AASHTO LRFD (2012 were compared with the experimental results. An empirical equation was proposed to modify the principal tensile strain value in the bottle-shaped strut of deep beams. The equation of the strut effectiveness factor from AASHTTO LRFD was then modified through the aforementioned empirical equation. An investigation on the failure mode and crack propagation in RC deep beams subjected to load was also conducted.

  7. Comparison between half-cell potential of reinforced concrete exposed to carbon dioxide and chloride environment

    Directory of Open Access Journals (Sweden)

    Somnuk Tangtermsirikul

    2010-10-01

    Full Text Available The objective of this study is to investigate the effect of concrete mix proportion and fly ash on half-cell potential (HCPand corrosion current density (icorr of steel in concrete exposed to different environments. Reinforced concrete specimenswith different fly ash replacement percentages and water to binder ratios (w/b were studied in this paper. The specimenswere subjected to two highly corrosive environments which are chloride and carbon dioxide. HCP and icorr were used tomonitor the corrosion process. Results of this study demonstrate that both HCP and icorr indicated the same tendency,especially for corroded specimens after being exposed to chloride. This means that HCP can be used to inspect corrosion ofsteel due to chloride. In case of carbonation, concrete specimens with fly ash showed more negative potential values thanconcrete without fly ash. However, chloride exposure test exhibited that specimen with higher fly ash replacement corrodedearlier. Moreover, HCP measurement presented different values between concrete exposed to chloride and carbon dioxide.There was an effect of carbonation to increase HCP during the initiation stage. A proper evaluation guideline for steelcorrosion due to carbonation needs to be further studied.

  8. An investigation of the seismic behavior of a deck-type reinforced concrete arch bridge

    Science.gov (United States)

    Farahani, Emadoddin Majdabadi; Maalek, Shahrokh

    2017-07-01

    This paper attempts to explore potential benefits of form in a deck-type reinforced concrete (RC) arch bridge in connection with its overall seismic behavior and performance. Through a detailed three-dimensional finite element modeling and analysis of an actual existing deck-type RC arch bridge, some useful quantitative information have been derived that may serve for a better understanding of the seismic behavior of such arch bridges. A series of the nonlinear dynamic analyses has been carried out under the action of seven different time histories of ground motion scaled to the AASHTO 2012 response spectrum. The concept of demand to capacity ratios has been employed to provide an initial estimation of the seismic performance of the bridge members. As a consequence of the structural form, a particular type of irregularity is introduced due to variable heights of columns transferring the deck loads to the main arch. Hence, a particular attention has been paid to the internal force/moment distributions within the short, medium, and long columns as well as along the main arch. A study of the effects of the vertical component of ground motion has demonstrated the need for the inclusion of these effects in the analysis of such bridges.

  9. Investigation of Limit States Specified for Reinforced Concrete Column Members in TEC–2007

    Directory of Open Access Journals (Sweden)

    Umut HASGÜL

    2016-01-01

    Full Text Available In this study, the deformation based limit states stipulated for reinforced concrete members in the Turkish Earthquake Code (TEC were experimentally investigated. Thus four RC cantilever columns which have low concrete compressive strengths and have not adequate confinement, were subjected to constant axial load and cyclic lateral load history. In the study, firstly, the strain values representing the damage limits were converted to top of the column lateral displacements by using fundamentals of structural mechanics. Subsequently the column damages corresponding to the displacement demands were observed, hence limit states were evaluated. After conducting all column tests, it was noted that no column damage was observed for the immediate occupancy (IO performance level defined in the code. For the life safety (LS and collapse prevention (CP performance levels, though somewhat residual deformations occurred on the critical regions, the column members can pretty much sustain their lateral load capacities. It was also observed for all columns that significant damages and strength losses occurred beyond the collapse prevention level. The results of experimental study indicate that the evaluation procedure in the TEC is still in good relationship with the limit states even if the columns have not adequate compressive strength and confinement.

  10. Strengthening reinforced concrete beams using prestressed glass fiber-reinforced polymer-Part Ⅱ: Analytical study

    Institute of Scientific and Technical Information of China (English)

    HUANG Yue-lin; HUNG Chien-hsing; YEN Tsong; WU Jong-hwei; LIN Yiching

    2005-01-01

    Strengthening reinforced concrete (R. C.) beams using prestressed glass fiber-reinforced polymer (PGFRP) was studied experimentally as described in Part Ⅰ of this paper (Huang et al., 2005). In that paper, R. C. beams, R. C. beams with GFRP(glass fiber-reinforced polymer) sheets, and R. C. beams with PGFRP sheets were tested in both under-strengthened and over-strengthened cases. The test results showed that the load-carrying capacities (ultimate loads) of the beams with GFRP sheets were greater than those of the beams without polymer sheets. The load-carrying capacities of beams with PGFRP sheets were greater than those of beams with GFRP sheets. The objective of this work is to develop an analytical method to compute all of these load-carrying capacities. This analytical method is independent of the experiments and based only on the traditional R. C.and P. C. (prestressed concrete) theory. The analytical results accorded with the test results. It is suggested that this analytical method be used for analyzing and designing R. C. beams strengthened using GFRP or PGFRP sheets.

  11. Degradation and Mechanism of the Mechanics and Durability of Reinforced Concrete Slab in A Marine Environment

    Institute of Scientific and Technical Information of China (English)

    吴胜兴; 刘冠国; 卞汉兵; 吕维波; 蒋建华

    2016-01-01

    An experimental research was conducted to determine the corrosion and bearing capacity of a reinforced concrete (RC) slab at different ages in a marine environment. Results showthat the development of corrosion-induced cracks on a slab in a marine environment can be divided into three stages according to crack morphology at the bottom of the slab. In the first stage, cracks appear. In the second stage, cracks develop from the edges to the middle of the slab. In the third stage, longitudinal and transverse corrosion-induced cracks coexist. The corrosion ratio of reinforcements nonlinearly increases with theage, and the relationship between the corrosion ratio of the reinforcements and the corrosion-induced crack width of the concrete is established. The flexural capacity of the corroded RC slab nonlinearly decreases with the age, and the model for the bearing capacity factor of the corroded RC slab is established. The mid-span deflection of the corroded RC slab that corresponds to the yield of the reinforcements linearly increases with the increase in corrosion ratio. Finally, the mechanisms of corrosion morphology and the degradation of the mechanical properties of an RC slab in a marine environment are discussed on the basis of the basic theories of steel corrosion in concrete and concrete structure design.

  12. Fracture Behavior and Properties of Functionally Graded Fiber-Reinforced Concrete

    Science.gov (United States)

    Roesler, Jeffery; Bordelon, Amanda; Gaedicke, Cristian; Park, Kyoungsoo; Paulino, Glaucio

    2008-02-01

    In concrete pavements, a single concrete mixture design is selected to resist mechanical loading without attempting to adversely affect the concrete pavement shrinkage, ride quality, or noise attenuation. An alternative approach is to design distinct layers within the concrete pavement surface which have specific functions thus achieving higher performance at a lower cost. The objective of this research was to address the structural benefits of functionally graded concrete materials (FGCM) for rigid pavements by testing and modeling the fracture behavior of different combinations of layered plain and synthetic fiber-reinforced concrete materials. Fracture parameters and the post-peak softening behavior were obtained for each FGCM beam configuration by the three point bending beam test. The peak loads and initial fracture energy between the plain, fiber-reinforced, and FGCM signified similar crack initiation. The total fracture energy indicated improvements in fracture behavior of FGCM relative to full-depth plain concrete. The fracture behavior of FGCM depended on the position of the fiber-reinforced layer relative to the starter notch. The fracture parameters of both fiber-reinforced and plain concrete were embedded into a finite element-based cohesive zone model. The model successfully captured the experimental behavior of the FGCMs and predicted the fracture behavior of proposed FGCM configurations and structures. This integrated approach (testing and modeling) demonstrates the viability of FGCM for designing layered concrete pavements system.

  13. Degradation and mechanism of the mechanics and durability of reinforced concrete slab in a marine environment

    Science.gov (United States)

    Wu, Sheng-xing; Liu, Guan-guo; Bian, Han-bing; Lv, Wei-bo; Jiang, Jian-hua

    2016-04-01

    An experimental research was conducted to determine the corrosion and bearing capacity of a reinforced concrete (RC) slab at different ages in a marine environment. Results show that the development of corrosion-induced cracks on a slab in a marine environment can be divided into three stages according to crack morphology at the bottom of the slab. In the first stage, cracks appear. In the second stage, cracks develop from the edges to the middle of the slab. In the third stage, longitudinal and transverse corrosion-induced cracks coexist. The corrosion ratio of reinforcements nonlinearly increases with the age, and the relationship between the corrosion ratio of the reinforcements and the corrosion-induced crack width of the concrete is established. The flexural capacity of the corroded RC slab nonlinearly decreases with the age, and the model for the bearing capacity factor of the corroded RC slab is established. The mid-span deflection of the corroded RC slab that corresponds to the yield of the reinforcements linearly increases with the increase in corrosion ratio. Finally, the mechanisms of corrosion morphology and the degradation of the mechanical properties of an RC slab in a marine environment are discussed on the basis of the basic theories of steel corrosion in concrete and concrete structure design.

  14. Drying Shrinkage of Recycled Aggregate Reinforced Concrete Shear Wall%再生骨料钢筋混凝土剪力墙干燥收缩性能

    Institute of Scientific and Technical Information of China (English)

    崔正龙; 庄宇; 汪振双

    2011-01-01

    在约束条件下对再生骨科钢筋混凝土剪力墙和普通钢筋混凝土剪力墙进行了干燥收缩应变测试,同时观察墙体表面干燥收缩裂缝产生的情况.结果表明:2种剪力墙内部收缩应变均明显小于相应的外表面收缩应变;2种剪力墙内部收缩应变相差不大;再生骨料钢筋混凝土剪力墙外表面收缩应变明显比普通钢筋混凝土剪力墙小,而细微收缩裂缝则明显增多.%Drying shrinkage strains of recycled aggregate reinforced concrete shear wall and common reinforced concrete shear wall were measured under constraint conditions, and cracks situations on shear wall surface were observed. The results reveal that for recycled aggregate reinforced concrete shear wall and common reinforced concrete shear wall, the internal shrinkage strain are obviously less than surface shrinkage strain. There is a little difference of internal shrinkage strains between recycled aggregate reinforced concrete shear wall and common reinforced concrete shear wall. The surface shrinkage strain of recycled aggregate reinforced concrete shear wall is obviously lower than that of common reinforced concrete shear wall, while micro shrinkage cracks is obviously more than the latter.

  15. Corrosion detection of steel reinforced concrete using combined carbon fiber and fiber Bragg grating active thermal probe

    Science.gov (United States)

    Li, Weijie; Ho, Siu Chun Michael; Song, Gangbing

    2016-04-01

    Steel reinforcement corrosion is one of the dominant causes for structural deterioration for reinforced concrete structures. This paper presents a novel corrosion detection technique using an active thermal probe. The technique takes advantage of the fact that corrosion products have poor thermal conductivity, which will impede heat propagation generated from the active thermal probe. At the same time, the active thermal probe records the temperature response. The presence of corrosion products can thus be detected by analyzing the temperature response after the injection of heat at the reinforcement-concrete interface. The feasibility of the proposed technique was firstly analyzed through analytical modeling and finite element simulation. The active thermal probe consisted of carbon fiber strands to generate heat and a fiber optic Bragg grating (FBG) temperature sensor. Carbon fiber strands are used due to their corrosion resistance. Wet-dry cycle accelerated corrosion experiments were performed to study the effect of corrosion products on the temperature response of the reinforced concrete sample. Results suggest a high correlation between corrosion severity and magnitude of the temperature response. The technique has the merits of high accuracy, high efficiency in measurement and excellent embeddability.

  16. Separate effects testing and analyses to investigate liner tearing of the 1:6-scale reinforced concrete containment building

    Energy Technology Data Exchange (ETDEWEB)

    Spletzer, B.L.; Lambert, L.D.; Bergman, V.L. [Sandia National Labs., Albuquerque, NM (United States)] [and others

    1995-06-01

    The overpressurization of a 1:6-scale reinforced concrete containment building demonstrated that liner tearing is a plausible failure mode in such structures under severe accident conditions. A combined experimental and analytical program was developed to determine the important parameters which affect liner tearing and to develop reasonably simple analytical methods for predicting when tearing will occur. Three sets of test specimens were designed to allow individual control over and investigation of the mechanisms believed to be important in causing failure of the liner plate. The series of tests investigated the effect on liner tearing produced by the anchorage system, the loading conditions, and the transition in thickness from the liner to the insert plate. Before testing, the specimens were analyzed using two- and three-dimensional finite element models. Based on the analysis, the failure mode and corresponding load conditions were predicted for each specimen. Test data and post-test examination of test specimens show mixed agreement with the analytical predictions with regard to failure mode and specimen response for most tests. Many similarities were also observed between the response of the liner in the 1:6-scale reinforced concrete containment model and the response of the test specimens. This work illustrates the fact that the failure mechanism of a reinforced concrete containment building can be greatly influenced by details of liner and anchorage system design. Further, it significantly increases the understanding of containment building response under severe conditions.

  17. System-Level Logistics for Dual Purpose Canister Disposal

    Energy Technology Data Exchange (ETDEWEB)

    Kalinina, Elena A.

    2014-06-03

    The analysis presented in this report investigated how the direct disposal of dual purpose canisters (DPCs) may be affected by the use of standard transportation aging and disposal canisters (STADs), early or late start of the repository, and the repository emplacement thermal power limits. The impacts were evaluated with regard to the availability of the DPCs for emplacement, achievable repository acceptance rates, additional storage required at an interim storage facility (ISF) and additional emplacement time compared to the corresponding repackaging scenarios, and fuel age at emplacement. The result of this analysis demonstrated that the biggest difference in the availability of UNF for emplacement between the DPC-only loading scenario and the DPCs and STADs loading scenario is for a repository start date of 2036 with a 6 kW thermal power limit. The differences are also seen in the availability of UNF for emplacement between the DPC-only loading scenario and the DPCs and STADs loading scenario for the alternative with a 6 kW thermal limit and a 2048 start date, and for the alternatives with a 10 kW thermal limit and 2036 and 2048 start dates. The alternatives with disposal of UNF in both DPCs and STADs did not require additional storage, regardless of the repository acceptance rate, as compared to the reference repackaging case. In comparison to the reference repackaging case, alternatives with the 18 kW emplacement thermal limit required little to no additional emplacement time, regardless of the repository start time, the fuel loading scenario, or the repository acceptance rate. Alternatives with the 10 kW emplacement thermal limit and the DPCs and STADs fuel loading scenario required some additional emplacement time. The most significant decrease in additional emplacement time occurred in the alternative with the 6 kW thermal limit and the 2036 repository starting date. The average fuel age at emplacement ranges from 46 to 88 years. The maximum fuel age at

  18. SEISMIC DESIGN OF TWO STOREY REINFORCED CONCRETE BUILDING IN MALAYSIA WITH LOW CLASS DUCTILITY

    Directory of Open Access Journals (Sweden)

    MOHD IRWAN ADIYANTO

    2014-02-01

    Full Text Available Since Malaysia is not located in active seismic fault zones, majority of buildings in Malaysia had been designed according to BS8110, which not specify any seismic provision. After experienced several tremors originating from neighbouring countries especially from Sumatra, Indonesia, the Malaysian start to ask questions on integrity of existing structures in Malaysia to withstand the earthquake load. The question also arises regarding the economical effect in term of cost of construction if seismic design has to be implemented in Malaysian construction industry. If the cost is increasing, how much the increment and is it affordable? This paper investigated the difference of steel reinforcement and concrete volume required when seismic provision is considered in reinforced concrete design of 2 storey general office building. The regular office building which designed based on BS8110 had been redesigned according to Eurocode 2 with various level of reference peak ground acceleration, agR reflecting Malaysian seismic hazard for ductility class low. Then, the all frames had been evaluated using a total of 800 nonlinear time history analyses considering single and repeated earthquakes to simulate the real earthquake event. It is observed that the level of reference peak ground acceleration, agR and behaviour factor, q strongly influence the increment of total cost. For 2 storey RC buildings built on Soil Type D with seismic consideration, the total cost of material is expected to increase around 6 to 270%, depend on seismic region. In term of seismic performance, the repeated earthquake tends to cause increasing in interstorey drift ratio around 8 to 29% higher compared to single earthquake.

  19. Self-centering seismic retrofit scheme for reinforced concrete frame structures: SDOF system study

    Science.gov (United States)

    Zhang, Yunfeng; Hu, Xiaobin

    2010-06-01

    This paper presents the results of a parametric study of self-centering seismic retrofit schemes for reinforced concrete (RC) frame buildings. The self-centering retrofit system features flag-shaped hysteresis and minimal residual deformation. For comparison purpose, an alternate seismic retrofit scheme that uses a bilinear-hysteresis retrofit system such as buckling-restrained braces (BRB) is also considered in this paper. The parametric study was carried out in a single-degree-of-freedom (SDOF) system framework since a multi-story building structure may be idealized as an equivalent SDOF system and investigation of the performance of this equivalent SDOF system can provide insight into the seismic response of the multi-story building. A peak-oriented hysteresis model which can consider the strength and stiffness degradation is used to describe the hysteretic behavior of RC structures. The parametric study involves two key parameters — the strength ratio and elastic stiffness ratio between the seismic retrofit system and the original RC frame. An ensemble of 172 earthquake ground motion records scaled to the design basis earthquake in California with a probability of exceedance of 10% in 50 years was constructed for the simulation-based parametric study. The effectiveness of the two seismic retrofit schemes considered in this study is evaluated in terms of peak displacement ratio, peak acceleration ratio, energy dissipation demand ratio and residual displacement ratio between the SDOF systems with and without retrofit. It is found from this parametric study that RC structures retrofitted with the self-centering retrofit scheme (SCRS) can achieve a seismic performance level comparable to the bilinear-hysteresis retrofit scheme (BHRS) in terms of peak displacement and energy dissipation demand ratio while having negligible residual displacement after earthquake.

  20. Evaluation of seismic performance of reinforced concrete (RC) buildings under near-field earthquakes

    Science.gov (United States)

    Moniri, Hassan

    2017-03-01

    Near-field ground motions are significantly severely affected on seismic response of structure compared with far-field ground motions, and the reason is that the near-source forward directivity ground motions contain pulse-long periods. Therefore, the cumulative effects of far-fault records are minor. The damage and collapse of engineering structures observed in the last decades' earthquakes show the potential of damage in existing structures under near-field ground motions. One important subject studied by earthquake engineers as part of a performance-based approach is the determination of demand and collapse capacity under near-field earthquake. Different methods for evaluating seismic structural performance have been suggested along with and as part of the development of performance-based earthquake engineering. This study investigated the results of illustrious characteristics of near-fault ground motions on the seismic response of reinforced concrete (RC) structures, by the use of Incremental Nonlinear Dynamic Analysis (IDA) method. Due to the fact that various ground motions result in different intensity-versus-response plots, this analysis is done again under various ground motions in order to achieve significant statistical averages. The OpenSees software was used to conduct nonlinear structural evaluations. Numerical modelling showed that near-source outcomes cause most of the seismic energy from the rupture to arrive in a single coherent long-period pulse of motion and permanent ground displacements. Finally, a vulnerability of RC building can be evaluated against pulse-like near-fault ground motions effects.

  1. Evaluation of seismic performance of reinforced concrete (RC) buildings under near-field earthquakes

    Science.gov (United States)

    Moniri, Hassan

    2017-01-01

    Near-field ground motions are significantly severely affected on seismic response of structure compared with far-field ground motions, and the reason is that the near-source forward directivity ground motions contain pulse-long periods. Therefore, the cumulative effects of far-fault records are minor. The damage and collapse of engineering structures observed in the last decades' earthquakes show the potential of damage in existing structures under near-field ground motions. One important subject studied by earthquake engineers as part of a performance-based approach is the determination of demand and collapse capacity under near-field earthquake. Different methods for evaluating seismic structural performance have been suggested along with and as part of the development of performance-based earthquake engineering. This study investigated the results of illustrious characteristics of near-fault ground motions on the seismic response of reinforced concrete (RC) structures, by the use of Incremental Nonlinear Dynamic Analysis (IDA) method. Due to the fact that various ground motions result in different intensity-versus-response plots, this analysis is done again under various ground motions in order to achieve significant statistical averages. The OpenSees software was used to conduct nonlinear structural evaluations. Numerical modelling showed that near-source outcomes cause most of the seismic energy from the rupture to arrive in a single coherent long-period pulse of motion and permanent ground displacements. Finally, a vulnerability of RC building can be evaluated against pulse-like near-fault ground motions effects.

  2. The effect of silica fume and metakaolin on glass-fibre reinforced concrete (GRC ageing

    Directory of Open Access Journals (Sweden)

    Enfedaque Díaz, A.

    2010-12-01

    Full Text Available The deterioration of the mechanical properties of glassfibre reinforced concrete (GRC over time rules out the use of this material in load-bearing structures. While one possible solution to this problem is the addition of pozzolans or metakaolin to the cement mortar, the amounts needed to ensure GRC integrity raise its price to non-competitive levels. Experimental research has been conducted to analyze whether the addition of small amounts of silica fume or metakaolin can prevent or mitigate the ageing issue. Unfortunately, the findings indicate that the addition of small proportions of metakaolin or silica fume to GRC are ineffective in improving its long-term performance.

    Para el uso del mortero de cemento reforzado con fibras de vidrio (GRC en estructuras portantes se han de solucionar los problemas de reducción de las propiedades mecánicas que aparecen con el paso del tiempo. Estos problemas pueden ser solucionados mediante la adición de puzolanas o de metacaolín, a la pasta de mortero de cemento. Sin embargo, la cantidad de metacaolín que ha de ser añadida es elevada y el precio del GRC fabricado está fuera del mercado. Se ha realizado una campaña experimental que analiza si la adición de humo de sílice o de metacaolín en proporciones reducidas consigue evitar o paliar el problema del envejecimiento, que supone un freno al uso del GRC en elementos estructurales. Desgraciadamente, los resultados experimentales muestran que proporciones bajas de metacaolín o de humo de sílice no son efectivas para reducir el problema de pérdida de propiedades mecánicas.

  3. Repairing and Strengthening of an Existing Reinforced Concrete Building: A North Cyprus Perspective

    Directory of Open Access Journals (Sweden)

    Hakan Yalciner

    2010-01-01

    Full Text Available Problem statement: Inadequate attention during design and construction of some of Reinforced Concrete (RC buildings in North Cyprus has raised questions about the performance level of these existing buildings under future earthquakes. Approach: Column jacketing, adding steel braces and new shear walls to an existing building are common strengthening methods used by practical engineers in North Cyprus to increase the performance level of an existing building. Results: The aim of this study was to determine the most effective strengthening method among these three mentioned techniques. As a case study, a four stories RC existing building was selected and assessed using finite element method. To remodel of the existing building, the survey works done included three main steps, detecting the reinforcement bars for beams and columns, actual used concrete strength and soil type. The beams and columns reinforcement bars were determined using Ferro scan method and the soil was sampled in Girne city to determine the soil type. The actual concrete strength was determined using core test. Three common strengthening techniques mentioned above, were applied to the existing building. Then the efficiency of each strengthening method was investigated on the basis of removing of weak columns, not-safe beam-column joints in shear and performance levels based on the FEMA356 and Turkish earthquake code. Conclusion/Recommendations: Results showed that column jacketing is the most effective method to remove the weak columns and not-safe column-beam joints in shear. Nonlinear static pushover results showed that despite that adding shear walls caused an increase in the structural base shear and a reduction in the maximum roof displacement and the number of collapsed elements at FEMA356 performance point, but it caused a remarkable reduction in the building ductility ratio. Finally, results showed that the column jacketing is the most effective and the most economic

  4. Flexural rigidity evolvement laws of reinforced concrete beams strengthened with carbon fiber laminates

    Institute of Scientific and Technical Information of China (English)

    NIU Peng-zhi; HUANG Pei-yan; DENG Jun; HAN Qiang

    2007-01-01

    Extensive research has shown that externally bonded carbon fiber reinforced polymer (CFRP) laminates are particularly suitable for improving the fatigue behavior of reinforced concrete (RC) beams. This paper presents the research on flexural rigidity evolvement laws by testing 14 simple-supported RC beams strengthened with carbon fiber laminates (CFL) under cyclic load, and 2 under monotone load as a reference. The cyclic load tests revealed the peak load applied onto the surface of a supported RC beam strengthened with CFL is linear to the logarithm of its fatigue life, and the flexural rigidity evolvement undergoes three distinct phases: a rapid decrease from the start to about 5% of the fatigue life; an even development from 5% to about 99% of the fatigue life; and a succedent rapid decrease to failure. When the ratio of fatigue cycles to the fatigue life is within 0.05 to 0.99, the flexural rigidity varies linearly with the ratio. The peak load does not affect the flexural rigidity evolvement if it is not high enough to make the main reinforcements yield. The dependences of the flexural rigidity of specimens formed in the same group upon their fatigue cycles normalized by fatigue life are almost coincident. This implies the flexural rigidity may be a material parameter independent of the stress level. These relationships of flexural rigidity to fatigue cycles, and fatigue life may be able to provide some hints for fatigue design and fatigue life evaluation of RC member strengthened with CFL; nevertheless the findings still need verifying by more experiments.

  5. Strengthening reinforced concrete beams using prestressed glass fiber-reinforced polymer-Part Ⅰ: Experimental study

    Institute of Scientific and Technical Information of China (English)

    HUANG Yue-lin; WU Jong-hwei; YEN Tsong; HUNG Chien-hsing; LIN Yiching

    2005-01-01

    This work is aimed at studying the strengthening of reinforced concrete (R. C.) beams using prestressed glass fiber-reinforced polymer (PGFRP). Carbon fiber-reinforced polymer (CFRP) has recently become popular for use as repair or rehabilitation material for deteriorated R. C. structures, but because CFRP material is very stiff, the difference in CFRP sheet and concrete material properties is not favorable for transferring the prestress from CFRP sheets to R. C. members. Glass fiber-reinforced polymer (GFRP) sheets with Modulus of Elasticity quite close to that of concrete was chosen in this study. The load-carrying capacities (ultimate loads) and the deflections of strengthened R. C. beams using GFRP and PGFRP sheets were tested and compared. T- and ⊥-shaped beams were used as the under-strengthened and over-strengthened beams. The GFRP sheets were prestressed to one-half their tensile capacities before being bonded to the T- and l-shaped R. C. beams. The prestressed tension in the PGFRP sheets caused cambers in the R. C. beams without cracks on the tensile faces. The PGFRP sheets also enhanced the load-carrying capacity. The test results indicated that T-shaped beams with GFRP sheets increased in load-carrying capacity by 55% while the same beams with PGFRP sheets could increase load-carrying capacity by 100%. The ⊥-shaped beams with GFRP sheets could increase load-carrying capacity by 97% while the same beams with PGFRP sheets could increase the loading-carrying capacity by 117%. Under the same external loads, beams with GFRP sheets underwent larger deflections than beams with PGFRP sheets. While GFRP sheets strengthen R. C. beams, PGFRP sheets decrease the beams' ductility, especially for the over-strengthened beams (⊥-shaped beams).

  6. Optimization of the Infrastructure of Reinforced Concrete Reservoirs by a Particle Swarm Algorithm

    Science.gov (United States)

    Kia, Saeed; Sebt, Mohammad Hassan; Shahhosseini, Vahid

    2015-03-01

    Optimization techniques may be effective in finding the best modeling and shapes for reinforced concrete reservoirs (RCR) to improve their durability and mechanical behavior, particularly for avoiding or reducing the bending moments in these structures. RCRs are one of the major structures applied for reserving fluids to be used in drinking water networks. Usually, these structures have fixed shapes which are designed and calculated based on input discharges, the conditions of the structure's topology, and geotechnical locations with various combinations of static and dynamic loads. In this research, the elements of reservoir walls are first typed according to the performance analyzed; then the range of the membrane based on the thickness and the minimum and maximum cross sections of the bar used are determined in each element. This is done by considering the variable constraints, which are estimated by the maximum stress capacity. In the next phase, based on the reservoir analysis and using the algorithm of the PARIS connector, the related information is combined with the code for the PSO algorithm, i.e., an algorithm for a swarming search, to determine the optimum thickness of the cross sections for the reservoir membrane's elements and the optimum cross section of the bar used. Based on very complex mathematical linear models for the correct embedding and angles related to achain of peripheral strengthening membranes, which optimize the vibration of the structure, a mutual relation is selected between the modeling software and the code for a particle swarm optimization algorithm. Finally, the comparative weight of the concrete reservoir optimized by the peripheral strengthening membrane is analyzed using common methods. This analysis shows a 19% decrease in the bar's weight, a 20% decrease in the concrete's weight, and a minimum 13% saving in construction costs according to the items of a checklist for a concrete reservoir at 10,000 m3.

  7. Optimization of the Infrastructure of Reinforced Concrete Reservoirs by a Particle Swarm Algorithm

    Directory of Open Access Journals (Sweden)

    Kia Saeed

    2015-03-01

    Full Text Available Optimization techniques may be effective in finding the best modeling and shapes for reinforced concrete reservoirs (RCR to improve their durability and mechanical behavior, particularly for avoiding or reducing the bending moments in these structures. RCRs are one of the major structures applied for reserving fluids to be used in drinking water networks. Usually, these structures have fixed shapes which are designed and calculated based on input discharges, the conditions of the structure's topology, and geotechnical locations with various combinations of static and dynamic loads. In this research, the elements of reservoir walls are first typed according to the performance analyzed; then the range of the membrane based on the thickness and the minimum and maximum cross sections of the bar used are determined in each element. This is done by considering the variable constraints, which are estimated by the maximum stress capacity. In the next phase, based on the reservoir analysis and using the algorithm of the PARIS connector, the related information is combined with the code for the PSO algorithm, i.e., an algorithm for a swarming search, to determine the optimum thickness of the cross sections for the reservoir membrane’s elements and the optimum cross section of the bar used. Based on very complex mathematical linear models for the correct embedding and angles related to achain of peripheral strengthening membranes, which optimize the vibration of the structure, a mutual relation is selected between the modeling software and the code for a particle swarm optimization algorithm. Finally, the comparative weight of the concrete reservoir optimized by the peripheral strengthening membrane is analyzed using common methods. This analysis shows a 19% decrease in the bar’s weight, a 20% decrease in the concrete’s weight, and a minimum 13% saving in construction costs according to the items of a checklist for a concrete reservoir at 10,000 m3.

  8. Detection of bond failure in the anchorage zone of reinforced concrete beams via acoustic emission monitoring

    Science.gov (United States)

    Abouhussien, Ahmed A.; Hassan, Assem A. A.

    2016-07-01

    In this study, acoustic emission (AE) monitoring was utilised to identify the onset of bond failure in reinforced concrete beams. Beam anchorage specimens were designed and tested to fail in bond in the anchorage zone. The specimens included four 250 × 250 × 1500 mm beams with four variable bonded lengths (100, 200, 300, and 400 mm). Meanwhile, an additional 250 × 250 × 2440 mm beam, with 200 mm bonded length, was tested to investigate the influence of sensor location on the identification of bond damage. All beams were tested under four-point loading setup and continuously monitored using three distributed AE sensors. These attached sensors were exploited to record AE signals resulting from both cracking and bond deterioration until failure. The variations in the number of AE hits and cumulative signal strength (CSS) versus test time were evaluated to achieve early detection of crack growth and bar slippage. In addition, AE intensity analysis was performed on signal strength of collected AE signals to develop two additional parameters: historic index (H (t)) and severity (S r). The analysis of these AE parameters enabled an early detection of both first cracks (at almost the mid-span of the beam) and bar slip in either of the anchorage zones at the beams’ end before their visual observation, regardless of sensor location. The results also demonstrated a clear correlation between the damage level in terms of crack development/measured free end bar slip and AE parameters (number of hits, CSS, H(t), and S r).

  9. Proposed Methodology for Design of Carbon Fiber Reinforced Polymer Spike Anchors into Reinforced Concrete

    Energy Technology Data Exchange (ETDEWEB)

    MacFarlane, Eric Robert [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-05-26

    The included methodology, calculations, and drawings support design of Carbon Fiber Reinforced Polymer (CFRP) spike anchors for securing U-wrap CFRP onto reinforced concrete Tbeams. This content pertains to an installation in one of Los Alamos National Laboratory’s facilities. The anchors are part of a seismic rehabilitation to the subject facility. The information contained here is for information purposes only. The reader is encouraged to verify all equations, details, and methodology prior to usage in future projects. However, development of the content contained here complied with Los Alamos National Laboratory’s NQA-1 quality assurance program for nuclear structures. Furthermore, the formulations and details came from the referenced published literature. This literature represents the current state of the art for FRP anchor design. Construction personnel tested the subject anchor design to the required demand level demonstrated in the calculation. The testing demonstrated the ability of the anchors noted to carry loads in excess of 15 kips in direct tension. The anchors were not tested to failure in part because of the hazards associated with testing large-capacity tensile systems to failure. The calculation, methodology, and drawing originator was Eric MacFarlane of Los Alamos National Laboratory’s (LANL) Office of Seismic Hazards and Risk Mitigation (OSHRM). The checker for all components was Mike Salmon of the LANL OSHRM. The independent reviewers of all components were Insung Kim and Loring Wyllie of Degenkolb Engineers. Note that Insung Kim contributed to the initial formulations in the calculations that pertained directly to his Doctoral research.

  10. Integrity assessment of grouted posttensioning cables and reinforced concrete of a nuclear containment building

    Directory of Open Access Journals (Sweden)

    Shenton B.

    2011-04-01

    Full Text Available The Containment Buildings of CANDU Nuclear Generating Stations were designed to house nuclear reactors and process equipment and also to provide confinement of releases from a potential nuclear accident such as a Loss Of Coolant Accident (LOCA. To meet this design requirement, a post-tensioning system was designed to induce compressive stresses in the structure to counteract the internal design pressure. The CANDU reactor building at Gentilly-1 (G-1, Quebec, Canada (250 MWe was built in the early 1970s and is currently in a decommissioned state. The structure at present is under surveillance and monitoring. In the year 2000, a field investigation was conducted as part of a condition assessment and corrosion was detected in some of the grouted post-tension cable strands. However, no further work was done at that time to determine the cause, nature, impact and extent of the corrosion. An investigation of the Gentilly-1 containment building is currently underway to assess the condition of grouted post-tensioning cables and reinforced concrete. At two selected locations, concrete and steel reinforcements were removed from the containment building wall to expose horizontal cables. Individual cable strands and reinforcement bars were instrumented and measurements were taken in-situ before removing them for forensic examination and destructive testing to determine the impact of ageing and corrosion. Concrete samples were also removed and tested in a laboratory. The purpose of the field investigation and laboratory testing, using this structure as a test bed, was also to collect material ageing data and to develop potential Nondestructive Examination (NDE methods to monitor Containment Building Integrity. The paper describes the field work conducted and the test results obtained for concrete, reinforcement and post-tensioning cables.

  11. Non-destructive inspection protocol for reinforced concrete barriers and bridge railings

    Science.gov (United States)

    Chintakunta, Satish R.; Boone, Shane D.

    2014-02-01

    Reinforced concrete highway barriers and bridge railings serve to prevent errant vehicles from departing the travel way at grade separations. Despite the important role that they play in maintaining safety and their ubiquitous nature, barrier inspection rarely moves beyond visual inspection. In August 2008, a tractor-trailer fatally departed William Preston Lane, Jr. Memorial Bridge after it dislodged a section of the bridge barrier. Investigations following the accident identified significant corrosion of the anchor bolts attaching the bridge railing to the bridge deck. As a result of the information gathered during its investigation of the accident, the National Transportation Safety Board (NTSB) made recommendations to the Federal Highway Administration concerning Non-Destructive Evaluation (NDE) of concrete bridge railings. The Center for nondestructive evaluation (NDE) at Turner Fairbank Highway Research Center in McLean, VA is currently evaluating feasibility of using four technologies - ground penetrating radar (GPR), ultrasonic pulse-echo, digital radiography and infrared thermal imaging methods to develop bridge inspection methods that augment visual inspections, offer reliable measurement techniques, and are practical, both in terms of time and cost, for field inspection work. Controlled samples containing predefined corrosion levels in reinforcing steel were embedded at barrier connection points for laboratory testing. All four NDE techniques were used in the initial phase I testing. An inspection protocol for detecting and measuring the corrosion of reinforced steel embedded in the anchorage system will be developed as part of phase II research. The identified technologies shall be further developed for field testing utilizing a structure with a barrier in good condition and a structure with a barrier in poor condition.

  12. Ductility in a new low nickel stainless steel for reinforced concrete

    Directory of Open Access Journals (Sweden)

    Cobo, A.

    2011-12-01

    Full Text Available This paper discusses the stress-strain curves for a new low nickel stainless steel, a conventional AISI 304 stainless steel and a carbon steel commonly used in reinforced concrete structures. Ductility was studied in terms of ultimate tensile strength (fmax, elastic limit (fy and total elongation at maximum force [ultimate strain; uniform elongation] (εmax. The three materials were assessed with internationally accepted criteria, such as plastic rotational capacity, necking region and the toughness index (total energy absorbed at uniform elongation. The findings were compared to the properties of three types of conventional reinforcing steel: 500SD, 500N and 500H (EC-2.

    En este trabajo se presentan los diagramas tensióndeformación de un nuevo acero inoxidable con bajo contenido en níquel, un inoxidable convencional AISI 304 y un acero al carbono de uso común en estructuras de hormigón armado. Dicha ductilidad se ha estudiado determinando la tensión máxima (fmax, la tensión en el límite elástico (fy y la deformación bajo carga máxima (εmax. Los tres materiales se han evaluado utilizando criterios aceptados internacionalmente, como son el índice p (capacidad de rotación plástica, el índice A* (área plástica de endurecimiento y el índice de tenacidad Id (energía total absorbida en el punto de alargamiento bajo carga máxima, los resultados obtenidos se han comparado con los aceros convencionales de armaduras 500SD, 500N y 500H (EC-2.

  13. Seismic response evaluation of base-isolated reinforced concrete buildings under bidirectional excitation

    Science.gov (United States)

    Bhagat, Satish; Wijeyewickrema, Anil C.

    2017-04-01

    This paper reports on an investigation of the seismic response of base-isolated reinforced concrete buildings, which considers various isolation system parameters under bidirectional near-fault and far-fault motions. Three-dimensional models of 4-, 8-, and 12-story base-isolated buildings with nonlinear effects in the isolation system and the superstructure are investigated, and nonlinear response history analysis is carried out. The bounding values of isolation system properties that incorporate the aging effect of isolators are also taken into account, as is the current state of practice in the design and analysis of base-isolated buildings. The response indicators of the buildings are studied for near-fault and far-fault motions weight-scaled to represent the design earthquake (DE) level and the risk-targeted maximum considered earthquake (MCER) level. Results of the nonlinear response history analyses indicate no structural damage under DE-level motions for near-fault and far-fault motions and for MCER-level far-fault motions, whereas minor structural damage is observed under MCER-level near-fault motions. Results of the base-isolated buildings are compared with their fixed-base counterparts. Significant reduction of the superstructure response of the 12-story base-isolated building compared to the fixed-base condition indicates that base isolation can be effectively used in taller buildings to enhance performance. Additionally, the applicability of a rigid superstructure to predict the isolator displacement demand is also investigated. It is found that the isolator displacements can be estimated accurately using a rigid body model for the superstructure for the buildings considered.

  14. Design aid for shear strengthening of reinforced concrete T-joints using carbon fiber reinforced plastic composites

    Science.gov (United States)

    Gergely, Ioan

    The research presented in the present work focuses on the shear strengthening of beam column joints using carbon fiber composites, a material considered in seismic retrofit in recent years more than any other new material. These composites, or fiber reinforced polymers, offer huge advantages over structural steel reinforced concrete or timber. A few of these advantages are the superior resistance to corrosion, high stiffness to weight and strength to weight ratios, and the ability to control the material's behavior by selecting the orientation of the fibers. The design and field application research on reinforced concrete cap beam-column joints includes analytical investigations using pushover analysis; design of carbon fiber layout, experimental tests and field applications. Several beam column joints have been tested recently with design variables as the type of composite system, fiber orientation and the width of carbon fiber sheets. The surface preparation has been found to be critical for the bond between concrete and composite material, which is the most important factor in joint shear strengthening. The final goal of this thesis is to develop design aids for retrofitting reinforced concrete beam column joints. Two bridge bents were tested on the Interstate-15 corridor. One bent was tested in the as-is condition. Carbon fiber reinforced plastic composite sheets were used to externally reinforce the second bridge bent. By applying the composite, the displacement ductility has been doubled, and the bent overall lateral load capacity has been increased as well. The finite element model (using DRAIN-2DX) was calibrated to model the actual stiffness of the supports. The results were similar to the experimental findings.

  15. Numerical simulation of the throwing power of cathodic prevention applied to marine reinforced concrete piles by means of sacrificial anodes

    Energy Technology Data Exchange (ETDEWEB)

    Bertolini, Luca; Redaelli, Elena [Politecnico di Milano, Dipartimento di Chimica, Materiali e Ingegneria Chimica ' G. Natta' , Via Mancinelli, 7, 20131 Milan (Italy)

    2004-07-01

    The paper deals with the determination of current and potential distribution in reinforced concrete elements partially submerged in seawater aimed at predicting the throwing power of cathodic prevention applied by means of sacrificial anodes. Previous laboratory studies carried out on reinforced concrete columns 15 cm x 15 cm x 120 cm showed that the use of sacrificial anodes placed in the solution at the bottom of the column could provide protection of corroding steel bars in the emerged part of the pile up to about 60 cm from the water level. However, if sacrificial anodes were applied when the concrete was chloride free and steel bars were still passive, even the highest bar, placed at 1 m from the level of water, was protected. This is due to the higher polarizability of passive steel, that makes the throwing power of cathodic prevention higher compared to that of cathodic protection. In order to extend the results obtained on small-scale specimens to elements of higher dimensions, numerical simulations of current and potential distribution were carried out. Two-dimensional models were set up of reinforced concrete piles containing steel bars at different heights protected with sacrificial anodes placed in the water in which they were partially submerged. Boundary conditions describing the electrochemical behaviour of bars were obtained from polarisation curves measured on the previously mentioned columns. Values of concrete conductivity at different heights from the water level were also obtained from those tests. Several cases were considered, representative of conditions differing in electrochemical behaviour of steel bars, dimensions of element, position of sacrificial anodes. The paper discusses the results obtained from the models and compares them in terms of the throwing power that can be reached by using sacrificial anodes immersed in the seawater to protect reinforcing steel bars in the emerged part of a pile. (authors)

  16. The Reinforced Concrete Structure Reinforcement Technology%钢筋混凝土结构加固技术

    Institute of Scientific and Technical Information of China (English)

    李孝余

    2014-01-01

    This article mainly from the carbon fiber reinf-orcement technology, grouting reinforcement technology, che.-mical y-planted steel bars technology, change the stress system, etc. to discuss the reinforced concrete structure reinforcement technology and carries on the comprehensive comparison of these methods.%本文主要从碳纤维加固技术、注浆加固技术、化学植筋技术、改变受力体系等方面,论述了钢筋混凝土结构加固技术,并对这几种方法进行了全面对比。

  17. Predicting method of local damage in reinforced concrete plate with absorber sandwiched between two concrete panels under hard projectile impact

    Energy Technology Data Exchange (ETDEWEB)

    Shirai, Tetsuo; Kambayashi, Atsushi; Ueda, Masatoshi [Takenaka Corp., Osaka (Japan); Ohno, Tomonori; Ishikawa, Nobutaka

    1995-07-01

    The predicting method of local damage in reinforced concrete plate with absorber sandwiched between two concrete panels (double-layered RC plate) under the impact of hard projectile is studied in this paper. The results of high-velocity impact tests to investigate the impact resistance of double-layered RC plates are reported. To evaluate quantitatively the extent of local damage, the existing formulae and the alternative predicting formulae with the multivariate analysis presented here are employed. The prediction of the proposed formulae can agree reasonably well with the actual observed damage, thus can be a useful method in impact resistant design. (author).

  18. Topology optimization of reinforced concrete beams by a spread-over reinforcement model with fixed grid mesh

    Directory of Open Access Journals (Sweden)

    Benjapon Wethyavivorn

    2011-02-01

    Full Text Available For this investigation, topology optimization was used as a tool to determine the optimal reinforcement for reinforcedconcrete beam. The topology optimization process was based on a unit finite element cell with layers of concrete and steel.The thickness of the reinforced steel layer of this unit cell was then adjusted when the concrete layer could not carry thetensile or compressive stress. At the same time, unit cells which carried very low stress were eliminated. The process wasperformed iteratively to create a topology of reinforced concrete beam which satisfied design conditions.

  19. Review of the use of phase change materials (PCMs in buildings with reinforced concrete structures

    Directory of Open Access Journals (Sweden)

    Pons, O.

    2014-09-01

    Full Text Available Phase change materials are capable of storing and releasing energy in the form of heat in determined temperature ranges, so to increase a building’s thermal inertia, stabilize its indoor temperatures and reduce its energetic demand. Therefore, if we used these materials we could have more energetically efficient buildings. Nevertheless, are these materials most appropriate to be used in buildings? Could the incorporation of phase change materials in buildings with concrete structures be generalized? This article aims to carry out a review of these phase change materials from construction professionals’ points of view, study their applications for buildings with reinforced concrete structures and the key points for these applications, draw conclusions and provide recommendations useful for all professionals within the sector who are considering the application of these materials.Los materiales de cambio de fase son capaces de almacenar y liberar energía en forma de calor en un determinando rango de temperaturas, y así aumentar la inercia térmica de un edificio, estabilizar las temperaturas en el interior y reducir la demanda energética. En consecuencia, si utilizáramos estos materiales podríamos tener un parque de edificios más eficientes energéticamente. No obstante, ¿estos materiales son apropiados para usarse en edificios? ¿Se podría generalizar la incorporación de materiales de cambio de fase en edificios con estructuras de hormigón? Este artículo tiene como objetivos hacer una revisión del estado del arte de estos materiales de cambio de fase desde el punto de vista de los profesionales de la construcción, estudiar las aplicaciones en edificios con estructuras de hormigón armado y los puntos clave para estas aplicaciones, extraer conclusiones y recomendaciones útiles para los profesionales del sector que se planteen la utilización de estos materiales.

  20. Response of reinforced concrete and corrugated steel pipes to surface load

    Science.gov (United States)

    Lay, Geoff R.

    Full-scale simulated live load tests were conducted in a controlled laboratory setting using a single-axle frame on 600-mm-inner-diameter reinforced concrete pipe (RCP) and corrugated steel pipe (CSP) when buried in dense, well-graded sand and gravel. Measurements of the RCP at nominal and working forces and beyond are reported for 0.3, 0.6 and 0.9 m of soil cover above the pipe crown. The RCP experienced no cracking when buried at 0.3 m under nominal and working CL-625 and CL-800 single-axle design loads. At these loads, the vertical contraction of the pipe diameter was less than 0.08 and 0.10 mm and the largest tensile strains in the pipe were 75 and 100 muepsilon (50-60% of the cracking strain), respectively. A 0.15 (+/-0.05)-mm-wide axial crack developed at the inner crown in the presence of a 6 kNm/m circumferential bending moment (70% of the theoretical ultimate moment capacity) at the fully factored CL-625 load. This crack did not propagate or widen from 3 series of cyclic load-unload tests. At 1300 kN of applied load the change in pipe diameter was less than 3.5 mm. Increasing soil cover from 0.3 to 0.6 to 0.9 m reduced the circumferential crown bending moment from 6.0 to 3.9 to 2.1 kNm/m, respectively, at 400 kN of axle load. A 1.6- and a 2.8-mm-thick CSP were also subjected to axle loading. No yielding or limit states occurred in the 1.6-mm-thick CSP when buried 0.9-m-deep. However, at 0.6 m of cover a 300 kN axle load caused local yielding at the pipe crown. Increasing soil cover from 0.6 to 0.9 m decreased the vertical diameter change from -3.0 to -1.2 mm and the crown bending moment from 0.7 to 0.2 kNm/m (75% and 20% of the yield moment), respectively, at a 250 kN axle load. Deflections of the thicker CSP were less than the thinner pipe below the CL-625 single-axle load, however further increases in applied load produced a greater response in the thicker pipe, likely due to a haunch support issue. Shallow axle loading produced a greater 3-dimensional