WorldWideScience

Sample records for bridge piers

  1. Hysteretic behavior of prestressed concrete bridge pier with fiber model.

    Science.gov (United States)

    Wang, Hui-li; Feng, Guang-qi; Qin, Si-feng

    2014-01-01

    The hysteretic behavior and seismic characteristics of the prestressed concrete bridge pier were researched. The effects of the prestressed tendon ratio, the longitudinal reinforcement ratio, and the stirrup reinforcement ratio on the hysteretic behavior and seismic characteristics of the prestressed concrete bridge pier have been obtained with the fiber model analysis method. The analysis show some results about the prestressed concrete bridge pier. Firstly, greater prestressed tendon ratio and more longitudinal reinforcement can lead to more obvious pier's hysteresis loop "pinching effect," smaller residual displacement, and lower energy dissipation capacity. Secondly, the greater the stirrup reinforcement ratio is, the greater the hysteresis loop area is. That also means that bridge piers will have better ductility and stronger shear capacity. The results of the research will provide a theoretical basis for the hysteretic behavior analysis of the prestressed concrete pier.

  2. Impact of bridge pier on the stability of ice jam

    Institute of Scientific and Technical Information of China (English)

    王军; 施发义; 陈胖胖

    2015-01-01

    River ice jam is one of the most important issues in rivers in cold regions during winter time. With the extra solid boundary due to the ice cover, the flow condition under ice-covered conditions is completely different from that of a open channel flow. The presence of bridge piers will further change the velocity field around the bridge piers. As a consequence, the formation and the accumulation of ice jams in the vicinity of the bridge pier will be affected. On the other side, the formation of an ice jam around the piers can cause extra turbulence to reduce the stability of a river bridge. The present study focuses on the stress analysis of the ice jam in the vicinity of a bridge pier. By developing a governing equation for describing the equilibrium state of an ice jam, the stability of the ice jam around bridge piers is analyzed and determined. As seen from the field data in literature, the stability estimations of an ice jam around bridge piers determined by the present method agree well with the field observations. Therefore, the proposed approach can be used for the prediction of the formation of ice jams around bridge piers.

  3. Research on Local Scour at Bridge Pier under Tidal Action

    Directory of Open Access Journals (Sweden)

    Wang Jianping

    2015-01-01

    Full Text Available Through the local scour test at bridge pier under tidal action in a long time series, this paper observes the growing trend of the deepest point of local scour at bridge pier under tidal conditions with different characteristic parameters, analyzes the impact of repeat sediment erosion and deposition in the scouring pit caused by reversing current on the development process of the scouring pit, and clarifies the relation between the tide and local scouring depth at bridge pier under steady flow conditions, so as to provide a scientific basis for bridge design and safe operation of estuary and harbor areas.

  4. SCOUR MITIGATION AT BRIDGE PIERS USING SACRIFICIAL PILES

    Institute of Scientific and Technical Information of China (English)

    M. Anisul HAQUE; Md. Munsur RAHMAN; G.M. Tarekul ISLAM; M. Asad HUSSAIN

    2007-01-01

    To mitigate scour around bridge piers, sacrificial piles are economic method where natural processes are involved. The arrangement should be such that scoured materials from the sacrificial piles should have enough volume to fill the scour hole created upstream of the pier in such a way that sediments are trapped inside the scour hole. This concept differs from earlier study made with sacrificial piles that mainly deals to reduce the strength of horseshoe vortex. To determine the effect of sacrificial piles for scour mitigation, alternative arrangements of piles were tested in front of a rectangular pier under clear-water condition and found that when the group of piles is placed at a distance of twice the projected width of the pier, for which percentage of blockage of the pier width is 60%, the scour volume can be reduced upto 61% while the maximum scour depth can be reduced upto 50%.

  5. Study of the time-dependent clear water scour around circular bridge piers

    Directory of Open Access Journals (Sweden)

    Aksoy Aysegul Ozgenc

    2017-03-01

    Full Text Available The local scour around bridge piers influences their stabilities and plays a key role in the bridge failures. The estimation of the maximum possible scour depth around bridge piers is an important step in the design of the bridge pier foundations. In this study, the temporal evolution of local scour depths as well as the equilibrium scour depths were analyzed.

  6. THE EXPERIMENT OF THE COMPLEX INSPECTION OF THE RAILROAD BRIDGE PIER

    Directory of Open Access Journals (Sweden)

    B. M. Usachenko

    2010-03-01

    Full Text Available The procedure and results of a visual inspection and vibrosonic diagnostics of the railroad bridge pier are described. The spatial model of the pier with an arrangement of large cracks is presented.

  7. Application of Bridge Pier Scour Equations for Large Woody Vegetation

    Science.gov (United States)

    2016-07-01

    the Colorado State University (CSU) equation (Richardson and Davis 2001), and (2) to investigate potential model ERDC TR-16-10 2 corrections...guidance manual. Often referred to as the Colorado State University (CSU) equation due to of the location of its development, the method extends back...ER D C TR -1 6- 10 Application of Bridge Pier Scour Equations for Large Woody Vegetation En gi ne er R es ea rc h an d D ev el op m

  8. Centrifuge modeling of rocking-isolated inelastic RC bridge piers

    OpenAIRE

    Loli, Marianna; Knappett, Jonathan A; Brown, Michael J.; Anastasopoulos, Ioannis; GAZETAS, George

    2014-01-01

    Experimental proof is provided of an unconventional seismic design concept, which is based on deliberately underdesigning shallow foundations to promote intense rocking oscillations and thereby to dramatically improve the seismic resilience of structures. Termed rocking isolation, this new seismic design philosophy is investigated through a series of dynamic centrifuge experiments on properly scaled models of a modern reinforced concrete (RC) bridge pier. The experimental method reproduces th...

  9. Rigid-Plastic Dynamic Response of Reinforced Concrete Bridge Pier Impacted by Automobile

    Institute of Scientific and Technical Information of China (English)

    ZHENG Xiaoning; DIAO Bo; YE Yinghua

    2006-01-01

    Bridge piers are impacted by autos sometimes.The pier usually has not been destroyed after once impact by auto.But there are few research on damage which will affect pier's capability,and most relative studies have focused the problems on piers impacted by vessels.The methods involve mainly sutra experience theory,numerical analysis,and experimental method.Owing to the complicacy of the bridge pier impacted by a vessel,there are few research derived with the sutra mechanics model and the piers impacted by autos.The dynamic response is studied here under the assumption of the rigid-plastic small-deformation for the pier impacted by auto.According to the Parkes beam model,the rigid-plastic theoretical solution is deduced.The final deformation is calculated by a practical example for the pier impacted by auto.

  10. Experimental study on the width of the turbulent area around bridge pier

    Institute of Scientific and Technical Information of China (English)

    ZHUANG Yuan; LIU Zu-yuan

    2007-01-01

    At present, the method of calculating the turbulent flow width around the bridge pier is not given in the "Standard for Inland River Navigation" (GB50139-2004) in China, and the bridge designer usually increases the bridge span in order to ensure the navigation safety, which increases both of the structural design difficulty and the project investments. Therefore, it is extremely essential to give a research on the turbulent flow width around the bridge pier. Through the experiments of the fixed bed and the mobile bed, the factors influencing the turbulent flow width around the bridge pier have been analyzed, such as the approaching flow speed, the water depth, the angles between the bridge pier and the flow direction, the sizes of bridge pier, the shapes of the bridge pier, and the scouring around the bridge pier, etc. Through applying the dimension analytic method to the measured data, the formula of calculating the turbulent flow width around the bridge pier is then inferred.

  11. Numerical Hybrid Simulation Modeling Verification for a Curved 3-Pier Bridge (Investigation of Combined Actions on Reinforced Concrete Bridge Piers (CABER Project

    Directory of Open Access Journals (Sweden)

    Adel Abdelnaby

    2013-06-01

    Full Text Available Reinforced concrete bridge piers are subjected to complex loading conditions under earthquake ground motions. Bridge geometric irregularities and asymmetries result in combined actions imposed on the piers as a combination of displacements and rotations in all six degrees of freedom at the pier-deck juncture. Existing analytical tools have proven their inadequacy in representing the actual behavior of piers under these combined actions, particularly in their inelastic range. The objective of this investigation is to develop a fundamental understanding of the effects of these combined actions on the performance of RC piers and the resulting system response. This paper describes a part of the CABER project that verifies the numerical hybrid simulation of the curved bridge. In this part two models were introduced, a whole model and a sub-structured hybrid model. The whole model was established using the Zeus-NL analysis platform, which is capable of performing inelastic nonlinear response history analysis of the whole curved bridge. The hybrid model was divided into three modules which comprised the deck, left and right piers, and the middle pier of the bridge. The three modules were modeled by Zeus-NL as a static analysis module interface. The simulation coordinator (SimCor software was utilized to communicate between these modules using a Pseudo-Dynamic time integration scheme. Results obtained from both models were compared and conclusions were drawn.

  12. Catastrophic model for stability analysis of high pile-column bridge pier

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    According to the engineering features of higher pile-column bridge pier in mountainous area, a clamped beam mechanical model was set up by synthetically analyzing the higher pile-column bridge pier buckling mechanism. Based on the catastrophe theory, the cusp catastrophe model of higher pile-column bridge pier was established by the determination of its potential function and bifurcation set equation, the necessary instability conditions of high pile-column bridge pier were deduced, and the determination method for column-buckling and lateral displacement of high pile-column bridge pier was derived. The comparison between the experimental and calculated results show that the calculated curves agree with testing curves and the method is reasonable and effective.

  13. Mathematical Modeling of Local Scour at Slender and Wide Bridge Piers

    Directory of Open Access Journals (Sweden)

    Youssef I. Hafez

    2016-01-01

    Full Text Available Most existing equations for predicting local scour at bridge piers suffer from overprediction of the scour depths which results in higher foundation costs. To tackle this problem, a mathematical model for predicting bridge pier scour is developed herein based on an energy balance theory. The present study equation was compared to commonly used bridge scour equations using scour field data in USA. The developed equation has several advantages among which we have the following: it adds to the understanding of the physics of bridge pier scour, is valid for slender and wide piers, does not suffer from overprediction of scour depths, addresses clear water and live bed scour, and includes the effects of various characteristics of the bed material such as specific gravity (or density, porosity, size, and angle of repose. In addition, the developed equation accounts for the debris effect and aids in the design of scour mitigation methods such as collars, side bars, slots, and pier protective piles.

  14. The effect of circular bridge piers with different inclination angles toward downstream on scour

    Indian Academy of Sciences (India)

    Mohammad Vaghef; Masoud Ghodsian; Saeid Salimi

    2016-01-01

    A fundamental principle in the safe design of bridge piers is to estimate maximum scour depth. As such, many researchers devoted their efforts to study the phenomenon of scour around bridge piers and to present relationships to estimate maximum scour depth. In the current research, scour around circular bridge piers with two different diameters and different inclination angles toward downstream has been investigated experimentally under clear water and different discharges. The obtained results revealed that increase in the inclination angle leads to a significant decrease in the scour depth, dimensions of sediment ridge and scour hole. Moreover, by comparing the data obtained from vertical bridge pier and well-known relationships, a relationship having the most agreement with the results was selected and modified to estimate equilibrium scour depth around inclined piers.

  15. Seismic Behavior of Posttensioned Concrete Bridge Piers with External Viscoelastic Dampers

    Directory of Open Access Journals (Sweden)

    Anxin Guo

    2016-01-01

    Full Text Available This paper investigates the seismic performance of posttensioned concrete piers with external viscoelastic dampers to improve the energy dissipation capacity of this type of structure. An installation scheme for viscoelastic dampers on bridge piers is proposed, and the mechanical models of the damper are analyzed according to the installation scheme. By attaching the viscoelastic dampers to the posttensioned bridge piers, the analytical model of the hybrid system is established using the OpenSees finite element analysis package. Cyclic behavior and time history analyses are conducted on a posttensioned bridge with and without viscoelastic dampers using the established finite element model. The analysis results indicate that the viscoelastic dampers can effectively improve the seismic performance of the bridge structures with posttensioned piers.

  16. Study on Repaired Earthquake-Damaged Bridge Piers under Seismic Load

    Directory of Open Access Journals (Sweden)

    Jun Deng

    2015-01-01

    Full Text Available The concrete bridge pier damaged during earthquakes need be repaired to meet the design standards. Steel tube as a traditional material or FRP as a novel material has become popular to repair the damaged reinforced concrete (RC bridge piers. In this paper, experimental and finite element (FE studies are employed to analyze the confinement effectiveness of the different repair materials. The FE method was used to calculate the hysteretic behavior of three predamaged circle RC bridge piers repaired with steel tube, basalt fiber reinforced polymer (BFRP, and carbon fiber reinforced polymer (CFRP, respectively. Meanwhile, the repaired predamaged circle concrete bridge piers were tested by pseudo-static cyclic loading to study the seismic behavior and evaluate the confinement effectiveness of the different repair materials and techniques. The FE analysis and experimental results showed that the repaired piers had similar hysteretic curves with the original specimens and all the three repair techniques can restore the seismic performance of the earthquake-damaged piers. Steel tube jacketing can significantly improve the lateral stiffness and peak load of the damaged pier, while the BFRP and CFRP sheets cannot improve these properties due to their thin thickness.

  17. Local-based damage detection of cyclically loaded bridge piers using wireless sensing units

    Science.gov (United States)

    Hou, Tsung-Chin; Lynch, Jerome P.; Parra-Montesinos, Gustavo

    2005-05-01

    Concrete bridge piers are a common structural element employed in the design of bridges and elevated roadways. In order to ensure adequate behavior under earthquake-induced displacements, extensive reinforcement detailing in the form of closely spaced ties or spirals is necessary, leading to congestion problems and difficulties during concrete casting. Further, costly repairs are often necessary in bridge piers after a major earthquake which in some cases involve the total or partial shutdown of the bridge. In order to increase the damage tolerance while relaxing the transverse reinforcement requirements of bridge piers, the use of high-performance fiber reinforced cementitious composites (HPFRCC) in earthquake-resistant bridge piers is explored. HPFRCCs are a relatively new class of cementitious material for civil structures with tensile strain-hardening behavior and high damage tolerance. To monitor the behavior of this new class of material in the field, low-cost wireless monitoring technologies will be adopted to provide HPFRCC structural elements the capability to accurately monitor their performance and health. In particular, the computational core of a wireless sensing unit can be harnessed to screen HPFRCC components for damage in real-time. A seismic damage index initially proposed for flexure dominated reinforced concrete elements is modified to serve as an algorithmic tool for the rapid assessment of damage (due to flexure and shear) in HPFRCC bridge piers subjected to large shear reversals. Traditional and non-traditional sensor strategies of an HPFRCC bridge pier are proposed to optimize the correlation between the proposed damage index model and the damage observed in a circular pier test specimen. Damage index models are shown to be a sufficiently accurate rough measure of the degree of local-area damage that can then be wirelessly communicated to bridge officials.

  18. Reduction of scour around bridge piers using a modified method for vortex reduction

    Directory of Open Access Journals (Sweden)

    Entesar A.S. EL-Ghorab

    2013-09-01

    Full Text Available The current study presents a modified method to reduce the scour depth in front of the bridge piers. The idea of this method is based on reducing the stagnation of the flow and vortex formation in front of the pier. Therefore, the pressure difference around the pier is used for driving the flow through an arrangement of openings in front and connected to the openings along the pier’s side. A test program was planned using an experimental flume at the Hydraulics Research Institute (HRI and three hundred thirty six runs were conducted. Three different pier shapes, circular, square, and rectangular, provided with different openings arrangement and vertical spacing are tested. This method showed that the scour depth is reduced by 45% and also the volume of the scoured material is decreased up to 64%. These results were obtained using opening diameter of 20% of the pier width (w and vertical spacing equals the pier width (w. Also, a dimensionless regression equation was developed based on the obtained results. These findings when implemented in the field can easily safeguard the bridge piers and dramatically reduce the maintenance efforts and costs as well as improve the hydraulic performance of the water structure.

  19. Pushover analysis of the seismic capacity of reinforced concrete double-column bridge piers

    Directory of Open Access Journals (Sweden)

    WANG Hongwei

    2013-02-01

    Full Text Available This article deacribes the basic principle and implementation steps of the Pushover analysis method.By a numerical example,RC double-column piers with different lateral force distribution pattern,different heights and different reinforcement ratio were analyzed.The results show that the analysis results for lower piers of simple supported beam bridges are approximately identical under different lateral force distribution,while with the increase of pier height and longitudinal ratio of reinforcement,the displacement ductility factor is reduced.

  20. Multi-objective optimization design of bridge piers with hybrid heuristic algorithms

    Institute of Scientific and Technical Information of China (English)

    Francisco J. MARTINEZ-MARTIN; Femando GONZALEZ-VIDOSA; Antonio HOSPITALER; Victor YEPES

    2012-01-01

    This paper describes one approach to the design of reinforced concrete (RC) bridge piers,using a three-hybrid multiobjective simulated annealing (SA) algorithm with a neighborhood move based on the mutation operator from the genetic algorithms (GAs),namely MOSAMO1,MOSAMO2 and MOSAMO3.The procedure is applied to three objective functions:the economic cost,the reinforcing steel congestion and the embedded CO2 emissions.Additional results for a random walk and a descent local search multi-objective algorithm are presented.The evaluation of solutions follows the Spanish Code for structural concrete.The methodology was applied to a typical bridge pier of 23,97 m in height.This example involved 110 design variables.Results indicate that algorithm MOSAMO2 outperforms other algorithms regarding the definition of Pareto fronts.Further,the proposed procedure will help structural engineers to enhance their bridge pier designs.

  1. Realistic modelling of the effects of asynchronous motion at the base of bridge piers

    CERN Document Server

    Romanelli, F; Vaccari, F

    2002-01-01

    Frequently long-span bridges provide deep valley crossings, which require special consideration due to the possibility of local amplification of the ground motion as a consequence of topographical irregularities and local soil conditions. This does in fact cause locally enhanced seismic input with the possibility for the bridge piers to respond asynchronously. This introduces special design requirements so that possible out-of-phase ground displacements and the associated large relative displacements of adjacent piers can be accommodated without excessive damage. Assessment of the local variability of the ground motion due to local lateral heterogeneities and to attenuation properties is thus crucial toward the realistic definition of the asynchronous motion at the base of the bridge piers. We illustrate the work done in the framework of a large international cooperation to assess the importance of non-synchronous seismic excitation of long structures. To accomplish this task we compute complete synthetic acc...

  2. Experimental research and finite element analysis of bridge piers failed in flexure-shear modes

    Institute of Scientific and Technical Information of China (English)

    Sun Zhiguo; Si Bingjun; Wang Dongsheng; Guo Xun

    2008-01-01

    In recent earthquakes,a large number of reinforced concrete (RC) bridges were severely damaged due to mixed flexure-shear failure modes of the bridge piers.An integrated experimental and finite element (FE) analysis study is described in this paper to study the seismic performance of the bridge piers that failed in flexure-shear modes.In the first part,a nonlinear cyclic loading test on six RC bridge piers with circular cross sections is carried out experimentally.The damage states,ductility and energy dissipation parameters,stiffness degradation and shear strength of the piers are studied and compared with each other.The experimental results suggest that all the piers exhibit stable flexural response at displacement ductilities up to four before exhibiting brittle shear failure.The ultimate performance of the piers is dominated by shear capacity due to significant shear cracking,and in some cases,rupturing of spiral bars.In the second part,modeling approaches describing the hysteretic behavior of the piers are investigated by using ANSYS software.A set of models with different parameters is selected and evaluated through comparison with experimental results.The influences of the shear retention coefficients between concrete cracks,the Bauschinger effect in longitudinal reinforcement,the bond-slip relationship between the longitudinal reinforcement and the concrete and the concrete failure surface on the simulated hysteretie curves are discussed.Then,a modified analysis model is presented and its accuracy is verified by comparing the simulated results with experimental ones.This research uses models available in commercial FE codes and is intended for researchers and engineers interested in using ANSYS software to predict the hysteretic behavior of reinforced concrete structures.

  3. Experimental research and finite element analysis of bridge piers failed in flexure-shear modes

    Science.gov (United States)

    Sun, Zhiguo; Si, Bingjun; Wang, Dongsheng; Guo, Xun

    2008-12-01

    In recent earthquakes, a large number of reinforced concrete (RC) bridges were severely damaged due to mixed flexure-shear failure modes of the bridge piers. An integrated experimental and finite element (FE) analysis study is described in this paper to study the seismic performance of the bridge piers that failed in flexure-shear modes. In the first part, a nonlinear cyclic loading test on six RC bridge piers with circular cross sections is carried out experimentally. The damage states, ductility and energy dissipation parameters, stiffness degradation and shear strength of the piers are studied and compared with each other. The experimental results suggest that all the piers exhibit stable flexural response at displacement ductilities up to four before exhibiting brittle shear failure. The ultimate performance of the piers is dominated by shear capacity due to significant shear cracking, and in some cases, rupturing of spiral bars. In the second part, modeling approaches describing the hysteretic behavior of the piers are investigated by using ANSYS software. A set of models with different parameters is selected and evaluated through comparison with experimental results. The influences of the shear retention coefficients between concrete cracks, the Bauschinger effect in longitudinal reinforcement, the bond-slip relationship between the longitudinal reinforcement and the concrete and the concrete failure surface on the simulated hysteretic curves are discussed. Then, a modified analysis model is presented and its accuracy is verified by comparing the simulated results with experimental ones. This research uses models available in commercial FE codes and is intended for researchers and engineers interested in using ANSYS software to predict the hysteretic behavior of reinforced concrete structures.

  4. Rapid repair of severely earthquake-damaged bridge piers with flexural-shear failure mode

    Science.gov (United States)

    Sun, Zhiguo; Wang, Dongsheng; Du, Xiuli; Si, Bingjun

    2011-12-01

    An experimental study was conducted to investigate the feasibility of a proposed rapid repair technique for severely earthquake-damaged bridge piers with flexural-shear failure mode. Six circular pier specimens were first tested to severe damage in flexural-shear mode and repaired using early-strength concrete with high-fluidity and carbon fiber reinforced polymers (CFRP). After about four days, the repaired specimens were tested to failure again. The seismic behavior of the repaired specimens was evaluated and compared to the original specimens. Test results indicate that the proposed repair technique is highly effective. Both shear strength and lateral displacement of the repaired piers increased when compared to the original specimens, and the failure mechanism of the piers shifted from flexural-shear failure to ductile flexural failure. Finally, a simple design model based on the Seible formulation for post-earthquake repair design was compared to the experimental results. It is concluded that the design equation for bridge pier strengthening before an earthquake could be applicable to seismic repairs after an earthquake if the shear strength contribution of the spiral bars in the repaired piers is disregarded and 1.5 times more FRP sheets is provided.

  5. Determine of velocity field with PIV and CFD during the flow around of bridge piers

    Directory of Open Access Journals (Sweden)

    Picka D.

    2013-04-01

    Full Text Available The article describes the processing of specific junior research FAST-J-11-51/1456 which dealt with physical and CFD of the velocity field during the flow around of bridge piers. Physical modelling has been carried out in Laboratory of water management research in Institute of Water Structures in Brno University of Technology – Faculty of Civil Engineering. To measure of the velocity field in profile of bridge piers were used laser measuring method PIV (Particle Image Velocimetry. The results of PIV served as a basis for comparing experimental data with CFD results of this type of flow in the commercial software ANSYS CFX.

  6. A study on ship impacting a flexible crashworthy device for protecting bridge pier

    Directory of Open Access Journals (Sweden)

    Yang Liming

    2015-01-01

    Full Text Available As the accident of a vessel impacting a bridge pier will cause serious disaster, such as destroyed bridge, sinking ship and polluting environment, the technology and method to protect bridge pier from ship collision have been widely investigated recently. Due to the huge kinetic energy of large-tonnage ship and the short time duration in the collision, the studies involve impact mechanics. A developed flexible crashworthy device has been developed to protect bridges, which consists of an outer steel-periphery, an inner steel-periphery and the rubber coating SWRCs(soft elements installed between them. When the SWRC crashworthy device is installed, the collision duration under low impact force is prolonged due to its high compliance, which results in the ship having enough time to turn its navigation direction and most of the remainder kinetic energy being carried off by the turned away ship. Consequently, both impact forces on the ship and on the bridge pier decrease markedly. This is the key reason as to why the SWRC crashworthy device can avoid the destruction of both the bridge and the ship. Based on our results of theoretical studies and numerical simulations, the present paper will propose an experiment-adopted a real ship to impact a flexible crashworthy device. The collision test has been performed 12 times with different speed, carrying capacity, and impact angle of the ship. After the experiments, the ship, flexible crashworthy device and the pier are not damaged. The experiments show that the flexible crashworthy device can turn away the impact ship, so that the ship moves along the outer part of the device, which reduces the ship impact force on the bridge pier obviously. It not only protects bridges but also avoids the damage to ships.

  7. Cyclic Load Responses of GFRP-Strengthened Hollow Rectangular Bridge Piers

    Directory of Open Access Journals (Sweden)

    Junfeng Jia

    2014-01-01

    Full Text Available This study investigated the seismic behavior of glass fiber reinforced polymer (GFRP strengthened hollow rectangular bridge piers. Cyclic testing of reinforced concrete (RC piers retrofitted with GFRP was carried out under constant axial loading and lateral bending. The failure characteristics, flexural ductility, dissipated energy, and hysteretic behaviors, were analyzed based on experimental results. A simplified GFRP-confined concrete model is developed by considering effective strength coefficient and area distribution ratio of GFRP sheets. The results indicate that the failure modes and damage region would be changed and the ductility and dissipated energy of the GFRP-strengthened hollow rectangular bridge piers were improved greatly but not much improvement for the lateral load capacity. The analytical results of the force-displacement hysteretic loops based on the GFRP-confined concrete model developed in this paper agreed well with the experimental data.

  8. Construction technology on pile foundation of No. 6 main pier in Dashengguan Yangtze Bridge

    Institute of Scientific and Technical Information of China (English)

    Hongbin YU; Zeping LIAN

    2009-01-01

    Based on pile foundation construction of No. 6 main pier, deep mudstone geological foundation and deep-water construction in Nanjing-Dashengguan Yangtze Bridge, the method of super-large-diameter bored pile in deep water is studied. The spread drill, application of PHP mud, and choice of machine are solved by adopting two machines of KTY4000 and KPG300A. Besides, the airlift reversing circulation is selected in slag discharge. The results show that this method can ensure successfully the construction of pier foundation to satisfy the demands of codes.

  9. Effect of downward seepage on turbulent flow characteristics and bed morphology around bridge piers

    Science.gov (United States)

    Chavan, Rutuja; Sharma, Anurag; Kumar, Bimlesh

    2017-03-01

    In this work, experimental investigations have been pursued to analyse the influence of downward seepage on the turbulent characteristics of flow and corresponding changes in vortex structure around circular bridge pier in alluvial channel. Experiments were conducted in sand bed channel with circular piers of different sizes for no seepage, 10% seepage and 20% seepage cases. The measurement of turbulent flow statistics such as velocity and Reynolds stresses is found to be negative within the scour hole at upstream of the pier whereas application of downward seepage retards the reversal of the flow causing a decrement in the velocity and Reynolds stresses. Higher Reynolds shear stress prevails at the downstream side because of the production of wake vortices. Contribution of all bursting events to the total Reynolds shear stress production has been observed to increase with downward seepage. The analysis of integral scale suggest that size of eddies increases with seepage, which is responsible for increase in particle mobility. Initially rate of scouring is more which abatements gradually with expanding time as well as with the increased of downward seepage. Presence of downward seepage reduces the depth and length of vortex and shifts towards downstream side of the pier.

  10. Pier and contraction scour prediction in cohesive soils at selected bridges in Illinois

    Science.gov (United States)

    Straub, Timothy D.; Over, Thomas M.

    2010-01-01

    This report presents the results of testing the Scour Rate In Cohesive Soils-Erosion Function Apparatus (SRICOS-EFA) method for estimating scour depth of cohesive soils at 15 bridges in Illinois. The SRICOS-EFA method for complex pier and contraction scour in cohesive soils has two primary components. The first component includes the calculation of the maximum contraction and pier scour (Zmax). The second component is an integrated approach that considers a time factor, soil properties, and continued interaction between the contraction and pier scour (SRICOS runs). The SRICOS-EFA results were compared to scour prediction results for non-cohesive soils based on Hydraulic Engineering Circular No. 18 (HEC-18). On average, the HEC-18 method predicted higher scour depths than the SRICOS-EFA method. A reduction factor was determined for each HEC-18 result to make it match the maximum of three types of SRICOS run results. The unconfined compressive strength (Qu) for the soil was then matched with the reduction factor and the results were ranked in order of increasing Qu. Reduction factors were then grouped by Qu and applied to each bridge site and soil. These results, and comparison with the SRICOS Zmax calculation, show that less than half of the reduction-factor method values were the lowest estimate of scour; whereas, the Zmax method values were the lowest estimate for over half. A tiered approach to predicting pier and contraction scour was developed. There are four levels to this approach numbered in order of complexity, with the fourth level being a full SRICOS-EFA analysis. Levels 1 and 2 involve the reduction factors and Zmax calculation, and can be completed without EFA data. Level 3 requires some surrogate EFA data. Levels 3 and 4 require streamflow for input into SRICOS. Estimation techniques for both EFA surrogate data and streamflow data were developed.

  11. 串列双桥墩紊流特性研究%Research of tandem double bridge pier turbulence characteristics

    Institute of Scientific and Technical Information of China (English)

    2016-01-01

    Using the combination of generalized flume experiment and mathematical model test methods,a two-dimensional generalized model of water and bridge is established, through the study of the trace,trailing vortex intensity and shedding frequency,analyzing the pier spacing influence of turbulent flow characteristics around pier.The research has shown that:when tandem double bridge pier spacing smaller (L/D ≤ 2.0),the upstream bridge has no vortex shedding,the upstream bridge pier shear layer alternate adhere to the downstream piers,causing shear layer thickened before exercise,reducing trail vortex shed-ding frequency,the turbulence intensity increases.When 3.0 ≤L/D < 5.0,upstream and downstream bridge piers both have vortex shedding,and as bridge pier spacing bigger,vor-tex shedding phenomenon more obvious,the trailing vortex of the turbulence intensity re-duce along with the increase of spacing.After the bridge pier spacing increases to 5.0,up-stream and downstream turbulence of trailing vortex and trailing vortex shedding are similar to single bridge pier.%采用概化水槽试验和数值模拟相结合的方法,建立了水流与桥墩的二维概化水槽模型.通过对迹线、尾涡强度及脱落频率的研究,分析了桥墩间距对桥墩周围紊流特性的影响.研究结果表明,串列双桥墩间距较小(L/D≤2.0)时,上游桥墩没有形成涡的脱落,上游桥墩的剪切层交替的附着在下游桥墩上,导致剪切层在运动之前变厚,尾涡脱落频率减小,紊动强度增大;当3.0≤L/D<5.0时,上、下游桥墩均有涡的脱落,且桥墩间距越大涡脱落现象越明显,尾涡的紊动强度随间距的增大而减小;当桥墩间距增大到5.0后,上、下游尾涡的紊动及尾涡脱落类似单个桥墩.

  12. Stability Analysis of Long-Span Continuous Rigid Frame Bridge with Thin-Wall Pier

    Institute of Scientific and Technical Information of China (English)

    HE Bo; SHI Ya-nan; ZHU Hong-ping; GUO Wen-zeng; CHEN Yong

    2008-01-01

    During cantilever cast in construction of high-pier and large-span continuous rigid frame bridges, structural stability in the longest cantilevered stage is very important. Based on a practical design case of a large-span continuous rigid frame bridge in Wuhan, the longest span stability coefficient is calculated with linear-buckling and nonlinear-buckling methods, respectively. The influences of both geometrical nonlinearity and the dual nonlinearity of material and geometry are considered. Numerical results indicate that the nonlinear solution is necessary to stability analysis because linear buckling loads axe much higher than those of nonlinear buckling. Thus, the edge fiber yield criterion is more convenient and faster than ultimate loading criterion when estimating nonlinear stability of structure, and can be used easily in the initial engineering design.

  13. Seismic response of bridge pier on rigid caisson foundation in soil stratum

    Institute of Scientific and Technical Information of China (English)

    C. Tsigginos; N. Gerolymos; D. Assimaki; G. Gazetas

    2008-01-01

    An analytical method to study the seismic response of a bridge pier supported on a rigid caisson foundation embedded in a deep soil stratum underlain by a homogeneous half space is developed. The method reproduces the kinematic and inertial responses, using translational and rotational distributed Winkler springs and dashpots to simulate the soil-caisson interaction. Closed-form solutions are given in the frequency domain for vertical harmonic S-wave excitation. Comparison with results from finite element (FE) analysis and other available solutions demonstrates the reliability of the model. Results from parametric studies are given for the kinematic and inertial responses. The modification of the fundamental period and damping ratio of the bridge due to soil-structure interaction is graphically illustrated.

  14. Experimental and numerical investigation of the effect of different shapes of collars on the reduction of scour around a single bridge pier.

    Directory of Open Access Journals (Sweden)

    Afshin Jahangirzadeh

    Full Text Available The scour phenomenon around bridge piers causes great quantities of damages annually all over the world. Collars are considered as one of the substantial methods for reducing the depth and volume of scour around bridge piers. In this study, the experimental and numerical methods are used to investigate two different shapes of collars, i.e, rectangular and circular, in terms of reducing scour around a single bridge pier. The experiments were conducted in hydraulic laboratory at university of Malaya. The scour around the bridge pier and collars was simulated numerically using a three-dimensional, CFD model namely SSIIM 2.0, to verify the application of the model. The results indicated that although, both types of collars provides a considerable decrease in the depth of the scour, the rectangular collar, decreases scour depth around the pier by 79 percent, and has better performance compared to the circular collar. Furthermore, it was observed that using collars under the stream's bed, resulted in the most reduction in the scour depth around the pier. The results also show the SSIIM 2.0 model could simulate the scour phenomenon around a single bridge pier and collars with sufficient accuracy. Using the experimental and numerical results, two new equations were developed to predict the scour depth around a bridge pier exposed to circular and rectangular collars.

  15. Ultimate pier and contraction scour prediction in cohesive soils at selected bridges in Illinois

    Science.gov (United States)

    Straub, Timothy D.; Over, Thomas M.; Domanski, Marian M.

    2013-01-01

    The Scour Rate In COhesive Soils-Erosion Function Apparatus (SRICOS-EFA) method includes an ultimate scour prediction that is the equilibrium maximum pier and contraction scour of cohesive soils over time. The purpose of this report is to present the results of testing the ultimate pier and contraction scour methods for cohesive soils on 30 bridge sites in Illinois. Comparison of the ultimate cohesive and noncohesive methods, along with the Illinois Department of Transportation (IDOT) cohesive soil reduction-factor method and measured scour are presented. Also, results of the comparison of historic IDOT laboratory and field values of unconfined compressive strength of soils (Qu) are presented. The unconfined compressive strength is used in both ultimate cohesive and reduction-factor methods, and knowing how the values from field methods compare to the laboratory methods is critical to the informed application of the methods. On average, the non-cohesive method results predict the highest amount of scour, followed by the reduction-factor method results; and the ultimate cohesive method results predict the lowest amount of scour. The 100-year scour predicted for the ultimate cohesive, noncohesive, and reduction-factor methods for each bridge site and soil are always larger than observed scour in this study, except 12% of predicted values that are all within 0.4 ft of the observed scour. The ultimate cohesive scour prediction is smaller than the non-cohesive scour prediction method for 78% of bridge sites and soils. Seventy-six percent of the ultimate cohesive predictions show a 45% or greater reduction from the non-cohesive predictions that are over 10 ft. Comparing the ultimate cohesive and reduction-factor 100-year scour predictions methods for each bridge site and soil, the scour predicted by the ultimate cohesive scour prediction method is less than the reduction-factor 100-year scour prediction method for 51% of bridge sites and soils. Critical shear stress

  16. Investigation of chloride induced corrosion of bridge pier and life-cycle repair cost analysis using fiber reinforced polymer composites

    Science.gov (United States)

    Dhakal, Dinesh

    Bridges are the long term investment of the highway agencies. To maintain the required service level throughout the life of a bridge, a series of maintenance, repair, and rehabilitation (MRℝ) works can be performed. To investigate the corrosion deterioration and maintenance and repair practices in the bridge pier columns constructed in chloride-laden environment, a questionnaire survey was conducted within the 50 state Departments of Transportation (DOTs). Based on the survey data, two corrosion deterioration phases were identified. They were corrosion crack initiation phase and corrosion propagation phase. The data showed that the mean corrosion crack initiation phase for bridge pier column having cover of 50 mm, 75 mm, and 100 mm was 18.9 years, 20.3 years, and 22.5 years, respectively. The corrosion propagation phase starts after the corrosion crack initiation. The corrosion propagation is defined in a single term, corrosion damage rate, measured as percentage of area damaged due to corrosion cracking, spalling, and delamination. From the survey, the corrosion damage rate was found 2.23% and 2.10% in the bridge pier columns exposed to deicing salt water and exposed to tidal splash/spray, respectively. For this study, two different corrosion damage rates were proposed before and after the repair criteria for minor damage repair as practiced by DOTs. This study also presents the collected data regarding the corrosion effectiveness of using sealers and coatings, cathodic protection, corrosion inhibitors, carbon fiber/epoxy composites, and glass fiber/epoxy composites as maintenance and repair technique. In this study, the cost-effectiveness of wrapping carbon fiber/epoxy composites and glass fiber/epoxy composites in bridge pier columns constructed in a chloride-laden environment was investigated by conducting life-cycle cost analysis. As a repair work, externally bonded two layer of carbon fiber/epoxy and glass fiber/epoxy composites were installed by wet

  17. 限制位移桥墩的连续刚构桥抗震性能研究%Seismic Performance of a Continuous Rigid Frame Bridge with Displacement-restricted Piers

    Institute of Scientific and Technical Information of China (English)

    刘鹏

    2015-01-01

    Since the beginning of the 1 990s,performance-based seismic design theory has entered the mainstream of structural seismic research.The purpose of performance-based seismic design theory is to determine the seismic performance objectives of a building based on its use,impor-tance,and level of seismic fortification.Buildings designed in accordance with those objectives will safely withstand earthquakes that may occur in the future.On the bridge,plastic hinges placed on the piers were used to consume earthquake energy.Design for ductility can avoid collapse of the bridge.However,permanent deformation of the plastic hinges could cause serious damage to the pier.It is difficult to immediately repair bridges following earthquakes.Many transportation func-tions are significantly slowed or lost.In order to ensure that the transportation capacity of bridges is recovered quickly after a strong earthquake,many structural systems have been proposed,inclu-ding rocking bridge piers and self-centering bridge piers.The continuous rigid frame bridge system with displacement-restricted piers was consistent with the concept of rocking piers.This structure can realize three important functions:(1 )limit the maximum displacement of pier,(2 )prevent the bridge from overturning,and (3 )adjust the coefficient of friction at the pier bottom.By adhering to these objectives between the pier bottom and the pier cap,the displacement-restricted earthquake mitigation. This study concluded that the continuous rigid frame bridge system with displacement-restricted piers could reduce ductility and strength demands on the bridge piers.This paper compared the displacement limits of 2 cm,5 cm,8 cm and traditional piers.The results showed that the displacement of the pier top,the bending moment at the pier bottom,and the bending moment of the pier at the bridge beam with the displacement-restricted 2 cm,5 cm,8 cm piers were much less than the piers of a traditional continuous rigid frame bridge

  18. 钢筋混凝土空心墩抗震数值分析模型%Numerical seismic analysis model for hollow reinforced concrete bridge piers

    Institute of Scientific and Technical Information of China (English)

    杨春喜

    2014-01-01

    钢筋混凝土空心墩在大型铁路、公路桥梁工程中占有相当大的比例。准确模拟空心墩抗震能力对保证桥梁工程抗震安全具有重要意义。采用Open Sees数值分析平台,基于纤维梁柱单元和零长度转动弹簧单元,考虑试件弯曲和纵筋拔出变形,对3个钢筋混凝土空心墩抗震拟静力试验结果进行模拟计算。将模拟得到的滞回曲线与试验结果进行了对比分析。结果表明,模拟结果与试验结果吻合较好。%Hol ow reinforced concrete bridge piers are extensively used in highway and railway bridges. Simulation of the seismic behavior of hol ow bridge piers is important to ensure the seismic safety of bridges. Based on fiber beam-column element and zero length rotation spring element, three hol ow reinforced concrete bridge piers are modeled by using OpenSees software, in which the flexural and bond-slip deformation of the piers are considered. The simulated hysteretic curves are compared with test results. The results show that the simulated results agreed wel with test results.

  19. Earthquake Response Analysis of High Pier T -beam Bridge in Mountainous Region%山区高墩梁桥抗震分析

    Institute of Scientific and Technical Information of China (English)

    杨相展

    2012-01-01

    A seven spans of 40m T - beam high pier bridge is studied in this paper. By utilizing the finite ele- ment software, a three - dimensional mechanics model is established. Based on the model, seismic behavior of T - beam high pier bridge, in which various support links between pier and beam are considered, is investigated by u- sing the nonlinear time history method. The results indicate that structural earthquake -resistance performance can be improved by using seismic isolation bearing.%以一座7—40mT梁高架桥为研究对象,建立了三维空间模型,采用非线性时程分析方法,分析了不同墩梁连接方式的山区高墩T梁桥的抗震性能,计算结果表明:采用铅芯隔震橡胶支座可以提高桥梁的抗震性能。

  20. A型高墩大跨混凝土连续刚构桥地震反应影响分析%Impact Analysis of Seismic Response A Type High Pier and Long Span Concrete Continuous Rigid Frame Bridge

    Institute of Scientific and Technical Information of China (English)

    陈思孝; 夏修身; 李锐

    2014-01-01

    Remarkable characteristics of A type high pier and long span concrete continuous rigid frame bridge are high pier, larye span, massive girder and pier. This paper analyzes the influence of P-delta effect, the traveling wave effect on the A type high pier and long-span continuous rigid frame bridge seismic response of concrete and elastic plastic re-sponse characteristics of earthquake, it also discusses the seismic ductility design method of A type high pier and long span concrete continuous rigid frame bridge. The results showed that: A type continuous rigid frame bridge with high piers on seismic design limited ductility is reasonable, P-delta has little effect on type A high pier and long-span continu-ous rigid frame bridge’s response in earthquake, which cauld be ignared in design; traveling wave effect on the A type high pier and long-span continuous rigid frame bridge response earthquake should be combined with a specific type of bridge and bridge site selection. Reasonable seismic wave velocity and proper travelling wave speed should be selected in analysis. The research could sexve as a reference for high pier and long-span Railway Bridge design.%A型高墩大跨混凝土连续刚构桥的显著特点是墩高、跨度大、梁体及墩身质量巨大。文章分析了P-Δ效应、行波效应对A型高墩大跨混凝土连续刚构桥地震反应的影响及弹塑性地震反应特点,探讨了A型高墩大跨混凝土连续刚构桥的延性抗震设计方法。结果表明: A型高墩连续刚构桥按有限延性的抗震设计比较合理,P-Δ效应对A型高墩大跨连续刚构桥地震反应的影响较小,设计中可以忽略;行波效应对A型高墩大跨连续刚构桥地震反应的影响应结合具体的桥型、桥址场地类别,选取合理的地震动、恰当的行波速度进行分析。

  1. A new fender system for bridge pier protection against vessel collision%桥墩新型防船撞装置防撞性能研究

    Institute of Scientific and Technical Information of China (English)

    姜华; 耿波; 张锡祥

    2014-01-01

    桥墩防船撞装置通常用于减小船撞力或者拨转船只使其远离桥墩,有效的防撞装置对桥梁和船只安全运行都非常重要。采用 LSDYNA 对一座五跨连续刚构桥采用的新型浮式耗能防船撞装置的防撞性能进行评估。这种新型防船撞装置可以既保护桥墩又可以保护船只,其结构由模块化的 FRP 套箱组成,套箱内部由八边形 FRP 柱壳组成,具有初始造价低、施工方便和维修养护成本低等优点。介绍了所用 FRP 材料的强度试验,包括拉伸、压缩、弯曲和剪切,并根据强度试验定义了正交各向异性本构模拟 FRP 材料。研究表明:该新型防撞装置具有非常好的吸能能力,可以显著减小作用在桥墩和船只上的撞击力。%Bridge physical protection systems are typically used to reduce vessel impact loads to non-destructive levels or to redirect aberrant vessels away from bridge piers.An efficient physical protection system is critical for safe operation of bridges and vessels.Here,a performance evaluation of a new floating fender system used for a five-span pre-stressed concrete bridge was performed by utilizing LS-DYNA.This new floating fender system could protect both bridge piers and vessels.It was composed of FRP box modules filled with rows of FRP tubes with advantages of low initial cost, modular construction /repairing,and low maintenance cost.The vessel-bridge collision analysis was conducted using an orthotropic FRP composite material model defined with the results of strength tests including tension,compression, bending,and shear tests of FRP specimens.It was shown that this new fender system has excellent energy absorbing capabilities and significantly reduces collision forces imposed on bridge piers and colliding vessels.

  2. Comparison and Analysis for High Pier Formwork Construction of Bridge Engineering%桥梁工程高墩模板施工技术比较分析

    Institute of Scientific and Technical Information of China (English)

    易达; 葸振东

    2016-01-01

    The economical indexes for suspension formwork, climbing formwork, sliding formwork, roller formwork and hanging formwork construction used in bridge piers are compared. From the construction principle, formwork cost, personnel and equipment, construction schedule, construction quality and safety, this paper describes their applicability. The analysis results show that if the bridge has oblique piers, the hydraulic climbing formwork is best; if the pier is not high and has loose schedule, the suspension formwork is suitable;and if it has tight schedule, the sliding formwork should be considered;if considering the comprehensive factors, hanging formwork and roller formwork should be applied.%对桥梁工程高墩用悬模、爬模、滑模、辊模和吊模施工技术经济指标进行比较,从各种施工技术的原理、模板系统成本、人员及机械设备、施工进度、施工质量和施工安全性等方面阐述了其适用性.分析结果表明:如果是带斜率的桥墩施工,则最好用液压爬模施工;如果桥墩不高、进度宽松时可以用悬模施工;强调进度的山区高墩,可考虑滑模施工;如果综合考虑各方因素,则可考虑吊模、辊模施工.

  3. Three Dimensional Analysis of the Final Design of Pier Extensions and West Guide Wall to Mitigate Local Scour Risk at the BNSF Railroad Bridge Downstream of the Prado Dam Supplemental Report

    Energy Technology Data Exchange (ETDEWEB)

    Lottes, S. A. [Argonne National Lab. (ANL), Argonne, IL (United States); Sinha, N. [Argonne National Lab. (ANL), Argonne, IL (United States); Bojanowski, C. [Argonne National Lab. (ANL), Argonne, IL (United States); Kerenyi, K. [Turner-Fairbank Highway Research Center, McLean, VA (United States); Sharp, Jeremy [U.S. Army Corps of Engineers, Vicksburg, MI (United States), Coastal and Hydraulics Lab

    2016-06-01

    This report is a supplement to a previous report [ref] covering optimization of wedge shaped pier extensions to streamline large bluff body piers as a local scour countermeasure for the Burlington Northern and Santa Fe (BNSF) Railroad Bridge over the Santa Ana River downstream of Prado Dam in Riverside County, CA. The optimized design was tested in a 1/30 scale physical model at U.S. Army Engineer Research and Development Center (ERDC) in Vicksburg, MS, and the optimized design was used as the base for the construction design. Constructability issues having to do with both materials and site conditions including access underneath the BNSF bridge yielded a construction design that required making the pier extensions wider and either moving the western curve of the west guide wall upstream or changing its geometry.

  4. 高架桥薄壁空心高墩施工%Construction Organizational Design for High Hollow Thin-wall Pier of Viaduct Bridge

    Institute of Scientific and Technical Information of China (English)

    冯世敏

    2014-01-01

    PJ-200 Cantilever formwork ( climbing formwork ) and big steel formwork lifted with tower crane ( turnover formwork construction) have been adopted for the construction of high hollow thin-wall pier of Hewei Bridge at Km:253+353 of Lechang-Guangzhou Expressway, which has achieved good economic benefits.%乐昌至广州高速公路K253+353河尾大桥薄壁空心高墩施工组织设计采用PJ-200悬臂模板(即爬模施工)和塔吊提升大块钢模的方法施工(即翻模施工)相结合的方式,取得了较好的经济效益。

  5. 论斜拉桥墩台基础及桩基施工放样%On the cable-stayed bridge pier foundation and pile foundation construction stakeout

    Institute of Scientific and Technical Information of China (English)

    王成全

    2012-01-01

      结合实例介绍了斜拉桥墩台基础、桩基施工放样技术、墩台定位的方法、索塔施工测量放样以及高塔柱施工测量的施工方法。%  The cable-stayed bridge pier foundation, pile foundation construction stakeout technical positioning pier, Sarasota Construction Setting High Tower Construction Survey Construction Methods with examples.

  6. 钢筋混凝土桥墩承载力计算方法讨论%Discussion of Computing Methods for Bearing Capacity of Reinforced Concrete Bridge Piers

    Institute of Scientific and Technical Information of China (English)

    林上顺

    2015-01-01

    在我国山区公路桥梁工程中,钢筋混凝土高桥墩较为常见。对国内外钢筋混凝土高桥墩承载力计算方法进行分析与比较,发现我国公路桥涵设计规范的计算方法还存在不合理之处,且偏于不安全。为此,提出钢筋混凝土高桥墩承载力计算需要进一步研究的内容。%In highway bridge projects in mountainous area of China reinforced concrete high bridge piers are common.This paper analyzes and compares computing methods for bearing capacity of reinforced concrete high bridge piers at home and abroad and finds out that the computing methods in desing codes for China national highway bridges and culverts are irrational and unsafe .For this reasons , the paper proposes the conents to be further researched in computation of bearing capacity of reinforced concrete high brdige piers .

  7. Inquiry on construction technology of high bridge pier%桥梁高墩施工技术探讨

    Institute of Scientific and Technical Information of China (English)

    郭卫琦

    2012-01-01

    针对现在工程建设主要采用的翻模、滑模及爬模三种高墩施工技术进行了分析,结合墩柱尺寸为5.5 m×2.5 m的等截面矩形高墩柱为例加以阐述,主要从施工构成、施工工艺及施工要点等方面分别对三种施工技术进行了论述,并提出了施工中的优缺点,以期为类似工程施工提供参考。%The paper analyzes the construction technologies of turnover formwork, sliding formwork and climbing formwork adopted in contemporary engineering construction. Taking the high rectangular pier column with section size of 5.5 m × 2.5 m as an example, the paper discusses three construction techniques from aspects of construction composition, construction technology and construction points and so on, and puts forward construction pros and cons, with a view to provide certain reference for similar engineering construction.

  8. Bridge pier failure probabilities under combined hazard effects of scour, truck and earthquake. Part I: occurrence probabilities

    Science.gov (United States)

    Liang, Zach; Lee, George C.

    2013-06-01

    In many regions of the world, a bridge will experience multiple extreme hazards during its expected service life. The current American Association of State Highway and Transportation Officials (AASHTO) load and resistance factor design (LRFD) specifications are formulated based on failure probabilities, which are fully calibrated for dead load and nonextreme live loads. Design against earthquake loads is established separately. Design against scour effect is also formulated separately by using the concept of capacity reduction (or increased scour depth). Furthermore, scour effect cannot be linked directly to an LRFD limit state equation, because the latter is formulated using force-based analysis. This paper (in two parts) presents a probability-based procedure to estimate the combined hazard effects on bridges due to truck, earthquake and scour, by treating the effect of scour as an equivalent load effect so that it can be included in reliability-based bridge failure calculations. In Part I of this series, the general principle of treating the scour depth as an equivalent load effect is presented. The individual and combined partial failure probabilities due to truck, earthquake and scour effects are described. To explain the method of including non-force-based natural hazards effects, two types of common scour failures are considered. In Part II, the corresponding bridge failure probability, the occurrence of scour as well as simultaneously having both truck load and equivalent scour load are quantitatively discussed.

  9. Bridge pier failure probabilities under combined hazard effects of scour, truck and earthquake. Part II: failure probabilities

    Science.gov (United States)

    Liang, Zach; Lee, George C.

    2013-06-01

    In many regions of the world, a bridge will experience multiple extreme hazards during its expected service life. The current American Association of State Highway and Transportation Officials (AASHTO) load and resistance factor design (LRFD) specifications are formulated based on failure probabilities, which are fully calibrated for dead load and non-extreme live loads. Design against earthquake load effect is established separately. Design against scour effect is also formulated separately by using the concept of capacity reduction (or increased scour depth). Furthermore, scour effect cannot be linked directly to an LRFD limit state equation because the latter is formulated using force-based analysis. This paper (in two parts) presents a probability-based procedure to estimate the combined hazard effects on bridges due to truck, earthquake and scour, by treating the effect of scour as an equivalent load effect so that it can be included in reliability-based failure calculations. In Part I of this series, the general principle for treating the scour depth as an equivalent load effect is presented. In Part II, the corresponding bridge failure probability, the occurrence of scour as well as simultaneously having both truck load and equivalent scour load effect are quantitatively discussed. The key formulae of the conditional partial failure probabilities and the necessary conditions are established. In order to illustrate the methodology, an example of dead, truck, earthquake and scour effects on a simple bridge pile foundation is represented.

  10. 连盐铁路连续梁桥异形墩结构分析%On analysis of special-shaped pier structure of continuous beam bridges along Lianyungang-Yancheng railway

    Institute of Scientific and Technical Information of China (English)

    王军生

    2011-01-01

    The paper adopts the common finite element analysis procedure ANSYS to undertake the space finite element analysis of No.117 pier of Xinshuhe Bridge along Lianyungang-Yancheng railway,establishes the space finite element analysis model for No.117 pier,simulates the loading of the boundary conditions,the dead load,and the active load,and concludes the spatial analysis of the pier stressed status and the internal results,so as to provide the theoretic direction for the pier structure design.%采用通用有限元分析程序ANSYS对连盐铁路新沭河特大桥117号墩进行了空间有限元分析,建立了117号墩的空间有限元模型,模拟了边界条件、恒载和活载的加载等,得到空间分析的墩身应力状态和内力结果,以期为墩身结构设计提供理论指导。

  11. Effect of pier shape and pier alignment on the equilibrium scour depth at single piers

    Institute of Scientific and Technical Information of China (English)

    Cristina Fael; Rui Lança; António Cardoso

    2016-01-01

    The equilibrium scour depth at uniform single bridge piers depends on a large number of variables, including the pier horizontal cross-section shape and its alignment angle towards the flow direction. The influence of these variables has been studied by only a few researchers, mostly, on the basis of tests that were far from approaching equilibrium. This experimental study aims at revisiting the influence of piers' shape and alignment on local scouring for length–width ratios smaller than or equal to 4, by increasing the experimental evidence. Fifty five long-duration laboratory tests were run under steady, clear-water flow, close to the threshold for initiation of sediment motion. Five pier shapes were considered:circular, rectangular square-nosed, rectangular round-nosed, oblong, and zero-spacing (packed) pile-groups;the tested skew-angles were 0°, 30°, 45°, 60°, and 90°. It was concluded that i) the shape factor can be taken as 1.0, for rectangular round-nosed and oblong cross-section piers, and as 1.2, for rectangular square-nosed and packed pile-group cross-section piers, ii) the shape factor does not vary significantly with the duration of tests, this way confirming the robustness of the shape factors reported to date, iii) the effect of shape is present at skewed piers although the associated coefficients remain in the narrow range of 1.0–1.2, and iv) for length–width ratios smaller than 4, the shape factor is of the same order of magnitude as the skew angle factor and should not be neglected.

  12. Three Dimensional Analysis of Pier Extension and Guide Wall Design Alternatives to Mitigate Local Scour Risk at the BNSF Railroad Bridge Downstream of the Prado Dam

    Energy Technology Data Exchange (ETDEWEB)

    Lottes, S. A. [Argonne National Lab. (ANL), Argonne, IL (United States); Bojanowski, C. [Argonne National Lab. (ANL), Argonne, IL (United States); Sinha, N. [Argonne National Lab. (ANL), Argonne, IL (United States); Kerenyi, K [Argonne National Lab. (ANL), Argonne, IL (United States)

    2015-03-01

    The primary objectives of the computational fluid dynamics (CFD) analysis are (1) to verify that the design concept of using wedge shaped pier extensions to divert flow around piers as a scour counter measure has the intended effect on the flow, (2) to refine the design of the length and orientation of the pier extensions within the channel and (3) to optimize the guide walls that will protect a set of outer piers and the abutments on each side of the channel. The original proposed design is shown in Figure 1.3. The results of this effort are the recommended designs that are judged to be the best designs based on results from the set of test cases run combined with engineering judgment. The refined designs from the CFD analysis are expected to be tested in a limited set of physical model experiments to verify that they work well.

  13. 钢筋混凝土双柱桥墩抗震能力Pushover分析%Pushover analysis of the seismic capacity of reinforced concrete double-column bridge piers

    Institute of Scientific and Technical Information of China (English)

    王红伟; 刘建新

    2013-01-01

    介绍了Pushover分析方法的基本原理及实施步骤.通过一个算例分析,针对不同侧向力分布模式、不同高度、不同纵向配筋率的双柱桥墩进行Pushover分析.结果表明:对于普通简支梁双柱墩,高度比较低,不同侧向力加载模式对Pushover分析结果影响不大,随着桥墩高度的增加,位移延性系数降低,桥墩延性随着纵向配筋率的提高而降低.%This article deacribes the basic principle and implementation steps of the Pushover analysis method. By a numerical example, RC double-column piers with different lateral force distribution pattern, different heights and different reinforcement ratio were analyzed. The results show that the analysis results for lower piers of simple supported beam bridges are approximately identical under different lateral force distribution, while with the increase of pier height and longitudinal ratio of reinforcement, the displacement ductility factor is reduced.

  14. 驶经桥墩船体非定常水动力相互作用数值预报%Numerical prediction of the unsteady hydrodynamic interaction between a ship and a bridge pier

    Institute of Scientific and Technical Information of China (English)

    张晨曦; 邹早建; 王化明

    2012-01-01

    应用CFD软件对船舶通过桥区时的船体-桥墩水动力相互作用进行数值研究,通过使用动网格技术及UDF进行船舶运动过程中的网格更新,对船舶沿直线航线匀速驶经桥墩时的非定常粘性流场进行数值模拟,对桥墩诱导的船体非定常水动力进行数值预报,其中假设船舶航速很小,因而自由面兴波的影响可以忽略.以一艘集装箱船和一个垂直柱体桥墩模型为例,选取不同的船体-桥墩横向距离进行了数值计算,得到了作用在船体上的横向力和转首力矩时历曲线,分析了船体-桥墩横向距离对船体非定常水动力的影响.%A general-purpose CFD software is applied to study the hydrodynamic interaction between a bridge pier and a ship passing through the bridge area along a straight course at constant speed. By using the dynamic mesh technique and UDF to update the mesh, the unsteady viscous flow around the ship is numerically simulated and the unsteady hydrodynamic force on the hull induced by the pier is predicted. The ship speed is assumed to be small, so that the effect of free surface elevation is negligible. Numerical calculations are performed for a container ship and a vertical column as a simplified pier model at various distances between the ship and the pier. The time histories of the lateral force and yaw moment are obtained. The influence of the distance between the ship and the pier is analyzed.

  15. Shaft Blasting Control Technology of Subway Near Bridge Pier%临近桥墩地铁竖井爆破控制技术

    Institute of Scientific and Technical Information of China (English)

    贾晓旭; 赵玉成

    2016-01-01

    taking project between Xia Yuan station ~Nan Gang station of Guangzhou metro line 13 first period en-gineering construction (fish bead to like neck ridge section ) as the background ,carried out blasting control design of the minimum distance of the shaft to the nearest building as the safety distance . The paper carried out blasting isolation de-sign mainly from the blasting parameters ,hole arrangement ,charge structure ,packing ,initiation and initiation network etc. At the same time ,grouting reinforcement on the basis of the nearest overpass bored pile so that reduced the founda-tion affected by vibration. Stetted the blasting safety protection system , prevent the surrounding buildings and vehicle pedestrian injuries from fly rock. Monitor the bridge pier vibration speed ,which is controlled within the 2cm/s during the construction period. It shows that the design of shock absorption and vibration reduction technology can meet the require-ments of design and engineering ,which provides a reference for similar blasting construction control technology .%以广州市轨道交通十三号线首期工程(鱼珠至象颈岭段)施工五标夏园站~南岗站区间临时竖井工程为背景,进行了以竖井到最近建筑物最小距离为安全控制距离的爆破控制设计。主要从爆破参数、布孔方式、装药结构、填塞方式、起爆方式和起爆网络等方面进行爆破减震设计,同时对最近立交桥钻孔灌注桩基础进行注浆加固,减小基础所受震动影响。设置爆破安全防护系统,防止爆破飞石对周边建筑物和车辆行人造成伤害。施工期间监测立交桥桥墩振速,均控制在允许振速范围内,表明此爆破减震设计以及采取的减震技术措施满足设计和工程实际要求,为类似爆破施工控制技术提供了可以借鉴的依据。

  16. 兰新二线桥墩防风蚀措施及施工方法%Method and measure of wind-erosion prevention for bridge piers on Lanzhou-Xinjiang second railway

    Institute of Scientific and Technical Information of China (English)

    公彦良

    2016-01-01

    The second double-track rail line in Xinjiang of Lanzhou-Xinjiang railway crosses five strong wind areas. In order to solve the wind-erosion problem of bridge concrete piers,the measure of rigid-flexible combination of wind-erosion prevention was adopted by test. T he technology is a multistep process,using flexible polyester resin and steel wire webs to make a rigid-flexible composite on the surface of piers. It has high compressive and tensile strength,corrosion and erosion resistance,satisfactory anti-ultraviolet aging and durability,then contribute to wind-erosion prevention of bridge piers.%兰新铁路第二双线新疆段穿越新疆风力最强的五大风区,为了解决风蚀对兰新铁路桥墩混凝土结构的磨蚀问题,经过试验研究兰新铁路第二双线采取了刚柔结合的防风蚀措施。由柔性树脂胶加不锈钢丝网经过多道工序施工,在桥墩表面形成具有较高的压缩与拉伸强度、优良的耐风蚀和磨蚀性能、良好的耐紫外光老化性能及耐气候性的一种刚柔结合复合体,从而实现了桥墩抗风蚀的目标。

  17. Cyclic Testing on Rectangular Hollow Bridge Piers Under Axial Load and Biaxial Bending%双向压弯状态下矩形空心桥墩循环试验

    Institute of Scientific and Technical Information of China (English)

    韩强; 杜修力; 赵彦; 王利辉

    2013-01-01

    To investigate the seismic performance of reinforced concrete (RC) rectangular hollow bridge piers, cyclic testing on five well-confined specimens was performed under constant axial load and biaxial bending. The test variables included axial load ratio, longitudinal reinforcement ratio and lateral reinforcement ratio. The results show that these specimens are flexural failure modes; biaxial force and displacement hysteretic loops show significant stiffness and strength degradation, pinching effect and coupling interaction of the structural seismic resistances in both directions; the ductility coefficient, varying from 3. 5 to 5. 7, and the equivalent viscous damping ratio, varying from 0. 19 to 0. 26, can meet the requirements of seismic design; RC rectangular hollow bridge piers with configurations of lateral reinforcement subject to bi-directional earthquake components have excellent earthquake resistance, and can substitute for current hollow RC rectangular section configurations described in the Chinese Guideline for Seismic Design of Highway Bridges (JTG/T B02-01-2008); and the length of the plastic hinge region is found to approach one sixth of the the hollow RC rectangular bridge pier height for all specimen piers, which is far less than the currently specified minimum value in Chinese Guideline, so the length of plastic hinge region is more concentrated for RC rectangular hollow bridge piers.%为了研究水平双向地震作用下矩形空心桥墩的抗震性能,对约束良好但轴压比和纵向、横向配筋率不同的5个钢筋混凝土(RC)矩形空心桥墩在轴力和双向弯曲作用下的性能进行了循环试验研究.结果表明:试件破坏形态为桥墩底部形成塑性铰的弯曲形破坏,桥墩双向力-位移滞回曲线显示了双向压弯状态下RC矩形空心桥墩刚度和强度退化、捏拢效应以及2个水平方向抗震性能的相互影响;试件桥墩的延性系数在3.5~5.7之间,等效粘滞阻尼系数在0

  18. 高墩大跨连续刚构桥的稳定性分析%Analysis of Stability of Long-span Continuous Rigid Frame Bridge with High Pier

    Institute of Scientific and Technical Information of China (English)

    王菲; 田山坡; 禚一

    2012-01-01

    Research purposes: The highway in western China or the remote region needs to cross over rivers and valleys and passes the regions with complex terrains due to the limitation of topographical condition . For this reason, the long -span continuous rigid frame bridge with high pier becomes more and more and the height of the bridge increases from several decameters to hundreds of meters. With increases of the pier height and the span length, the research on the stability of such kind of bridge is becoming more and more important. Research conclusions:Taking the long - span continuous rigid frame bridge with(90 + 168+90) m high pier in Shanxi province as the engineering background, the basic principle related to the structure stability is discussed and the stability of the high pier, the stability of the longest cantilever during construction and the stability in complete stage of the bridge are analyzed. From the calculation results it can be seen that for the bridge presented in this paper, the temperature effect has a little influence on the high pier stability, the wind load along the bridge axial direction has the most negative impact on the structure stability in the construction stage of the longest cantilever, and during the complete stage of the bridge, the lane load and the load of the crowded people set on the middle span has the most negative impact on the bridge stability. Furthermore, wind has a little influence and the influence of the temperature effect can be ignored in this stage. The calculation results also show this bridge has a good stability during its construction process and in the complete stage of bridge. The calculation and analysis processes presented in this paper can provide the reference to the similar works.%研究目的:西部地区及偏远地区受地形条件的限制,修建公路时常需要跨越河流、沟谷等复杂地形,因此高墩大跨连续刚沟桥的修建日益增多,其墩高也由原来的几十米提

  19. Floating Resistance Analysis for No .28 Pier Steel Caisson of Hutong Changjiang River Bridge%沪通长江大桥28号墩钢沉井浮运阻力分析

    Institute of Scientific and Technical Information of China (English)

    陈涛

    2015-01-01

    The main navigational channel bridge of Hutong Changjiang River Bridge is a steel truss girder cable‐stayed bridge with span arrangement of (142+462+1 092+462+142) m .The foundations of the pylon piers adopt caisson foundations ,among w hich the top plan dimension of steel caisson of pier No .28 is 86 .9 m by 58 .7 m ,and 44 m high .The steel caisson for the pier No .28 was fabricated in a dock and then transported to the bridge site by floating ,with a total floating weight of up to 14 500 t .To rationally allocate the floating tugboats and assure smooth floating ,the theoretical method ,numerical simulation method and physical model testing method were used to calculate the floating resistance of the steel caissons .Based on the comparative analy‐sis ,by modifying the head and end shapes of the boats ,the results gained by using the method presented in the Guidelines for Towage At Sea is approximate to those gained respectively by nu‐merical simulation and physical model testing ,w hich is proved applicable to the floating resistance calculation for the steel caisson of pier No .28 .It is proposed by calculation that the steel caissons have a draft of 8 m ,when the wind speed is at Grade 6 ,and the tugboat′s speed through water is 2 . 5 m/s ,the total resistance for a steel caisson is 2 167 kN under the condition of longitudinal to‐wing .The arrangement of the tugboats adopts the“7+1”mode ,namely one used as a backup tug‐boat ,the efficient output towing force is 3 060 kN ,and the maximum resistance of the towing is 2 326 .74 kN ,satisfying the floating requirements of the steel caisson .%沪通长江大桥主航道桥为(142+462+1092+462+142) m钢桁梁斜拉桥,桥塔墩基础采用沉井基础,其中28号墩钢沉井顶平面尺寸为86.9 m ×58.7 m ,高44 m。28号墩钢沉井在船坞内制造完后整体浮运至桥址处,浮运总重达14500 t。为合理地配置浮运拖轮,确保浮运顺利,采用理论方

  20. 复杂环境下的桥墩基坑支护施工及监测%CONSTRUCTION AND MONITORING TECHNIQUE OF BRIDGE PIER FOUNDATION PIT SUPPORT UNDER COMPLEX CONDITIONS

    Institute of Scientific and Technical Information of China (English)

    姜志刚

    2012-01-01

    In Caofeidian Nachao River Bridge project, the foundation pit of main bridge pier base has a maximum depth of 13.5m and it is adjacent to railway and breakwater. During construction of foundation pit, the combined supporting system of steel sheet pile plus internal support is adopted, D-type beam is used to strengthen adjacent rail line, and pile foundation is selected as a base supporting the beam, so as to guarantee construction safety and safe operation of existing railway and to successfully complete the Nachao River Bridge project.%曹妃甸纳潮河大桥工程,主桥墩承台基坑最大深度达13.5m,且紧邻既有铁路线及防浪堤,承台基坑施工中采用钢板桩+内支撑组合支护体系,并采取D型便梁对紧邻的铁路线路进行加固,选择桩基作为便梁的支墩,达到确保施工安全和既有铁路安全运营,顺利完成纳潮河大桥建设.

  1. Influence analysis of the approach bridges on the earthquake response of V-shaped piers of continuous rigid-frame bridge%引桥对V形墩连续刚构桥地震响应的影响分析

    Institute of Scientific and Technical Information of China (English)

    谢修辞; 徐永路

    2016-01-01

    With the background of Hainan Province Dinghai Bridge,time history analysis method was used on the V-shaped piers of continuous rigid-frame main bridge,main bridge which anti-seismic bearing and entire bridge without anti-seismic bearing. The result indicated that ap-proach bridges is more effective on shock absorption than anti-seismic bearing. So could make some detailed designs on approach bridges to in-crease the seismic capability of rigid frame bridge.%以海南省定海大桥为工程背景,采用时程分析法,对 V 形墩连续刚构主桥、仅使用抗震支座的主桥和联入引桥的全桥三种情况分别进行时程分析,结果表明,引桥对 V 形墩连续刚构桥的影响大于抗震支座,即可以在引桥上做精细化设计来提升刚构桥的抗震能力。

  2. 浅埋式桩基础钢筋混凝土拱桥桥墩防撞安全性评价与加固技术研究%Pier anti-collision safety evaluation of reinforced concrete arch bridge with shallow-buried piles and its strengthening technology research

    Institute of Scientific and Technical Information of China (English)

    吴超; 李德建; 宁夏元; 胡先春

    2013-01-01

    On the background of Yuan River bridge in Wuqiangxi,a method of pier anti-cillision safety evaluation,based on "Highway Bridge Code for Design",was put forward for reinforced concrete arch bridge with shallao-buried piles.On the basis of safety evaluation of Yuan River Bridge pier,a pier strengthening project of Yuan River Bridge in Wuqiangxi was proposed.In order to simulate the interaction of new and old concrete after strengthening of foundation,three-dimensional solid elements were adopted,where two situations of the interface between new and old concrete,i.e.,fully bonded or sliding were taken into account.The feasibility of this pier reinforcement project was studied,which can also provide reference for the similar bridge strengthening engineering.%以五强溪沅水大桥为工程背景,针对浅埋式桩基础钢筋混凝土拱桥,提出基于我国公路桥涵设计规范桥墩防撞安全性评价方法.通过对该桥的桥墩防撞安全性评价提出了相应的桥墩加固方案.采用三维实体单元来模拟基础加固后新老混凝土的共同作用,同时考虑新老混凝土接触面按完全粘结与滑动2种情况建立计算模型,对桥墩防撞加固方案的可行性进行了研究,亦可供同类桥梁加固参考.

  3. 黄冈公铁两用长江大桥主墩基础围堰施工技术%Construction Techniques of Cofferdams for Main Pier Foundations of Huanggang Changjiang River Rail-cum-Road Bridge

    Institute of Scientific and Technical Information of China (English)

    金红岩

    2012-01-01

    The main bridge of Huanggang Changjiang River Rail-cum-Road Bridge is a steel truvss girder cable-stayed bridge with double pylons and double cable planes and the foundations for the main piers of the bridge were constructed by the double-wall steel boxed cofferdams. The cofferdams were integrally manufactured and assembled on bank and by means of survey, the o-verall dimensions, pile locations and the locations and concentricity of the upper and lower guiding rings of the cofferdams were controlled in order to ensure that the deviations of the bored piles and pile caps of the main piers could comply with the relevant requirements in the standards after construction and to obtain the accuracy of positioning of the cofferdams according to the results of comprehensive analysis of the survey. The cofferdams were launched to the river by air bags by way of gradually adjusting the launching gradient from 1:30 to 1: 5 so as to ensure the launching speed and sliding distances of the cofferdams. After the cofferdams were launched to the river, they were floated to the pier sites, tugged by the strong house power tug boats and were positioned by the gravity anchors plus positioning barges in three stages of initially positioning, accurately positioning and system transformation. The final accuracy of positioning of the cofferdams in plan is 5 cm, the perpendicularity is within 1/1 000 and the perpendicularity of the steel casings is within 1/500, which all meet the requirements in the standards.%黄冈公铁两用长江大桥主桥为双塔双索面钢桁梁斜拉桥,主墩基础采用双壁钢吊箱围堰法施工.钢吊箱围堰在岸上整体拼装制造,通过测量控制围堰的轮廓尺寸,桩位,上、下导环的位置与同心度等,确保基础施工后主墩钻孔桩及承台施工偏差符合标准要求,并根据实测结果综合分析得出钢围堰的定位精度;采用气囊法下水,将下水坡度从1∶30逐渐调整为1∶5,保证了

  4. 地震作用下超高墩刚构桥倒塌易损性分析%Seismic Collapse Fragility Analysis of Rigid Frame Bridge with Super High Piers

    Institute of Scientific and Technical Information of China (English)

    范振华; 张谢东; 张行

    2013-01-01

    防止地震作用下结构倒塌是基于性能的地震工程的核心目标,目前基于弹塑性时程分析的倒塌易损性分析是结构抗倒塌能力评价最合理的方法.倒塌易损性分析的关键之一是建立合理的倒塌判别准则,文中提出了超高墩刚构桥地震倒塌破坏的判别准则.结合某工程实例,基于OpenSees建立了结构的非线性分析模型,对其进行了非线性地震时程分析,在此基础上建立了结构的易损性曲线,并讨论了混凝土保护层剥落和钢筋锈蚀等结构劣化对倒塌易损性的影响.%An important goal of performance-based seismic design is to prevent collapse of bridges.At present collapse fragility analysis based on the elasto-plastic time-history calculation is the most reasonable method to evaluate the collapse ability.The collapse criterion is the most important problem to be resolved.In this paper,a criterion of collapse for rigid frame bridge with high piers is proposed.An engineering example is demonstrated to study the collapse fragility of a rigid frame bridge with super high piers.The structure model is establish by OpenSees and the nonlinear time-history calculation is carried out to obtain the collapse fragility.Also the effect of deterioration,such as concrete spalling,the decreasing of strength and area of reinforcement,on the collapse fragility is discussed in detail.

  5. Seismic Damage Analysis of Reinforced Concrete Bridge Piers Based on Beam-Column Elements%基于梁柱单元的钢筋混凝土桥墩地震损伤分析

    Institute of Scientific and Technical Information of China (English)

    李正; 李忠献

    2011-01-01

    Faria-Oliver model is a simple and effective damage model for concrete.The uniaxial version of the FariaOliver damage model was proposed in the present paper.Meanwhile, the modification of Faria-Oliver model was introduced to describe the unilateral effect of concrete more properly.In addition, the material subroutines i.e.the modified Menegotto-Pinto model for reinforcing steel and the uniaxial modified Faria-Oliver model for concrete were implemented into VUMAT and the equivalent modeling strategy of fiber model was established within the FEA software ABAQUS.Furthermore, the numerical simulations of a cyclic loading test and a shaking table test of the reinforced concrete (RC) bridge piers were conducted.The results of the numerical simulations agreed well with the experimental ones.The present study indicates that the aforementioned uniaxial constitutive models and the equivalent modeling strategy of fiber model are effective and the seismic analysis of RC bridge piers using beam-column elements not only has a high computational efficiency but also provides information about seismic damage evolution.%Faria-Oliver模型是一个简单而有效的混凝土损伤模型.基于Faria-Oliver模型提出了混凝土单轴损伤模型,且加以修正以更好地模拟混凝土单边效应;在ABAQUS软件平台上,编制了含有钢筋修正Menegotto-Pinto模型和混凝土单轴修正Faria-Oliver损伤模型的用户材料子程序VUMAT,建立了纤维模型等效模拟方法;分别模拟了一钢筋混凝土桥墩试件的循环加载试验和一钢筋混凝土桥墩试件的振动台试验,模拟结果与试验结果基本吻合.研究表明:本文所给出的单轴本构模型及纤维模型等效模拟方法有效、适用;基于梁柱单元的钢筋混凝土桥墩地震损伤分析不仅计算效率高而且提供了地震损伤演化过程信息,具有较强的工程实用性.

  6. USE OF SURFACE GUIDE PANELS AS PIER SCOUR COUNTERMEASURES

    Institute of Scientific and Technical Information of China (English)

    Chin-Kun HUANG; Chii-Jau TANG; Ting-Yuan KUO

    2005-01-01

    This paper presents a laboratory study on bridge pier protection with surface guide panels (SGP) in clear-water experiments. The SGP is installed by piercing a set of two vertical panels partially into the water, with some interior angle and leading opening, setting at a distance ahead of the protected pier. The suitable installation of the SGP can effectively adjust the flow pattern to reduce the downflow motion and the horseshoe vortex ahead of the pier. We consider some dominant factors to set up SGP for pier protection, including the interior angle θ, leading opening Ow, distance between panel and pier L, submerged depth of panel Pd, pier diameter D and water depth H. After evaluation of these parameters through laboratory tests, the optimal setup conditions of θ=60o, Ow/D=0.1~0.2, L/D=2~2.5 and Pd/H=0.7 are determined. Under these conditions, the usage of SGP leads to a best performance on decrement of the maximum scour depth at pier up to 90% with ignorable side effects on the SGP scour.

  7. Seismic Behavior of Fatigue-Retrofitted Steel Frame Piers

    Directory of Open Access Journals (Sweden)

    Kinoshita K.

    2013-01-01

    Full Text Available Fatigue retrofit works have been conducted on severely fatigue damaged beam-to-column connections of existing steel frame bridge piers in Japan. It is clear that retrofit works provides additional stiffness but the significance on the seismic behavior of steel frame piers is not clear. Since fatigue retrofit works have become prevalent, the effect of fatigue retrofit works on the seismic behavior of steel frame piers need to be understood. The objective of this study is therefore to investigate these effects of the retrofit work, especially installation of bolted splices, which is the most common technique. Elasto-plastic finite element earthquake response analyses were carried out. It is shown that the existence of bolted splices may increase seismic demand on the piers when plastic hinge zone is located on the beam. In addition, longer bolted splices using low yield strength steel are proposed to overcome this problem and are shown to give beneficial effects.

  8. Segmental joint behavior analysis of a high performance multifunctional permanent form work of a bridge pier%高性能多功能桥墩永久模板节段节点性能分析

    Institute of Scientific and Technical Information of China (English)

    吴香国; 陈思远; 赵新宇

    2012-01-01

    为了给高性能多功能桥墩永久模板节段节点设计提供科学依据,根据超高性能水泥基复合材料( UHPCC)纵向节段间的节点联接构造,分析了界面应力,建立了切向应力和法向应力分量的表达,提出了界面联接率的设计参量,并给出了焊缝节点应力极限状态方程.基于荷载规范,给出了永久模板的施工荷载计算参量表达.简要介绍了UHPCC的基本性能、计算模型,提出了将UHPCC应用于桥墩用多功能永久模板的设计概念,并结合典型墩柱结构进行了UHPCC管界面节点性能的计算,分析了壁厚、焊缝有效厚度等设计参量对节点性能的影响规律,分析了界面联接参量对焊缝应力的影响规律,提出了UHPCC管连接节点的设计方案.该研究为UHPCC永久模板管结构节段节点强度设计奠定了基础.%In order to propose trre scientific basis for the segmental joint design of the high performance and multifunctional permanent form work of a pier, the interfacial stress was analyzed according to the segmental joint structure of longitudinal sections of ultra high performance cementitious composites (UHPCC), and the expressions of tangential stress and normal stress were given, the design parameters of interface connection rate was proposed, and the ultimate state equation of the weld joint stress was given. Based on the construction load code, the calculating parameter expressions of construction loads for the UHPCC thin circular tube were presented. The basic properties and calculating constitutive model of UHPCC were introduced. The design concept of applying UHPCC into multifunctional permanent form work for bridge piers was presented in this paper. With geometrical dimensions of a typical pier, the interfacial joint performance parameters of a UHPCC tube under typical construction loads were calculated. The effect of the geometrical parameters such as wall thickness and effective thickness of a weld joint on the

  9. 钢筋混凝土桥墩加固与修复技术研究%Research on the Reinforcement and the Repair Techniques for RC Bridge Piers

    Institute of Scientific and Technical Information of China (English)

    曹兴; 魏洋; 李国芬; 吴刚; 吴智深

    2011-01-01

    Several traditional reinforcement techniques and the latest ones are researched and summarized for the conventional reinforcement and the seismic reinforcement and the repair in this paper, including increasing cross-section area, near-surface-mounted, external pre-stressing, steel jacket, FRP composites, exterior spiral and longitudinal rebar repaired with dog bone bars. The scheme principle, materials and applicable range of all different reinforcement technique are discussed and compared; the different techniques are applicable to different reinforcement demand for improving the bearing capacity of bridge piers, seismic strengthening and post-earthquake repair.%针对钢筋混凝土桥墩常规加固及抗震加固与修复,研究总结了几种国内外传统加固技术及最新加固技术,包括增大截面加固技术、嵌入加固技术、体外预应力加固技术、钢套管加固技术、FRP加固技术、绕丝加固技术及“狗骨式”筋修复纵筋技术等,对不同加固技术的方案原理、材料及适用范围进行了论述比较,不同的加固技术适用于桥墩承载力提高、抗震加固、震后修复等不同的加固需求.

  10. 襄樊汉江三桥主墩承台大体积混凝土施工技术%Large Volume Concrete Construction Technology of Hanjiang the Third Bridge Main Pier Pile Cap in Xiangfan

    Institute of Scientific and Technical Information of China (English)

    吴刚; 蒲赞全; 钟启凯; 刘开扬

    2011-01-01

    Based on the large volume pile cap construction of Hanjiang the Third Bridge main pier in Xiangfan,the construction technology of the large volume pile cap is analyzed. , including cofferdam construction of steel sheet pile, bottom sealing of underwater concrete. A series of measures from concrete raw material to concrete pouring are taked to prevent exorbitant hydration temperature in mass concrete causing concrete crack, including mix design of low hydration heat concrete, temperature control calculation of concrete, field temperature control measures of mass concrete, temperature monitoring during construction. Thus,pile cap construction is completed successfully.%结合襄樊汉江三桥主墩大体积承台施工,分析了大体积承台施工技术,包括:钢板桩围堰施工,水下混凝土封底.为防止大体积混凝土在水化过程中结构内部产生过高的水化热温度,致使结构产生有害裂缝,从混凝土原材料到混凝土浇筑施工采取了一系列有效的技术控制措施,包括低水化热混凝土配合比设计、混凝土温控计算、大体积混凝土温度现场控制措施,以及施工过程中的温度监测,从而使得承台施工得以顺利完成.

  11. RISK LEVEL ANALYSIS ON THE PREVENTIVE EROSION CAPACITY OF BRIDGES

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Deficiency of the Preventive Erosion Capacity (PEC) of a bridge pier is the main factor leading to bridge failures. In this paper, the PEC of bridge piers was analyzed using the stochastic analysis method. The definitions of the reliability and risk level of a bridge pier subjected to water erosion were proposed and a computational model for erosion depth and risk level in was suggested.

  12. 辅助墩对混合梁斜拉桥非线性静动力特性的影响%Impacts of auxiliary pier upon non-linear static and dynamic characteristics of single staved-cable bridge with composite beam

    Institute of Scientific and Technical Information of China (English)

    钟加峰

    2012-01-01

    利用有限元分析软件建立了混合梁独塔斜拉桥的空间模型,分析了混合梁独塔斜拉桥在有、无辅助墩情况下的非线性静动力特性的异同,讨论了在有、无辅助墩情况下对混合梁独塔斜拉桥非线性静动力特性的影响,得出了有指导意义的结论。%The paper establishes spatial model of single stayed-cable bridge with composite beam by using finite element analysis software, ana- lyzes similarities and differences of non-linear static and dynamic characteristics of single stayed-cable bridge with composite beam under the con- dition of with and without auxiliary pier, and discusses the impacts of within and without auxiliary pier upon non-linear dynamic and static char- acteristics of single stayed-cable bridge with composite beam, and finally draws some guiding conclusions.

  13. 粘钢加固损伤混凝土箱型桥墩的抗震性能Ⅱ:动力响应数值分析%Anti-seismic properties of damaged concrete bridge piers with hollow cross-section strengthened with adhering steel platesⅡ:numerical analysis on seismic dynamic responses

    Institute of Scientific and Technical Information of China (English)

    邓江东; 宗周红; 黎雅乐; 刘爱荣

    2013-01-01

    The flexibility method and the fiber model were used to numerically simulate the earth-quake dynamic response of the damaged concrete bridge piers with hollow cross-section strengthened with adhering steel plates.The performance index,such as the seismic forces at the piers bottom, pier top displacement and residual stiffness,were analyzed,and on the basis of model tests the seis-mic mechanics behaviors of the strengthened piers were comprehensively studied.The analysis re-sults show that the failure modes of the strengthened bridge piers under the earthquake actions are al-so displayed as the occurrences of plastic hinge in the superior margin of the steel plates,which coin-cides with the pier model testing results.The comparison of the seismic performances before and af-ter strengthening validates the effectiveness of the strengthening method with steel plates of making new plastic hinge.The effects of the initial damage degree,steel plate thickness and slenderness rati-os on the seismic safety degrees of the bridge piers are small.However,when the axial compression ratio is large,the seismic safety degrees decrease quickly.%针对具有初始弯曲损伤的粘钢加固混凝土箱型桥墩,采用柔度法和纤维模型,进行了系统的地震动力响应数值模拟计算,分析了地震作用下加固桥墩的地震剪力、墩顶位移、剩余刚度等性能指标,并在拟静力试验的基础上综合研究其抗震加固力学行为。分析结果表明,地震荷载作用下地震中桥墩仍然发生加固钢板上缘产生塑性铰的破坏模式,与拟静力试验结果一致。加固前后桥墩抗震性能的对比结果表明,经粘钢加固形成新塑性铰的加固方式可有效增强桥墩的抗震能力。初始损伤程度、加固钢板厚度和长细比等对加固桥墩抗震安全度的影响较小。大轴压情况下,安全度快速降低。

  14. Riverbed Pre-Protection Techniques for Main Pier No .29 of Main Ship Channel Bridge of Hutong Changjiang River Bridge%沪通长江大桥主航道桥 29 号主墩河床预防护技术

    Institute of Scientific and Technical Information of China (English)

    崔一兵

    2015-01-01

    The main ship channel bridge of the Hutong Changjiang River Bridge is a double-py-lon continuous steel truss girder cable-stayed bridge with span arrangement (140+462+1 092+462+140) m .The foundation for the main pier No .29 of the bridge is the open caisson ,the di-mensions of the caisson top are 86 .9 m × 58 .7 m and the caisson height is 115 m .Because the silty sand stratum at the pier is deep and the stratum is prone to scouring under the action of water cur-rent ,the local scouring of the riverbed at the pier in the process of landing the caisson onto the ri-verbed can be severe .To ensure that the caisson could be stably and safely landed onto the river-bed ,the riverbed was hence pre-protected .The pre-protection system for the riverbed included the inverted filter layer ,protection layer and prism structure ,respectively composed of the 1~6 mm , 3~10 cm and 6~10 cm grading crushed stones and the riprapping depth is respectively 1 ,1 and 2 m ,of which the riprapping range of the protection layer extended 25 m outwards from the caisson wall .At the time the riverbed was pre-protected by the riprapping ,the virtual grids were deter-mined according to the riprapping tests ,the positioning barge ,grab barge ,material hoppers and ducts were all used to riprap at the fixed points .The inverted filter layer was riprapped first ,the protection lay was then and the prism structure was finally .With the application of the riverbed pre-protection technique ,the protection effect of the riverbed at the pier was evident and after the caisson was landed onto the riverbed and positioned ,the plan position and posture of the caisson almost had no changes .%沪通长江大桥主航道桥为(140+462+1 092+462+140 ) m双塔连续钢桁梁斜拉桥 , 29号主墩采用沉井基础 ,沉井顶平面尺寸为86 .9 m × 58 .7 m、高115 m.由于29号主墩位处粉砂层较厚 ,水流作用下这部分泥砂易被冲刷 ,对沉井着床过程中的局部冲刷大 ,为

  15. 可液化场地桥梁群桩-独柱墩结构地震反应振动台试验研究%Shaking table tests for seismic response of pile-supported bridge structure with single-column pier in liquefiable ground

    Institute of Scientific and Technical Information of China (English)

    唐亮; 凌贤长; 徐鹏举; 高霞; 王东升

    2009-01-01

    针对两种土层结构的可液化场地条件,采用2×2低承台群桩一独柱墩结构形式,完成了两个试验体的群桩-独柱墩结构地震反应振动台试验,很好地再现了自然地震触发场地液化及结构反应的各种宏观现象.结果表明,桩的最大加速度反应位置与地层结构关系密切且随场地液化发展而不断变化;低承台条件下,三层土场地较二层土场地对墩顶的加速度反应放大作用更显著;场地液化过程中,承台附近或液化与非液化土层分界处桩发生最大或较大动应变;低承台下,二层土场地中柱墩反应较小、桩反应较强,三层土场地中柱墩反应较强.%Two shaking table tests for seismic pile-soil-bridge interaction in liquefiable ground, with a low-cap 4-pile group and two typical soil profiles, were performed. The tests reproduced the macroscopic phenomena of soil liquefaction and seismic response of the structures in liquefiable ground. It is observed that the portions of the piles with maximum acceleration were in close contact with the soil layers and varied with the development of soil liquefaction. For the low-cap pile-supported bridge structure, the ground with three soil layers exerted more significant amplification effect on the acceleration response of the pier top than the ground with two soil layers. During soil liquefaction, the strains of the piles near the cap and the soil interface between liquefied soil and non-liquefied soil were comparatively greater than those at other positions. For the low-cap pile groups, the response of the pier was comparatively less significant and the pile strongly responded to the input motion of the ground with two soil layers, while the response of the pier was more significant under input motion of the ground with three soil layers.

  16. Study on the seismic flexural-shear damage mechanisms and rapid repair techniques for earthquake damaged bridge piers%钢筋混凝土桥墩地震弯剪破坏机理与震后快速修复技术研究

    Institute of Scientific and Technical Information of China (English)

    司炳君; 孙治国; 杜修力; 王东升; 黄照南

    2011-01-01

    Quasi-static tests were conducted to study the seismic flexural-shear damage mechanisms and rapid repair techniques for earthquake damaged bridge piers.Six original pier specimens of circular cross sections were severely damaged under cyclic lateral force and constant axial load,and the damaged specimens were subsequently repaired using high-fluidity concrete with high early-strength and Carbon Fiber-Reinforced Polymer(CFRP),and then put into test again within a week.The failure pattern,strength,ductility and dissipated energy parameters and stiffness degradation of the repaired specimens were compared with the original ones.It is founded that the ultimate performance of bridge piers designed according to current seismic design codes of JTG/T B02-01—2008 and Caltrans with minimum confining reinforcement ratios may be dominated by shear failure in the plastic hinge zones.The repaired specimens show lower initial stiffness and larger yield displacement as a result of the pre-existing damage.But the failure for all of the repaired specimens was due to flexure,with higher strength,larger or the same ductility and dissipated energy parameters and recovered stiffness,which demonstrated the effectiveness of the proposed repair techniques.%为研究钢筋混凝土桥墩的地震弯剪破坏机理与震后快速修复技术,首先进行了6个圆形截面桥墩试件的拟静力试验,试件均发生严重弯剪破坏,然后利用高流动性早强混凝土和CFRP布对其进行快速修复并在1周内重新进行加载试验,将原桥墩与修复后试件的破坏形态、承载力、延性与耗能能力、刚度退化等进行了对比分析。研究表明:塑性铰区配箍满足我国《公路桥梁抗震设计细则》(JTG/T B02-01—2008)及美国Caltrans规范要求的钢筋混凝土桥墩试件,最终仍有可能因塑性铰区抗剪强度不足发生弯剪破坏。由于初始损伤的存在,震后修复

  17. Seismic damage analysis of RC high bridge piers using a modified elastoplastic damage model%基于修正弹塑性损伤模型的钢筋混凝土高桥墩地震损伤分析

    Institute of Scientific and Technical Information of China (English)

    李正; 李忠献

    2011-01-01

    Faria-Oliver损伤本构模型是一种模型参数少、标定方便、计算效率较高的混凝土弹塑性损伤本构模型,但此模型对循环荷载作用下混凝土受拉行为的描述略有不足;针对此点提出了修正模型,并基于大型有限元软件ABAQUS编制了修正模型的用户材料子程序VUMAT,对钢筋混凝土高桥墩进行了地震损伤分析。分析结果表明:基于提出的修正Faria-Oliver损伤模型对高桥墩进行地震损伤分析,能有效识别高桥墩在地震作用下的典型损伤破坏过程。并进而发现高桥墩在地震作用下易发生多处损伤,且损伤位置以及损伤演化过程对地震动频谱%The Faria-Oliver damage model is a simple and efficient elasto-plastic damage constitutive model for concrete.However,there is a drawback about the description of the tensile behavior of concrete under cyclic loading.A modification is introduced,and a material subroutine is implemented into the finite element software ABAQUS.Seismic damage analysis of a RC high bridge pier is performed using the modified Faria-Oliver damage model.The results show that seismic damage analysis can effectively capture the typical damage evolution process of the high pier.Moreover,it is observed that for the high bridge pier,multiple damages tend to occur and the damage process is sensitive to the frequency of the earthquake.

  18. NSGA - II Optimization on Life-cycle Seismic Design of Single Circular Reinforced Concrete Bridge Piers%基于 NSGA - II 的规则桥梁圆形单柱 RC 桥墩全寿命造价优化设计

    Institute of Scientific and Technical Information of China (English)

    柳春光; 张士博; 柳英洲

    2015-01-01

    以基于抗震性能设计基本原则-“投资-效益”准则为理论支撑,提出了将多目标遗传算法与延性抗震设计、地震风险相结合的抗震结构集成全寿命抗震优化设计的新方法,建立了规则桥梁圆形单柱 RC 桥墩多目标全寿命造价优化设计的通用框架。并应用 NSGA - II 建立了以圆形单柱 RC 桥墩截面直径、纵筋和箍筋的配筋率为决策变量,以初始造价和地震损失期望为多目标的全寿命造价优化设计模型。计算结果表明:RC 桥墩多目标全寿命造价优化设计为投资者提供了更加灵活的初始投资的选择空间,同时 NSGA - II 也为该优化设计提供了一个较好的算法支持。%Based on the cost-effectiveness criterion ,a fundamental principle for performance-based seismic design ,a new method for optimizing total life-cycle seismic design of bridge piers was put forward with the consideration of multi -objec-tive genetic algorithm ,seismic ductility design and earthquake risks .According to which ,the general framework of multi-objective total life-cycle cost optimization design for regular reinforced concrete single circular bridge piers was estab -lished .On the platform of NSGA - II ,a total life-cycle cost optimization model of this pier was constructed with the deci -sion variable as section diameter ;the ratios of the longitudinal reinforcement ,the lateral reinforcement ,the initial cost of the structure and the expectation of earthquake loss as multiple objectives .The calculation results indicate that this method can provide the investors with a more flexible initial investment options ,meanwhile NSGA - II can also equip the designers with a better algorithm support for optimization design .

  19. Nonlinear Seismic Response Characteristics of Bridge with Double-column High-rise Piers Considering Pounding Effect%考虑碰撞效应的双柱式高墩桥梁非线性地震反应特性研究

    Institute of Scientific and Technical Information of China (English)

    高玉峰; 蒲黔辉; 李晓斌

    2011-01-01

    以西南山区线路中常用的双柱式高墩桥梁为研究对象,建立典型桥跨结构的空间动力分析模型,采用非线性动力时程分析方法,详细研究了考虑地震碰撞效应时桥梁结构的地震响应特性,并探讨了接触单元刚度取值、间隙宽度、桥台刚度以及支座滑动性能等非线性边界条件的影响.结果表明:梁间碰撞作用主要发生在近桥台伸缩缝处,碰撞作用减小桥墩的地震响应,同时在梁体中产生较大的短时加速度脉冲效应;考虑桥台的纵向约束作用将使得梁间碰撞效应增强;对于通常设计采用的间隙宽度范围,强震作用时碰撞现象会不可避免地发生;支座滑动性能对桥墩的地震响应起到隔震的作用,考虑支座滑动性能后梁间碰撞次数减少;各种非线性边界条件因素的综合作用使得桥跨结构的地震响应变得较为复杂,为获得结构真实响应结果应该合理考虑这些因素的影响.%Based on the double-column highway bridges with high-rise piers in southwest mountain area, the spatial dynamic analysis models of representative bridge span were established. The seismic response characteristics of the bridge considering the pounding effect were studied in detail by using nonlinear dynamic time history analysis method. The influence of some nonlinear boundary conditions, including value of contact element stiffness, gap width, abutment stiffness and sliding performance of bearings, were discussed. The results indicate that ( 1 ) the seismic pounding effect between adjacent beams occurs mainly in the expansion joint near the bridge abutments, the pounding reduces the seismic response of piers but generates high magnitude and short duration acceleration pluses in the beams; (2) the pounding effect between adjacent beams will be enhanced when the longitudinal constraint effect of abutments is considered; (3) for the range of gap width usually· adoptod in design, the pounding

  20. 基于支持向量机的高墩大跨桥梁体系可靠度计算%Computation of Structural System Reliability of High-Rise Pier and Long Span Bridge Based on Support Vector Machine

    Institute of Scientific and Technical Information of China (English)

    张士福; 康海贵; 郑元勋; 李玉刚

    2012-01-01

    为解决高墩大跨桥梁结构体系可靠度求解过程中失效模式复杂、极限状态方程无法显式表达等问题,提出一种基于支持向量机(SVM)分类技术的体系可靠度计算方法.该方法采用拉丁超立方抽样法产生样本库,通过重复筛选构造一个精确的SVM分类器函数(而不是构造功能函数本身的响应面函数),然后采用蒙特卡罗法进行数值模拟计算体系失效概率.以济邵高速公路逢石河特大桥为例验证了采用该方法计算高墩大跨桥梁体系可靠度的实用性,计算结果表明该桥体系可靠度满足设计要求.%To cope with the problems that the failure modes in the solving process of structural system reliability of high-rise pier and long span bridge are complicated and the limit state e-quations can not be displayed and expressed, a method for computation of the system reliability based on the support vector machine (SVM) classification technique is proposed. The proposed method can generalize the sample bank, using the Latin hypercube sampling method and can construct a precise SVM classifier function (rather than the response surface function of the structure function itself) by repeated screening and the numerical simulation and computation of the system failure probability are accordingly carried out, using the Monte Carlo method. By way of example of the Fengshi River Bridge on Jiyuan-Shaoyuan Expressway, the practicability of the method for computation of the system reliability of the high-rise pier and long span bridge is verified and the results of the computation prove that the system reliability of the bridge can meet the design requirements

  1. Seismic performance of neotype column-slab high piers in double-column model of railway bridge%铁路桥梁新型柱板式高墩双柱模型的抗震性能

    Institute of Scientific and Technical Information of China (English)

    周雁群; 张晔芝; 叶梅新; 刘斌

    2013-01-01

    采用往复荷载下的钢筋和混凝土本构,用非线性有限元分析法研究铁路桥梁新型柱板式高墩双柱模型在低周往复荷载作用下的滞回特性、延性及耗能等抗震性能,研究墩柱截面形式、腹板厚度、墩柱配筋率对这些特性的影响.通过对4个缩尺模型的拟静力试验,进一步研究轴压比、腹板厚度和水平加载制度等对柱板式高墩破坏性状的影响.研究结果与数值模拟结果吻合较好,说明本文采用的分析方法结果可靠,新型柱板式高墩具有较好的抗震性能.%Hysteresis constitutive laws of concrete and steel reinforcement were adopted to study the hysteretic characteristics,ductility behavior,energy dissipation capacity and seismic performance of the late-model column-slab high piers in double-column model under cyclic loads.And the influences of column cross-section forms,wall slab thickness and reinforcement ratio of columns were also taken into account.Based on the pseudo-static test conducted on 4 reduced scale model,the effect of axial compression ratio,web thickness and horizontal loading system on the failure behavior of the column-slab high piers was further studied.The test results are agreed well with the numerical simulation results,which shows that the analysis method used in this work is reliable.The late-model Column-slab high pier has a better seismic performance.

  2. Effects of Multiple-mode Vibration on Elastic-plastic Seismic Responses of High Flexible Piers of Railway Bridge%多振型效应对铁路高柔桥墩弹塑性地震响应的影响

    Institute of Scientific and Technical Information of China (English)

    李宇; 朱晞; 杨庆山

    2011-01-01

    Nonlinear static analysis considering multiple-mode effects in FEMA356 and ATC-40 is improved. Basing on the capacity spectrum method (CSM) of soil-structure interaction effects (SSI) in FEMA440, taking the piers of one extra-long bridge of a railway line in southwest of China as the object of research and choosing eighty strong ground motion records in agreement with stipulations of site H specified in the Code of Seismic Design for Railway Engineering, the ductility and performance points of high flexible piers are solved by using the modified acceleration-displacement response spectrum (MADRS) locus of possible performance points introduced in FEMA440. From nonlinear time history analyses, the rationality and feasibility of the improved nonlinear static analysis method considering multiple-mode effects is verified by comparing with the average of seismic responses. The practicability of CSM considering SSI for railway bridge aseismic assessment is also verified.%对FEMA356和ATC-40中考虑多自度效应的非线性静力分析法进行改进.并在FEMA440考虑土-结构相互作用能力谱法基础上,以我国西南某铁路特大桥桥墩为研究对象,选取与我国《铁路工程抗震规范》Ⅱ类场地相符合的80条强震记录,利用FEMA440性能点轨迹法求解高柔桥墩结构延性及性能点;并与80条强震记录非线性时程分析计算结果平均值进行比较.验证本文改进的非线性静力分析法反映高柔桥墩多自度效应的合理性,及考虑土-结构相互作用能力谱法在铁路桥梁工程中应用的可行性.

  3. Docks and Piers, Fishing Piers in, Published in unknown, Manatee County Information Services Dept..

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Docks and Piers dataset as of unknown. It is described as 'Fishing Piers in'. Data by this publisher are often provided in State Plane coordinate system; in a...

  4. 安庆长江铁路大桥主墩在深水无覆盖层条件下的围堰定位技术%Positioning Techniques for Steel Cofferdam of Main Pier of Anqing Changjiang River Railway Bridge Under Condition of Deepwater and Geology Without Overburden

    Institute of Scientific and Technical Information of China (English)

    郑大超; 田继开

    2012-01-01

    安庆长江铁路大桥主桥为主跨580 m的多跨连续钢桁梁斜拉桥,该桥3号墩基础采用圆形双壁钢围堰施工,围堰定位采用无导向船重锚锚碇定位系统.针对3号墩基础深水无覆盖层地质条件下围堰施工,为实现围堰的精确定位,从钢筋混凝土梳齿锚、收锚平台及转向马口3个方面进行围堰锚碇定位系统研究.围堰部分锚碇采用钢筋混凝土梳齿锚取代铁锚,钢筋混凝土梳齿锚由混凝土实体、起吊座、锚座、梳齿组成;围堰部分边锚通过新型转向马口转向至前、后定位船收锚;锚绳转向采用新型马口结构.%The main bridge of Anqing Changjiang River Railway Bridge is a multi-span continuous steel truss girder cable-stayed bridge with a main span 580 m and the foundation for the Pier No. 3 of the bridge was constructed by the circular double-wall steel boxed cofferdam that was positioned by the heavy anchor anchorage system without utilizing the guiding barge. In the light of the construction of the cofferdam under the condition of deepwater and geology without o-verburden and to achieve the purpose of accurate positioning of the cofferdam, the positioning system for the cofferdam was systematically studied from three aspects of the reinforced concrete (RC) comb anchors, anchor weighing platform and steering fair leaders. According to the study, it was determined that for part of the anchors of the cofferdam, the iron anchors should be replaced with the RC comb anchors and a comb anchor of such type was composed of the concrete body, lifting base, anchor base and comb teeth. Part of the side anchors of the cofferdam were steered to the front and rear positioning barges via the new type of the steering fair leaders and were weighed on the barges there and for steering of the anchor ropes, the new type of the steering fair leaders were provided also.

  5. Control Technique for Accurate Landing of Caisson of Pier No.3 of Tongling Changjiang River Bridge on Hefei-Fuzhou Railway onto Riverbed%合福铁路铜陵长江大桥3号墩沉井精确着床控制技术

    Institute of Scientific and Technical Information of China (English)

    覃勇刚; 涂满明; 王东辉

    2013-01-01

    The main bridge of Tongling Changjiang River Bridge on Hefei-Fuzhou Railway is a steel truss girder cable-stayed bridge with three cable planes and with a main span 630 m. The Pier No. 3 of the north pylon of the bridge is supported on the foundation of round-ended caisson that was constructed by the scheme of "two-time positioning and quick landing of the caisson onto the riverbed by water pumping". To make sure that the caisson could be accurately landed onto the riverbed, the spatial model for the caisson and its tie anchor rope system was set up by the finite element software MIDAS 2006, the process of the landing of the caisson was simulated, the changing laws of the caisson offsetting and anchor rope forces in the process of the landing were analyzed and it was determined that the distance between the bottom of the caisson and the riverbed should be kept 2 m at the time the caisson was being positioned. To minimize the influences of the scouring, soil non-uniformity of the riverbed, waves and vortex vibration on the accurate landing of the caisson onto the riverbed, the measures of pumping water into the caisson for quick landing of the caisson, rectifying the offsetting of the caisson by winching the anchors, increasing the numbers and rigidity of the side anchors of the caisson and increasing the mass and damping of the caisson itself were respectively taken.%合福铁路铜陵长江大桥主桥为主跨630 m的三索面钢桁梁斜拉桥,其北桥塔3号墩采用圆端形沉井基础,沉井着床采用“二次定位、注水快速着床”的方案.为使沉井精确着床,采用MIDAS 2006有限元软件建立沉井和拉缆系统空间模型,模拟沉井着床过程,分析沉井着床过程中的偏移及拉缆索力变化规律,确定定位时沉井底与河床的距离为2 m.为减小冲刷、河床平面土质分布不均、波浪和涡激振动等对沉井精确着床的影响,分别采取了注水快速着床、绞锚纠偏回位、增加沉井边

  6. Shaking Table Tests of Curved Bridge considering Bearing Friction Sliding Isolation

    Directory of Open Access Journals (Sweden)

    Lei Yan

    2016-01-01

    Full Text Available Specific to severe damage to curved bridges in earthquakes caused by the excessive force of the fixed bearings and piers, a new seismic design method on curved bridges considering bearing friction sliding isolation is proposed in this paper. Seismic model bridge and isolation model bridge with similarity ratio of 1/20 were made and the shaking table comparison test was conducted. The experimental results show that the isolation model curved bridge suffered less seismic damage than the seismic model curved bridge. The fundamental frequencies of the seismic model bridge and isolation model bridge decreased and the damping ratio increased with the increase of seismic intensity. Compared with seismic curved bridge, the maximum reduction rates of peak acceleration along the radial and tangential directions on the top of pier of the isolation model curved bridge were 47.3% and 55.5%, respectively, and the maximum reduction rate of the peak strain on the bottom of pier of the isolation model curved bridge was 43.4%. For the isolation model curved bridge, the maximum reduction rate of peak acceleration on the top of pier was 24.6% compared with that on the bottom of pier. The study results can provide experimental basis for the seismic design of curved bridges.

  7. 连续梁墩柱合理设计的影响因素分析%Factor Analysis of Continuous Beam Pier Columns Rational Design

    Institute of Scientific and Technical Information of China (English)

    张帅; 肖锋文; 赵杰丽

    2012-01-01

    随着连续梁桥的广泛应用,连续梁桥墩柱的合理设计值得深入研究.从影响连续梁桥墩柱设计的主要因素出发,深入分析各影响因素的重要性,为连续梁桥墩柱合理设计提供参考.%With the wide application of the continuous beam bridge, the rational design of continuous beam pier column worthy of further study. In this article, starting from the main factors affecting the continuous beam bridge pier column design. In-depth analysis of the importance of each factor in order to give reference for the rational design of continuous beam bridge pier column.

  8. MPA 方法在不同高度桥墩地震响应分析中的适用性研究%Application of Modal Pushover Analysis Method to Seismic Response of Piers with Different Heights

    Institute of Scientific and Technical Information of China (English)

    蒋崇文; 王典斌; 卢皓

    2015-01-01

    Bridges are usually lifeline engineering-in-traffic projects,and their seismic performance is very important.As an important bridge construction component,piers are vulnerable to dam-age under strong ground motion.In this paper,in accord with the typical pier structure form of bridge piers in mountainous areas,a nonlinear numerical analysis model is constructed based on a fiber model.The seismic response of different piers under El-Centro is performed using modal pushover analysis (MPA).By comparison with the nonlinear time history analysis method,the applicability of the MPA method for the seismic analysis of different piers is investigated.The results show that the MPA method is not suitable for higher piers where the contribution of higher modes in seismic response is significant.With the implementation of the Western Develop-ment Program in recent years,a lot of highways and railways have been planned and built in western China.For bridges with high piers in mountainous areas,a nonlinear numerical analysis model is constructed based on a fiber model.The finite-element analysis is simulated with the code Open Sees,which was developed by Pacific Earthquake Engineering Research (PEER).The Mander model is used to imitate the constitutive model of concrete,and the Giuffré-Menegotto-Pinto model is used to imitate the constitutive model of reinforcement.The incremental dynamic analysis is used to research distribution features of pier section curvature under strong earthquake motions.As a result of the effects of higher modal contributions,the seismic response and seis-mic performance of bridges with high piers are complicated.The forming and development of a plastic range in the upper position of a pier,the damage process,and the failure mechanism of high piers under different earthquake motions are studied.The base section curvature of high piers and its top displacement are not simultaneous;it is inappropriate for pier top displacement to be used as the

  9. 21 CFR 1240.86 - Protection of pier water system.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Protection of pier water system. 1240.86 Section... DISEASES Source and Use of Potable Water § 1240.86 Protection of pier water system. No vessel engaged in interstate traffic shall make a connection between its nonpotable water system and any pier potable...

  10. Ship collisions against wind turbines, quays and bridge piers

    DEFF Research Database (Denmark)

    Pedersen, Preben Terndrup

    2013-01-01

    expressions are derived for the maximum values of collision forces and energy released for local crushing. The expressions are derived for arbitrary impact locations and they are well suited for application in risk analysis procedures. Numerical results show that for piled towers the structural flexibility...

  11. General design of Sutong Bridge

    Institute of Scientific and Technical Information of China (English)

    Zhang Xigang; Yuan Hong; Pei Minshan; Dai Jie; Xu Lin

    2009-01-01

    The main span of Sutong Bridge is a double-pylon, double-plane cable-stayed bridge with steel box girder, which has the world's longest central span of 1 088 m within cable-stayed bridges. To overcome problems caused by severe meteorological conditions, perplexing hydrological conditions, deep buried bedrock and higher navigation level, many new technics and methods were created. Keys including structural system, steel box girder, stayed cable, tower, pier, tower foundation, collision avoidance system, wind-resistance, seismic-resistance, structural nonlinear response and structural static stability were presented individually in this paper.

  12. Aerodynamic stability of cable-stayed bridges under erection

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xin-jun; SUN Bing-nan; XIANG Hai-fan

    2005-01-01

    In this work, nonlinear multimode aerodynamic analysis of the Jingsha Bridge under erection over the Yangtze River is conducted, and the evolutions of structural dynamic characteristics and the aerodynamic stability with erection are numerically generated. Instead of the simplified method, nonlinear multimode aerodynamic analysis is suggested to predict the aerodynamic stability of cable-stayed bridges under erection. The analysis showed that the aerodynamic stability maximizes at the relatively early stages, and decreases as the erection proceeds. The removal of the temporary piers in side spans and linking of the main girder to the anchor piers have important influence on the dynamic characteristics and aerodynamic stability of cable-stayed bridges under erection.

  13. 安庆长江铁路大桥3号墩围堰锚碇系统设计与施工%Design and Construction of Mooring System for Cofferdam of Pylon Pier No.3 of Anqing Changjiang River Railway Bridge

    Institute of Scientific and Technical Information of China (English)

    刘爱林; 农代培

    2011-01-01

    The bored pile foundation of pylon pier No. 3 of Anqing Changjiang River Railway Bridge was constructed with the circular double-wall steel boxed cofferdam. To realize the accurate positioning and construction safety of the cofferdam, through comparison of the different schemes, it was decided that the cofferdam would be positioned by the mooring system from the front and rear positioning barges without utilizing guiding barge. The types and numbers of the mooring anchors, the mooring ropes and positioning barges were determined according to the calculation of the total tensile force of the main anchors and the force of each anchor after sinking thecofferdam in place. In the design, the problem of steering and reeling of the large diameter mooring ropes was tackled by the tie points on the sides of the cofferdam and by the one-way or multi-way rolling fairleaders set at the top of the cofferdam. The side anchors were heaved by the winches installed on the anchor weighing platforms on the front and rear positioning barges and at the top of the cofferdam and the anchors could be therefore cast, weighed and changed. The side anchors on the shore and ground anchors were embedded in the excavated pits and the anchors under water were cast by the 240 t barge. The mooring ropes were timely tied, untied, tightened and the anchors were adjusted in pace of sinking of the cofferdam to finally complete the construction of the mooring system.%安庆长江铁路大桥3号桥塔墩钻孔桩基础采用圆形双壁钢套箱围堰施工.为实现围堰的精确定位和施工安全,经方案比较采用无导向船的前、后定位船锚碇系统定位方案,锚型与数量、锚绳及定位船通过计算围堰下沉到位后主锚总拉力及各锚碇受力确定.设计中通过在围堰侧面的边锚拉结点及围堰顶面设置单向或多向转动的辊轴式马口解决大直径锚绳转向和收放难题;通过在前、后定位船和围堰顶的收锚平台上安装

  14. 33 CFR 127.103 - Piers and wharves.

    Science.gov (United States)

    2010-07-01

    ...) WATERFRONT FACILITIES WATERFRONT FACILITIES HANDLING LIQUEFIED NATURAL GAS AND LIQUEFIED HAZARDOUS GAS Waterfront Facilities Handling Liquefied Natural Gas § 127.103 Piers and wharves. (a) If the...

  15. Structural safety monitoring for Nanjing Yangtze River Bridge

    Institute of Scientific and Technical Information of China (English)

    黄方林; 何旭辉; 陈政清; 曾储惠

    2004-01-01

    In order to evaluate objectively and accurately the integrity, safety and operating conditions in real time for the Nanjing Yangtze River Bridge, a large structural safety monitoring system was described. The monitoring system is composed of three parts: sensor system, signal sampling and processing system, and safety monitoring and assessment system. Combining theoretical analysis with measured data analysis, main monitoring contents and layout of measuring points were determined. The vibration response monitoring was significantly investigated. The main contents of safety monitoring on vibration response monitoring are vibration of the main body of the Nanjing Yangtze river bridge, collision avoidance of the bridge piers, vibration of girders on high piers for the bridge approach and earthquake. As a field laboratory, the safety monitorying system also provides information to investigate the unknown and indeterminate problems on bridge structures and specific environment around bridges.

  16. Theology and practice in Piers Plowman

    Directory of Open Access Journals (Sweden)

    D. Levey

    1995-05-01

    Full Text Available The fourteenth-century English poem Piers Plowman, by William Langland, tells of a quest for and pilgrimage to Truth, or God. The poem is lengthy and diffuse, and evidences Langland’s keen interest in philosophy, theology, politics, social conditions and apocalyptic literature, to mention only some areas. Underlying all, however, is a concern with the practical living-out of abstruse doctrinal concepts in everyday life. This essay explores certain characters and concepts which embody the doctrine and practice of charity, in order to demonstrate the interweaving of theory and practice which characterizes Langland at his best.

  17. Effect of nonlinearity of restrainer and supports on the elasto-plastic seismic response of continuous girder bridge

    Directory of Open Access Journals (Sweden)

    Wang Changfeng

    2014-10-01

    Full Text Available During an earthquake, the nonlinearity of the bridge structure mainly occurs at the supports, bridge piers and restrainers. When entering nonlinear stage, members of the bridge structure affect the elasto-plastic seismic response of the whole structure to a certain extent; for multi-span continuous bridges, longitudinal restrainers can be installed on the movable piers to optimise the distribution of seismic force and enable the movable piers to bear a certain amount of seismic effect. In order to evaluate the effect of nonlinearity of restrainer and supports on the elasto-plastic seismic response of continuous girder bridge, analytical models of continuous girder bridge structure considering the nonlinearity of movable supports, restrainers and bridge piers were built and the nonlinear time history analysis was conducted to evaluate the effect of nonlinearity of restraining devices and supports on the elasto-plastic seismic response of continuous girder bridge. Relevant structural measures and recommendation were made to reduce the seismic response of the fixed piers of the continuous girder bridge.

  18. Scour and Scour Countermeasures at Bridge Sites

    Institute of Scientific and Technical Information of China (English)

    CHIEW Yee-Meng

    2008-01-01

    This paper examines scour and scour countermeasures at bridge piers and abutments.Abutment scour is by far more complex than its counterpart associated with piers because of the possibility of the presence of a floodplain. Notwithstanding this, the mechanism of scour at both piers and abutments is very similar; moreover, the failure mechanisms associated with both armor-ing and flow-altering countermeasures are not very different. In rivers with a floodplain, abutment scour becomes much more complex. In cases where the abutment ends at or near to the flood-plain, it can initiate bank erosion, which clearly is an important erosion problem that is quite distinct from the customary scour at either an abutment in rivers without a floodplain or a pier. For this rea-son, abutment scour can be very site-specific while pier-scour is more generic in nature. To this end, the ability to identify the type of abutment scour that may form in a particular channel is closely related to an engineer's ability to propose devices for effective scour countermeasure.By summarizing research efforts on using riprap as a pier or abutment countermeasure over the past few decades, this paper highlights the deficiencies of riprap in arresting pier scour. To this end,different failure mechanisms are identified. They are shear failure, winnowing failure, edge failure,bedform-induced failure and bed-degradation induced failure. Each failure mechanism can singly or, more likely, combine to cause the eventual breakdown of the riprap layer. The study shows that a riprap layer is vulnerable to other failure mechanisms even though it is adequately designed against shear failure, rendering it ineffective in arresting scour.

  19. Development and evaluation of clear-water pier and contraction scour envelope curves in the Coastal Plain and Piedmont Provinces of South Carolina

    Science.gov (United States)

    Benedict, Stephen T.; Caldwell, Andral W.

    2016-01-01

    The U.S. Geological Survey in cooperation with the South Carolina Department of Transportation collected clear-water pier- and contraction-scour data at 116 bridges in the Coastal Plain and Piedmont Physiographic Provinces of South Carolina. Pier-scour depths collected in both provinces ranged from 0 to 8.0 feet. Contraction-scour depths collected in the Coastal Plain ranged from 0 to 3.9 feet. Using hydraulic data estimated with a one-dimensional flow model, predicted clear-water scour depths were computed with scour equations from the Federal Highway Administration Hydraulic Engineering Circular 18 and compared with measured scour. This comparison indicated that predicted clear-water scour depths, in general, exceeded measured scour depths and at times were excessive. Predicted clear-water contraction scour, however, was underpredicted approximately 30 percent of the time by as much as 7.1 feet. The investigation focused on clear-water pier scour, comparing trends in the laboratory and field data. This comparison indicated that the range of dimensionless variables (relative depth, flow intensity, relative grain size) used in laboratory investigations of pier scour, were similar to the range for field data in South Carolina, further indicating that laboratory relations may have some applicability to field conditions in South Carolina. Variables determined to be important in developing pier scour in laboratory studies were investigated to understand their influence on the South Carolina field data, and many of these variables appeared to be insignificant under field conditions in South Carolina. The strongest explanatory variables were pier width and approach velocity. Envelope curves developed from the field data are useful tools for evaluating reasonable ranges of clear-water pier and contraction scour in South Carolina. A modified version of the Hydraulic Engineering Circular 18 pier-scour equation also was developed as a tool for evaluating clearwater pier

  20. Docks and Piers, Pier point, line, and polygon locations within Iredell County, NC, Published in 2005, 1:2400 (1in=200ft) scale, Iredell County GIS.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Docks and Piers dataset, published at 1:2400 (1in=200ft) scale, was produced all or in part from Orthoimagery information as of 2005. It is described as 'Pier...

  1. Pier Luigi Nervi architetture voltate Verso nuove strutture

    OpenAIRE

    Solomita, Pasqualino

    2012-01-01

    L’ingegner Pier Luigi Nervi (1891-1979), progettista, costruttore e teorico del “Costruire Correttamente”, ha intrapreso un proprio esclusivo percorso professionale che ha decretato negli anni una notevole fortuna critica fino a un sostanziale oblio dopo la sua morte. La presente ricerca di dottorato intende approfondire le tematiche legate a una significativa tipologia strutturale che ha contrassegnato il percorso professionale di Pier Luigi Nervi: le architetture voltate. Cupole, vol...

  2. Aerodynamic stability of cable-stayed-suspension hybrid bridges

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xin-jun; SUN Bing-nan

    2005-01-01

    Three-dimensional nonlinear aerodynamic stability analysis was applied to study the aerodynamic stability of a cable-stayed-suspension (CSS) hybrid bridge with main span of 1400 meters, and the effects of some design parameters (such as the cable sag, length of suspension portion, cable plane arrangement, subsidiary piers in side spans, the deck form, etc.) on the aerodynamic stability of the bridge are analytically investigated. The key design parameters, which significantly influence the aerodynamic stability of CSS hybrid bridges, are pointed out, and based on the wind stability the favorable structural system of CSS hybrid bridges is discussed.

  3. Study on the Spatial Stress of the Chongqing Yangtze River Bridge in China

    Directory of Open Access Journals (Sweden)

    Yan Li

    2014-09-01

    Full Text Available Continuous rigid-frame bridges are usually used in building bridges with long span and high piers. It is characterized by the consolidation between piers and beams in the middle of bridge piers and flexible bridge piers in the lower part. Among all the factors, curvature has the most obvious influence on the stress of curved continuous rigid-frame bridge, because of which, the curved beam bridge produces coupling effect of bending moment and receives complicated stress, leading to the deformation such as torsion and displacement of radial direction. No matter it is the castscaffold construction or cantilever construction, for continuous rigid-frame bridges, considering that after the long term creep of concrete, structure stress tends to be in a drop-frame state, so it is necessary to know the mechanical properties of the finished bridge. Taking the Chongqing Yangtze River Bridge as an example, this paper mainly analyzes the internal forces and deformations of a finished curved continuotus rigid-frame bridge by establishing a spatial finite element model with Midas Civil 2006 software and by changing the model’s radius of curvature. The results show that as the curvature increases, the vertical deformation and torsion angle of the long-span curved continuous rigid-frame bridge are both reduced under the effect of a dead load and prestressed load, presenting mechanical properties of bridge, namely, “coupling effect of bending moment”. In the model analyzed, the deformation of the bridge in the transverse direction also behaves a trend of gradual decrease with an increase in radius of curvature with the range 500–2000 m.

  4. Near-fault directivity pulse-like ground motion effect on high-speed railway bridge

    Institute of Scientific and Technical Information of China (English)

    陈令坤; 张楠; 蒋丽忠; 曾志平; 陈格威; 国巍

    2014-01-01

    The vehicle-track-bridge (VTB) element was used to investigate how a high-speed railway bridge reacted when it was subjected to near-fault directivity pulse-like ground motions. Based on the PEER NAG Strong Ground Motion Database, the spatial analysis model of a vehicle-bridge system was developed, the VTB element was derived to simulate the interaction of train and bridge, and the elasto-plastic seismic responses of the bridge were calculated. The calculation results show that girder and pier top displacement, and bending moment of the pier base increase subjected to near-fault directivity pulse-like ground motion compared to far-field earthquakes, and the greater deformation responses in near-fault shaking are associated with fewer reversed cycles of loading. The hysteretic characteristics of the pier subjected to a near-fault directivity pulse-like earthquake should be explicitly expressed as the bending moment-rotation relationship of the pier base, which is characterized by the centrally strengthened hysteretic cycles at some point of the loading time-history curve. The results show that there is an amplification of the vertical deflection in the girder’s mid-span owing to the high vertical ground motion. In light of these findings, the effect of the vertical ground motion should be used to adjust the unconservative amplification constant 2/3 of the vertical-to-horizontal peak ground motion ratio in the seismic design of bridge.

  5. 48 CFR 52.247-40 - Ex Dock, Pier, or Warehouse, Port of Importation.

    Science.gov (United States)

    2010-10-01

    ... Warehouse, Port of Importation. 52.247-40 Section 52.247-40 Federal Acquisition Regulations System FEDERAL... Provisions and Clauses 52.247-40 Ex Dock, Pier, or Warehouse, Port of Importation. As prescribed in 47.303-12..., pier, or warehouse, port of importation: Ex Dock, Pier, or Warehouse, Port of Importation (APR 1984)...

  6. 78 FR 32274 - Scorpion Pier Replacement Project, Channel Islands National Park, Santa Barbara County, California

    Science.gov (United States)

    2013-05-29

    ... National Park Service Scorpion Pier Replacement Project, Channel Islands National Park, Santa Barbara... analysis process for the proposed replacement and potential relocation of the existing Scorpion Pier at..., Attn: Scorpion Pier Project, 1901 Spinnaker Drive, Ventura, CA 93001 or electronically to...

  7. 76 FR 1521 - Security Zone: Fleet Industrial Supply Center Pier, San Diego, CA

    Science.gov (United States)

    2011-01-11

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA87 Security Zone: Fleet Industrial Supply Center Pier, San... Fleet Industrial Supply Center Pier. The pier is no longer owned by the U.S. Navy and the existing... of the San Diego Bay, San Diego, CA. The existing security zone is around the former Fleet...

  8. Pier Paolo Pasolini (1922-1975) / Andres Ehin

    Index Scriptorium Estoniae

    Ehin, Andres, 1940-2011

    2006-01-01

    Itaalia filmilavastajast ja kirjanikust Pier Paolo Pasolinist. Sisaldab ka tema luuletusi "Laul kirikukellast", "Saladus", "Olen rõõmus", "Varastatud päevad", "Tuhat üheksasada nelikümmend neli", "Tuhat üheksasada nelikümmend viis"

  9. Railroad Bridges

    Data.gov (United States)

    Department of Homeland Security — Bridges-Rail in the United States According to The National Bridge Inspection Standards published in the Code of Federal Regulations (23 CFR 650.3), a bridge isA...

  10. The development of iron British piers in the XIX century. The discovery of new materials

    Directory of Open Access Journals (Sweden)

    González-García de Velasco, C.

    2011-12-01

    Full Text Available In this article, the authors study the decadence of wood piers along XIX century, mainly because of problems inherent to the attacks of invertebrates. Soon, the wood structures will be substituted by iron ones, appearing two extraordinary materials, cast iron and wrought iron. Cast iron was a material with a great compression resistance, but weak for traction and flexion. It was not welding, but its resistance to the corrosion was notable, because of it, was very used at piles of British sea piers. On the contrary, wrought iron offered high conditions for traction and flexion, so it appeared like a very useful material to make girders and joists, but suffering the problem of a lack of resistance to corrosion. The combination of both materials supposed a great success in the construction of bridges and piers, since 1850.

    Se estudia en el presente artículo cómo los embarcaderos de madera iban languideciendo a partir de mediados del siglo XIX, aquejados especialmente por los ataques de invertebrados. Pronto, en los embarcaderos británicos, la madera iba a ser sustituida por el hierro, en la versión de dos nuevos materiales, la fundición y el hierro forjado. La fundición poseía una gran resistencia a la compresión, aunque poca a la tracción y a la flexión. Tampoco permitía la soldabilidad, pero presentaba un comportamiento magnífico frente a la corrosión, siendo muy utilizada para pilares en los nuevos embarcaderos. El hierro forjado presentaba menor resistencia a la corrosión pero, en cambio, ofrecía altas prestaciones a tracción y flexión, lo que lo hacía muy valioso para su colocación en vigas y forjados en los muelles. De la combinación de ambos materiales resultó el gran éxito habido en la construcción de puentes y embarcaderos metálicos, a partir de 1850.

  11. 考虑支座摩擦和墩柱损伤的桥梁用液体粘滞阻尼器参数确定方法%Parameter determination method for fluid viscous damper used in bridges considering bearing friction and pier damage

    Institute of Scientific and Technical Information of China (English)

    焦驰宇; 张恺; 张连普; 龙佩恒

    2013-01-01

    对桥梁阻尼器参数确定方法的相关文献进行了回顾,指出现有常用参数分析法费时费力;而简化分析法存在仅适用于结构保持在弹性阶段、无法考虑罕遇地震下支座摩擦及墩柱轻度损伤等复杂情况的弊端.以非线性静力分析获得的能力曲线为基础,利用性能点、目标点求解时获得的关键参数,结合等效弹性单自由度体系附加非线性粘滞阻尼器的参数确定公式,提出了考虑支座摩擦和墩柱损伤的桥用阻尼器参数确定方法.将该方法应用于某三跨连续梁桥抗震加固分析,验证了该方法的实用性及准确性.指出了该方法具有的优势及使用时需注意的问题.本文方法可用于中小跨径桥梁抗震加固时液体粘滞阻尼器的参数确定.%By reviewing parameter determination methods for fluid viscous damper ( FVD) applied in structural engineering, the defect of time consuming when using parameter analysis method, and the defect of not considering the bearing friction and other nonlinearity when using normal simplified method were pointed out. A new parameter determinations method which can easily and quickly consider the above effects was proposed. It can be expressed as follows; based on the pushover curve given by nonlinear static analysis, getting the key parameters when calculating performance point and target point, then substituting them into the structural dynamic formula of elastic SDF system with non - linear fluid viscous dampers, the approprite parameter of the viscous damper can be achieved. Taking a seismic retrofitting example of a three-span continuous girder bridge using FVD, the accuracy and practicality of the parameter determination method given in the paper was validated. The advantages and some problems which should be noticed when using this method were given. The parameter determination method can be used in similar seismic retrofit design of medium and small-span bridges when FVD were

  12. 车—桥碰撞的数值模拟研究%Research on numeric simulation of crash between vehicle and bridges

    Institute of Scientific and Technical Information of China (English)

    邓乙民; 刘吉波

    2012-01-01

    利用有限元分析软件ANSYS/LS-DYNA,建立了汽车—桥墩碰撞的有限元模型,通过对汽车—桥墩的碰撞过程进行数值模拟分析,得到了碰撞过程中的碰撞力、碰撞能量和桥墩墩顶位移,分析了桥墩受撞破坏的机理,对车—桥碰撞研究具有十分重要的意义。%The paper adopts the finite element analysis software,ANSYS/LS-DYNA,establishes the finite element model for the crash between the vehicle and bridge piers,analyzes the numeric simulation the crashing process between the vehicle and bridge piers,achieves the collision force,crashing energy and the displacement of pier top of the bridge piers,and analyzes the mechanism for the damage of the bridge piers,so as to have the important significance for the research on crash between vehicle and bridges.

  13. 75 FR 18160 - Small Takes of Marine Mammals Incidental to Specified Activities; Antioch Bridge Seismic Retrofit...

    Science.gov (United States)

    2010-04-09

    ... in shallow water (out to Pier 11). The temporary marine trestle will be constructed from the south... existing bridge structure. This is where water depths are less than 10-ft below mean lower-low water (MLLW... installed with a vibratory hammer. Vibrating a single 24-in pile into place requires, at the most,...

  14. Acque, fiumi e paesaggi. riflessioni con Pier Francesco Ghetti

    Directory of Open Access Journals (Sweden)

    Michele Ercolini

    2015-11-01

    Full Text Available The object of the interview with Pier Francesco Ghetti can be so listed: to provide a summary, the much possible complete and updated of motivations and causes of what can be defined the very basic mistake facing, from a cultural and planning point of view, the water, river an landscape. In particular, understanding what has already been done and what can still be done for the defence, the government and the requalification of the system of resources. 

  15. Simplified Calculation of "Crack front " of Double Reinforced Concrete Rectangular Piers%双筋矩形截面混凝土墩柱的开裂前沿简化计算

    Institute of Scientific and Technical Information of China (English)

    彭建中; 叶永

    2011-01-01

    According to the theory in basal mechanics, this thesis predigested the mechanical mode of the double reinforced rectangular concrete column, built the mechanical balance equation, and analysed stress process of the pier in theory. Under the condition that regarding concrete is being pulled, we should search the position of neutral axis of the cracking section by "three-phase" theory in order to get function expression of the concrete's resisting power along the length direction of the pier. These calculated results can be applied to the deformation analysis of the reinforced concrete cantilever bridge piers; and " three-phase " theory can be used to calculate stiffness of pier's each section; and the displacement of pier's top; and then be helped to do cracking mechanism of reinforced concrete piers under complex loads.%基于力学理论,对双筋矩形截面混凝土墩柱受力模式进行简化,建立模型的力学平衡方程,并分析墩柱模型的受力过程及开裂机理.运用“三段式”方法,在考虑混凝土受拉的条件下,求解墩柱开裂截面中性轴的位置,得到混凝土抗力△P(z)沿墩身分布的函数表达式.计算结果可适用于钢筋混凝土悬臂桥墩变形分析,提出的“三段式”分析方法可以求出墩柱各截面刚度以及墩柱墩顶位移曲线,有助于钢筋混凝土墩柱在复杂载荷作用下的开裂机理研究.

  16. Analytical Evaluation of Reinforced Concrete Pier and Cast-in-Steel-Shell Pile Connection Behavior considering Steel-Concrete Interface

    Directory of Open Access Journals (Sweden)

    Jiho Moon

    2016-01-01

    Full Text Available The seismic design of bridges may require a large-diameter deep pile foundation such as a cast-in-steel-shell (CISS pile where a reinforced concrete (RC member is cast in a steel casing. In practice, the steel casing is not considered in the structural design and the pile is assumed to be an RC member. It is partially attributed to the difficulties in evaluation of composite action of a CISS pile. However, by considering benefits provided by composite action of the infilled concrete and the steel casing, both the cost and size of CISS pile can be reduced. In this study, the structural behavior of the RC pier and the CISS pile connection is simulated by using an advanced 3D finite element (FE method, where the interface between the steel and concrete is also modeled. Firstly, the FE model is verified. Then, the parametric study is conducted. The analysis results suggest that the embedment length and the friction coefficient between the steel casing and the infilled concrete affect the structural behavior of the RC pier. Finally, the minimum embedment length with reference to the AASHTO design guideline is suggested considering the composite action of the CISS pile.

  17. A Numerical Investigation of the Seismic Response of the Aggregate Pier Foundation System

    OpenAIRE

    Girsang, Christian Hariady

    2001-01-01

    The response of an aggregate pier foundation system during seismic loading was investigated. The factors and phenomena governing the performance of the aggregate pier and the improved ground were identified and clarified. The key factors affecting the performance of the aggregate pier include soil density, stiffness modulus, and drainage capacity. The improved ground is influenced by soil stratification, soil properties, pore pressure dissipation, and earthquake time history. Comprehensiv...

  18. A Study on Ductility of Prestressed Concrete Pier Based on Response Surface Methodology

    OpenAIRE

    Wang, H.; Zhang, Y; Qin, S.

    2016-01-01

    The ductility of prestressed concrete pier is studied based on response surface methodology. Referring to the pervious prestressed concrete pier, based on Box-Behnken design, the ductility of 25 prestressed concrete piers is calculated by numerical method. The relationship between longitudinal reinforcement ratio, shear reinforcement ratio, prestressed tendon quantity, concrete compressive strength and ductility factor is gotten. The influence of the longitudinal reinforcement ratio, the shea...

  19. Study on the shock absorbing technique of high speed railway bridges

    Institute of Scientific and Technical Information of China (English)

    Li Chenggen; Gao Ri

    2011-01-01

    Based on the idea of "bearing function separation", a structural member called shock absorber that makes use of its plastic deformation is presented for reducing the seismic response of the bridge. The design criterion for matching material stress, strain and earthquake fortification aim, is also given. The analysis results show that the high speed railway box girder with the absorber in this paper has great reduction effect in seismic response of the bridge piers.

  20. Statistical Analysis of Ship Collisions with Bridges in China Waterway

    Institute of Scientific and Technical Information of China (English)

    DAI Tong-yu; NIE Wu; LIU Ying-jie; WANG Li-ping

    2002-01-01

    Having carried out investigations on ship collision accidents with bridges in waterway in China, a database of ship collision with bridge (SCB) is developed in this paper. It includes detailed information about more than 200 accidents near ship's waterways in the last four decades, in which ships collided with the bridges. Based on the information a statistical analysis is presented tentatively. The increase in frequency of ship collision with bridges appears, and the accident quantity of the barge system is more than that of single ship. The main reason of all the factors for ship collision with bridge is the human errors, which takes up 70%. The quantity of the accidents happened during flooding period shows over 3~6 times compared with the period from March to June in a year. The probability follows the normal distribution according to statistical analysis. Visibility, span between piers also have an effect on the frequency of the accidents.

  1. 新型耗能辅助墩抗震性能的参数研究%PARAMETRIC STUDIES OF SEISMIC PERFORMANCE ON ENERGY DISSIPATION SUBSIDIARY PIERS

    Institute of Scientific and Technical Information of China (English)

    魏俊; 孙利民

    2012-01-01

    基于地震损伤控制设计的思想,作者提出了一种耗能型辅助墩结构形式.为了研究辅助墩的抗震性能,保护强震作用下超大跨斜拉桥的主塔,该文采用非线性静力分析方法对辅助墩的各种参数进行了分析,探讨了墩柱尺寸及间距,软钢剪力连杆尺寸、布置道数及间距等参数变化对辅助墩抗震性能的影响.结果表明:混凝土墩柱和剪力连杆的刚度需要一个合适的比例,墩柱间距应满足剪力连杆发生剪切型屈服的要求,剪力连杆布置方式的影响可以忽略.%Based on seismic damage control design strategies, a kind of new energy dissipation subsidiary piers is proposed. In order to investigate the seismic performance of subsidiary piers and protect the towers of long span cable-stayed bridges under a strong earthquake, various parameters of subsidiary piers are analyzed employing a nonlinear static analysis method in this paper. The influences of the parameters which include dimensions and spacing of columns, dimensions, numbers and spacing of shear links on the seismic performance of subsidiary piers are discussed. The results show that appropriate stiffness ratio of columns and shear links is needed, and the distance between columns satisfies the requirement of the shear yield of shear links, and the influence of the layout fashion of shear links is ignored.

  2. Pier scour monitoring system by bed-level image tracking

    Institute of Scientific and Technical Information of China (English)

    Wen-Yi CHANG; Jihn-Sung LAI; Teng-Yi YU; Franco LIN; Lung-Cheng LEE; Whey-Fone TSAI; Chin-Hsiung LOH

    2014-01-01

    A scour monitoring system with a micro camera tracking the bed-level images is proposed in this study. Two image recognition algorithms have been developed to support the bed-level image tracking approach. Through the laboratory experiments of pier scour, this study demonstrates that the proposed system is able to accurately monitor the scour-depth evolution in real time. In addition, five commonly-used temporal scour models are employed to simulate scour-depth evolution and their results are compared with monitoring data. In general, the results indicate that the proposed scour monitoring system has the potential for further applications in the field.

  3. 77 FR 51475 - Safety Zone; Apache Pier Labor Day Fireworks; Myrtle Beach, SC

    Science.gov (United States)

    2012-08-24

    ... INFORMATION: Table of Acronyms DHS Department of Homeland Security FR Federal Register NPRM Notice of Proposed... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Apache Pier Labor Day Fireworks; Myrtle... establishing a temporary safety zone on the waters of the Atlantic Ocean in the vicinity of Apache Pier...

  4. 48 CFR 47.303-12 - Ex dock, pier, or warehouse, port of importation.

    Science.gov (United States)

    2010-10-01

    ... warehouse, port of importation. 47.303-12 Section 47.303-12 Federal Acquisition Regulations System FEDERAL..., pier, or warehouse, port of importation. (a) Explanation of delivery term. Ex dock, pier, or warehouse... in the warehouse at the specified port of importation. (b) Contractor responsibilities....

  5. 77 FR 35862 - Safety Zone; Fleet Week Maritime Festival, Pier 66 Elliott Bay, Seattle, WA

    Science.gov (United States)

    2012-06-15

    ... SECURITY Coast Guard 33 CFR Part 165 Safety Zone; Fleet Week Maritime Festival, Pier 66 Elliott Bay... Guard will enforce the Fleet Week Maritime Festival's Pier 66 Safety Zone in Elliott Bay, WA from 8 a.m... Guard will enforce the Safety Zone for the Fleet Week Maritime Festival in 33 CFR 165.1330 on August...

  6. Seismic Response Analysis of Continuous Multispan Bridges with Partial Isolation

    Directory of Open Access Journals (Sweden)

    E. Tubaldi

    2015-01-01

    Full Text Available Partially isolated bridges are a particular class of bridges in which isolation bearings are placed only between the piers top and the deck whereas seismic stoppers restrain the transverse motion of the deck at the abutments. This paper proposes an analytical formulation for the seismic analysis of these bridges, modelled as beams with intermediate viscoelastic restraints whose properties describe the pier-isolator behaviour. Different techniques are developed for solving the seismic problem. The first technique employs the complex mode superposition method and provides an exact benchmark solution to the problem at hand. The two other simplified techniques are based on an approximation of the displacement field and are useful for preliminary assessment and design purposes. A realistic bridge is considered as case study and its seismic response under a set of ground motion records is analyzed. First, the complex mode superposition method is applied to study the characteristic features of the dynamic and seismic response of the system. A parametric analysis is carried out to evaluate the influence of support stiffness and damping on the seismic performance. Then, a comparison is made between the exact solution and the approximate solutions in order to evaluate the accuracy and suitability of the simplified analysis techniques for evaluating the seismic response of partially isolated bridges.

  7. 78 FR 54574 - Safety Zone; Tall Ships Erie 2013 Fireworks Show, Holland Street Pier, Presque Isle Bay, Erie, PA

    Science.gov (United States)

    2013-09-05

    ..., Holland Street Pier, Presque Isle Bay, Erie, PA AGENCY: Coast Guard, DHS. ACTION: Temporary final rule... of Holland Street Pier, Presque Isle Bay in Erie, PA. The Captain of the Port Buffalo has determined... all waters off Holland Street Pier, Presque Isle Bay, Erie, PA within a 420-foot radius of position...

  8. Supplemental Environmental Assessment for the Mid-Bay Bridge Connector Phases 2 and 3, Eglin Air Force Base, Florida

    Science.gov (United States)

    2010-08-03

    Places. 2. Educational materials, such as lesson plnn.s, developed for elementary school children in grades 4 tbrough 7 on site 80K900 and the...Impacts- Elizabeth Orr asked about these Rocky Creek: T resile or work bridge thru limits of wetlands limited number of temporary piers in stream

  9. Construction Technique for Accurate Positioning of Large Steel Boxed Cofferdam Using Pulling and Berthing Pier System%大型钢吊箱拉靠墩系统精确定位施工技术

    Institute of Scientific and Technical Information of China (English)

    陈超华; 徐斯林; 穆清君

    2011-01-01

    The main bridge of Wuhan Erqi Changjiang River Bridge is a three-pylon composite girder cable-stayed bridge. The pile cap of pylon pier No. 3 of the bridge is located in deepwater and was constructed in dry environment in large steel boxed cofferdam. To resolve the problem of accurate positioning of the large cofferdam, the pulling and berthing pier system was used after comparison of the different positioning schemes. The pier system is composed of a pulling pier at the upstream side and a berthing pier at the downstream side, on the pulling pier, the main pulling cables and tie-down cables were set while on thg berthing pier, the crisscross pulling cables were set. The positioning anchors were cast into the river longitudinally along the bridge and the side anchoring cables were set. After construction preparation, the cofferdam was initially posi-tioned by the pulling and berthing pier system to make the cofferdam basically set in place in plan position. By using the side anchoring cables, pulling cables and by means of non-uniform pumping of water into the bulks of the cofferdam, the plan position, plan torsion, oscillation and perpendicularity of the cofferdam were adjusted and the plan offsetting of the cofferdam was brought to be within +12 mm, the torsional angle to be 58" and the inclination to be 1/3 000 so as to make the construction of the cofferdam meet the relevant requirements in the codes and eventually realize the accurate positioning of the cofferdam.%武汉二七长江大桥主桥为三塔结合梁斜拉桥,其3号墩位于深水中,采用钢吊箱实现承台干施工.为解决大型钢吊箱精确定位难题,经过方案比选,采用拉靠墩系统定位方案,该系统由上游拉墩和下游靠墩组成,拉墩设主拉缆和下拉缆,靠墩设交叉拉缆,顺桥向抛锚,设置边锚缆.施工准备后,利用拉靠墩系统进行钢吊箱初定位,使其平面位置基本就位;通过边锚缆系统、拉缆系统及夹壁舱不均衡灌

  10. Myocardial Bridging

    Directory of Open Access Journals (Sweden)

    Shi-Min Yuan

    2016-02-01

    Full Text Available Abstract Myocardial bridging is rare. Myocardial bridges are most commonly localized in the middle segment of the left anterior descending coronary artery. The anatomic features of the bridges vary significantly. Alterations of the endothelial morphology and the vasoactive agents impact on the progression of atherosclerosis of myocardial bridging. Patients may present with chest pain, myocardial infarction, arrhythmia and even sudden death. Patients who respond poorly to the medical treatment with β-blockers warrant a surgical intervention. Myotomy is a preferred surgical procedure for the symptomatic patients. Coronary stent deployment has been in limited use due to the unsatisfactory long-term results.

  11. Human-simulated intelligent control of train braking response of bridge with MRB

    Science.gov (United States)

    Li, Rui; Zhou, Hongli; Wu, Yueyuan; Wang, Xiaojie

    2016-04-01

    The urgent train braking could bring structural response menace to the bridge under passive control. Based on the analysis of breaking dynamics of a train-bridge vibration system, a magnetorheological elastomeric bearing (MRB) whose mechanical parameters are adjustable is designed, tested and modeled. A finite element method (FEM) is carried out to model and optimize a full scale vibration isolation system for railway bridge based on MRB. According to the model above, we also consider the effect of different braking stop positions on the vibration isolation system and classify the bridge longitudinal vibration characteristics into several cases. Because the train-bridge vibration isolation system has multiple vibration states and strongly coupling with nonlinear characteristics, a human-simulated intelligent control (HSIC) algorithm for isolating the bridge vibration under the impact of train braking is proposed, in which the peak shear force of pier top, the displacement of beam and the acceleration of beam are chosen as control goals. The simulation of longitudinal vibration control system under the condition of train braking is achieved by MATLAB. The results indicate that different braking stop positions significantly affect the vibration isolation system and the structural response is the most drastic when the train stops at the third cross-span. With the proposed HSIC smart isolation system, the displacement of bridge beam and peak shear force of pier top is reduced by 53.8% and 34.4%, respectively. Moreover, the acceleration of bridge beam is effectively controlled within limited range.

  12. Seismic damage analysis of the outlet piers of arch dams using the finite element sub-model method

    Science.gov (United States)

    Song, Liangfeng; Wu, Mingxin; Wang, Jinting; Xu, Yanjie

    2016-09-01

    This study aims to analyze seismic damage of reinforced outlet piers of arch dams by the nonlinear finite element (FE) sub-model method. First, the dam-foundation system is modeled and analyzed, in which the effects of infinite foundation, contraction joints, and nonlinear concrete are taken into account. The detailed structures of the outlet pier are then simulated with a refined FE model in the sub-model analysis. In this way the damage mechanism of the plain (unreinforced) outlet pier is analyzed, and the effects of two reinforcement measures (i.e., post-tensioned anchor cables and reinforcing bar) on the dynamic damage to the outlet pier are investigated comprehensively. Results show that the plain pier is damaged severely by strong earthquakes while implementation of post-tensioned anchor cables strengthens the pier effectively. In addition, radiation damping strongly alleviates seismic damage to the piers.

  13. Real-time data collection of scour at bridges

    Science.gov (United States)

    Mueller, David S.; Landers, Mark N.

    1994-01-01

    The record flood on the Mississippi River during the summer of 1993 provided a rare opportunity to collect data on scour of the streambed at bridges and to test data collection equipment under extreme hydraulic conditions. Detailed bathymetric and hydraulic information were collected at two bridges crossing the Mississippi River during the rising limb, near the peak, and during the recession of the flood. Bathymetric data were collected using a digital echo sounder. Three-dimensional velocities were collected using Broadband Acoustic Doppler Current Profilers (BB-ADCP) operating at 300 kilohertz (kHz), 600 kHz, and 1,200 kHz. Positioning of the data collected was measured using a range-azimuth tracking system and two global positioning systems (GPS). Although differential GPS was able to provide accurate positions and tracking information during approach- and exit-reach data collection, it was unable to maintain lock on a sufficient number of satellites when the survey vessel was under the bridge or near the piers. The range-azimuth tracking system was used to collect position and tracking information for detailed data collection near the bridge piers. These detailed data indicated local scour ranging from 3 to 8 meters and will permit a field-based evaluation of the ability of various numerical models to compute the hydraulics, depth, geometry, and time-dependent development of local scour.

  14. An innovative steel-concrete joint for integral abutment bridges

    Directory of Open Access Journals (Sweden)

    Bruno Briseghella

    2015-08-01

    Full Text Available Integral abutment bridges are becoming rather common, due to the durability problems of bearings and expansion joints. At the same time, among short- and medium-span bridges, multi-beam steel-concrete composite deck with hot-rolled girder is an economical and interesting alternative to traditional pre-stressed concrete solutions. The two concepts can be linked together to design integral steel-concrete composite bridges with the benefits of two typologies. The most critical aspect for these bridges is usually the joints between deck and piers or abutments. In this paper, an innovative beam-to-pier joint is proposed and a theoretical and experimental study is introduced and discussed. The analyzed connection is aimed at combining general ease of construction with a highly simplified assembly procedure and a good transmission of hogging and sagging moment at the supports in continuous beams. For this purpose, the traditional shear studs, used at the interface between steel beam and upper concrete slab, are also used at the ends of steel profiles welded horizontally to the end plates. To better understand the behaviour of this kind of joints and the roles played by different components, three large-scale specimens were tested and an FE model was implemented. The theoretical and experimental results confirmed the potential of the proposed connection for practical applications and indicated the way to improve its structural behaviour.

  15. Pounding Effects in Simply Supported Bridges Accounting for Spatial Variability of Ground Motion: A Case Study

    Directory of Open Access Journals (Sweden)

    G. Tecchio

    2012-01-01

    Full Text Available This study carries out a parametrical analysis of the seismic response to asynchronous earthquake ground motion of a long multispan rc bridge, the Fener bridge, located on a high seismicity area in the north-east of Italy. A parametrical analysis has been performed investigating the influence of the seismic input correlation level on the structural response: a series of nonlinear time history analyses have been executed, in which the variation of the frequency content in the accelerograms at the pier bases has been described by considering the power spectral density function (PSD and the coherency function (CF. In order to include the effects due to the main nonlinear behaviours of the bridge components, a 3D finite element model has been developed, in which the pounding of decks at cap-beams, the friction of beams at bearings, and the hysteretic behaviour of piers have been accounted for. The sensitivity analysis has shown that the asynchronism of ground motion greatly influences pounding forces and deck-pier differential displacements, and these effects have to be accurately taken into account for the design and the vulnerability assessment of long multispan simply supported bridges.

  16. A Proposal for 4000m-span Cable-stayed Suspension Bridge

    Directory of Open Access Journals (Sweden)

    Haijun Wang

    2013-06-01

    Full Text Available This study proposed a compound bridge of suspension bridges and cable-stayed bridges with 4000 m super-long-span over the Tsugaru Strait, Japan. Near to the main towers, cable-stayed bridges and prestressed concrete decks are proposed. It is helpful to enhance rigidity and endure the great axial compression force. In the center of the span, suspension bridges and steel box decks are stiffened by trusses, it can reduce self-weigh and the space between girders, thus contribute to aero-elastic stability. RCFT main tower, RC shell pier and RCFT jacket foundation can enhance rigidity and reduce self-weigh. As a result, the live-dead load ratio of proposal is 0.05 and it is equivalent to 2500m-span suspension bridge.

  17. Bridge Management Systems

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    In this paper bridge management systems are discussed with special emphasis on management systems for reinforced concrete bridges. Management systems for prestressed concrete bridges, steel bridges, or composite bridges can be developed in a similar way....

  18. Security enhancement of littoral combat ship class utilizing an autonomous mustering and pier monitoring system

    OpenAIRE

    Stubblefield, Philip N.

    2010-01-01

    Approved for public release; distribution is unlimited Littoral Combat Ships (LCS) are designed and built to have minimum crew sizes thus, while the ship is in port, there are fewer crewmembers to facilitate pier monitoring, security, and conducting mustering of personnel. The crew of LCS ships presently have too many responsibilities to ensure 100% coverage of the Pier area 100% of the time, and cannot manually maintain a real time muster of all ships personnel. This lack of coverage a...

  19. Topographic effects on seismic response of long-span rigid-frame bridge under SV seismic wave

    Institute of Scientific and Technical Information of China (English)

    WANG Lei; ZHAO Cheng-gang; QU Tie-jun

    2008-01-01

    Seismic ground motions of two neighboring mountains and the free surface between them are calculated under the SV seismic waves with three different incident angles. The results are then taken as the inputs of multi-point seismic excitations for the foundation of a long-span bridge built over the valley in the analysis considering the inte-grated influence of traveling wave and topography. On the basis of a dynamic analytical method, a finite element model is created for the seismic responses of a four-span rigid-frame bridge of 440 m. The pier-top displacement and the pier-bottom internal force of the bridge are calculated. Then the results are compared with those considering traveling-wave effect only. The conclusions can serve as a seismic design reference for the structures located on the complex mountain topography.

  20. Topographic effects on seismic response of long-span rigid-frame bridge under SV seismic wave

    Science.gov (United States)

    Wang, Lei; Zhao, Cheng-Gang; Qu, Tie-Jun

    2008-05-01

    Seismic ground motions of two neighboring mountains and the free surface between them are calculated under the SV seismic waves with three different incident angles. The results are then taken as the inputs of multi-point seismic excitations for the foundation of a long-span bridge built over the valley in the analysis considering the integrated influence of traveling wave and topography. On the basis of a dynamic analytical method, a finite element model is created for the seismic responses of a four-span rigid-frame bridge of 440 m. The pier-top displacement and the pier-bottom internal force of the bridge are calculated. Then the results are compared with those considering traveling-wave effect only. The conclusions can serve as a seismic design reference for the structures located on the complex mountain topography.

  1. National Bridge Inventory (NBI) Bridges

    Data.gov (United States)

    Department of Homeland Security — The NBI is a collection of information (database) describing the more than 600,000 of the Nation's bridges located on public roads, including Interstate Highways,...

  2. Expected damages of retrofitted bridges with RC jacketing

    Science.gov (United States)

    Montes, O.; Jara, J. M.; Jara, M.; Olmos, B. A.

    2015-07-01

    The bridge infrastructure in many countries of the world consists of medium span length structures built several decades ago and designed for very low seismic forces. Many of them are reinforced concrete structures that according to the current code regulations have to be rehabilitated to increase their seismic capacity. One way to reduce the vulnerability of the bridges is by using retrofitting techniques that increase the strength of the structure or by incorporating devices to reduce the seismic demand. One of the most common retrofit techniques of the bridges substructures is the use of RC jacketing; this research assesses the expected damages of seismically deficient medium length highway bridges retrofitted with reinforced concrete jacketing, by conducting a parametric study. We select a suite of twenty accelerograms of subduction earthquakes recorded close to the Pacific Coast in Mexico. The original structures consist of five 30 m span simple supported bridges with five pier heights of 5 m, 10 m, 15 m 20 and 25 m and the analyses include three different jacket thickness and three steel ratios. The bridges were subjected to the seismic records and non-linear time history analyses were carried out by using the OpenSEEs Plataform. Results allow selecting the reinforced concrete jacketing that better improves the expected seismic behavior of the bridge models.

  3. Development of base isolation system for existing bridges; Kisetsu kyoryo no menshinka koho no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Nagumo, H.; Hishiki, T.; Niihara, Y.; Aizawa, J.; Ichinomiya, T. [Kajima Corp., Tokyo (Japan)

    1997-12-20

    The new base-isolation system has been developed for existing bridges, which meets the functional and executional requirements. Described herein are outline of the new system, results of the shaking table tests conducted to confirm its validity, and simulation analysis of the test results. These results confirm that the new system, which uses horizontal force dampers and sliding bearings, is suited for existing bridges. Its basic characteristics are also described. The new system exhibits a sufficient base isolation effect, because the observed acceleration of the girder can be reduced to 1/2 to 1/3 that of a girder supported by the conventional system. It is also confirmed that the relative displacement between the pier and girder during a level 1 earthquake is below 5mm for an RC bridge with a span of 20m or so, a level which does not lead to damage of the bridge joints. The simulation analysis indicates that the new system could reduce the relative displacement between the pier and girder during a level 1 earthquake to 1/5 that associated with the bridge supported by the conventional system, by additional damping effects coming from the horizontal force dampers and sliding bearings. The simulation analysis also indicates that a bridge destroyed by the Great Hanshin Earthquake would have been safe if it had been supported by the new system, which also confirms sufficiently improved resistance to earthquake provided by the new system. 4 refs., 14 figs., 6 tabs.

  4. Evaluation of streambed scour at bridges over tidal waterways in Alaska

    Science.gov (United States)

    Conaway, Jeffrey S.; Schauer, Paul V.

    2012-01-01

    Engineering Center’s River Analysis System model, and scour depths were calculated using methods recommended by the Federal Highway Administration. Computed contraction-scour depths were greater than 2.0 feet at five bridges and computed pier-scour depths were 4.0 feet or greater at 15 bridges. The potential for streambed scour by both coastal and riverine processes at the bridges considered in this study were evaluated, ranked, and summed to determine a cumulative risk factor for each bridge. Possible factors that could mitigate the scour risks were investigated at 22 bridges that had high individual or cumulative rankings. Mitigating factors such as piers founded in bedrock, deep pier foundations relative to scour depths, and lack of observed scour during field measurements were documented for 13 sites, but additional study and monitoring is needed to better quantify the streambed scour potential for nine sites. Three bridges prone to being affected by storm surges will require more data collection and possibly complex hydrodynamic modeling to accurately quantify the streambed scour potential. Continuous monitoring of water-surface and streambed elevation at one or more piers is needed for two bridges to better understand the tidal and riverine influences on streambed scour.

  5. Critical insights for advanced bridge scour detection using the natural frequency

    Science.gov (United States)

    Bao, Ting; Andrew Swartz, R.; Vitton, Stanley; Sun, Ye; Zhang, Chao; Liu, Zhen

    2017-01-01

    Scour around bridge foundations is regarded as one of the predominant causes of bridge failures. The concept of vibration-based real-time bridge scour detection has been explored in recent years by investigating the change in the natural frequency spectrum of a bridge or a bridge component with respect to the scour depth. Despite the progress, significant issues still remain unsolved in the application of this concept. This paper investigates three unsolved issues in the current framework of scour detection using the natural frequency spectrum: the physical meaning of the measured predominant natural frequency, the location of sensor installation, and the influence of the shape of scour holes, which are easily neglected but critical to the further implementations of the natural frequency spectrum-based bridge scour detection. Firstly, in-depth discussions of these three major issues were made separately by numerically modeling the scour progression of a typical and documented laboratory test. Laboratory tests were then performed to validate the conclusions made in the discussions. It was found that for an eigenproblem of the system with soil-structure interaction, the physical meaning of the natural frequency obtained from modal analysis can be understood by comparing the modal natural frequency with the natural frequency calculated from the dynamic response of the test component in that system. The results also verified that the obtained predominant natural frequency of the pier body greatly varies with the location of the pier body where a sensor is mounted for signal pickup. The shape of the scour hole affects the predominant natural frequency of the pier, causing difficulties in practical measurements. To address such a problem, a new criterion was proposed to identify the depth of unsymmetrical scour holes for the first time, which is of practical significance to advance the natural frequency spectrum-based scour detection framework.

  6. Bridged graphite oxide materials

    Science.gov (United States)

    Herrera-Alonso, Margarita (Inventor); McAllister, Michael J. (Inventor); Aksay, Ilhan A. (Inventor); Prud'homme, Robert K. (Inventor)

    2010-01-01

    Bridged graphite oxide material comprising graphite sheets bridged by at least one diamine bridging group. The bridged graphite oxide material may be incorporated in polymer composites or used in adsorption media.

  7. Construction Technique for River Pier Foundations Sitting on Bare Rock Riverbed%裸岩河床水中墩基础施工技术

    Institute of Scientific and Technical Information of China (English)

    申永利

    2016-01-01

    长昆客专罗旧舞水特大桥主桥为(48+2×80+48) m连续梁桥,1号~3号桥墩位于主河槽内,低桩承台嵌入河床裸岩中,设16根φ1.5 m钻孔桩。根据裸岩河床、低桩承台的特点,确定水中墩基础施工采用施工栈桥为交通便道、施工平台,栈桥标准跨度18 m ,设4组贝雷梁、双排钢管桩基础,并在钢管桩周围抛填砂砾、投放石笼或下放钢套箱、灌注水下混凝土以及拉设缆风绳。水中墩基础采用矩形双壁钢围堰围护方案,按照“先堰后桩”顺序施工。水中墩基础施工中,采用长臂挖机清底,利用岩石乳化炸药和非电微差雷管进行水下岩石爆破;钢护筒采用振动锤夹持、插打;双壁钢围堰依靠钻孔桩护筒、平台辅助钢管桩逐块拼装,用倒链下放、汽车吊接高下沉施工;围堰封底混凝土等强后,进行钻孔桩、承台和墩柱施工,最后拆除围堰。%The main bridge of Luojiu Wushui River Bridge on the Changsha‐Kunming Passen‐ger Dedicated Railway is a (48+2 × 80+48) m continuous beam bridge .The pier No .1 ,pier No .2 and pier No .3 stand in the main river channel ,the low pile caps of w hich are embedded in the bare rocks on the riverbed .T he foundation of the pier consists of 16 bored piles each 1 .5 m in diameter . To suit the characteristics of the bare rock riverbed and the low pile caps ,the construction trestle was used as the transportation access and the construction platform during the construction of the river pier foundations .The trestle ,with standard span length of 18 m ,consists of 4 groups of bai‐ley beams that are supported by two rows of steel pipe piles .The steel pipe piles were surrounded by riprap ,based on which the stone cage or suspended steel box was lowered .Then the tremie concrete was cast and wind cables were installed and tensioned .The river pier foundation was con‐structed with the assistance of the rectangular

  8. HYDRAULIC CHARACTERISTICS OF BOTTOM UNDERLAY-TYPE PIER FOR WATER-WING CONTROL

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The pier, placed at the outlet of the pressure flow section, is an effective design to deal with the problems of the manufacture and operation of the gates for a discharge tunnel with high water head. It is crucial to control the water-wing, induced by this type of the pier. Through observing the phenomena of the water-wing, the reason of the water-wing inception, i.e., the concave of the flow surface, was presented, and a type of the new pier with bottom underlay was designed. The hydraulic characteristics of the pier, including the variations of the water-wing features, both length and height, with the water head, as well as with the concave depth, and with the height of the bottom underlay, and the variations of the concave depth with the height of the bottom underlay, were investigated by physical model experiments. The results show that the approach of the modification of the concave through the structures with the bottom underlay-type pier is remarkably effective in the water-wing control.

  9. On maintenance strategies of roads and bridges%谈公路桥梁养护对策

    Institute of Scientific and Technical Information of China (English)

    赵文峰

    2015-01-01

    The paper analyzes the meaning and aims of the road and bridge maintenance,illustrates factual maintenance measures of bridges and roads from the bridge beam maintenance,bridge pier maintenance,and deck maintenance,so as to prolong the life of roads and bridges and re-duce the times and cost of the roads and bridge maintenance by the maintenance measures.%分析了公路桥梁养护的意义及目的,从桥梁梁板养护、桥梁墩台养护、桥面铺装养护三方面,阐述了公路桥梁的具体养护措施,以延长公路桥梁的使用年限,减少公路桥梁修复的次数与成本。

  10. Mechanics model of additional longitudinal force transmission between bridges and continuously welded rails with small resistance fasteners

    Institute of Scientific and Technical Information of China (English)

    徐庆元; 周小林; 曾志平; 杨小礼

    2004-01-01

    A new mechanics model, which reveals additional longitudinal force transmission between the continuously welded rails and the bridges, is established on the fact that the influence of the mutual relative displacement among the rail, the sleeper and the beam is taken into account. An example is presented and numerical results are compared. The results show that the additional longitudinal forces calculated with the new model are less than those of the previous, especially in the case of the flexible pier bridges. The new model is also suitable for the analysis of the additional longitudinal force transmission between rails and bridges of ballastless track with small resistance fasteners without taking the sleeper displacement into account, and compared with the ballast bridges, the ballastless bridges have a much stronger additional longitudinal force transmission between the continuously welded rails and the bridges.

  11. Building Bridges

    DEFF Research Database (Denmark)

    The report Building Bridges adresses the questions why, how and for whom academic audience research has public value, from the different points of view of the four working groups in the COST Action IS0906 Transforming Audiences, Transforming Societies – “New Media Genres, Media Literacy and Trust...... in the Media”, “Audience Interactivity and Participation”, “The Role of Media and ICT Use for Evolving Social Relationships” and “Audience Transformations and Social Integration”. Building Bridges is the result of an ongoing dialogue between the Action and non-academic stakeholders in the field of audience...... Belgrade), Leo Pekkala (Finnish Centre for Media Education and Audiovisual Media/MEKU), Julie Uldam (Network on Civic Engagement and Social Innovation) and Gabriella Velics (Community Media Forum Europe)....

  12. Mathematical bridges

    CERN Document Server

    Andreescu, Titu; Tetiva, Marian

    2017-01-01

    Building bridges between classical results and contemporary nonstandard problems, Mathematical Bridges embraces important topics in analysis and algebra from a problem-solving perspective. Blending old and new techniques, tactics and strategies used in solving challenging mathematical problems, readers will discover numerous genuine mathematical gems throughout that will heighten their appreciation of the inherent beauty of mathematics. Most of the problems are original to the authors and are intertwined in a well-motivated exposition driven by representative examples. The book is structured to assist the reader in formulating and proving conjectures, as well as devising solutions to important mathematical problems by making connections between various concepts and ideas from different areas of mathematics. Instructors and educators teaching problem-solving courses or organizing mathematics clubs, as well as motivated mathematics students from high school juniors to college seniors, will find Mathematical Bri...

  13. Numerical Analysis of Interaction Between Pile-Supported Pier and Bank Slope

    Institute of Scientific and Technical Information of China (English)

    王年香

    2001-01-01

    Two- and three-dimensional finite element analysis programs for pile-soil interaction are compiled. Duncan-Chang's Model is used. The construction sequence of the pier is modeled. The pile-soil interface element is used. The influence of the combination type of piles on the deformation of bank slope and pile behaviour is analyzed. Different designs of a pile-supported pier are compared thoroughly. Calculation results show that the stresses and displacements of the pile are directly related to the distance from the bank slope and the direction of inclination. An inclined prop pile set in the rear platform would remarkably reduce the stresses of piles and the displacement of the pier.

  14. Plastic Bridge

    Institute of Scientific and Technical Information of China (English)

    履之

    1994-01-01

    Already ubiquitous in homes and cars, plastic is now appearing inbridges. An academic-industrial consortium based at the University ofCalifornia in San Diego is launching a three-year research program aimed atdeveloping the world’s first plastic highway bridge, a 450-foot span madeentirely from glass-,carbon,and polymer-fiber-reinforced composite mate-rials, the stuff of military aircraft. It will cross Interstate 5 to connect thetwo sides of the school’s campus.

  15. Design of T-Frame Bridge of Mashui River Bridge%马水河特大桥T形刚构桥设计

    Institute of Scientific and Technical Information of China (English)

    陈晓波

    2011-01-01

    Mashui River Bridge is a long span T-frame bridge with span arrangement (116 +116) m. The main girder of the bridge is a prestressed concrete girder of variable section, having a single cell single box and vertical webs. The top of the girder is 10.7 m in width and the bottom varies in round arc. The main pier of the bridge is 108 m high and the pier shaft is the high-rise rectangular hollow pier that has no solid section close to the top of the pier and is connected with the girder in a way of spatial frame. The foundation for the pier is composed of 24 nos. of φ2.5 m reinforced concrete bored piles, the concrete for the piles is of C30 and a 7.5 m high training dike is set at the footing of the pier. The BSAS and ANSYS are respectively used to conduct the structural static force calculation and spatial static and dynamic force analysis. The results of the calculation and analysis show that the static force, wind resistance, seismic resistance and dynamic response of the vehicle and bridge can all satisfy the relevant requirements in the codes. The pier shaft of the bridge is constructed by the backward inclined cantilever formwork and the main girder is constructed by the free balanced cantilever concreting method.%马水河特大桥为(116+116)m的大跨度T形刚构桥.主梁采用变截面预应力混凝土箱梁,单箱单室直腹板,箱梁顶宽10.7 m,梁底缘按圆弧变化.主墩高108 m,墩身采用矩形空心高墩,墩顶不设实体段,与梁部按空间框架形式相接,桩基采用24-φ2.5 m钢筋混凝土钻孔桩,混凝土强度等级为C30,在墩底设置7.5 m高的导流堤.分别采用BSAS和ANSYS对全桥进行结构静力计算及空间静力和动力分析.分析结果表明:该桥静力、抗风、抗震、车桥动力响应验算结果均满足规范要求.该桥主墩墩身采用后倾式悬臂模板法施工,主梁采用对称悬臂浇筑法施工.

  16. 78 FR 20623 - Environmental Impact Statement for Modernization and Repair of Piers 2 and 3, Military Ocean...

    Science.gov (United States)

    2013-04-05

    ... and 3 are used to transport military supplies in the Pacific region. There may be significant impacts... Department of the Army Environmental Impact Statement for Modernization and Repair of Piers 2 and 3, Military...-needed modernization and repairs of Piers 2 and 3, Military Ocean Terminal Concord (MOTCO) due...

  17. 18 CFR 1304.206 - Requirements for community docks, piers, boathouses, or other water-use facilities.

    Science.gov (United States)

    2010-04-01

    ... 18 Conservation of Power and Water Resources 2 2010-04-01 2010-04-01 false Requirements for community docks, piers, boathouses, or other water-use facilities. 1304.206 Section 1304.206 Conservation of....206 Requirements for community docks, piers, boathouses, or other water-use facilities. (a)...

  18. LARGE-EDDY SIMULATION OF THREE-DIMENSIONAL TURBULENT FLOW AROUND A CIRCULAR PIER

    Institute of Scientific and Technical Information of China (English)

    ZHAO Wei; Huhe Aode

    2006-01-01

    In this article, the turbulent flow field and the scouring mechanism around a circular pier were numerically investigated using the Large Eddy Simulation (LES) method for three scouring holes. The effects of the bottom topographies on the flow structure were studied in detail. The results show that at the downstream of the pier, as the scouring depth increases, the bed shear stress decreases and approaches to the undisturbed shear stress, however, the turbulent intensity, the fluctuating pressure, and the vertical pressure gradient increase gradually.

  19. Discussion on the Construction Technology of Variable Cross-section Hollow Thin-walled Pier%浅谈变截面空心薄壁方墩施工技术

    Institute of Scientific and Technical Information of China (English)

    陈显福

    2014-01-01

    Variable cross-section hol ow thin-walled pier has the obvious superiority and good economy, and can use less material to obtain larger sectional resistance moment which is often used by mountain bridge engineering. Taking the Yujiagou1# bridge as the example, this article introduces the construction technology of variable cross-section hol ow thin-wal ed pier, and provides reference for similar engineering construction.%变截面空心薄壁方墩具有明显的优越性和较好的经济性,可以用较少的材料获取较大的截面抵抗矩,这种技术常常被山区、深沟建桥的工程所采用。本文以余家沟1号大桥为例,介绍了变截面空心薄壁方墩施工技术,可为类似工程施工提供借鉴。

  20. Behavior of composite rigid frame bridge under bi-directional seismic excitations

    Directory of Open Access Journals (Sweden)

    Xiaogang Liu

    2014-02-01

    Full Text Available Pushover analysis and time history analysis are conducted to explore the bi-directional seismic behavior of composite steel-concrete rigid frame bridge, which is composed of RC piers and steel-concrete composite girders. Both longitudinal and transverse directions excitations are investigated using OpenSees. Firstly, the applicability of pushover analysis based on the fundamental mode is discussed. Secondly, an improved pushover analysis method considering the contribution of higher modes is proposed, and the applicability on composite rigid frame bridges under bi-directional earthquake is verified. Based on this method, an approach to predict the displacement responses of composite rigid frame bridge under random bi-directional seismic excitations by revising the elasto-plastic demand curve is also proposed. It is observed that the developed method yield a good estimate on the responses of composite rigid frame bridges under bi-directional seismic excitations.

  1. 城市桥梁被车辆撞击后损伤分析%Analysis on Damage of Urban Bridges Caused by Vehicle Collision

    Institute of Scientific and Technical Information of China (English)

    裴小吟; 文传勇; 张永水

    2011-01-01

    The stress state of the bridge pier under the collision of heavy vehicles with different speeds, and the collision mechanism of vehicle and bridge are mainly studied. The simulation analysis of piers and vehicles is carried out on the basis of the general finite element program ABAQUS. The plain concrete three-dimensional entity model is used as the pier model. The nonlinearity of concrete material is fully considered and reinforced steel is calculated with the consideration of liner elasticity. Ordinary steel entity model is used as the vehicle model, without the consideration of the impact on the vehicles in the collision. Simulated analyses which aim at the situation of vertical impact on the pier caused by different vehicles with three different speeds are carried out. Analyses show that the stress of the pier's collision point is firstly increased with the increase of time, and then the stress will decrease when it reaches the maximum value. This characteristic conforms to the plastic destruction law of the concrete. Meanwhile, analyses also show that the higher the vehicle speed is, the larger the stress and displacement of the pier reaches.%通过研究城市桥梁中当桥墩在重型车辆撞击下的受力状态及车-桥的碰撞机理,采用有限元软件ABAQUS对3种不同车速车辆垂商撞击桥墩的情况进行了模拟分析.分析表明:桥墩被撞击位置处的应力先随时间的增加而增大,达到最大值时,既又随之减小,符合混凝土的弹塑性破坏;并且车速越大,桥墩局部达到的应力及位移也越大.

  2. EXPERIMENTAL STUDY ON CAVITATION AND WATER-WING FOR MIDDLE-PIERS OF DISCHARGE TUNNELS

    Institute of Scientific and Technical Information of China (English)

    WU Jian-hua; CAI Chang-guang; JI Wei; RUAN Shi-ping; LUO Chao

    2005-01-01

    In construction of high dams, design of a middle-pier, placed in a discharge tunnel to divide it into two parts, is a better choice that could breakthrough the limits of the manufacture and operation of the gate due to the high head to it. However, cavitation and water-wing, a kind of flow striking the top and side walls of the tunnel, induced by the middle-pier, may take place and bring about bad effects on operation of the tunnel. The experiments of the six comparing plans were conducted, consisting of atmospheric and vacuum tank models, and the interesting areas included relationships between discharges and reservoir levels, measurements of side wall pressures, comparisons of water-wing states for the various middle-piers, estimations of the incipient cavitation numbers and the flow cavitation numbers, and analyses of cavitation characteristics for the tunnel. A kind of new bodily form of middle-pier was developed. Water-wing states were better improved and non-cavitation conditions were satisfied.

  3. 75 FR 8563 - Safety Zone; Fleet Week Maritime Festival, Pier 66, Elliott Bay, Seattle, WA

    Science.gov (United States)

    2010-02-25

    ... public dockets in the January 17, 2008, issue of the Federal Register (73 FR 3316). Public Meeting We do... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Fleet Week Maritime Festival, Pier 66... aerial spectator events associated with the annual Fleet Week Maritime Festival. Entry into,...

  4. 33 CFR 165.1121 - Security Zone: Fleet Supply Center Industrial Pier, San Diego, CA.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Security Zone: Fleet Supply... Guard District § 165.1121 Security Zone: Fleet Supply Center Industrial Pier, San Diego, CA. (a... feet from the north, west, and south sides of the Fleet Industrial Supply Center enclosed by...

  5. 24 CFR 3285.306 - Design procedures for concrete block piers.

    Science.gov (United States)

    2010-04-01

    ... piers less than 36 inches high are permitted to be constructed of single, open, or closed-cell concrete... shown in Figure A to this section. (3) The concrete blocks must be stacked with their hollow cells... 24 Housing and Urban Development 5 2010-04-01 2010-04-01 false Design procedures for...

  6. Real-time seismic monitoring of the integrated cape girardeau bridge array and recorded earthquake response

    Science.gov (United States)

    Celebi, M.

    2006-01-01

    This paper introduces the state of the art, real-time and broad-band seismic monitoring network implemented for the 1206 m [3956 ft] long, cable-stayed Bill Emerson Memorial Bridge in Cape Girardeau (MO), a new Mississippi River crossing, approximately 80 km from the epicentral region of the 1811-1812 New Madrid earthquakes. The bridge was designed for a strong earthquake (magnitude 7.5 or greater) during the design life of the bridge. The monitoring network comprises a total of 84 channels of accelerometers deployed on the superstructure, pier foundations and at surface and downhole free-field arrays of the bridge. The paper also presents the high quality response data obtained from the network. Such data is aimed to be used by the owner, researchers and engineers to assess the performance of the bridge, to check design parameters, including the comparison of dynamic characteristics with actual response, and to better design future similar bridges. Preliminary analyses of ambient and low amplitude small earthquake data reveal specific response characteristics of the bridge and the free-field. There is evidence of coherent tower, cable, deck interaction that sometimes results in amplified ambient motions. Motions at the lowest tri-axial downhole accelerometers on both MO and IL sides are practically free from any feedback from the bridge. Motions at the mid-level and surface downhole accelerometers are influenced significantly by feedback due to amplified ambient motions of the bridge. Copyright ASCE 2006.

  7. Reduction of seismic response long-span PC cable-stayed bridge by passive dampers; Damper ni yoru saidai PC shachokyo no jishinji oto no teigen

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, T.; Yamanobe, S.; Niihara, Y. [Kajima Corp., Tokyo (Japan)

    1994-10-31

    It is important in designing a PC cable-stayed bridge to properly estimate the seismic response of the bridge for reduction of the response. In this paper, an improvement of the seismic resistance of PC cable-stayed bridges when dampers are installed between the deck and piers and lateral vibration of the deck is restricted is investigated using a time history response model. PC cable-stayed bridges with a span length of 400 m, particularly two types of bridges of harp and semi-harp are investigated and the following is found by analyzing the case where there are installed hysteresis type dampers (with 1 cm yield displacement and secondary rigidity assumed to be 1/10 times that of initial rigidity, the initial rigidity being parametrically changed.) or viscous type dampers (a damping factor is changed.) The result shows that the dampers can reduce the seismic response of a PC cable-stayed bridge and that a semi-harp configuration of stay cables where stay cable members are substantially vertically arranged is more effective than a harp configuration for the seismic performance of PC cable-stayed bridges. The damper partly bear inertial force of the bridge upon earthquake whereby tension of the stay cable members is reduced and bending moment of the deck is reduced. There is existing an optimum characteristic value of the damper concerning the bending moment of the piers. 5 refs., 7 figs., 2 tabs.

  8. High Performance Building Facade Solutions - PIER Final Project Report

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eleanor; Selkowitz, Stephen

    2009-12-31

    Building facades directly influence heating and cooling loads and indirectly influence lighting loads when daylighting is considered, and are therefore a major determinant of annual energy use and peak electric demand. Facades also significantly influence occupant comfort and satisfaction, making the design optimization challenge more complex than many other building systems.This work focused on addressing significant near-term opportunities to reduce energy use in California commercial building stock by a) targeting voluntary, design-based opportunities derived from the use of better design guidelines and tools, and b) developing and deploying more efficient glazings, shading systems, daylighting systems, facade systems and integrated controls. This two-year project, supported by the California Energy Commission PIER program and the US Department of Energy, initiated a collaborative effort between The Lawrence Berkeley National Laboratory (LBNL) and major stakeholders in the facades industry to develop, evaluate, and accelerate market deployment of emerging, high-performance, integrated facade solutions. The LBNL Windows Testbed Facility acted as the primary catalyst and mediator on both sides of the building industry supply-user business transaction by a) aiding component suppliers to create and optimize cost effective, integrated systems that work, and b) demonstrating and verifying to the owner, designer, and specifier community that these integrated systems reliably deliver required energy performance. An industry consortium was initiated amongst approximately seventy disparate stakeholders, who unlike the HVAC or lighting industry, has no single representative, multi-disciplinary body or organized means of communicating and collaborating. The consortium provided guidance on the project and more importantly, began to mutually work out and agree on the goals, criteria, and pathways needed to attain the ambitious net zero energy goals defined by California and

  9. Design of Danyang Road Bridge in Heze City%菏泽市丹阳路大桥设计

    Institute of Scientific and Technical Information of China (English)

    张伟

    2015-01-01

    菏泽市丹阳路大桥为(40+100+240+100+40) m 双塔中央单索面半飘浮体系混凝土斜拉桥。该桥塔、墩固结,主梁与塔、墩间设置横、竖向支座和纵向液压阻尼器;主梁采用单箱三室斜腹板截面,高3.6m。桥塔采用顺桥向人字形的独柱混凝土塔,高68.2m,单箱单室矩形空心截面。人字形塔柱穿过主梁,与墩身顺接,墩身采用十字形空心薄壁截面,矩形承台,布置33根φ2.0m钻孔灌注桩。辅助墩和交接墩均采用花瓶形双柱式框架墩,矩形承台,布置8根φ1.5m钻孔灌注桩。斜拉索采用φ7 mm镀锌高强平行钢丝束。采用MIDAS Civil 2006和SCDS平面程序对该桥进行计算分析,结果表明该桥各项检算均满足规范要求。%T he Danyang Road Bridge in Heze City is a semi‐floating system concrete cable‐stayed bridge with double pylons ,a central single cable plane and with span arrangement (40+100+240+100+40) m .T he pylons and piers of the bridge are rigidly fixed and in betw een the main girder and pylons and piers ,the lateral and vertical bearings and the longitudinal hydraulic damp‐ers are arranged .The cross section of the main girder is the section of triple‐cell single box with in‐clined webs and the girder is 3 .6 m in depth .In the longitudinal direction of the bridge ,a pylon is the single‐column concrete pylon in the shape of inverted Y ,is 68 .2 m in height and the cross sec‐tion of the pylon is the rectangular hollow section of single‐cell single box .The inverted Y‐shape pylon passes through the main girder and is smoothly fixed with the pylon pier .The cross section of the pylon pier is the crisscross hollow thin‐wall section and the pier stands on the rectangular pile cap under w hich 33 nos .of φ2 .0 m bored piles are arranged .T he auxiliary piers and boundary piers are all the vase‐shape double‐column frame piers and respectively stand on each rectangular

  10. Seismic Analysis for Rigid-Framed Prestressed Reinforced Concrete Bridge in Tianjin Light Railway

    Institute of Scientific and Technical Information of China (English)

    丁阳; 李楠; 李忠献

    2004-01-01

    The seismic analysis of a rigid-framed prestressed concrete bridge in Tianjin Light Railway is performed. A 3-D dynamic finite element model of the bridge is established considering the weakening effect caused by the soft soil foundation. After the dynamic characteristics are calculated in terms of natural frequencies and modes, the seismic analysis is carried out using the modal response spectrum method and the time-history method, respectively. Based on the calculated results, the reasonable design values are finally suggested as the basis of the seismic design of the bridge, and meanwhile the problems encountered were also analyzed. Finally, some conclusions are drawn as: 1) Despite the superiority of rigid-framed prestressed concrete bridge, the upper and lower ends of the piers of the bridge are proved to be the crucial parts of the bridge, which are easily destroyed under designed earthquake excitations and should be carefully analyzed and designed; 2) The soft soil foundation can possibly result in rather weakening of the lateral rigidity of the rigid-framed bridge, and should be paid considerable attention; 3) The modal response spectrum method, combined with time-history method, is suggested for the seismic analysis in engineering design of the rigid-framed prestressed concrete bridge.

  11. Study of the aerostatic and aerodynamic stability of super long-span cable-stayed bridges

    Institute of Scientific and Technical Information of China (English)

    Zhang Xinjun; Sun Hailing

    2014-01-01

    With the increase of span length,the bridge tends to be more flexible,and the wind stability be-comes an important problem for the design and construction of super long-span cable-stayed bridges. By taking a super long-span cable-stayed bridge with a main span of 1 400 m as example,the aerostatic and aerodynamic stability of the bridge are investigated by three-dimensional nonlinear aerostatic and aerodynamic stability analy-sis,and the results are compared with those of a suspension bridge with a main span of 1 385 m,and from the aspect of wind stability,the feasibility of using cable-stayed bridge in super long-span bridge with a main span above 1 000 m is discussed. In addition,the influences of design parameters including the depth and width of the girder,the tower structure,the tower height-to-span ratio,the side-to-main span ratio,the auxiliary piers in the side span and the anchorage system of stay cables,etc on the aerostatic and aerodynamic stability of su-per long-span cable-stayed bridges are investigated numerically;the key design parameters are pointed out,and also their reasonable values are proposed.

  12. Docks and Piers, Published in 2008, 1:1200 (1in=100ft) scale, Brown County, WI.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Docks and Piers dataset, published at 1:1200 (1in=100ft) scale, was produced all or in part from Orthoimagery information as of 2008. Data by this publisher...

  13. Apparent Sea Level Rise due to Loading of the Atlantic City Pier by Spectators Viewing (1929-1978) Diving Horses

    Science.gov (United States)

    Galvin, C.

    2012-12-01

    Cyril Galvin, Coastal Engineer Springfield, Virginia 22150 USA Since 1911, the Steel Pier at Atlantic City, New Jersey, has been the site of the Atlantic City tide gauge, except for two intervals: 1911-1921 when the gauge was at the Million Dollar Pier in Atlantic City, and 1985-1991 when the gauge was at the Ventnor Fishing Pier (see Table 2, Zervos, 2009). By design, the Steel Pier was an amusement pier, and its most famous amusement was the Diving Horses: they dove bareback with a woman rider from a platform about 40 feet above sea level. They did that between 1929 and 1978, except for seven years - a post-war period, 1945 to 1953, when diving was suspended. The popularity of the diving horses is recorded on photos of crowds which occupied the bleachers at the seaward end of the pier to view the diving horses. By my count, the crowd pictured in the end papers of the book by Steve Liebowitz (2009) was about 4000 people. Typically, there were multiple shows daily. The weight of the crowd, estimated from the count of the crowd, was about 150 tons. This weight was loaded down on the piles by the crowd of spectators, and unloaded between shows of the diving horses. Most of the piles supporting the pier deck were imbedded in sand newly deposited since 1850. Using Atlantic City sea levels from the PSMSL data base and historical facts from Liebowitz (2009), and beginning with a 1912 start of the tide gauge, the apparent sea level rose at a rate of 3.1mm/yr until 1929 when the horses began diving. With the 1929 start of diving, the apparent sea level rise tripled, averaging 9.4 mm/yr until the act was suspended in 1945. In the 1945-1953 interval, when the horses did not dive (no crowds on the pier), apparent sea level fell (sea level FELL) at a rate of -1.6 mm/yr. The horses resumed diving in 1953, when the apparent sea level resumed at a rate of 4.0mm/yr. This 4.0 mm/yr is identical to the longtime sea level trend (1911-2006) from Zervos (2009) of 3.99mm/yr The history

  14. Cable Supported Bridges

    DEFF Research Database (Denmark)

    Gimsing, Niels Jørgen

    Cable supported bridges in the form of suspension bridges and cable-stayed bridges are distinguished by their ability to overcome large spans.The book concentrates on the synthesis of cable supported bridges, covering both design and construction aspects. The analytical part covers simple methods...

  15. Probabilistic seismic response and reliability assessment of isolated bridges

    Institute of Scientific and Technical Information of China (English)

    Giuseppe Carlo Marano

    2005-01-01

    Bridge seismic isolation strategy is based on the reduction of shear forces transmitted from the superstructure to the piers by two means: shifting natural period and earthquake input energy reduction by dissipation concentrated in protection devices. In this paper, a stochastic analysis of a simple isolated bridge model for different bridge and device parameters is conducted to assess the efficiency of this seismic protection strategy. To achieve this aim, a simple nonlinear softening constitutive law is adopted to model a wide range of isolation devices, characterized by only three essential mechanical parameters. As a consequence of the random nature of seismic motion, a probabilistic analysis is carried out and the time modulated Kanai-Tajimi stochastic process is adopted to represent the seismic action. The response covariance in the state space is obtained by solving the Lyapunov equation for a stochastic linearized system. After a sensitivity analysis, the failure probability referred to extreme displacement and the mean value of dissipated energy are assessed by using the introduced stochastic indices of seismic bridge protection efficiency. A parametric analysis for protective devices with different mechanical parameters is developed for a proper selection of parameters of isolation devices under different situations.

  16. Seismic Behavior and Force-Displacement Characterization of Neotype Column-Slab High Piers

    Directory of Open Access Journals (Sweden)

    YanQun Zhou

    2014-01-01

    Full Text Available The seismic behavior and plasticity spreading of a neotype column-slab high pier are researched in this paper. Four scale model tests of a web slab with two boundary columns are carried out under cyclic inelastic lateral displacements simulating seismic response. The test results show that the neotype column-slab high pier has strong and stable bearing capacity, good ductility, and energy dissipation capacity. The experimental values pertaining to the spread of plasticity are derived. An approach for deriving the spread of plasticity analytically is deduced and applied to the four tests. This method accurately assesses a pier’s spread of plasticity for most ductility levels. At nearly all ductility levels, the mean difference between analytical assessments of the spread of plasticity and results from 4 large-scale tests is 12% with a 9% coefficient of variation.

  17. RELATIONSHIP OF FIRST STEP HEIGHT, STEP SLOPE AND CAVITY IN X-SHAPED FLARING GATE PIERS

    Institute of Scientific and Technical Information of China (English)

    WANG Bo; WU Chao; HU Yao-hua; MO Zheng-yu

    2007-01-01

    The energy dissipation of X-shaped flaring gate piers ahead of a stepped spillway was adopted in the Suofengying Hydroplant. Under the circumstance that the first step is higher than others, at the step surface an aerated cavity occured behind piers. The interaction of the weir head, the elevation difference between crest and chamber outlet, the first step height, the slopes of weir end and step, and the size of cavity, was investigated, the expression was derived to characterize their relationship, and the corresponding curves were plotted. The comparison of the calculated and simulated results with the measured data was performed. When the slopes of step and weir end are equivalent, the relative height difference between the first and second steps becomes the main factor influencing the aerated cavity. These findings may be useful in practical applications.

  18. HYDRAULIC CHARACTERISTICS OF WATER-WINGS FOR THE MIDDLE-PIER OF A DISCHARGE TUNNEL

    Institute of Scientific and Technical Information of China (English)

    WU Jian-hua; CAI Chang-guang; JI Wei; RUAN Shi-ping

    2006-01-01

    Water-wings, induced by the middle-pier placed in the inlet of a discharge tunnel, have harmful effects on the operation of the discharge tunnel.Based on dimensional analysis and physical model tests, the hydraulic characteristics of water-wings were investigated and their causes were analyzed in this study.The results show that the height and length of the water-wings increased with the increase of three factors, i.e., the Froude number Frd of the outlet of the pressure section, the depth Hc of the water surface concave at the end of the middle-pier, and the impact length Li of the two flows after this end.

  19. Damage investigation of girder bridges under the Wenchuan earthquake and corresponding seismic design recommendations

    Institute of Scientific and Technical Information of China (English)

    Li Jianzhong; Peng Tianbo; Xu yan

    2008-01-01

    An investigation of girder bridges on National Highway 213 and the Doujiangyan-Wenchuan expressway after the Wenchuan earthquake showed that typical types of damage included:span collapses due to unseating at expansion joints;shear key failure;and damage of the expansion joint due to the slide-induced large relative displacement between the bottom of the girder and the top of the laminated-rubber bearing.This slide,however,can actually act as a form of isolation for the substructure,and as a result,the piers and foundation of most of the bridges on state route 213 suffered minor damage.The exception was the Baihua Bridge,which suffered severe damage.Corresponding seismic design recommendations are presented based on this investigation.

  20. Silicone-modified graphene oxide fillers via the Piers-Rubinsztajn reaction

    DEFF Research Database (Denmark)

    Zhang, Jianfeng; Liang, Shuai; Yu, Liyun

    2016-01-01

    While graphene or graphene oxide can make significantimprovements in the properties of a wide variety of polymericmaterials, their incorporation can be challenged byincompatibility with the polymeric matrix. The modification ofgraphene oxide with silicones or silanes using the Piers......-Rubinsztajn reaction improves dispersibility in nonpolar materials,including organic solvents and silicone pre-elastomers. Ahigh loading (up to 10 wt %) of modified graphene oxide insilicone elastomers could be achieved, which resulted inenhanced mechanical performance and reduced gas permeability....

  1. Earthquake Response Analysis of Approach Bridge of Suramadu Sea-Crossing Bridge%苏拉马都大桥引桥抗震分析

    Institute of Scientific and Technical Information of China (English)

    郭河; 范轶峰

    2011-01-01

    苏拉马都大桥是印度尼西哑的一座特大型桥梁,其引桥为预应力混凝土连续箱梁结构,通过V形墩与主桥相连.由于桥址处抗震设防烈度较高,又是跨越马都拉海峡的特大型桥梁,其抗震性能尤为重要.采用两水平的抗震设计方法,从地震输入、地震反应谱分析、非线性时程分析、结构的抗震性能验算等方面对苏拉马都大桥引桥的抗震性能进行分析,结果表明,在2 500年1重现期的地震作用下,该桥的抗震性能均满足抗震设防要求.%Surammadu Bridge is an especially large bridge in Indonesia. Its structure style is prestressed concrete continuous box bridge and links with the main bridge by V-style pier. The seismic performance of Suramadu Bridge is particularly important because of the bridge across the Madula Strait and the high seismic intensity at the bridge site. In this paper, based on the antiseismic design of Suramadu Approach Bridge, seismic behavior of cable-stayed bridge is investigated by two-level earthquake-resistance method from the seismic input, the analysis of earthquake response spectrum, the analysis of nonlinear time history and the checking of structural earthquake-resistance performance. It is indicated that, the resistance of Suramadu Approach Bridge is larger than the requirement under the 2 500-year recurrence interval (2% in 50year) earthquake load.

  2. Bridges in Complex Networks

    CERN Document Server

    Wu, Ang-Kun; Liu, Yang-Yu

    2016-01-01

    A bridge in a graph is an edge whose removal disconnects the graph and increases the number of connected components. We calculate the fraction of bridges in a wide range of real-world networks and their randomized counterparts. We find that real networks typically have more bridges than their completely randomized counterparts, but very similar fraction of bridges as their degree-preserving randomizations. We define a new edge centrality measure, called bridgeness, to differentiate the importance of a bridge in damaging a network. We find that certain real networks have very large average and variance of bridgeness compared to their degree-preserving randomizations and other real networks. Finally, we offer an analytical framework to calculate the bridge fraction and average bridgeness for uncorrelated random networks with arbitrary degree distributions.

  3. Bridge recognition based on Gabor filter in forward-looking infrared images

    Science.gov (United States)

    Liu, Songlin; Sun, Gang; Niu, Zhaodong; Chen, Zengping

    2013-10-01

    Conventional methods often assume that water region is homogeneous and bridge is brighter than background. They usually recognize target by parallel lines detection. But grayscale of bridge has bipolar problem in FLIR images due to interference of complex background and constraints of imaging conditions, which means that it can be greater or lower than river. Furthermore, water is not a homogeneous area as a whole because of the interference of water clutter and shoals. This paper proposes a novel algorithm of bridge recognition based on Gabor filter. Firstly, we obtain target ROI by extracting the horizontal line. And then ROI sub-images are enhanced by Gabor filter and target polarity is determined by bridge body detection. Finally, bridge recognition can be achieved by pier detection according to the target polarity and location of bridge body. Experimental results of nearly 3000 frames show that the proposed algorithm can effectively overcome problems such as bipolar target and low image contrast. It offers a good practicability and accuracy in bridge recognition in FLIR images.

  4. Long-Term Structural Health Monitoring System for a High-Speed Railway Bridge Structure.

    Science.gov (United States)

    Ding, You-Liang; Wang, Gao-Xin; Sun, Peng; Wu, Lai-Yi; Yue, Qing

    2015-01-01

    Nanjing Dashengguan Bridge, which serves as the shared corridor crossing Yangtze River for both Beijing-Shanghai high-speed railway and Shanghai-Wuhan-Chengdu railway, is the first 6-track high-speed railway bridge with the longest span throughout the world. In order to ensure safety and detect the performance deterioration during the long-time service of the bridge, a Structural Health Monitoring (SHM) system has been implemented on this bridge by the application of modern techniques in sensing, testing, computing, and network communication. The SHM system includes various sensors as well as corresponding data acquisition and transmission equipment for automatic data collection. Furthermore, an evaluation system of structural safety has been developed for the real-time condition assessment of this bridge. The mathematical correlation models describing the overall structural behavior of the bridge can be obtained with the support of the health monitoring system, which includes cross-correlation models for accelerations, correlation models between temperature and static strains of steel truss arch, and correlation models between temperature and longitudinal displacements of piers. Some evaluation results using the mean value control chart based on mathematical correlation models are presented in this paper to show the effectiveness of this SHM system in detecting the bridge's abnormal behaviors under the varying environmental conditions such as high-speed trains and environmental temperature.

  5. 桥梁抗震结构计算%Anti-seismic Structure Calculation of Bridge

    Institute of Scientific and Technical Information of China (English)

    许鹏

    2012-01-01

    依托工程实例,对桥墩进行抗震计算,不仅可以更深入的理解抗震规范,而且定性地总结出利于结构抗震并且经济可行的结构处理方法。%Based on project case,anti-seismic calculation of bridge pier is performed.Therefore,not only can anti-seismic code be understood deeper,but also economic and feasible structure treatment method in favour of structure seismic resistance can be summarized qualitatively.

  6. Seismic fragility analysis of typical pre-1990 bridges due to near- and far-field ground motions

    Science.gov (United States)

    Mosleh, Araliya; Razzaghi, Mehran S.; Jara, José; Varum, Humberto

    2016-03-01

    Bridge damages during the past earthquakes caused several physical and economic impacts to transportation systems. Many of the existing bridges in earthquake prone areas are pre-1990 bridges and were designed with out of date regulation codes. The occurrences of strong motions in different parts of the world show every year the vulnerability of these structures. Nonlinear dynamic time history analyses were conducted to assess the seismic vulnerability of typical pre-1990 bridges. A family of existing concrete bridge representative of the most common bridges in the highway system in Iran is studied. The seismic demand consists in a set of far-field and near-field strong motions to evaluate the likelihood of exceeding the seismic capacity of the mentioned bridges. The peak ground accelerations (PGAs) were scaled and applied incrementally to the 3D models to evaluate the seismic performance of the bridges. The superstructure was assumed to remain elastic and the nonlinear behavior in piers was modeled by assigning plastic hinges in columns. In this study the displacement ductility and the PGA are selected as a seismic performance indicator and intensity measure, respectively. The results show that pre-1990 bridges subjected to near-fault ground motions reach minor and moderate damage states.

  7. The Multimedia Piers-Harris Children's Self-Concept Scale 2: Its Psychometric Properties, Equivalence with the Paper-and-Pencil Version, and Respondent Preferences.

    Science.gov (United States)

    Flahive, Mon-hsin Wang; Chuang, Ying-Chih; Li, Chien-Mo

    2015-01-01

    A multimedia version of Piers-Harris Children's Self-Concept Scale 2 (Piers-Harris 2) was created with audio and cartoon animation to facilitate the measurement of self-concept among younger children. This study aimed to assess the psychometric qualities of the computer version of Piers-Harris 2 scores, examine its score equivalence with the paper-and-pencil version, and survey the respondent preference of the two versions. Two hundred and forty eight Taiwanese students from the first to fourth grade were recruited. In regard to the psychometric properties, high internal consistency (α = .91) was found for the total score of multimedia Piers-Harris 2. High interscale correlations (.77 to .83) of the multimedia Piers-Harris 2 scores and the results of confirmatory factor analysis suggested the multimedia Piers-Harris 2 contained good structural characteristics. The scores of the multimedia Piers-Harris 2 also had significant correlations with the scores of the Elementary School Children's Self Concept Scale. The equality of convergence and criterion-related validities of Piers-Harris 2 scores for the multimedia and paper-and-pencil versions and the results of ICCs between the scores of the multimedia and paper-and-pencil Piers-Harris 2 suggested their high level of equivalence. Participants showed more positive attitudes towards the multimedia version.

  8. Il Decameron de Pier Paolo Pasolini: da prosa medieval ao roteiro cinematográfico Il Decameron by Pier Paolo Pasolini: from the medieval prose to the screenplay

    Directory of Open Access Journals (Sweden)

    Paula Regina Siega

    2012-12-01

    Full Text Available Este artigo situa-se no campo das teorias da recepção e trabalha com o conceito de "leitura como ato criativo", desenvolvido por Hans Robert Jauss e Wolfgang Iser. Interpretando o roteiro como estrutura textual produtora de imagens literárias, elegemos como objeto de estudo o texto Il Decameron, escrito por Pier Paolo Pasolini com base na obra de Giovanni Boccaccio. Na análise, investigamos os efeitos poéticos produzidos pela releitura do texto medieval, indicando as transformações que o realismo boccacciano assume na linguagem de Pasolini. Para tanto, evidenciamos a importância que as realidades do sexo e da morte adquirem no roteiro, observando como o autor conjuga estes temas às reflexões que faz sobre a própria contemporaneidade.Questo articolo è situato nel campo delle teorie della ricezione e lavora con il concetto di "lettura come atto creativo", sviluppato da Hans Robert Jauss e Wolfgang Iser. Nell'interpretare la sceneggiatura come struttura testuale produttrice di immagini letterarie, scegliamo come oggetto di studio il testo Il Decameron, scritto da Pier Paolo Pasolini basato sull'opera di Giovanni Boccaccio. Nell'analisi, investighiamo gli effetti poetici prodotti dalla rilettura del testo medioevale indicando le trasformazioni che il realismo boccacciano assume nel linguaggio di Pasolini. Pertanto, evidenziamo l'importanza che le realtà del sesso e della morte acquisiscono nella sceneggiatura, osservando come l'autore concilia questi temi con le riflessioni che fa sulla propria contemporaneità.This article is situated in the field of the reception theories and works with the concept of "reading as creative act", developed by Hans Robert Jauss and Wolfgang Iser. Seeing in the screenplay a textual structure that produces literary images, we choose as our object the text Il Decameron, written by Pier Paolo Pasolini based on Boccaccio's work. In the analysis, we investigate the poetic effects produced by the rereading of

  9. Construction craft of climb molding of variable cross-section high piers cantilever support%变截面高墩悬臂支架轻型爬模施工工艺

    Institute of Scientific and Technical Information of China (English)

    王利强

    2011-01-01

    Combining with piers climb molding construction practice of Hukou of the Yellow River large Bridge of Qing-Lan highway Lin-Ji section, summarized the construction technology of construction process, separately made introduction from the process characteristics, process principle, construction key points and other aspects, so as to accumulate relevant construction experience and guide engineering practice.%结合青兰高速临吉段壶口黄河特大桥的墩身爬模施工实践,对施工过程中的施工工艺做了总结,分别从工艺特点、工艺原理、施工要点等方面作了说明,以积累相关施工经验,指导工程实践。

  10. Longitudinal force in continuously welded rail on long-span tied arch continuous bridge carrying multiple tracks

    Institute of Scientific and Technical Information of China (English)

    YAN Bin; DAI Gong-lian; GUO Wen-hua; XU Qing-yuan

    2015-01-01

    Considering arch rib, lateral brace, suspender, girder, pier and track position, the model for the interaction between long-span tied arch continuous bridge and multiple tracks was established by using steel-concrete composite section beam element to simulate concrete-filled steel tube (CFST) arch rib, using the beam element with rigid arm to simulate the prestressed concrete girder and using nonlinear bar element to simulate longitudinal constraint between track and bridge. Taking a (77+3×156.8+77) m tied arch continuous bridge with four tracks on the Harbin-Qiqihar Passenger Dedicated Line as an example, the arrangement of continuously welded rail (CWR) was explored. The longitudinal force in CWR on the tied arch continuous bridge, the pier top horizontal force and torque due to the unbalance load case, were analyzed under the action of temperature, vertical live load, train braking and wind load. Studies show that, it can significantly reduce track displacement to set the track expansion devices at main span arch springing on both sides; the track stress due to arch temperature variation can reach 40.8 MPa; the track stress, pier top horizontal force and torque are related to the number of loaded tracks and train running direction, and the bending force applied to unloaded track is close to the loaded track, while the braking force applied to unloaded track is 1/4 to 1/2 of the loaded track; the longitudinal force of track due to the wind load is up to 12.4 MPa, which should be considered.

  11. Taizhou Yangtze River Bridge

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    Taizhou Bridge lies between Taizhou, Zhenjiang and Changzhou City in Jiangsu Province. The total length of Taizhou Bridge is 62.088 kin. The whole line is designed by freeway codes with six lanes in two directions. The wholeinvestment is 9.37 billion RMB and the planned construction duration is 5.5 years. The main bridge crossing the Yangtze River is a continuous three-pylon two-span suspension bridge with the main span of 1 080 m. The bridge system is realized for the first time and ranks first in the world until now.

  12. Long-Term Structural Health Monitoring System for a High-Speed Railway Bridge Structure

    Directory of Open Access Journals (Sweden)

    You-Liang Ding

    2015-01-01

    Full Text Available Nanjing Dashengguan Bridge, which serves as the shared corridor crossing Yangtze River for both Beijing-Shanghai high-speed railway and Shanghai-Wuhan-Chengdu railway, is the first 6-track high-speed railway bridge with the longest span throughout the world. In order to ensure safety and detect the performance deterioration during the long-time service of the bridge, a Structural Health Monitoring (SHM system has been implemented on this bridge by the application of modern techniques in sensing, testing, computing, and network communication. The SHM system includes various sensors as well as corresponding data acquisition and transmission equipment for automatic data collection. Furthermore, an evaluation system of structural safety has been developed for the real-time condition assessment of this bridge. The mathematical correlation models describing the overall structural behavior of the bridge can be obtained with the support of the health monitoring system, which includes cross-correlation models for accelerations, correlation models between temperature and static strains of steel truss arch, and correlation models between temperature and longitudinal displacements of piers. Some evaluation results using the mean value control chart based on mathematical correlation models are presented in this paper to show the effectiveness of this SHM system in detecting the bridge’s abnormal behaviors under the varying environmental conditions such as high-speed trains and environmental temperature.

  13. Finite element model updating of a prestressed concrete box girder bridge using subproblem approximation

    Science.gov (United States)

    Chen, G. W.; Omenzetter, P.

    2016-04-01

    This paper presents the implementation of an updating procedure for the finite element model (FEM) of a prestressed concrete continuous box-girder highway off-ramp bridge. Ambient vibration testing was conducted to excite the bridge, assisted by linear chirp sweepings induced by two small electrodynamic shakes deployed to enhance the excitation levels, since the bridge was closed to traffic. The data-driven stochastic subspace identification method was executed to recover the modal properties from measurement data. An initial FEM was developed and correlation between the experimental modal results and their analytical counterparts was studied. Modelling of the pier and abutment bearings was carefully adjusted to reflect the real operational conditions of the bridge. The subproblem approximation method was subsequently utilized to automatically update the FEM. For this purpose, the influences of bearing stiffness, and mass density and Young's modulus of materials were examined as uncertain parameters using sensitivity analysis. The updating objective function was defined based on a summation of squared values of relative errors of natural frequencies between the FEM and experimentation. All the identified modes were used as the target responses with the purpose of putting more constrains for the optimization process and decreasing the number of potentially feasible combinations for parameter changes. The updated FEM of the bridge was able to produce sufficient improvements in natural frequencies in most modes of interest, and can serve for a more precise dynamic response prediction or future investigation of the bridge health.

  14. Destrutturare le maiuscole. Pensiero debole, Italian Theory e politica. Conversazione con Pier Aldo Rovatti

    Directory of Open Access Journals (Sweden)

    Pier Aldo Rovatti

    2014-06-01

    Full Text Available The conversation focuses on the social and political role of the philosopher nowadays. Pier Aldo Rovatti discusses about the growing philosophical movement called “Italian Theory” while revisiting his own recent intellectual path. The italian philosopher retraces the cultural experience of the “pensiero debole”, whereof he has been one of the two promoters, and underlines the intellectual and political fight, against all the so-called universal truths (and ideological violences, inspired by this philosophical trend at the beginning of the Eighties. The interview ends with a discussion about the dawning perspectives of the political-philosophical action in the post-modern age.

  15. Observations for a profile of Pier Silverio Leicht as a medievalist

    Directory of Open Access Journals (Sweden)

    Enrico Artifoni

    2015-05-01

    Full Text Available This article offers some reflections about Pier Silverio Leicht’s position in the context of medieval italian studies. Leicht (1874-1956 belonged to the great generation of historians and law historians born in the Seventies of 19th century, but he maintained a specific profile as an historian of legal institutions. Two aspects are particularly investigated: 1 The thought of Leicht on relationship between Germanic legal traditions and Roman law; 2 His contributions on feudalism, Communes and guilds, which are significantly distant from those of Gioacchino Volpe.

  16. Assessing potential scour using the South Carolina bridge-scour envelope curves

    Science.gov (United States)

    Benedict, Stephen T.; Feaster, Toby D.; Caldwell, Andral

    2016-09-30

    SummaryBridge-scour equations presented in the Federal Highway Administration Hydraulic Engineering Circular No. 18 reflect the current state-of-the practice for predicting scour at bridges. Although these laboratory-derived equations provide an important resource for assessing scour potential, there is a measure of uncertainty when applying these equations to field conditions. The uncertainty and limitations have been acknowledged by laboratory researchers and confirmed in field investigations.Because of the uncertainty associated with bridge-scour equations, HEC-18 recommends that engineers evaluate the computed scour depths obtained from the equations and modify the resulting data if they appear unreasonable. Perhaps the best way to evaluate the reasonableness of predicted scour is to compare it to field measurements of historic scour. Historic field data show scour depths resulting from high flows and provide a reference for evaluating predicted scour. It is rare, however, that such data are available at or near a site of interest, making the evaluation of predicted scour as compared to field data difficult if not impossible. Realizing the value of historic scour measurements, the U.S. Geological Survey (USGS), in cooperation with the South Carolina Department of Transportation (SCDOT), conducted a series of three field investigations to collect historic scour data with the goal of understanding regional trends of scour at riverine bridges in South Carolina.Historic scour measurements, including measurements of clear-water abutment, contraction, and pier scour, as well as live-bed contraction and pier scour, were made at more than 200 bridges. These field investigations provided valuable insights into regional scour trends and yielded regional bridge-scour envelope curves that can be used as supplementary tools for assessing all components of scour at riverine bridges in South Carolina.The application and limitations of these envelope curves were documented in

  17. INVESTIGATION OF VEHICLE IMPACT FORCE ON BRIDGE WITH ROUGH RIDING SURFACE

    Directory of Open Access Journals (Sweden)

    O. L. Verbitskaya

    2014-01-01

    Full Text Available Nowadays heavy vehicles constitute a considerable volume in the transportation flow on the territory of the Republic of Belarus and bridge inequalities significantly increase a load on their bearing elements and cause a vibration in bridge superstructures. This leads to rapid wear and reduction in time between bridge repairs. The given problem has been insufficiently studied and it is considered as an actual one. Revision of analytical models is required in order to make prediction and evaluation of bridge structure wear. These models must take into account a dynamic impact of heavy vehicles caused by their movement on bridge rough riding surface.The purpose of scientific investigations is to develop a dynamic interactional model of a vehicle and a bridge plate. The paper proposes such dynamic model that permits to investigate impact forces of a heavy vehicle on bridge superstructures which have been initiated by bridge traffic-way inequalities. Weight of an vehicle and plate, rigidity and viscous damping of vehicle suspensions, a plate and piers have been taken into account while making the required calculations.An analysis of free oscillatory motions of the plate and vehicle have been carried out with due account of viscous damping. A dynamic interactional calculation for a vehicle and a plate has been made in the paper. Character of plate oscillatory motions has been determined at various parameters of the dynamic model. In this case non-linearity of reinforced concrete plate deformation has been taken into account and its calculation has been executed in accordance with the norms of the Republic of Belarus. The calculations have made it possible to obtain dynamic interaction coefficients of front axle wheels and bridge plate at various bench heights and also investigate its influence on maximum bending moments in plate sections.

  18. Real-Time Seismic Monitoring of Thenewcape Girardeau (mo) Bridge and Recorded Earthquake Response

    Science.gov (United States)

    çelebi, Mehmet

    This paper introduces the state of the art, real-time and broad-band seismic monitoring network implemented for the 1206 m [3956 ft] long, cable-stayed Bill Emerson Memorial Bridge in Cape Girardeau (MO), a new Mississippi River crossing, approximately 80 km from the epicentral region of the 1811-1812 New Madrid earthquakes. Design of the bridge accounted for the possibility of a strong earthquake (magnitude 7.5 or greater) during the design life of the bridge. The monitoring network consists of a superstructure and two free-field arrays and comprises a total of 84 channels of accelerometers deployed on the superstructure, pier foundations and free-field in the vicinity of the bridge. The paper also introduces the high quality response data obtained from the network. Such data is aimed to be used by the owner, researchers and engineers to (1) assess the performance of the bridge, (2) check design parameters, including the comparison of dynamic characteristics with actual response, and (3) better design future similar bridges. Preliminary analyses of low-amplitude ambient vibration data and that from a small earthquake reveal specific response characteristics of this new bridge and the free-field in its proximity. There is coherent tower-cabledeck interaction that sometimes results in amplified ambient motions. Also, while the motions at the lowest (tri-axial) downhole accelerometers on both MO and IL sides are practically free-from any feedback from the bridge, the motions at the middle downhole and surface accelerometers are significantly influenced by amplified ambient motions of the bridge.

  19. Nonlinear Stability Analysis of a Composite Girder Cable-Stayed Bridge with Three Pylons during Construction

    Directory of Open Access Journals (Sweden)

    Xiaoguang Deng

    2015-01-01

    Full Text Available Based on the nonlinear stability analysis method, the 3D nonlinear finite element model of a composite girder cable-stayed bridge with three pylons is established to research the effect of factors including geometric nonlinearity, material nonlinearity, static wind load, and unbalanced construction load on the structural stability during construction. Besides, the structural nonlinear stability in different construction schemes and the determination of temporary pier position are also studied. The nonlinear stability safety factors are calculated to demonstrate the rationality and safety of construction schemes. The results show that the nonlinear stability safety factors of this bridge during construction meet the design requirement and the minimum value occurs in the maximum double cantilever stage. Besides, the nonlinear stability of the structure in the side of edge-pylon meets the design requirement in the two construction schemes. Furthermore, the temporary pier can improve the structure stability, effectively, and the actual position is reasonable. In addition, the local buckling of steel girder occurs earlier than overall instability under load in some cable tension stages. Finally, static wind load and the unbalanced construction load should be considered in the stability analysis for the adverse impact.

  20. Sustainable Bridge Infrastructure Procurement

    DEFF Research Database (Denmark)

    Safi, Mohammed; Du, Guangli; Simonsson, Peter

    2016-01-01

    The lack of a flexible but systematic approach for integrating lifecycle aspects into bridge investment decisions is a major obstacle hindering the procurement of sustainable bridge infrastructures. This paper addresses this obstacle by introducing a holistic approach that agencies could use...... to procure the most “sustainable” (lifecycle-efficient) bridge through a fair design-build (D-B) tendering process, considering all the main aspects: life-cycle cost (LCC), service life-span, aesthetic demands and environmental impacts (LCA)....

  1. Bridge Crossing Simulator

    Science.gov (United States)

    2014-10-07

    Requirement BCS Computer-controlled hydraulic actuation system to impart simulated crossing loads on an entire bridge structure undergoing fatigue test ...structure. Bridge test site with prepared embankments corresponding to the span and bank condition requirements of the bridge under test Conduct real...Center (AEC). (5) Sample size and number of crossings required. The number of required simulated crossings to conduct fatigue testing per the

  2. Monitoring of levees, bridges, pipelines, and other critical infrastructure during the 2011 flooding in the Mississippi River Basin: Chapter J in 2011 floods of the central United States

    Science.gov (United States)

    Densmore, Brenda K.; Burton, Bethany L.; Dietsch, Benjamin J.; Cannia, James C.; Huizinga, Richard J.

    2014-01-01

    more prone to erosion or scour. Data collected from multibeam echosounder hydrographic surveys at selected bridges aided State agencies in evaluating the structural integrity of the bridges during the flood, by assessing the amount of scour present around piers and abutments. Hydrographic surveys of the riverbed detected scour depths ranging from zero (no scour) to approximately 5.8 meters in some areas adjacent to North Dakota bridge piers, zero to approximately 6 meters near bridge piers in Nebraska, and zero to approximately 10.4 meters near bridge piers in Missouri. Substructural support elements of some bridge piers in North Dakota, Nebraska, and Missouri that usually are buried were exposed to moving water and sediment. At five Missouri bridge piers the depth of scour left less than 1.8 meters of bed material between the bottom of the scour hole and bedrock. State agencies used this information along with bridge design and construction information to determine if reported scour depths would have a substantial effect on the stability of the structure. Multibeam echosounder hydrographic surveys of the riverbed near pipeline crossings did not detect exposed pipelines. However, analysis of the USGS survey data by pipeline companies aided in their evaluation of pipeline safety and led one company to further investigate the safety of their line and assisted another company in getting one offline pipeline back into operation. Multibeam echosounder hydrographic surveys of the banks, riverbed, and underwater infrastructure at Omaha Public Power District power plants documented the bed and scour conditions. These datasets were used by Omaha Public Power District to evaluate the effects that the flood had on operation, specifically to evaluate if scour during the peak of the flood or sediment deposition during the flood recession would affect the water intake structures. Hydrographic surveys at an Omaha Public Power District electrical transmission tower documented scour so

  3. Design of Non-Navigable Span Bridges of Hutong Changjiang River Bridge%沪通长江大桥非通航孔桥设计

    Institute of Scientific and Technical Information of China (English)

    梅新咏; 侯健; 刘琳杰

    2015-01-01

    沪通长江大桥设计通行4线铁路、6车道高速公路,其非通航孔桥为简支钢桁梁结构 ,桥梁跨度112 m ,全长2 912 m ,其中跨南岸大堤桥梁3跨共336 m、跨北岸大堤桥梁2跨共224 m、跨水中横港沙区段桥梁21跨共2 352 m.非通航孔桥主桁为三片钢主桁结构 ,上层公路桥面由钢纵横梁与混凝土桥面板结合而成 ,下层铁路桥面由下弦各节点处的钢横梁与混凝土槽形梁结合而成.桥墩采用钻孔灌注桩基础 ,墩身采用单箱三室的空心钢筋混凝土结构.%The Hutong Changjiang River Bridge is designed to carry 4-track railways and 6-lane expressways .The non-navigable span bridges of the bridge are the simply-supported steel truss girder structures with span length of 112 m .The bridges are totally 2 912 m long ,of which the part of the bridges to cross the river dyke on the south bank has 3 spans and is 336 m long ,to cross the river dyke on the north bank has 2 spans and is 224 m long and to cross the section of the Henggang Islet in the river has 21 spans and is 2 352 m long .T he main trusses of the bridges are the three steel main truss structures .The upper highway decks are the structures composited by the steel stringers ,steel cross beams and concrete deck slabs while the lower railway decks are the ones composited by the steel cross beams at the panel points at the lower chords and the concrete channel girders .T he foundations for the piers of the bridges are all the bored piles and the pier shafts are the reinforced concrete three-cell single-box hollow structures .

  4. Analysis on influence of seismic travelling wave effect on semi-active control for long-span rigid-continuous bridge

    Institute of Scientific and Technical Information of China (English)

    QI Xing-jun; LI Xiao-jun; ZHOU Guo-liang

    2006-01-01

    The analysis approach of semi-active control for long-span rigid-continuous bridge under seismic travelling wave input is established. Magnetorheological dampers are set on the positions of the bridge bearings. The semi-active control calculation and analysis are performed for a five-span rigid-continuous bridge under seismic travelling waves with different apparent surface velocities. The results indicate that travelling wave effect remarkably influences the uncontrolled seismic responses, the semi-active control seismic responses and vibration control effects for the long-span rigid-continuous bridge. It is disadvantageous to the responses of the beams and the piers under the travelling wave input with lower apparent surface velocity, and travelling wave effect can decrease the vibration control effects evidently. Therefore, the travelling wave effect should be considered for the selection of the parameter values of semi-active control system in order to get the designing control effect.

  5. Bridging the Gap

    OpenAIRE

    Kramer Overgaard, Majken; Broeng, Jes; Jensen, Monika Luniewska; Murdock, Karen; Schmidt, Iben Julie

    2015-01-01

    Bridging the Gap (BtG) is a 2-year project funded by The Danish Industry Foundation. The goal of Bridging the Gap has been to create a new innovation model which will increase the rate at which Danish universities can spinout new technology ventures. Bridging the Gap (BtG) is a 2-year project funded by The Danish Industry Foundation. The goal of Bridging the Gap has been to create a new innovation model which will increase the rate at which Danish universities can spinout new technology ve...

  6. Bridging the Gap

    DEFF Research Database (Denmark)

    Kramer Overgaard, Majken; Broeng, Jes; Jensen, Monika Luniewska;

    Bridging the Gap (BtG) is a 2-year project funded by The Danish Industry Foundation. The goal of Bridging the Gap has been to create a new innovation model which will increase the rate at which Danish universities can spinout new technology ventures.......Bridging the Gap (BtG) is a 2-year project funded by The Danish Industry Foundation. The goal of Bridging the Gap has been to create a new innovation model which will increase the rate at which Danish universities can spinout new technology ventures....

  7. Semiconductor bridge (SCB) detonator

    Science.gov (United States)

    Bickes, Jr., Robert W.; Grubelich, Mark C.

    1999-01-01

    The present invention is a low-energy detonator for high-density secondary-explosive materials initiated by a semiconductor bridge igniter that comprises a pair of electrically conductive lands connected by a semiconductor bridge. The semiconductor bridge is in operational or direct contact with the explosive material, whereby current flowing through the semiconductor bridge causes initiation of the explosive material. Header wires connected to the electrically-conductive lands and electrical feed-throughs of the header posts of explosive devices, are substantially coaxial to the direction of current flow through the SCB, i.e., substantially coaxial to the SCB length.

  8. Design of Cable-Stayed Bridge of Caofeidian Industry Zone Bridge No.1%曹妃甸工业区1号桥斜拉桥设计

    Institute of Scientific and Technical Information of China (English)

    陈亮; 卢永成; 周伟翔; 邵长宇

    2011-01-01

    The Caofeidian Industry Zone Bridge No. 1 is composed of navigable span bridge, non-navigable span bridges and approach bridges and is located in the cold and strong earthquake region in the northern part of China. A summarized account of the design of the navigable span bridge of the bridge is presented herewith. In accordance with the construction conditions and landscape requirements, the navigable span bridge is designed as a single pylon and single cable plane cable-stayed bridge with span arrangement 2 X 138 m, the pylon is the column pylon in shape of boat sail. The anchorage zone in the pylon is the steel anchor box exposed outside the pylon. The main girder is the steel and concrete composite girder having three cells and a single box. The stay cables are made up of φ7 mm galvanized parallel steel wires and the foundation of the pylon pier is the group pile foundation. The research of seismic resistance of the bridge show that for a major single pylon cable-stayed bridge located in the strong earthquake region, the rigid fixity system of pylon, girder and pier should be possibly avoided in order to reduce seismic response of the bridge structure.%曹妃甸工业区1号桥位于北方寒冷强震区,由通航孔桥、非通航孔桥及引桥组成,综述该桥通航孔桥设计.根据建设条件及景观要求,通航孔桥为跨径2×138 m独塔单索面斜拉桥;桥塔为独柱形,造型为船帆式;索塔锚固区采用外露式钢锚箱方案;主梁采用单箱三室钢-混凝土箱形结合梁;斜拉索采用φ7 mm镀锌平行钢丝;桥塔墩采用群桩基础.抗震性能研究表明,强震区大型独塔斜拉桥应尽量避免采用塔、梁、墩固结体系,以减小桥梁结构的地震响应.

  9. Implications of seismic pounding on the longitudinal response of multi-span bridges-an analytical perspective

    Institute of Scientific and Technical Information of China (English)

    Reginald DesRoches; Susendar Muthukumar

    2004-01-01

    Seismic pounding between adjacent frames in multiple-frame bridges and girder ends in multi-span simply supported bridges has been commonly observed in several recent earthquakes. The consequences of pounding include damage to piers, abutments, shear keys, bearings and restrainers, and possible collapse of deck spans. This paper investigates pounding in bridges from an analytical perspective. A simplified nonlinear model of a multiple-frame bridge is developed including the effects of inelastic frame action and nonlinear hinge behavior, to study the seismic response to longitudinal ground motion. Pounding is implemented using the contact force-based Kelvin model, as well as the momentum-based stereomechanical approach, Parameter studies are conducted to determine the effects of frame period ratio, column hysteretic behavior, energy dissipation during impact and near source ground motions on the pounding response of the bridge. The results indicate that pounding is most critical for highly out-of-phase frames and is not significant for frame period ratios greater than 0.7. Impact models without energy dissipation overestimate the displacement and acceleration amplifications due to impact, especially for elastic behavior of the frames. Representation of stiffness degradation in bridge columns is essential in capturing the accurate response of pounding frames subjected to far field ground motion. Finally, it is shown that strength degradation and pounding can result in significant damage to the stiffer frames of the bridge when subjected to large acceleration pulses from near field ground motion records.

  10. Fiber Section Based Flexure-Shear Coupling Analysis Model for RC Thin-Walled Piers%基于纤维截面的弯剪耦联薄壁墩柱模拟模型

    Institute of Scientific and Technical Information of China (English)

    李宁; 李忠献; 谢礼立

    2013-01-01

    Hollow section piers are often used in reinforced concrete(RC)bridges. It has been proved by earthquake damage investigation that the piers may perform flexure-shear coupling behavior,and eventually lead to pier failure and/or collapse. A fiber-section based RC pier simulation model considering flexure-shear coupling effect was pre-sented in this paper. By introducing bi-axial material constitutive relationship into the determination of fiber deforma-tion status,the sectional stiffness for beam column element can be obtained through the integration of fiber responses. Then the flexure-shear coupling Timoshenko beam element was implemented. The cyclic soften membrane model(CSMM)constitutive relationship was adopted for plane bi-axial RC components in the calculation of the nonlinear characteristic of fibers. The concrete uniaxial material model in CSMM was improved. By assuming the compatibility condition between each fiber and making use of the Newton iteration algorithm,the fiber and section responses were determined. At last,a scaled hollow section pier with quasi-static test result was compared with the numerical model,and the results show good agreement. The strength and stiffness degradation and pinching effect caused by flexure-shear coupling effect are captured by this model. And the fiber model shows sufficient accuracy and computational efficiency.%钢筋混凝土(RC)桥墩构件常采用空心截面,震害调查表明其失效模式多表现为弯剪耦联的非线性破坏。本文提出一种基于纤维截面、考虑弯剪耦联变形的混凝土墩柱模拟模型。首先将双轴材料本构引入纤维材料状态的计算,然后通过纤维截面积分,得到适用于 Timoshenko 梁柱单元的截面刚度矩阵,最终实现考虑弯剪耦联效应的梁柱单元。其中,双轴 RC 本构模型采用往复软化薄膜模型(CSMM),并对 CSMM 中单轴混凝土滞回模型进行修正。通过引入纤维

  11. 78 FR 70024 - Draft Environmental Impact Statement for the Modernization and Repair of Piers 2 and 3, Military...

    Science.gov (United States)

    2013-11-22

    ... infrastructure and supporting facilities at Pier 2; upgrades to shore- side roads and electrical infrastructure... resources; socioeconomics; environmental justice and protection of children; cultural resources; and... Availability in the Federal Register by the U.S. Environmental Protection Agency. ADDRESSES: Please...

  12. 33 CFR 334.102 - Sandy Hook Bay, Naval Weapons Station EARLE, Piers and Terminal Channel, restricted area...

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Sandy Hook Bay, Naval Weapons... DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.102 Sandy Hook Bay, Naval Weapons Station EARLE, Piers..., shall be enforced by the Commanding Officer, Naval Weapons Station Earle, and/or other persons...

  13. Vibration based structural assessment of the rehabilitation intervention in r.c. segmental bridge

    Directory of Open Access Journals (Sweden)

    Franchetti Paolo

    2015-01-01

    Full Text Available A vibration based structural assessment campaign was carried out on a r.c. segmental bridge in North East Italy. The bridge has a cantilever static scheme, fixed at the top of the piers and with a hinge at the centre of the span. The particular configuration of the hinge consists in a couple of steel elements, each one composed by a tongue and groove joint. Since the year 1960, the hinge was subjected to consumption and degradation, that caused a malfunctioning of the device. An intervention of rehabilitation of the bridge led to a reinforcement of the existing hinges with the coupling of new metallic devices: new tongue and groove hinges were applied, that by one side allow the horizontal displacements and rotation, by the other side strongly reduce the relative vertical displacements of the two parts of the bridge. A dynamic test campaign was set up in order to assess the effectiveness of the intervention. The principal dynamic parameters were calculated and analysed with respect to the intervention that was realized. The tests clearly showed the effectiveness of the intervention, and helped the designer to have a better understanding of the structural behaviour of the bridge.

  14. Indian practice on estimation of scour around bridge piers—A comment

    Indian Academy of Sciences (India)

    Umesh C Kothyari

    2007-06-01

    Well-laid foundation is mostly provided in road and railway bridges in India over large and medium-sized rivers. The age-old Lacey–Inglis method is used for estimation of the design scour depth around bridge elements such as pier, abutment, guide bank, spur and groyene. Codal provisions are seen to produce too large a scour depth around bridge elements resulting in bridge sub-structures that lead to increased construction costs. Limitations that exist in the codes of practice are illustrated in this paper using examples. The methods recently developed for estimation of the scour are described. New railway and road bridges are required to be built in large numbers in the near future across several rivers to strengthen such infrastructure in the country. It is strongly felt that provisions in the existing codes of practice for determination of design scour depth require immediate review. The present paper provides a critical note on the practices followed in India for estimating the design scour depth.

  15. Principles of Bridge Reliability

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle; Nowak, Andrzej S.

    The paper gives a brief introduction to the basic principles of structural reliability theory and its application to bridge engineering. Fundamental concepts like failure probability and reliability index are introduced. Ultimate as well as serviceability limit states for bridges are formulated...

  16. Shaking table test of a model bridge with sliding type base isolation system; Suberi hoshiki manshin system wo yusuru kyoryo no dotokusei ni kansuru jikkenteki kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Okamoto, S.; Fujii, S.; Ozaki, D. [Taisei Corp., Tokyo (Japan). Technology Research Center; Constantinou, M.; Tsopelas, P. [State Univ. of New York at Buffalo, New York, NY (United States)

    1995-01-21

    The vibration characteristics of a bridge with a sliding type isolation system composed of a sliding bearing and a rubber restoring force device are investigated experimentally. A quarter scale model bridge equipped with elastic piers is used for the model vibration test. It is confirmed that the acceleration created in the bridge beam is decreased satisfactorily by the use of a sliding type base isolation system wherein a rubber restoring force device, having functions of horizontal spring and bridge falling protection, and a sliding bearing, which utilizes the sliding phenomenon between a Teflon plate and a stainless steel sheet, are used in combination. It is confirmed that a very effective isolation effect can be obtained when bearing displacement is controlled within the range in which the reactive force of the rubber restoring force device does not increase rapidly. The residual displacement seems to be small enough and in the range of practical use unless a rubber device with low stiffness is used. It is confirmed that horizontal reactive force can be designed to be distributed optionally by varying the friction coefficient and the stiffness of the rubber restoring force device for each pier. 20 refs., 18 figs., 2 tabs.

  17. Pier Luigi Nervi e la scuola di Ingegneria e Architettura di Bologna

    Directory of Open Access Journals (Sweden)

    Vittorio Cimino

    2012-12-01

    Full Text Available Pier Luigi Nervi (1891-1979, poliedrico progettista, teorico, docente, costruttore e imprenditore, è stato senza dubbio uno dei protagonisti dell’architettura e dell’ingegneria del Novecento. Proprio l’essere riuscito a unire in sé le due figure – ormai da tempo distinte, nella formazione come nella professione – dell’ingegnere e dell’architetto, è stato uno dei fattori-chiave della sua opera, nella quale l’invenzione di nuove forme non è disgiunta dalla capacità di costruirle. Questo profilo interdisciplinare si è costruito negli anni della sua formazione nella Scuola di Applicazione per Ingegneri di Bologna, grazie agli insegnamenti ricevuti dai suoi maestri e alle esperienze di conoscenza e di pratica professionale, orientati a una “cultura politecnica”, alla coraggiosa volontà di sperimentazione e alla conoscenza della realtà tecnica e costruttiva.

  18. The Influence of Pier Stiffness Ratio on the Failure Modes of Masonry Structures

    Directory of Open Access Journals (Sweden)

    Yanru Wang

    2015-01-01

    Full Text Available Masonry structure is the main form of Chinese urban and rural housing construction structure. And heavy casualties and huge economic losses are caused by the damages of masonry structures in the previous destructive earthquake. So the failure modes of masonry structures are analyzed in the paper. ABAQUS software was used; and the Xuankou High School Student Dormitory of masonry structure in Yingxiu town, severely damaged under the Wenchuan earthquake, was taken for example. The influence of the stiffness ratio of pier between windows and spandrel on the failure modes of masonry structures is discussed. The results show that the failure modes in the earthquake could be changed by controlling the stiffness ratio. Suitable stiffness ratio helps proper design of masonry structures.

  19. NLP-PIER: A Scalable Natural Language Processing, Indexing, and Searching Architecture for Clinical Notes.

    Science.gov (United States)

    McEwan, Reed; Melton, Genevieve B; Knoll, Benjamin C; Wang, Yan; Hultman, Gretchen; Dale, Justin L; Meyer, Tim; Pakhomov, Serguei V

    2016-01-01

    Many design considerations must be addressed in order to provide researchers with full text and semantic search of unstructured healthcare data such as clinical notes and reports. Institutions looking at providing this functionality must also address the big data aspects of their unstructured corpora. Because these systems are complex and demand a non-trivial investment, there is an incentive to make the system capable of servicing future needs as well, further complicating the design. We present architectural best practices as lessons learned in the design and implementation NLP-PIER (Patient Information Extraction for Research), a scalable, extensible, and secure system for processing, indexing, and searching clinical notes at the University of Minnesota.

  20. Hydrographic surveys of the Missouri and Yellowstone Rivers at selected bridges and through Bismarck, North Dakota, during the 2011 flood

    Science.gov (United States)

    Densmore, Brenda K.; Strauch, Kellan R.; Dietsch, Benjamin J.

    2013-01-01

    The U.S. Geological Survey (USGS), in cooperation with the North Dakota Department of Transportation and the North Dakota State Water Commission, completed hydrographic surveys at six Missouri River bridges and one Yellowstone River bridge during the 2011 flood of the Missouri River system. Bridges surveyed are located near the cities of Cartwright, Buford, Williston, Washburn, and Bismarck, N. Dak. The river in the vicinity of the bridges and the channel through the city of Bismarck, N. Dak., were surveyed. The hydrographic surveys were conducted using a high-resolution multibeam echosounder (MBES), the RESON SeaBatTM 7125, during June 6–9 and June 28–July 9, 2011. The surveyed area at each bridge site extended 820 feet upstream from the bridge to 820 feet downstream from the bridge. The surveyed reach through Bismarck consisted of 18 miles of the main channel wherever depth was sufficient. Results from these emergency surveys aided the North Dakota Department of Transportation in evaluating the structural integrity of the bridges during high-flow conditions. In addition, the sustained high flows made feasible the surveying of a large section of the normally shallow channel with the MBES. In general, results from sequential bridge surveys showed that as discharge increased between the first and second surveys at a given site, there was a general trend of channel scour. Locally, complex responses of scour in some areas and deposition in other areas of the channel were identified. Similarly, scour around bridge piers also showed complex responses to the increase in flow between the two surveys. Results for the survey area of the river channel through Bismarck show that, in general, scour occurred around river structures or where the river has tight bends and channel narrowing. The data collected during the surveys are provided electronically in two different file formats: comma delimited text and CARIS Spatial ArchiveTM (CSARTM) format.

  1. Bathymetric and velocimetric surveys at highway bridges crossing the Missouri River in and into Missouri during summer flooding, July-August 2011

    Science.gov (United States)

    Huizinga, Richard J.

    2012-01-01

    Bathymetric and velocimetric surveys were conducted by the U.S. Geological Survey, in cooperation with the Kansas and Missouri Departments of Transportation, in the vicinity of 36 bridges at 27 highway crossings of the Missouri River between Brownville, Nebraska and St. Louis, Missouri, from July 13 through August 3, 2011, during a summer flood. A multibeam echo sounder mapping system was used to obtain channel-bed elevations for river reaches ranging from 1,350 to 1,860 feet and extending across the active channel of the Missouri River. These bathymetric scans provide a "snapshot" of the channel conditions at the time of the surveys and provide characteristics of scour holes that may be useful in the development of predictive guidelines or equations for scour holes. These data also may be used by the Kansas and Missouri Departments of Transportation to assess the bridges for stability and integrity issues with respect to bridge scour during floods. Bathymetric data were collected around every pier that was in water, except those at the edge of water, in extremely shallow water, or surrounded by debris rafts. Scour holes were present at most piers for which bathymetry could be obtained, except at piers on channel banks, those near or embedded in lateral or longitudinal spur dikes, and those on exposed bedrock outcrops. Scour holes observed at the surveyed bridges were examined with respect to depth and shape. Although exposure of parts of foundational support elements was observed at several piers, at most sites the exposure likely can be considered minimal compared to the overall substructure that remains buried in bed material; however, there were several notable exceptions where the bed material thickness between the bottom of the scour hole and bedrock was less than 6 feet. Such substantial exposure of usually buried substructural elements may warrant special observation in future flood events. Previous bathymetric surveys had been done at several of the sites

  2. Bridge technology report

    CERN Document Server

    2013-01-01

    Please note this is a Short Discount publication. As LANs have proliferated, new technologies and system concepts have come to the fore. One of the key issues is how to interconnect networks. One means of interconnection is to use a 'bridge'. Other competing technologies are repeaters, routers, and gateways. Bridges permit traffic isolation, connect network segments together and operate at the MAC layer. Further, because they operate at the MAC layer, they can handle a variety of protocols such as TCP/IP, SNA, and X.25. This report focuses on the specific technology of bridging two netw

  3. Docks and Piers, Port of Green Bay docks along the Fox River are complete, Published in 2008, 1:1200 (1in=100ft) scale, Brown County, WI.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Docks and Piers dataset, published at 1:1200 (1in=100ft) scale, was produced all or in part from Orthoimagery information as of 2008. It is described as 'Port...

  4. Bridged Race Population Estimates

    Data.gov (United States)

    U.S. Department of Health & Human Services — Population estimates from "bridging" the 31 race categories used in Census 2000, as specified in the 1997 Office of Management and Budget (OMB) race and ethnicity...

  5. Bridging Humanism and Behaviorism.

    Science.gov (United States)

    Chu, Lily

    1980-01-01

    Humanistic behaviorism may provide the necessary bridge between behaviorism and humanism. Perhaps the most humanistic approach to teaching is to learn how certain changes will help students and how these changes can be accomplished. (Author/MLF)

  6. Germ Cell Intercellular Bridges

    Science.gov (United States)

    Greenbaum, Michael P.; Iwamori, Tokuko; Buchold, Gregory M.; Matzuk, Martin M.

    2011-01-01

    Stable intercellular bridges are a conserved feature of gametogenesis in multicellular animals observed more than 100 years ago, but their function was unknown. Many of the components necessary for this structure have been identified through the study of cytokinesis in Drosophila; however, mammalian intercellular bridges have distinct properties from those of insects. Mammalian germ cell intercellular bridges are composed of general cytokinesis components with additional germ cell–specific factors including TEX14. TEX14 is an inactive kinase essential for the maintenance of stable intercellular bridges in gametes of both sexes but whose loss specifically impairs male meiosis. TEX14 acts to impede the terminal steps of abscission by competing for essential component CEP55, blocking its interaction in nongerm cells with ALIX and TSG101. Additionally, TEX14-interacting protein RBM44, whose localization in stabile intercellular bridges is limited to pachytene and secondary spermatocytes, may participate in processes such as RNA transport but is nonessential to the maintenance of intercellular bridge stability. PMID:21669984

  7. Long Span Bridges in Scandinavia

    DEFF Research Database (Denmark)

    Gimsing, Niels Jørgen

    1998-01-01

    The first Scandinavian bridge with a span of more than 500 m was the Lillebælt Suspension Bridge opened to traffic in 1970.Art the end of the 20th century the longest span of any European bridge is found in the Storebælt East Bridge with a main span of 1624 m. Also the third longest span in Europe...... is found in Scandinavia - the 1210 m span of the Höga Kusten Bridge in Sweden.The Kvarnsund Bridge in Norway was at the completion in 1991 the longest cable-stayed bridge in the world, and the span of 530 m is still thge longest for cable-stayed bridges in concrete. The Øresund Bridge with its sapn of 490...... m is the longest among cable-stayed bridges for both road and railway traffic....

  8. A Multimode Adaptive Pushover Procedure for Seismic Assessment of Integral Bridges

    Directory of Open Access Journals (Sweden)

    Ehsan Mohtashami

    2013-01-01

    Full Text Available This paper presents a new adaptive pushover procedure to account for the effect of higher modes in order to accurately estimate the seismic response of bridges. The effect of higher modes is considered by introducing a minimum value for the total effective modal mass. The proposed method employs enough number of modes to ensure that the defined total effective modal mass participates in all increments of the pushover loading. An adaptive demand curve is also developed for assessment of the seismic demand. The efficiency and robustness of the proposed method are demonstrated by conducting a parametric study. The analysis includes 18 four-span integral bridges with various heights of piers. The inelastic response history analysis is employed as reference solution in this study. Numerical results indicate excellent accuracy of the proposed method in assessment of the seismic response. For most bridges investigated in this study, the difference between the estimated response of the proposed method and the inelastic response history analysis is less than 25% for displacements and 10% for internal forces. This indicates a very good accuracy compared to available pushover procedures in the literature. The proposed method is therefore recommended to be applied to the seismic performance evaluation of integral bridges for engineering applications.

  9. A task analysis of pier side ship-handling for virtual environment ship-handling simulator scenario development

    OpenAIRE

    Grassi, Charles R.

    2000-01-01

    Approved for public release: distribution is unlimited Researchers at the Naval Air Warfare Center Training Systems Divisions (NAWCTSD) in Orlando, FL have developed a testbed for the Conning Officer Virtual Environment (COVE) Ship-handling simulator. The purpose of this task analysis was to provide a workable document that they could use in the development of pier side ship-handling scenarios for their simulator. The task analysis not only identified the general procedures and methodologi...

  10. 缓冲器对钢筋混凝土桥墩撞击性能影响的试验研究%Experimental Research on Effect of Buffer on Impact Performance of Reinforced Concrete Pier

    Institute of Scientific and Technical Information of China (English)

    张南; 许琦; 刘钊; 臧华

    2009-01-01

    The dynamic performance test of reinforced concrete bridge pier model under lateral impact loading was conducted by falling-weight impact equipment to study the action of buffer installed on pier surface on the impact dynamic response of specimen. The buffer effects of different buffers were compared. The main factors that influence the crack propagation and failure pattern of pier under impact load were analyzed. The relation of impact energy with peak dynamic response of specimen and mean impact force was researched. The experimental result proves that the buffers installed can reduce the impact dynamic response of specimen greatly: the peak strain of compressive reinforcement can be decreased by 74.60%, the peak strain of compressive concrete can be decreased by 54.69%, the peak strain of tensile reinforcement can be decreased by 63.02%, the peak deflection at mid-span can be decreased by 57.73%, the anti-crack impact energy can be increased by 180%, the mean impact force of impact body can be decreased by 78.59%. The research result demonstrates that the buffer action of the reasonably designed buffer is effective enough to increase the anti-crash capacity of pier.%采用落锤冲击实验装置,进行钢筋混凝土桥墩模型在侧向撞击荷载下的动力性能试验,研究在桥墩模型表面设置缓冲器对试件撞击动力响应的影响.比较了不同缓冲器的缓冲效果,分析了影响桥墩模型冲击裂缝扩展和破坏模式的主要因素,研究了冲击能量和试件峰值动力响应及撞击体平均冲击力的关系.试验证明,所设置的缓冲器可以较大程度地减少构件的冲击动力响应,对撞击区受压钢筋峰值压应变可降低74.60%,受压混凝土峰值压应变可降低54.69%,受拉钢筋峰值拉应变可降低63.02%,跨中峰值位移可降低57.73%,抗开裂冲击能增加180%,撞击体的平均冲击力可降低78.59%.研究结果表明,经合理设计的缓冲器具有高效的缓冲作用,可用以提高桥墩的抗撞能力.

  11. Estimation of potential scour at bridges on local government roads in South Dakota, 2009-12

    Science.gov (United States)

    Thompson, Ryan F.; Wattier, Chelsea M.; Liggett, Richard R.; Truax, Ryan A.

    2014-01-01

    In 2009, the U.S. Geological Survey and South Dakota Department of Transportation (SDDOT) began a study to estimate potential scour at selected bridges on local government (county, township, and municipal) roads in South Dakota. A rapid scour-estimation method (level-1.5) and a more detailed method (level-2) were used to develop estimates of contraction, abutment, and pier scour. Data from 41 level-2 analyses completed for this study were combined with data from level-2 analyses completed in previous studies to develop new South Dakota-specific regression equations: four regional equations for main-channel velocity at the bridge contraction to account for the widely varying stream conditions within South Dakota, and one equation for head change. Velocity data from streamgages also were used in the regression for average velocity through the bridge contraction. Using these new regression equations, scour analyses were completed using the level-1.5 method on 361 bridges on local government roads. Typically, level-1.5 analyses are completed at flows estimated to have annual exceedance probabilities of 1 percent (100-year flood) and 0.2 percent (500-year flood); however, at some sites the bridge would not pass these flows. A level-1.5 analysis was then completed at the flow expected to produce the maximum scour. Data presented for level-1.5 scour analyses at the 361 bridges include contraction, abutment, and pier scour. Estimates of potential contraction scour ranged from 0 to 32.5 feet for the various flows evaluated. Estimated potential abutment scour ranged from 0 to 40.9 feet for left abutments, and from 0 to 37.7 feet for right abutments. Pier scour values ranged from 2.7 to 31.6 feet. The scour depth estimates provided in this report can be used by the SDDOT to compare with foundation depths at each bridge to determine if abutments or piers are at risk of being undermined by scour at the flows evaluated. Replicate analyses were completed at 24 of the 361 bridges

  12. Research on Motion Performance of the Mobile Double-Causeway Pier System

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Mobile offshore double-causeway pier system, a type of seashore unloading equipment, consists of two groups of multiple connected semi-submersible modules. This structure has wide application because most of the middle or mini type of vessels and ships can be moored to it. Based on the analysis of computational methods of multi-body motion response, a hydrodynamic model is set up and the three-dimensional potential theory in finite depth is adopted to calculate the three-dimensional motion response of this system. The double P-M spectrum is used to analyze the motion response in irregular waves. Different wave directions are specially taken into consideration, due to their various effects to the motion response. Furthermore, the calculated result is compared with that of the experiment, and it is proved that sway, heave, pitch and yaw motion are greatly constrained by mooring system. The comparison also indicates that the model can forecast the motion performance of the target, and that the calculated result can also be used as reference in connector and mooring system design.

  13. 京石客运专线重点桥渡设计综述%The Summary of Important Bridge Design for Beijing-Shijiazhuang Passenger Dedicated Railway

    Institute of Scientific and Technical Information of China (English)

    牛远志

    2015-01-01

    With reference to the design of bridges on Beijing-Shijiazhuang passenger dedicated line, the focus is placed on the end thorn rigid frame, the Liu Xinzhuang rotating continuous beam, the Fifth Ring Road basket arch, the high pier large span rigid turnout beam and the high frame pier. A brief introduction is made to the four kinds of important pier design. The related results may provide references for future high-speed railway construction in China.%结合京石客运专线桥梁设计,着重介绍端刺刚构梁、柳辛庄转体连续梁、五环路提篮拱、高墩大跨刚构道岔梁、高框架墩等5项重点桥渡设计,简要介绍4项重点桥墩设计。相关成果可为今后的中国高速铁路建设提供借鉴。

  14. The aesthetic composite bridge.

    Science.gov (United States)

    Feinman, R A

    1997-01-01

    New developments are constantly introduced in the search for the optimal treatment modality to restore a single anterior tooth. The patient attention has shifted to aesthetics of the restoration, biocompatibility of the dental materials utilized, conservative preparation of the teeth to be restored, and the retention of intact adjacent dentition. The learning objective of this article is to review the methods currently utilized and to present a recently introduced treatment modality--the two-component bridge, which combines the strength and resiliency of composite resin with the aesthetic advantages of porcelain. The technology of the material is reviewed, the predominantly lingual tooth preparation procedures are outlined, and the bridge try-in is described. The advantages of the two-component bridge are presented along with the contraindications and suggestions of careful case selection. Three cases with congenitally missing maxillary lateral incisors in youthful patients are presented to supplement the theoretical outline and to describe and illustrate the clinical procedure.

  15. Istanbul Bridge Conference 2014

    CERN Document Server

    Gülkan, Polat; Mahmoud, Khaled

    2016-01-01

      The book includes peer-reviewed contributions selected from presentations given at the Istanbul Bridge Conference 2014, held from August 11 – 13 in Istanbul, Turkey. It reports on the current challenges in bridge engineering faced by professionals around the globe, giving a special emphasis to recently developed techniques, innovations and opportunities. The book covers key topics in the field, including modeling and analysis methods; construction and erection techniques; design for extreme events and condition assessment and structural health monitoring. There is a balanced presentation of theory, research and practice. This book, which provides the readers with a comprehensive and timely reference guide on current practices in bridge engineering, is intended for professionals, academic researchers and students alike.

  16. Active Control of Suspension Bridges

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    In this paper some recent research on active control of very long suspension bridges, is presented. The presentation is based on research work at Aalborg University, Denmark. The active control system is based on movable flaps attached to the bridge girder. Wind load on bridges with or without...... flaps attached to the girder is briefly presented. A simple active control system is discussed. Results from wind tunnel experiments with a bridge section show that flaps can be used effectively to control bridge girder vibrations. Flutter conditions for suspension bridges with and without flaps...

  17. 港珠澳大桥非通航孔桥钻孔平台施工方案比选%Comparison and Selection of Construction Schemes for Boring Platform of Non-Navigable Span Bridge of Hong Kong-Zhuhai-Macau Bridge

    Institute of Scientific and Technical Information of China (English)

    刘运洪

    2015-01-01

    The non‐navigable span bridge of Contract CB05 of the Hong Kong‐Zhuhai‐Macao Bridge is a 85‐m span steel and concrete continuous composite girder bridge .The foundations for the piers of the bridge are the ones of steel pipe composite piles .At each pier ,6 composite piles are provided and there are totally 372 piles for the whole bridge .In the light of the structural fea‐tures and construction difficulties of the bridge ,the construction schemes of a common boring plat‐form of the"steel pipe piles+ sectional steels" structure (Scheme 1) and an integral boring plat‐form of the"integral steel truss type"structure (Scheme 2) were proposed for construction of the foundations .T hrough comparison of those aspects of the civilization construction ,safety ,environ‐ment protection ,construction efficiency and construction cost ,it was determined that the Scheme 2 should be selected .For the Scheme 2 ,the components of the boring platform were all fabricated in workshop following the standardization requirements and were welded into the integral steel truss structure .The steel truss structure was then transported by ship to the pier site where the structure would be installed or integrally removed for repeated usage at other pier sites by floating crane and at this stage , the construction of the boring platform was completed . The selected Scheme 2 can effectively shorten the time interval of shifting the platform from pier site to pier site and has advantages of high efficiency , safety , environment protection , energy saving and fast speed .%港珠澳大桥CB05标非通航孔桥为跨径85 m的钢-混组合连续梁桥,采用钢管复合桩基础,每墩均由6根钢管复合桩组成,全桥共372根。针对该桥结构特点和施工难点,桩基础施工提出了“钢管桩+型钢”结构的普通钻孔平台(方案1)和“整体桁架式”结构的整体钻孔平台(方案2)施工方案,通过文明施工、安全环保、

  18. BUILDING "BRIDGES" WITH QUALITY ASSURANCE

    Science.gov (United States)

    The papr describes how, rather than building "bridges" across centuries, quality assurance (QA) personnel have the opportunity to build bridges across technical disciplines, between public and private organizations, and between different QA groups. As reviewers and auditors of a...

  19. Existing Steel Railway Bridges Evaluation

    Science.gov (United States)

    Vičan, Josef; Gocál, Jozef; Odrobiňák, Jaroslav; Koteš, Peter

    2016-12-01

    The article describes general principles and basis of evaluation of existing railway bridges based on the concept of load-carrying capacity determination. Compared to the design of a new bridge, the modified reliability level for existing bridges evaluation should be considered due to implementation of the additional data related to bridge condition and behaviour obtained from regular inspections. Based on those data respecting the bridge remaining lifetime, a modification of partial safety factors for actions and materials could be respected in the bridge evaluation process. A great attention is also paid to the specific problems of determination of load-caring capacity of steel railway bridges in service. Recommendation for global analysis and methodology for existing steel bridge superstructure load-carrying capacity determination are described too.

  20. DOE Information Bridge

    CERN Document Server

    United States. Department of Energy. Office of Scientific and Technical Information

    DOE Information Bridge, a component of EnergyFiles, provides free, convenient, and quick access to full-text DOE research and development reports in physics, chemistry, materials, biology, environmental sciences, energy technologies, engineering, computer and information science, renewable energy, and other topics. This vast collection includes over 43,000 reports that have been received and processed by OSTI since January 1995.

  1. Bridging the Technological Gap.

    Science.gov (United States)

    Lazow, Robert; And Others

    The aim of "Bridging the Technological Gap" (BTG), a federally funded demonstration project, is to use microcomputer technology in the rehabilitation of the psychiatrically disabled. Through the use of a custom designed microcomputer software package, clients receive remediation in areas of specific cognitive and behavioral deficits. The project…

  2. Bridging a Cultural Gap

    Science.gov (United States)

    Leviatan, Talma

    2008-01-01

    There has been a broad wave of change in tertiary calculus courses in the past decade. However, the much-needed change in tertiary pre-calculus programmes--aimed at bridging the gap between high-school mathematics and tertiary mathematics--is happening at a far slower pace. Following a discussion on the nature of the gap and the objectives of a…

  3. Bridge over troubled water?

    DEFF Research Database (Denmark)

    Svendsen, Gunnar Lind Haase; Nannestad, Peter; Svendsen, Gert Tinggaard

    2008-01-01

    The problem of integrating non-Western immigrants into Western welfare states is the focus of this paper. To address this issue, we suggest a social capital approach in which we apply the conceptual pair of bridging social capital (BR), which connects an individual to the broader social structure...

  4. Building a Straw Bridge

    Science.gov (United States)

    Teaching Science, 2015

    2015-01-01

    This project is for a team of students (groups of two or three are ideal) to design and construct a model of a single-span bridge, using plastic drinking straws as the building material. All steps of the design, construction, testing and critiquing stages should be recorded by students in a journal. Students may like to include labelled diagrams,…

  5. Building Bridges to China.

    Science.gov (United States)

    Wasta, Stephanie; Scott, Margaret

    1998-01-01

    Describes a theme cycle called "Building Bridges to China" developed for third grade students that focuses on the similarities between the lives of children and families in China and the United States. Explains that the theme cycle addresses the National Geography Standards and three of the National Council for the Social Studies standards. (CMK)

  6. 昌平钢-混凝土结合连续刚构桥的设计与施工%Design and Construction of Steel and Concrete Continuous Composite Rigid Frame of Changping Overpass Bridge

    Institute of Scientific and Technical Information of China (English)

    马立芬; 王冰

    2012-01-01

    The Changping Overpass Bridge is a steel and concrete continuous composite rigid-frame bridge arranged in two continuous units, each being (37 + 60 + 79 + 42. 5) m and (42. 5 + 79 + 42. 5) m. The main girder of the bridge is designed as a steel and concrete composite one, of which the steel box girder is of the single-cell, single-box and vertical web section and the deck slabs are the reinforced concrete structure. The box girder is rigidly fixed with the concrete pier shaft at the intermediate pier and all pier columns of the bridge are the rectangular ones. The fi-nite element program MIDAS Civil was used to establish the calculation model for spatial struc-ture of the whole bridge, the static force of the bridge was calculated and analyzed and the results of the calculation and analysis proved that the stress and structural strength of the box girder could meet the relevant requirements in the codes. To minimize the interference of construction to the traffic under the bridge, the box girder was fabricated in shop and lifted in place at the bridge site. The precast deck slabs were installed by the discontinuous method in the sequence of the parts of the bridge at the midspan first and the parts close to the supports late.%昌平跨线桥采用两联跨度为(37+60+79+42.5)m及(42.5+79+42.5)m的钢-混凝土结合连续刚构型式.该桥主梁为钢-混凝土结合梁,钢箱梁采用单箱单室直腹板截面,桥面板为钢筋混凝土结构,钢箱梁在中墩处与混凝土墩身固结,下部结构墩柱均采用矩形桥墩.采用有限元程序MIDAS Civil建立全桥空间结构计算模型,对该桥进行静力计算分析,结果表明钢箱应力及结构强度均满足规范要求.为减少对桥下交通的影响,该桥钢箱梁采用工厂预制、现场吊装的方法施工,预制桥面板按先跨中后支点的顺序施工,采用间断法安装.

  7. The Bridges of Taishun County

    Institute of Scientific and Technical Information of China (English)

    MaJianhe

    2003-01-01

    The American film The Bridges of Madison County captured the imagination of many Chinese moviegoers with its bittersweet love story and scenes of rustic covered bridges. But the U.S. can't lay sole claim to such spectacular rural sights:China has its own county worldrenowned for unforgettable bridges.

  8. Revised Rules for Concrete Bridges

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle; Jensen, F. M.; Middleton, C.;

    This paper is based on research performed for the Highway Agency, London, UK under the project DPU/9/44 "Revision of Bridge Assessment Rules Based on Whole Life Performance: Concrete Bridges" It contains details of a methodology which can be used to generate Whole Life (WL) reliability profiles....... These WL reliability profiles may be used to establish revised rules for Concrete Bridges....

  9. Research on Reinforcement Technology for Treating Earthquake Disaster of Bridge%桥梁震害加固技术研究

    Institute of Scientific and Technical Information of China (English)

    王丙堤

    2013-01-01

    Research purposes: After the bridge is impacted by earthquake, the main girder will displace, and the girder falling, the earthquake disaster of the bridge pier and the damages of the supporting seat and abutment will happen, resulting in partially or fully losing the load bearing capacity of the bridge. The research was done on regaining the original load bearing capacity of the bridge by adopting the reinforcement technology for the purpose of providing the reference to the similar works. Research conclusions: From the research on the reinforcement technology for treating the earthquake disaster of the Bridge 1 # in Mianzhu of the Deyang - Aba Highway, it can be seen it is very important to do the following works well: (1) The shelling-out and high pressure grouting should be conducted to the crack. (2) The in -site reinforcement and replacement reinforcement should be conducted. (3) The original pier reinforcement and replacement reinforcement should be conducted to the damaged pier. (4) The reinforcement should be conducted to damaged stuck steel plate of the girder. (5) The replacement reinforcement should be conducted to the damaged bridge deck.%研究目的:桥梁受地震影响后,会产生主梁移位和落梁、桥墩震害、支座破坏和桥台损坏等震坏情况,从而导致桥梁承载能力部分减弱,直至全部失去,通过加固技术处理后恢复其原来的设计承载能力,为今后同类工程施工提供借鉴经验.研究结论:本文以德阿公路绵竹段1#桥为背景,对桥梁进行了震害加固技术研究.要重点做好:(1)裂缝的涂刷和高压注浆封闭加固;(2)基础损坏的原位加固和更换加固;(3)桥墩损坏的原墩加固和更换加固;(4)梁体损坏的粘贴钢板加固;(5)桥面破坏的更换加固.

  10. Dynamic Bridge Response for a Bridge-friendly Truck

    Directory of Open Access Journals (Sweden)

    V. Šmilauer

    2004-01-01

    Full Text Available A truck with controlled semi-active suspensions traversing a bridge is examined for benefits to the bridge structure. The original concept of a road-friendly truck was extended to a bridge-friendly vehicle, using the same optimization tools. A half-car model with two independently driven axles is coupled with simply supported bridges (beam, slab model with the span range from 5 m to 50 m. Surface profile of the bridge deck is either stochastic or in the shape of a bump or a pot in the mid-span. Numerical integration in the MATLAB/SIMULINK environment solves coupled dynamic equations of motion with optimized truck suspensions. The rear axle generates the prevailing load and to a great extent determines the bridge response. A significant decrease in contact road-tire forces is observed and the mid-span bridge deflections are on average smaller, when compared to commercial passive suspensions. 

  11. Simulation of multivariate diffusion bridges

    DEFF Research Database (Denmark)

    Bladt, Mogens; Finch, Samuel; Sørensen, Michael

    We propose simple methods for multivariate diffusion bridge simulation, which plays a fundamental role in simulation-based likelihood and Bayesian inference for stochastic differential equations. By a novel application of classical coupling methods, the new approach generalizes a previously...... proposed simulation method for one-dimensional bridges to the mulit-variate setting. First a method of simulating approzimate, but often very accurate, diffusion bridges is proposed. These approximate bridges are used as proposal for easily implementable MCMC algorithms that produce exact diffusion bridges...

  12. Bridging Classroom Language Ethnography

    OpenAIRE

    GRENFELL, MICHAEL JAMES

    2012-01-01

    PUBLISHED Paper #5: Bridging Classroom Language Ethnography, New Literacy Studies and Bourdieu?s Social Philosophy: Principles and Practice The purpose of this paper is to analyze and synthesize the various ways that classroom language ethnography, NLS, and Bourdieu?s social philosophy, were integrated. The goal of the analysis and synthesis is to provide a fresh perspective and fruitful insights on literacy in all its manifestations that provides the foundations for a more robust...

  13. Bridging as Coercive Accommodation

    CERN Document Server

    Bos, J W; Mineur, A M; Bos, Johan; Buitelaar, Paul; Mineur, Anne-Marie

    1995-01-01

    In this paper we discuss the notion of "bridging" in Discourse Representation Theory as a tool to account for discourse referents that have only been established implicitly, through the lexical semantics of other referents. In doing so, we use ideas from Generative Lexicon theory, to introduce antecedents for anaphoric expressions that cannot be "linked" to a proper antecedent, but that do not need to be "accommodated" because they have some connection to the network of discourse referents that is already established.

  14. Metal and PAH concentrations in fruit of Vaccinium angustifolium Ait. (Lowbush Blueberry) : a comparison among Whitney Pier, North Sydney and supermarket

    Energy Technology Data Exchange (ETDEWEB)

    Hale, B. [Guelph Univ., ON (Canada). Dept. of Land Resource Science

    2004-07-01

    The concentration of various metals in the fruit harvested from Lowbush blueberry plants in Whitney Pier, Sydney, Nova Scotia (NS), North Sydney (NS) and supermarket were quantified in this report. The concentrations were compared among the 3 sources to determine whether the metal and Polycyclic Aromatic Hydrocarbons (PAHs) concentrations in the blueberries from Whitney Pier were higher or lower compared to the reference blueberries from North Sydney and the supermarket. Mean values for each of the analytes were compared using analysis of variance (ANOVA). The study determined whether washed berries have lower concentrations of contaminants than unwashed berries. The risk to human health of exposure to metals and PAHs through consumption of blueberry samples was also calculated. It was concluded that concentrations of selenium and zinc are elevated in blueberries from Whitney Pier compared to berries from North Sydney and the supermarket, but are well within safe levels. Other elements such as arsenic, titanium, vanadium, lead, copper and molybdenum were similar, and only thallium was elevated in supermarket berries relative to those from Whitney Pier and North Sydney. Chromium was not detected in any samples. It was determined that there was no risk to human health from exposure to any of the metals analyzed, regardless of whether they were Whitney Pier samples or reference samples. Only 2 PAHs were detected in one of the unwashed samples from Whitney Pier. No PAHs were found in washed berries or unwashed berries from the supermarket or North Sydney. It was concluded that there was no risk to human health from exposure to any of the PAHs. Washed and unwashed samples had similar metal concentrations, indicating that surface contamination did not occur. A full methodology of the testing program was provided. 11 refs., 7 tabs., 2 figs.

  15. 桥梁建设与河道行洪纳潮的适应性分析%Analysis of adaptability for bridge construction and river channel for coursing flood and tide

    Institute of Scientific and Technical Information of China (English)

    徐林春; 赵明登; 张庭荣; 何书琴

    2012-01-01

    Taking a grand bridge engineering for example,the method of combination of one-dimensional river network mathematical model and local river 2-D tidal flow mathematical model is used to calculate and analyze the influence of the bridge on river coursing flood and tide.The problem of adaptability for bridge construction and river coursing flood and tide is discussed from layout of axis,elevation of beam at the bridge bottom,form of pier and cushion cap,combination of the bridge span,degree of water resistance,relation between the pier of the bridge and the dike,etc.Some general suggestions about the arrangement of the bridge pier and cushion cap are proposed to make the bridge construction to adapt the ability of the river flood and tide as far as possible;and the suggestions can be provided to the department of water administration as a reference for administrative licensing.%以某特大桥为例,采用大范围一维网河数学模型与工程局部河道平面二维潮流数学模型相结合的方法,对该特大桥的行洪、纳潮影响进行了计算和分析.从大桥工程的轴线布置、梁底标高、墩台形式、桥跨组合、阻水程度、建设项目与堤防关系等方面论述了跨河桥梁建设与河道行洪、纳潮之间的适应性问题.为减少桥梁建设对河道行洪、纳潮的影响,从桥梁墩台布置等方面提出了指导性建议,使桥梁建设尽可能与河道行洪、纳潮能力相适应,也为水行政主管部门的行政许可提供参考.

  16. Overall Design of Baitanhu Lake Bridge%白潭湖大桥总体设计

    Institute of Scientific and Technical Information of China (English)

    张全阳

    2014-01-01

    基于城市桥梁的景观要求,白潭湖大桥主桥采用纵向对称布置的(150+150) m混凝土独塔斜拉桥的设计方案。桥塔以拱为形态元素,采用椭圆形拱塔结构;主梁采用预应力混凝土单箱三室斜腹板箱梁,人行道置于斜拉索锚固区外侧;斜拉索采用扇形空间双索面布置,主梁上锚固采用混凝土齿块锚固形式,塔上锚固采用混凝土锚块+隔板的锚固形式;过渡墩采用花瓶形板式墩。桥塔采用爬模施工,桥塔横梁采用分节段浇筑,设置2 m合龙段;主梁采用分节段支架现浇施工,共分13个施工节段。有限元计算结果表明,结构受力满足规范要求。%Given the demands of landscape effect of city bridges ,the design scheme of a (150+150) m concrete single pylon cable-stayed bridge that is symmetrically arranged in the longitudinal direction is chosen for the main bridge of Baitanhu Lake Bridge .The pylon which is basically an arch is designed as an elliptic arched pylon structure .The main girder is the prestressed concrete three-cell single box structure with inclined webs .The sidewalk is arranged along the outer side of the anchorage zone of the stay cables . The stay cables are fanned out in spatial double cable planes ,which are anchored to the main girder via concrete teeth ,but anchored to the pylon with the assistance of concrete blocks and bulkheads .T he transitional piers are vase-shaped plate piers . The pylon is constructed by climbing formwork and the pylon cross beam is cast in segments with a 2 m long closure section .The main girder is cast in segments on scaffoldings and a total of 13 construction segments are made .The results of the finite element calculation indicate that the force conditions of the structure can meet the code requirements .

  17. A comparative study between China and U.S. on seismic design philosophy and practice of a long span arch bridge

    Institute of Scientific and Technical Information of China (English)

    Xu Yan; George C Lee; Fan Lichu; Hu Shide

    2006-01-01

    This paper presents the first of a series of case studies on the seismic design of long span bridges (cablestayed bridges, suspension bridges and arch bridges) under a cooperative research project on seismic behavior and design of highway bridges between the State Key Laboratory for Disaster Reduction in Civil Engineering, Tongji University and the Multidisciplinary Center for Earthquake Engineering Research, University at Buffalo. The objective of this series of case studies is to examine the differences and similarities on the seismic design practice of long span bridges in China and the U.S., to identify research needs and to develop design guidelines beneficial to bridge engineers in both countries. Unlike short to medium span bridges, long span bridges are not included in most seismic design specifications, mainly because they are location dependent and structurally unique. In this paper, an available model of a steel tied half through arch bridge with a main span of 550m in China is discussed. Analysis is focused on comparisons of the seismic responses due to different ground motions. Seismic design criteria and seismic performance requirements for long span bridges in both countries were first introduced and compared, and then three near field earthquake records with large vertical components were selected as the excitations to examine the seismic behavior and seismic vulnerability of the bridge. Results show that (1) the selected near field ground motions cause larger responses to key components (critical sections) of the bridge (such as arch rib ends) with a maximum increase of more than twice those caused by the site specific ground motions; (2) piers, longitudinal girders and arch crowns are more vulnerable to vertical motions, especially their axial forces; and (3) large vertical components of near field ground motions may not significantly affect the bridge's internal forces provided that their peak acceleration spectra ordinates only appear at periods

  18. Design of Main Bridge of Xi′nan Bridge in Guigang City,Guangxi%广西贵港西南大桥主桥设计

    Institute of Scientific and Technical Information of China (English)

    李翠霞; 张巨生

    2015-01-01

    广西贵港市西南大桥主桥为(46+88+280+88+46) m双塔双索面预应力混凝土边主梁斜拉桥。主梁采用等高度带悬臂的矩形混凝土边主梁与“工”字形钢横梁相结合的形式,整幅桥面宽36.5m,设双向2.0%横坡。桥塔采用“鱼”状流线弧形框架钢筋混凝土结构,塔柱高102.5 m,采用外侧为“D”形圆弧段的箱形截面。桥塔设上、下横梁,均采用预应力混凝土单箱单室结构。全桥共设136根斜拉索,斜拉索采用φs 15.2 m m镀锌钢绞线索,空间双索面扇形布置。桥塔墩采用分离式基础,上、下游分离式基础中心距34.7 m ,其下各设9根φ2.5 m钻孔桩。承台为正方形钢筋混凝土结构。4号墩顶面设一圆端形塔座。%The main bridge of the Xi′nan Bridge in Guigang City ,Guangxi is a prestressed concrete edge main girders cable‐stayed bridge with double pylons ,double cable planes and with span arrangement (46+88+280+88+46) m .T he main girders of the bridge are of the structural type combining the rectangular concrete edge main girders having constant depth and cantilevers with the I‐shape steel cross beams .The width of the whole bridge deck is 36 .5 m and the deck is provided with dual 2 .0% transverse slopes .A pylon of the bridge is the“fish”‐shape streamlined arc frame reinforced concrete structure that is 102 .5 m in height and the outer side of the pylon is of the“D”‐shape round arc box section .The upper and lower cross beams of the pylon are all the prestressed concrete single‐cell single‐box structures .There are totally 136 stay cables arranged for the whole bridge .The stay cables are the φs 15 .2 mm galvanized steel wire strand cables and are arranged in fan shape and spatial double cable planes .The pylon pier is supported on the sep‐arated foundations .T he center‐to‐center distance of the foundations on the upstream and dow n‐stream sides is 34 .7

  19. Effect of Foundation Stiffness on Seismic Response of Frame Pier%基础刚度对框架墩地震响应的影响

    Institute of Scientific and Technical Information of China (English)

    刘孟云

    2016-01-01

    文章以京沈客专某跨线框架墩为研究对象,运用有限元软件 Midas/civil 建立框架墩的三维空间动力分析模型,研究了基础刚度对框架墩地震反应的影响。对该框架墩在0.5倍基础刚度、1倍基础刚度、2倍基础刚度、3倍基础刚度条件下分别进行多遇地震作用下的弹性时程反应分析,分析基础刚度的变化对框架墩地震反应的影响并总结影响规律。结果表明:(1)框架墩的基础刚度对其自振特性影响显著,自振频率随着基础刚度的增大而增大;(2)基础刚度的变化对框架墩的地震响应影响显著,尤其是对框架墩墩柱的地震响应影响更加明显,其地震响应随着框架墩基础刚度的增加而增加;(3)框架墩的地震响应并不是随着基础刚度线性变化的,当基础刚度较小时框架墩的地震响应变化更明显。%Taking a cross -line frame pier on Beijing -Shenyang passenger dedicated line as the research object,this paper established a spatial dynamic analysis model of frame pier with finite element software Midas/civil and analyzed the effect of foundation stiffness on seismic response of frame pier.Through elastic time history response analysis of the frame pier under earthquake action,which on the condition of 0.5 times of foundation stiffness,1 time of foundation stiffness,2 times of foundation stiffness and 3 times of foundation stiffness.The influence of the change of foundation stiffness on seismic response of frame pier is analyzed and the influence law is summarized.The results show:(1)The foundation stiffness of the frame pier has a significant impact on its free vibration characteristic,and the natural frequency increases with the increase of the foundation stiffness.(2)The change of foundation stiffness has a significant impact on the seismic response of frame pier,especially the seismic response of column of the frame pier,and the seismic response increases

  20. Influence of piers on functional groups of benthic primary producers and consumers in the channel of a subtropical coastal lagoon

    Directory of Open Access Journals (Sweden)

    Paulo Roberto Pagliosa

    2012-03-01

    Full Text Available Artificial habitats have become common in coastal areas worldwide and may influence the structure and functioning of benthic ecosystems. We analyze the influence of piers on the benthic morphofunctional groups of rocky seaweeds and of soft bottom macrofauna in the channel of Conceição Lagoon (southern Brazil. The main impact is a reduction in the luminosity available for photosynthetic activity which is directly related to a decrease in the biomasses of sediment microphytobenthos and of more highly structured macroalgae life-forms. Contrary to expectations, the morphotypes of potentially high biomass productivity, such as articulated coralline, corticated and leathery macroalgae, were in general less abundant and the low biomass foliose and filamentous macroalgae occurred in reference areas but not under the piers. The piers' effects on motile epifauna and infauna functional groups were site-specific and probably related to the general reduction in primary producer organisms in the new habitats. The discretely motile infauna was the only functional group able to thrive under the piers due to their reduced motility and fragile morphological structures, being benefited by the shelter provided by the artificial habitats. Our results showed that the piers might have a negative effect on the base-trophic level organisms responsible for bottom-up controls.Hábitats artificiais têm se tornado comum em áreas costeiras no mundo todo, podendo influenciar a estrutura e funcionamento de ecossistemas bênticos. Nós analisamos a influência de trapiches nos grupos morfofuncionais bênticos de algas associadas a substrato consolidado e de macrofauna em substrato inconsolidado, no canal da Lagoa da Conceição (sul do Brasil. O principal impacto da presença de trapiches é a redução da irradiação disponível para atividade fotossintética, o que está diretamente relacionado com o decréscimo na biomassa microfitobentônica no sedimento e de macroalga

  1. Vulnerability of bridges to fire

    DEFF Research Database (Denmark)

    Giuliani, Luisa; Crosti, C.; Gentili, F.

    2012-01-01

    Even if recent effort in developing methodology and measures for design structures against fire and explosions has been mostly focused on buildings, bridges can also be very sensitive to those actions, as witnesses by some recent bridge accidents, which caused major economic losses and also...... endangered people safety in few cases. Purpose of this paper is making a focus on the state of the art of the research and current regulations concerning the response of bridges to fire. Several cases of bridge fires are reported and a focus is made on the occurrence and consequence of bridge fires......, considering both the costs deriving by structural damages and by limited serviceability and other indirect societal aspects. Few cases of recent bridge fire are reviewed in detail and structural consequences are highlighted, distinguishing between damages directly induced by fire and damages induced by local...

  2. Morphological aspects of myocardial bridges.

    Science.gov (United States)

    Lujinović, Almira; Kulenović, Amela; Kapur, Eldan; Gojak, Refet

    2013-11-01

    Although some myocardial bridges can be asymptomatic, their presence often causes coronary disease either through direct compression of the "tunnel" segment or through stimulation and accelerated development of atherosclerosis in the segment proximally to the myocardial bridge. The studied material contained 30 human hearts received from the Department of Anatomy. The hearts were preserved 3 to 5 days in 10% formalin solution. Thereafter, the fatty tissue was removed and arterial blood vessels prepared by careful dissection with special reference to the presence of the myocardial bridges. Length and thickness of the bridges were measured by the precise electronic caliper. The angle between the myocardial bridge fibre axis and other axis of the crossed blood vessel was measured by a goniometer. The presence of the bridges was confirmed in 53.33% of the researched material, most frequently (43.33%) above the anterior interventricular branch. The mean length of the bridges was 14.64 ± 9.03 mm and the mean thickness was 1.23 ± 1.32 mm. Myocardial bridge fibres pass over the descending blood vessel at the angle of 10-90 degrees. The results obtained on a limited sample suggest that the muscular index of myocardial bridge is the highest for bridges located on RIA, but that the difference is not significant in relation to bridges located on other branches. The results obtained suggest that bridges located on other branches, not only those on RIA, could have a great contractive power and, consequently, a great compressive force, which would be exerted on the wall of a crossed blood vessel.

  3. Modular FRP Composite Bridge Deck

    OpenAIRE

    ECT Team, Purdue

    2007-01-01

    The bridge infrastructure of the United States is in constant need of repair and rehabilitation. It is reported that 43% of the bridges in the USA have been identified as being structurally deficient or functionally obsolete due to corrosion. SuperdeckTM, a non-corrosive fiber reinforced polymer (FRP) composite bridge deck. The Deck is designed and engineered into a lightweight, strong and rigid structure that will not corrode. The deck sections, composed of hexagon and double-trapezoid profi...

  4. Modelling railway bridge asset management

    OpenAIRE

    Le, Bryant Linh Hai

    2014-01-01

    The UK has a long history in the railway industry with a large number of railway assets. Railway bridges form one of the major asset groups with more than 35,000 bridges. The majority of the bridge population are old being constructed over 100 years ago. Many of the bridges were not designed to meet the current network demand. With an expected increasing rate of deterioration due to the increasing traffic loads and intensities, the management authorities are faced with the difficult task of k...

  5. Repair, Evaluation, Maintenance, and Rehabilitation Research Program. In Situ Repair of Deteriorated Concrete in Hydraulic Structures: Epoxy Injection Repair of a Bridge Pier

    Science.gov (United States)

    1990-09-01

    bearing seat. In addition, the top of the con- crete seat was sealed with fiber -reinforced "Black Jack" roof cement that was sloped toward the... fiber reinforced roof cement applied so that the surface slopes to the openings made in the curtain walls. 3. This work should be accomplished before...sox ORt REMARKS ELEATONDEPH EG RaCOV. SAMPLE (DUUWlbj *Am*. moto Jose. dilAh of ENT_ No IM66ifid dt- It60W* glp1 ,r-7vsPe -R TORO, Cra~eA. - CA/c r

  6. 高墩大跨连续刚构桥的Pushover分析%Pushover analysis of high pier and long span continuous steel bridge

    Institute of Scientific and Technical Information of China (English)

    李青宁; 高依强; 朱坤

    2013-01-01

    Pushover法作为一种非线性静立分析方法,在基于结构位移/性能的抗震思想下有更为广泛的应用前景.结合工程实例,对高墩大跨连续刚构桥进行Pushover分析,其结果与非线性时程分析法比较,结果表明该方法对桥梁结构有较好的适用性和发展潜力.

  7. 76 FR 31851 - Safety Zone; Put-in-Bay Fireworks, Fox's the Dock Pier; South Bass Island, Put-in-Bay, OH

    Science.gov (United States)

    2011-06-02

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Put-in-Bay Fireworks, Fox's the Dock Pier; South Bass Island, Put-in-Bay, OH AGENCY: Coast Guard, DHS. ACTION: Temporary final rule. SUMMARY: The..., Put-in-Bay, Ohio. This Zone is intended to restrict vessels from portions of Lake Erie for the...

  8. 33 CFR 334.1050 - Oakland Outer Harbor adjacent to the Military Ocean Terminal, Bay Area, Pier No. 8 (Port of...

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Oakland Outer Harbor adjacent to the Military Ocean Terminal, Bay Area, Pier No. 8 (Port of Oakland Berth No. 10); restricted area. 334..., DEPARTMENT OF DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.1050 Oakland Outer Harbor adjacent...

  9. Structural Design of Multi-Pylon Cable-Stayed Bridge with Corrugated Steel Webs for Chaoyang Bridge in Nanchang%南昌朝阳大桥波形钢腹板多塔斜拉桥结构设计

    Institute of Scientific and Technical Information of China (English)

    陈水生; 钟志斌; 桂水荣; 刘旭政; 钟汉清

    2014-01-01

    The PC composite box girder with corrugated steel webs is applicable to bridges with a variety of structural types ,which exhibits superior durability and economic features as com‐pared with the common concrete box girder .The cable‐stayed bridge with corrugated steel webs is regarded as the type of structure where composite box girder with corrugated steel webs is ingen‐iously used ,making better use of the properties of the two structures . The main navigational bridge of the Chaoyang Bridge in Nanchang is a (79+ 5 × 150+79) m continuous composite box girder cable‐stayed bridge with corrugated steel webs .The bridge has six pylons and the stay ca‐bles are arranged in single cable plane .In addition ,the bridge has two layers of decks ,on the up‐per deck ,dual eight vehicle lanes (four lanes each side) are arranged and pedestrian and non‐mo‐torized vehicle lanes are arranged on the lower deck .Based on the analysis and study undertaken , small side span‐to‐main span ratio was chosen .Due to the multiple pylons ,the load path from the intermediate pylons to the side pylons is long and the effect of ancillary piers in the side spans is minimal ,as a result ,no ancillary piers are installed .In the structural system ,the pylons and the main girder are fixed while the girder and piers are separated .The box girder is 43 .84 m wide , with transverse steel diaphragms .The stay cables are fanned out in single cable plane .The pylon looks like the Chinese character“合“ ,and double bearings are installed at the pylons .T he stay vi‐bration mitigation bearings are used as the vibration mitigation and isolation devices of the super‐structure ,which are installed below the two side pylons .%波形钢腹板PC组合箱梁适用于不同结构形式的桥梁,相比普通混凝土箱梁具有显著的耐久性和经济性,波形钢腹板斜拉桥将波形钢腹板组合箱梁应用到斜拉桥中,充分发挥了2种结构的特点。南昌朝

  10. London Bridge Is Shaking Funny

    Institute of Scientific and Technical Information of China (English)

    1995-01-01

    Bridges generally don’t fall down without warning;they crack first. Searching for cracks is a tedious business,though, and bridge inspectors bave been known to miss them. Charles Farrar,a civil engineer at Los Alamos Na-

  11. Fatigue tests on aluminium bridges

    NARCIS (Netherlands)

    Maljaars, J.; Soetens, F.; Straalen, IJ.J. van

    2004-01-01

    Traffic bridges are subjected to variable loads and should therefore be checked on fatigue. Especially low weight materials, like aluminium, are sensitive to fatigue, because the variable load is a substantial part of the total load. This paper shows the structural design of an aluminium bridge load

  12. Fatigue tests on aluminium bridges

    NARCIS (Netherlands)

    Maljaars, J.; Soetens, F.; Straalen, IJ.J. van

    2005-01-01

    Traffic bridges are subjected to variable loads and should therefore be checked on fatigue. Especially low weight materials, like aluminium, are sensitive to fatigue, because the variable load is a substantial part of the total load. This paper shows the structural design of an aluminium bridge load

  13. Nonlinear Seismic Response Analysis on Concrete-Filled Steel Tubular Frame Piers%框架式钢管混凝土桥墩非线性地震反应分析

    Institute of Scientific and Technical Information of China (English)

    常山; 朱东生; 何发礼

    2013-01-01

    以框架式钢管混凝土桥墩及钢筋混凝土空心薄壁墩为研究对象,采用纤维单元建立了框架式钢管混凝土桥墩及钢筋混凝土空心薄壁墩的非线性动力分析模型,输入3条地震波,计算得到了框架式钢管混凝土桥墩与钢筋混凝土空心薄壁墩的线性及非线性地震时程响应,比较了不同类型桥墩地震响应的差异,讨论了框架式钢管混凝土桥墩的地震反应特点.%Taking concrete-filled steel tubular frame pier and hollow thin-walled pier as the research projects,the dynamic time-history analysis models are established by using the fiber element for concrete-filled steel tubular frame pier and hollow thin-walled pier.By inputting 3 actual seismic waves into the analysis models,the linear and nonlinear time-history response is analyzed respectively.Based on the analysis results,the effect of seismic response for different piers is compared,and seismic response characteristics of frame pier are discussed.The results show that shear response appears linear distribution,moment response represents serrated distribution and axial force response emerges stepwise increase along the column height for frame pier under the action of waves.Shear,moment and axial force response of one column of frame pier are relatively smaller compared with hollow thin-walled pier under the action of waves.

  14. Development of cooperative system bridges

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhe; WAN Qi-bai; SHI Lei

    2008-01-01

    Cooperative system bridges comprise several basic structures that act jointly to improve structural characteristics. We delved into the historical development of cooperative system bridges. Cooperative systems are classified as different-load cooperative systems and same-load cooperative systems by distinguishing the modes of load distribution. For different-load cooperation, individual basic structures are at different positions in the direction along bridge axis and carry the loads separately. While for same-load cooperation, all basic structures overlap in geometrical locations and support the entire loads conjointly. The choosing of span ratios between basic structures, the design of connections of different-load cooperative systems were discussed as well as optimizations of relative rigidity for same-load cooperative systems which greatly influence structural characteristics. The general situation and several structural measurements of several cooperative bridges were demonstrated. This information can assist engineers in developing their concepts in cooperative systems and can lead to more efficient and economical cooperative bridges.

  15. APPLICATION OF STEEL PIPE PILE LOADING TESTS TO DESIGN VERIFICATION OF FOUNDATION OF THE TOKYO GATE BRIDGE

    Science.gov (United States)

    Saitou, Yutaka; Kikuchi, Yoshiaki; Kusakabe, Osamu; Kiyomiya, Osamu; Yoneyama, Haruo; Kawakami, Taiji

    Steel sheet pipe pile foundations with large diameter steel pipe sheet pile were used for the foundation of the main pier of the Tokyo Gateway bridge. However, as for the large diameter steel pipe pile, the bearing mechanism including a pile tip plugging effect is still unclear due to lack of the practical examinations even though loading tests are performed on Trans-Tokyo Bay Highway. In the light of the foregoing problems, static pile loading tests both vertical and horizontal directions, a dynamic loading test, and cone penetration tests we re conducted for determining proper design parameters of the ground for the foundations. Design parameters were determined rationally based on the tests results. Rational design verification was obtained from this research.

  16. Linguistic Barriers and Bridges

    DEFF Research Database (Denmark)

    Thuesen, Frederik

    2016-01-01

    and intercultural communication, this article analyses interviews with 31 employees from two highly ethnically diverse Danish workplaces. The article shows how linguistic barriers such as different levels of majority language competence and their consequent misunderstandings breed mistrust and hostility, whilst......The influence of language on social capital in low-skill and ethnically diverse workplaces has thus far received very limited attention within the sociology of work. As the ethnically diverse workplace is an important social space for the construction of social relations bridging different social...... groups, the sociology of work needs to develop a better understanding of the way in which linguistic diversity influences the formation of social capital, i.e. resources such as the trust and reciprocity inherent in social relations in such workplaces. Drawing on theories about intergroup contact...

  17. Looking Beyond the Bridge

    DEFF Research Database (Denmark)

    Jahn, Elke; Rosholm, Michael

    We perform a comprehensive analysis of the stepping-stone effect of temporary agency employment on unemployed workers. Using the timing-of-events approach, we not only investigate whether agency employment is a bridge into regular employment but also analyze its effect on post-unemployment wages ...... is even more effective in tight labor markets, where firms use agency employment primarily to screen po-tential candidates for permanent posts. Finally, our results suggest that agency employment may improve subsequent match quality in terms of wages and job duration....... and job stability for unemployed Danish workers. We find evidence of large positive treatment effects, particularly for immigrants. There is also some indication that higher treatment intensity increases the likelihood of leav-ing unemployment for regular jobs. Our results show that agency employment...

  18. Lithodynamic processes in the construction area of a bridge across the kerch strait

    Directory of Open Access Journals (Sweden)

    Vvedenskiy Aleksey Rostislavovich

    2016-11-01

    Full Text Available The information about the evolution of the bottom topography in the construction area is necessary in the design and construction of hydraulic structures in sea, as well as information about possible deformations of the bottom caused by both natural reasons and the appearance of new hydraulic objects in the waters. In the given research the authors propose an analysis of lithodynamic processes in the area of the construction of the bridge across the Kerch Strait. Several physico-mathematical models were used for calculation and description of lithodynamic processes in the construction site of the Kerch Bridge. They may be divided into two groups: atmospheric and water. Many important properties of hydrometeorological conditions may be obtained only by modeling. The model WRF is used in the research, which is applied in many foreign and domestic centers for simulation and forecast of regional atmospheric circulation due to its high quality and ease. The main steps of the calculations are provided: beginning with the collection of basic information up to combining the results of numerical experiments on several mathematical models. Special attention is paid to sedimentation and erosion associated with construction of temporary piers and waterways to them.

  19. Numerical Modeling of the Lake Mary Road Bridge for Foundation Reuse Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Sitek, M. A. [Argonne National Lab. (ANL), Argonne, IL (United States); Bojanowski, C. [Argonne National Lab. (ANL), Argonne, IL (United States); Lottes, S. A. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2015-04-01

    This project uses numerical techniques to assess the structural integrity and capacity of the bridge foundations and, as a result, reduces the risk associated with reusing the same foundation for a new superstructure. Nondestructive test methods of different types were used in combination with the numerical modeling and analysis. The onsite tests included visual inspection, tomography, ground penetrating radar, drilling boreholes and coreholes, and the laboratory tests on recovered samples. The results were utilized to identify the current geometry of the structure with foundation, including the hidden geometry of the abutments and piers, and soil and foundation material properties. This data was used to build the numerical models and run computational analyses on a high performance computer cluster to assess the structural integrity of the bridge and foundations including the suitability of the foundation for reuse with a new superstructure and traffic that will increase the load on the foundations. Computational analysis is more cost-effective and gives an advantage of getting more detailed knowledge about the structural response. It also enables to go beyond non-destructive testing and find the failure conditions without destroying the structure under consideration.

  20. Cascaded resonant bridge converters

    Science.gov (United States)

    Stuart, Thomas A. (Inventor)

    1989-01-01

    A converter for converting a low voltage direct current power source to a higher voltage, high frequency alternating current output for use in an electrical system where it is desired to use low weight cables and other circuit elements. The converter has a first stage series resonant (Schwarz) converter which converts the direct current power source to an alternating current by means of switching elements that are operated by a variable frequency voltage regulator, a transformer to step up the voltage of the alternating current, and a rectifier bridge to convert the alternating current to a direct current first stage output. The converter further has a second stage series resonant (Schwarz) converter which is connected in series to the first stage converter to receive its direct current output and convert it to a second stage high frequency alternating current output by means of switching elements that are operated by a fixed frequency oscillator. The voltage of the second stage output is controlled at a relatively constant value by controlling the first stage output voltage, which is accomplished by controlling the frequency of the first stage variable frequency voltage controller in response to second stage voltage. Fault tolerance in the event of a load short circuit is provided by making the operation of the first stage variable frequency voltage controller responsive to first and second stage current limiting devices. The second stage output is connected to a rectifier bridge whose output is connected to the input of the second stage to provide good regulation of output voltage wave form at low system loads.

  1. 工具式围堰在桥梁墩柱维修中的应用%Operation Method of the Tool-typed Recycling Double Wall Steel Cofferdam in Wate-pier Reinforcement Engineering in the Spring Tide of Poor Water

    Institute of Scientific and Technical Information of China (English)

    刘昂; 吴中鑫; 朱慈祥

    2015-01-01

    In this paper,in the engineering background of detection and reinforcement project of the No.14~18 Pier of a bridge,the construction method of the Tool-Typed Double Wall Steel Cofferdam in the bridge of low clearance flyovers which is removable and recyclable in the spring tide of poor wa-ter is introduced.In the method,the factors,the spring tide of poor water,low clearance flyovers, and details of design and fabrication of the steel cofferdams are considered.An application example shows that the method can reduce construction time,cost,energy conservation and environmental protection..%以某桥梁15~18号桥墩检测加固项目为工程背景,介绍了某桥梁高潮差低净空下的工具式可拆卸循环利用双壁钢围堰使用方法,该工具式可拆卸循环利用双壁钢围堰的施工考虑了涨落潮变化、桥下净空较小等环境因素,以及围堰及辅助措施的设计、制作安装。应用证明,该方法具有减少施工工期、降低成本、节能环保等特点。

  2. Torsional instability in suspension bridges: The Tacoma Narrows Bridge case

    Science.gov (United States)

    Arioli, Gianni; Gazzola, Filippo

    2017-01-01

    All attempts of aeroelastic explanations for the torsional instability of suspension bridges have been somehow criticised and none of them is unanimously accepted by the scientific community. We suggest a new nonlinear model for a suspension bridge and we perform numerical experiments with the parameters corresponding to the collapsed Tacoma Narrows Bridge. We show that the thresholds of instability are in line with those observed the day of the collapse. Our analysis enables us to give a new explanation for the torsional instability, only based on the nonlinear behavior of the structure.

  3. Engineering Geological Investigation and Monitor of Jinglan Bridge Reconstruction in LiuZhou%柳州市静兰大桥改建工程地质勘察及监测

    Institute of Scientific and Technical Information of China (English)

    关键超; 韦少典

    2012-01-01

    柳州市静兰大桥改建工程是将一座1992年8月建成通车、总长550m、主桥为5孔90rn跨的钢筋混凝土箱肋拱桥拆除原地重建,使桥面宽度由原来的16.5m扩至31m,桥面标高由原来的97m升高至98.6m。原桥位于河水中的四个桥墩乃利用石灰岩作浅基础形式,潜水录像显示墩基结构基本完好,但原灌浆固结处理溶蚀沟槽里的砾卵石层已不同程度地被淘蚀。通过勘察工作分析,认为经过基底补强处理后,利用旧桥墩建新桥的方案是可行的。%LiuZhou Jinglan Bridge is a Reinforced concrete box arch bridge, the overall length 550m, The main bridge for 5 holes 90m cross and built in August 1992. The project of the bridge reconstruction is to dismantle and rebuild it in the same place and to broaden the width of the bridge from 16.5 to 31 m, heighten the demarcate height from 97m to 98.6m. The shallow basement modalities of the former four piers lying in the river is limestone, as the diving video shows, the framework of the pier foundation is in good condition. But the former gravel pebble stratum in the corrode groove which treated by grouting concretion has been scouring; Through reconnaissance and job analysis, I think it's feasible that build the new bridge which base on the former piers after reinforcing the fundus.

  4. Analysis of seismic response of continuous rigid-frame bridge by considering the effect of the traveling wave%考虑行波效应的连续刚构桥地震响应分析

    Institute of Scientific and Technical Information of China (English)

    徐国英; 李明; 苗玉

    2015-01-01

    以某连续刚构桥为工程背景,运用有限元计算软件ANSYS对其进行数值模拟分析,求出了结构的自振频率、振型等动力参数。选择EL—Centro波作为激励,运用大质量法,采用时程分析法分析行波效应对结构动力响应的影响。分析结果表明:行波效应增大了桥墩的轴力,对桥墩的位移、横桥向弯矩和剪力影响不大,桥墩顺桥向的弯矩和剪力有不同程度的削弱。%Taking a continuous rigid frame bridge as an example,this paper obtained the structure's natural frequencies and virbration modes by using the finite element software ANSYS.Choosing EL-Centro wave as exciation,by way of great mass method and using time-history analysis method ananlysis the effect of traveling wave to structure dynamic response.The analysis results show that the traveling wave effect increases the axial force of the bridge piers and having little effect to the displacement,shear and moment in cross-bridge direction.The moment and shear of the main bridge piers are decresed at various degrees due to the traveling wave effect along the bridge direction.

  5. National Bridge Inventory - National Geospatial Data Asset (NGDA) Bridges

    Data.gov (United States)

    Department of Transportation — The NBI (NTAD 2015) is a collection of information (database) describing the more than 610,000 of the Nation's bridges located on public roads, including Interstate...

  6. Bridge Creek IMW database - Bridge Creek Restoration and Monitoring Project

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The incised and degraded habitat of Bridge Creek is thought to be limiting a population of ESA-listed steelhead (Oncorhynchus mykiss). A logical restoration approach...

  7. Reliability Assessment of Concrete Bridges

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle; Middleton, C. R.

    This paper is partly based on research performed for the Highways Agency, London, UK under the project DPU/9/44 "Revision of Bridge Assessment Rules Based on Whole Life Performance: concrete bridges". It contains the details of a methodology which can be used to generate Whole Life (WL) reliability...... profiles. These WL reliability profiles may be used to establish revised rules for concrete bridges. This paper is to some extend based on Thoft-Christensen et. al. [1996], Thoft-Christensen [1996] et. al. and Thoft-Christensen [1996]....

  8. Application of Microtremor Measurement Techniques to Detection of Structural Damage of an Ancient Arch Bridge%微动测试技术在古建筑拱桥结构检测中的应用①微动测试技术在古建筑拱桥结构检测中的应用

    Institute of Scientific and Technical Information of China (English)

    范岩旻; 车爱兰; 陈峰; 曹永康

    2015-01-01

    the observation of mutation of the vibration mode,quantitative evaluation of the structural damage is performed by comparing the deformation features of the structure after locating where the structural damage has occurred.Based on the experimental analysis of this study and consider-ing the structural characteristics and the present situation of the damage,the observation point is set.The location and form of the damage is qualitatively delimited and the three modal distribu-tions of the Yingxiang Bridge are obtained using microtremors.Comparing the three natural fre-quencies of the numerical results with the microtremor measurements,the significant weaknesses in the whole structure are determined.There is some damage to the Yingxiang Bridge.According to the measurement results,the bridge pier D is damaged most seriously.This indicates that the concrete curing of the middle bridge pier caused the imbalance of stiffness.The Yingxiang Bridge needs reinforcement by concrete,with large amounts in the middle pier of the bridge,to ensure sufficient stiffness to load bearing.In conclusion,microtremor measurements are useful in the detection of damage to ancient arch-bridges.

  9. Overall Design and Study of South and North Bridges of Xiazhang Sea-Crossing Bridge%厦漳跨海大桥南、北汊桥总体设计与研究

    Institute of Scientific and Technical Information of China (English)

    王福敏; 罗强; 李军

    2013-01-01

    厦漳跨海大桥主要由北汊桥、海门岛立交及收费服务区、南汊桥、海平立交四大部分组成,全长9.333 km.为适应复杂的自然与建设条件,对该桥桥位方案进行比选,并对项目中关键控制性工程(北汊主桥、南汊主桥)的桥型方案进行研究.经研究,最终确定北汊主桥采用主跨780m的五跨连续钢箱梁斜拉桥方案,南汊主桥采用主跨300 m的结合梁斜拉桥方案.针对项目中复杂的地质条件、高地震烈度和恶劣的风环境,分别采取设置适应性强的桩基础,对较差的桩基地质注浆;按抗震要求进行构造设计,在主桥塔梁处设置纵向阻尼器,引桥设置减隔震支座;北汊主桥采用一种翼型扶手栏杆、南汊主桥采用分流板抗风等措施进行处理.%The Xiazhang Sea-Crossing Bridge,totally 9.333 km long,is composed of four major parts of the north bridge,Haimen Island interchange and toll service area,south bridge and Haiping interchange.To accommodate the complicated natural and construction conditions of the bridge,the bridge site schemes were compared and the bridge type schemes for the critical control projects (the north and south main bridges) were studied.According to the study,it was finally determined that the 5-span continuous steel box girder cable-stayed bridge with a main span 780 m would be adopted for the north main bridge and the composite girder cable-stayed bridge with a main span 300 m would be adopted for the south main bridge.In consideration of the complicated geologic conditions,high intensity earthquake and harsh wind environment,the well adaptive pile foundations were respectively utilized.For the pile foundations at the locations with poor geology,the foundations would be grouted.The structures of the bridge were designed in compliance with the seismic resistance requirements.At the connections between the pylons and girders of the main bridges,the longitudinal dampers were arranged and on the piers

  10. The Higgs Bridge

    CERN Document Server

    Allen, Roland E

    2013-01-01

    The particle recently discovered at the Large Hadron Collider near Geneva is almost certainly a Higgs boson, the long-sought completion of the Standard Model of particle physics. But this discovery, an achievement by more than six thousand scientists (including students), is actually much more than a mere capstone of the Standard Model. It instead represents a bridge from the Standard Model to exciting discoveries of the future, at higher energies or in other experiments, and to the properties of matter at very low temperatures. The mere existence of a particle with zero spin implies a need for new physics, with the most likely candidate being supersymmetry, which requires that every known particle has a superpartner yet to be discovered. And phenomena similar to the Higgs are seen in superconducting metals and superfluid gases at low temperatures, which extend down to a millionth or even a billionth of a degree Kelvin. So the discovery of a Higgs boson has a central place in our attempts both to achieve a tr...

  11. Mineral bridges in nacre revisited

    CERN Document Server

    Checa, Antonio G; Willinger, Marc-Georg

    2012-01-01

    We confirm with high-resolution techniques the existence of mineral bridges between superposed nacre tablets. In the towered nacre of both gastropods and the cephalopod Nautilus there are large bridges aligned along the tower axes, corresponding to gaps (150-200 nm) in the interlamellar membranes. Gaps are produced by the interaction of the nascent tablets with a surface membrane that covers the nacre compartment. In the terraced nacre of bivalves bridges associated with elongated gaps in the interlamellar membrane (> 100 nm) have mainly been found at or close to the edges of superposed parental tablets. To explain this placement, we hypothesize that the interlamellar membrane breaks due to differences in osmotic pressure across it when the interlamellar space below becomes reduced at an advanced stage of calcification. In no cases are the minor connections between superimposed tablets (< 60 nm), earlier reported to be mineral bridges, found to be such.

  12. The stories of two bridges in Ghana

    DEFF Research Database (Denmark)

    Andreasen, Jørgen

    2004-01-01

    Public participation in bridge building was promoted by un habitat in the village of Mankrong. The neighbouring village did not participate in the construction of their bridge. The first flooding washed the second bridge down while the "participative bridge" stood up....

  13. Scheme of Pressure Boost and Floating Aid for Steel Open Caisson of Main Ship Channel Bridge of Hutong Changjiang River Bridge%沪通长江大桥主航道桥钢沉井增压助浮方案

    Institute of Scientific and Technical Information of China (English)

    余允锋; 邱琼海; 王立忠

    2015-01-01

    The main ship channel bridge of the Hutong Changjiang River Bridge is a double-py-lon continuous steel truss girder cable-stayed bridge with span arrangement (140+462+1 092+462+140) m .T he foundations for the main piers of the bridge are all the open caissons ,of w hich the plan dimensions of the caisson top of the main pier No .29 are 86 .9 m × 58 .7 m and in the plan of the caisson ,24 well holes are arranged .The total height of the caisson of the pier is 115 m and the lower part of the caisson is the steel caisson that is 56 m in height .In the state of free floating , the draught of the steel caisson is 12 .5 m ,the caisson can not be floated out of the shipyard be-cause of the deep draught and has the risk of grounding in the floating .To reduce the draught of the caisson and to keep the pressure in the air cabins of the caisson stable ,the scheme of pressure boost and floating aid for the caisson was proposed ,that was ,12 well holes in the caisson were symmetrically closed to make the well holes the sealed cabins .Meanwhile ,the active pressure boost system was arranged and the air was injected into the cabins from the tops of the closing cov-er plates of the well holes .The pressure boost system was composed of the air compressor ,main air pipes ,branch air pipes ,extension air pipes ,air pressure meters ,check valves ,stop valves and liquid level sensors .By the measures of injecting the air for pressure boost and releasing the air for pressure reduction ,the air pressure in each cabin was controlled .With the scheme of the pressure boost and floating aid ,the steel open caisson of the pier was finally floated out from the shipyard to the pier site only in 3 h and the effect of the scheme implementation was sound .%沪通长江大桥主航道桥为(140+462+1 092+462+140 ) m双塔连续钢桁梁斜拉桥 ,该桥主墩均采用沉井基础 ,其中 ,29号主墩沉井顶平面尺寸为86 .9 m × 58 .7 m ,平面布置24个井孔 ,高115m,下部钢沉井高56

  14. Unseating Damage to Simply Supported Bridges during Wenchuan Earthquake and Design Countermeasures%汶川大地震简支梁桥落梁震害与设计对策

    Institute of Scientific and Technical Information of China (English)

    王东升; 王吉英; 孙治国; 李晓莉

    2011-01-01

    The unseating damage to simply supported bridges and their main influencing factors during the Wenchuan earthquake are summarized. It is found that excepting the earthquake-induced landslide hazard, the earthquake surface rupture, near fault ground motion, punching shear failure of the abutment breast wall, the invalidity of the devices for preventing unseating damage to the bridges and the complex bridge types are main influencing factors leading to the unseating damage to the simply supported bridges. Basic seismic design idea and method to prevent unseating damage to simply supported bridges are presented in this paper, which include: (1) sliding between bridge girders and cap beams is allowed to reduce the seismic actions concentrated on the bridge piers; (2) cap beams with enough seating length are recommended for sliding between girder and pier to avoid unseating damage; (3) shear keys or cable restrainers should be used as added measures to prevent unseating damage. The design method for simply supported bridges with cable restrainers is illustrated in detail by using current seismic design code for bridges.%总结了5· 12汶川大地震中简支梁桥落梁震害及主要影响因素,发现除地震山体滑坡等地质灾害外,断层地表破裂、近断层地震动效应、桥台胸墙冲切破坏、防落梁构造措施单一及桥梁体型复杂等因素都是引起简支梁桥落粱震害的重要原因.提出了简支梁桥防落梁设计的基本理念及相关技术方案要点为允许墩梁间发生滑移,以降低桥墩承受的地震惯性力,以及盖梁提供允许的最大滑移长度及支座支承宽度,再辅助挡块或拉索限位器等共同防止落粱发生.最后结合现行规范,以拉索限位器为例给出了简支梁桥防落梁设计方法.

  15. «O utinam anima mea esset in corpore tuo!». Pier Damiani, l’amicitia monastica e la riforma

    Directory of Open Access Journals (Sweden)

    Umberto Longo

    2010-06-01

    Full Text Available L'amicizia si esprimeva attraverso la densissima serie di relazioni di Pier Damiani con una folla di interlocutori, a cominciare dai membri della sua comunità per finire con i monaci di Cassino e Cluny. Una speciale sensibilità emotiva e la condivisione di peculiari comportamenti ascetici e penitenziali alimentavano la forza vincolante che orientava la ristretta cerchia degli asceti seguaci di Pier Damiani a sviluppare, attorno alla passione di Gesù, una teologia per cercare di vivere la propria carne. Per quanto riguarda gli anni '60 del secolo XI si cerca di estendere la proposta di perfezione ascetica di questa cerchia, in particolare verso il monachesimo di Cassino.

  16. Redundancy Evaluation of Fracture Critical Bridges

    OpenAIRE

    Bapat, Amey Vivek

    2014-01-01

    Cases of brittle fractures in major bridges prompted AASHTO to publish its first fracture control plan in 1978. It focused on material and fabrication standards, and required periodic 24-month hands-on inspection of bridges with fracture critical members. The practical result of this plan was to significantly increase the life cycle cost of these bridges, rendering them uneconomical. Apart from the Point Pleasant Bridge that failed in 1967, no other bridge has collapsed in the USA following a...

  17. 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...... scenarios outlined. LCA study is performed with the ReCiPe methodology with life cycle inventories data from public database. Five selected mid-point level impact categories and the energy consumption are presented. The result shows that the steel bridge has a better environmental performance due...... to the recycling strategy, while the initial material manufacture is the most dominant phase that contributes large environmental impact in both design solutions....

  18. Simulation Study of Day-Night Variations in Emissions Impacts and Network Augmentation Schemes: An Application to PierPASS Policy for Port Trucks in California

    OpenAIRE

    Bhagat, Ankoor

    2014-01-01

    Freight operations are critical to our prosperity, but they also generate substantial external costs in the form of additional congestion, air pollution, and health impacts. Unfortunately these external costs are not well understood. In this dissertation, I focus on the drayage trucks that serve the San Pedro Bay Ports (or SPBP, i.e. the Ports of Los Angeles and Long Beach in Southern California), which is the largest port complex in the country. This research focuses on the PierPASS program,...

  19. 连续刚构桥顺桥向非线性地震反应研究%Nonlinear Seismic Response of Continuous Rigid Frame Bridge in Longitudinal Direction

    Institute of Scientific and Technical Information of China (English)

    曾金明; 朱东生; 张永水; 张洁

    2012-01-01

    Taking a high-pier and long-span continuous rigid frame bridge as the research project, the dynamic time-history analysis model is established by using the fiber element. By inputting the actual seismic waves in longitudinal direction of different site conditions into the analysis model, their nonlinear time-history responses are analyzed respectively. Based on the analysis results, the effects of seismic response due to different site conditions are compared. And some problems needing attention in seismic design of continuous rigid bridge are pointed out. And the effect of axial compression ratio on hys-teretic behavior of pier is also discussed.%以一座大跨高墩连续刚构桥为对象,采用纤维单元,建立该桥的动力分析模型,沿顺桥方向分别输入不同类型场地上的实际地震动,计算其非线性时程响应.比较了场地条件对大跨高墩连续刚构桥地震响应的影响,指出了连续刚构桥墩高差异较大时抗震设计中应注意的问题,并讨论了轴压比对桥墩滞回性能的影响.

  20. Design of (2í64)m T Shaped Rigid Frame Bridge on Huangling-Hancheng-Houma Railway%黄韩侯铁路2×64m T形刚构桥设计

    Institute of Scientific and Technical Information of China (English)

    鄢玉胜

    2014-01-01

    This paper studies the design main points of T shaped rigid frame bridge with double thin-wall pier. Relying on the design of 2í64m T shaped rigid frame bridge on the Huangling-Hancheng-Houma Railway, using finite element analysis, this paper introduces the characteristics of internal forces of the cross-brace. The study shows that arc shaped pre-stressed cross-brace can a better solution for the design of the cross-brace reinforcement for double thin wall piers.%重点研究双薄壁桥墩T形刚构桥的设计要点。依托黄韩侯铁路2×64m T形刚构桥,采用有限元分析方法,建立全桥模型进行计算,研究桥墩横撑内力特性,采用圆弧形预应力横撑能较好地解决双薄壁桥墩横撑配筋设计。

  1. The Akashi Kaikyo Bridge and the Storebælt Bridge

    DEFF Research Database (Denmark)

    Gimsing, Niels Jørgen

    1999-01-01

    With the completion of the Akashi Kaikyo Bridge and the Storebælt East Bridge the development of the suspension bridge technology in the 20th century has manifested itself in two impressive structures. With the present echnology may bridges of similar (and also more modest) dimensions...... will undoubtedly be built far into the next century. For bridges going beyond the spans of existing bridges it is, however, likely that new concepts will be developed....

  2. River ice jams at bridges

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, D. [New Brunswick Dept. of Transportation, Fredericton, NB (Canada); Beltaos, S. [National Water Research Institute, Burlington, ON (Canada)

    2000-12-01

    Ice jamming, known to cause high water levels at even moderate river flows, is described as both the main and least understood source of ice-related bridge damages. This paper describes a joint study by the New Brunswick Department of Transportation, the Department of the Environment, local governments, and the National Water Research Institute, designed to address problems associated with the interaction of ice jams and bridges. The study consists of collecting information at each of four sites in New Brunswick including: historical data on ice jam locations, causes, and water levels; channel bathymetry, width and slope within each study centred at the respective bridge; and documentation of ice conditions throughout the ice season, including measurement of ice cover thickness, observation of breakup mechanisms, times, causes, characteristics and possible impacts of ice jam release. Data analysis will include determination of high stages due to ice jams or surges caused by upstream ice jam releases, scour potential of surges, and quantification of the structure's capacity to restrain ice movement and to cause jams. The principal objective of the study is to advance beyond empiricism and to develop rational design criteria for bridges by anticipating the effects of climate changes and by incorporating local meteorological and hydrometric records into bridge design for added safety.

  3. Floating liquid bridge charge dynamics

    Science.gov (United States)

    Teschke, Omar; Soares, David Mendez; Gomes, Whyllerson Evaristo; Valente Filho, Juracyr Ferraz

    2016-01-01

    The interaction of liquid with electric fields is investigated in a configuration where up to 13 kV are applied between electrodes resulting in a 106 V/m electric field in the capillaries and where there is the formation of a free-standing fluid bridge in the interelectrode gap. The Mott-Gurney equation was fitted to the measured ionization current vs applied voltage curve which indicates that the ionization rate at the high-voltage anode electrode dimethylsulfoxide (DMSO) interface and space charging in the interelectrode gap determine the floating liquid bridge current for a given cathode-to-anode voltage. Space charge effects were measured in the cathode becker and also at the liquid bridge since the ionized charges at the anode migrate to the bridge outer surface and decrease the interfacial tension from 43 mJ/m2 to 29 mJ/m2. Two distinct structural regions then form the bridge, a charged plastic (bulk modulus ˜100 MPa) conducting outer layer with a surface conductivity of ˜10-9 Ω-1, which shapes and supports the floating fluid structure, and an inner liquid cylinder, where DMSO molecules flow.

  4. A strange bridge by Leonardo

    CERN Document Server

    Huylebrouck, Dirk

    2013-01-01

    On folio 855 recto of the Codex Atlanticus, Leonardo da Vinci drew three 'easily movable' bridges, but one of them is enigmatic: all 'replicas' in Leonardo museums and exhibitions come as a surprise, to say the least, to any engineer or architect whose attention is drawn to it. This is the case for models in Amboise (France), Chicago and Portland (USA), Florence (Italy) and for the one of the traveling exhibition by the Australian company 'Grande Exhibitions' that already visited 40 major cities in the world. All 'replicas' of the bridge model attributed to Leonardo have pillars standing on the deck of the bridge, while the deck is suspended by cables attached on these pillars. At first sight this problem does not catch the attention of the observer, as the bridge seems to be a mixed form of a beam and a suspension bridge, but it was not overlooked by my colleague architect-engineer Dr. Laurens Luyten (Gent, Belgium). Yet, after a TV-interview in Brussels so much pressure was exerted by some of the museum col...

  5. 3D NUMERICAL SIMULATION ON WATER AND AIR TWO-PHASE FLOWS OF THE STEPS AND FLARING GATE PIER

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ting; WU Chao; LIAO Hua-sheng; HU Yao-hua

    2005-01-01

    A new-style flood discharging dam, which consolidates the flaring gate pier and the stepped spillway for discharging the flood through the dam surface, had been applied in China. The theoretical study on it is in a beginning stage at present. The three-dimensional numerical simulation has not been reported. In this paper, the 3D numerical calculation on the two-phase flow of water and air with discharge per unit width 195m3/s* m is presented . The results indicate that there is negative pressure on the juncture of the spillway surface and the first step. There forms obvious longitudinal and transverse eddies on the steps and the velocity decreases obviously compared with the smooth spillway. The figures of the velocity distributions and the water-air two-phase flows are plotted. The results calculated on the pressure are in agreement with the experimental data. Based on the position of the negative pressure obtained from calculation, measurement points of pressure are arranged in physical model. The experimental results validate the existence of the negative pressure. Being an applied and trial study, the results obtained are of theoretical and practical significance.

  6. Thermal bridges of modern windows

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan de Place; Møller, Eva B.; Nielsen, Anker

    2013-01-01

    With its focus on reduced energy consumption, contemporary housing construction requires a highly insulated and airtight building envelope with as few thermal bridges as possible.Windows must be carefully designed, as thermal bridges can lead to surface condensation or mold growth, even...... if the window has an U-factor of 1 W/(m2·K) or lower. This paper describes the development of modern, energy efficient Danish windows with reduced thermal bridges. It focuses on materials, geometry, and sealing of window panes based on a literature review. Examples of modern windows are presented. Experience...... with the minimum acceptable surface temperature regarding surface condensation or mold growth, implemented in the Danish Building Regulations in 2010, and the calculation method for this temperature based on international standards is discussed. The introduction of the minimum acceptable surface temperature has...

  7. An Expert System for Concrete Bridge Management

    DEFF Research Database (Denmark)

    Brito, J. de; Branco, F. A.; Thoft-Christensen, Palle

    1997-01-01

    management systems are presently being implemented by bridge authorities in several countries. The prototype of an expert system for concrete bridge management is presented in this paper, with its functionality relying on two modules. The inspection module relies on a periodic acquisition of field......The importance of bridge repair versus new bridge construction has risen in recent decades due to high deterioration rates that have been observed in these structures. Budgets both for building new bridges and keeping the existing ones are always limited. To help rational decision-making, bridge...

  8. 乌苏大桥主桥上部结构设计与计算%Design and Calculation of Superstructure of Main Bridge of Wusu Bridge

    Institute of Scientific and Technical Information of China (English)

    康晋; 肖海珠; 徐伟

    2011-01-01

    The main bridge of the Wusu Bridge is a single pylon and single cable plane cablestayed bridge with span arrangement (140+140) m and with a structural system of rigid fixity of the pylon, pier and girder. A summarized account of the design and calculation of the superstructure of the bridge is presented herewith. The main girder of the bridge is a composite girder with long cantilevers, the central part of the girder is designed as a two-cell and single-box steel girder and the steel cantilever at each side of the girder is the variable depth I-beam and is provided wiht a trough stringer at the far side, which are all topped with 25 cm thick concrete deck slabs connected with the girder via shearing studs. The part of the main girder close to the pylon is designed as a prestressed concrete box girder to facilitate the fixity of the girder with the pylon. The pylon is the single column pylon, 117 m in height. The stay cables, made up of low relaxation galvanized high strength parallel steel wire strands, are of the harp pattern cable plane arranged in the central alignment of the bridge deck. The finite element software MIDAS Civil 2006 and the SCDS programme are employed to calculate and analyze structure of the bridge. The results of the calculation and analysis indicate that the static, stability and dynamic characteristics of the bridge can meet the requirements in the relevant codes.%乌苏大桥主桥为独塔单索面斜拉桥,跨径布置为(140+140) m,采用塔、墩、梁固结体系,综述该桥上部结构设计与计算.主梁为带大挑臂的钢箱结合梁,中间钢箱梁采用单箱双室截面,两侧钢挑臂为变高度工字形梁,挑臂端部设槽形小纵梁;混凝土桥面板厚25 cm,与钢梁通过剪力钉连接;塔根部主梁采用预应力混凝土箱梁,以方便与桥塔固结;桥塔采用独柱式塔,高117 m;斜拉索为竖琴形中央平行索面布置,采用低松弛镀锌高强度平行钢丝束.采用有限元软件MIDAS Civil

  9. Excitation Methods for Bridge Structures

    Energy Technology Data Exchange (ETDEWEB)

    Farrar, C.R.; Duffy, T.A.; Cornwell, P.J.; Doebling, S.W.

    1999-02-08

    This paper summarizes the various methods that have been used to excited bridge structures during dynamic testing. The excitation methods fall into the general categories of ambient excitation methods and measured-input excitation methods. During ambient excitation the input to the bridge is not directly measured. In contrast, as the category label implies, measured-input excitations are usually applied at a single location where the force input to the structure can be monitored. Issues associated with using these various types of measurements are discussed along with a general description of the various excitation methods.

  10. Balanced bridge feedback control system

    Science.gov (United States)

    Lurie, Boris J. (Inventor)

    1990-01-01

    In a system having a driver, a motor, and a mechanical plant, a multiloop feedback control apparatus for controlling the movement and/or positioning of a mechanical plant, the control apparatus has a first local bridge feedback loop for feeding back a signal representative of a selected ratio of voltage and current at the output driver, and a second bridge feedback loop for feeding back a signal representative of a selected ratio of force and velocity at the output of the motor. The control apparatus may further include an outer loop for feeding back a signal representing the angular velocity and/or position of the mechanical plant.

  11. Optimum selection on bridge erection with floating crane in East China Sea Bridge and Hangzhou Bay Bridge

    Institute of Scientific and Technical Information of China (English)

    Shunquan Qin; Pu Zhou; Youheng Hua

    2004-01-01

    @@ Introduction With the rapid development of China′s economy, many bridges will be built over the Chinese coastal waters of Pacific Ocean. Among them, construction of East China Sea Bridge has been commenced in June 2001, and will be completed at the end of 2005, Hangzhou Bay Bridge was also started to construct in June 2003(Fig. 1). These two ultralong bridges are designed as twin expressway bridges standing side by side each carries a 3-lane one-way carriageway. The total width is 31.5m and 33.0m respectively. East China Sea Bridge starts from Nanhui District, Shanghai and extends to the Yangshan Deep Water Port Area, which is located at one of the Qiqu Islands. The total length of the bridge is about 31.0 km, in which 25 km are on the sea, and 22 km is in the unnavigable region. Hangzhou Bay Bridge across the mouth of Qiantang River.

  12. Is myocardial bridging a bridge connecting to cardiovascular events?

    Institute of Scientific and Technical Information of China (English)

    LI Jian-jun

    2010-01-01

    @@ Coronary arteries and their major branches usually course on the surface of the heart in the subepicardial tissue. However, a muscle hber overlying the intramyocardial segment of an epicardial coronary artery was defined as myocardial bridging (MB), and subsequently the artery coursing within the myocardium is called a tunneled artery.

  13. 港珠澳大桥青州航道桥工程特点及关键技术%Engineering Characteristics and Key Techniques of Qingzhou Ship Channel Bridge of Hong Kong-Zhuhai-Macao Bridge

    Institute of Scientific and Technical Information of China (English)

    刘明虎; 孟凡超; 李国亮

    2013-01-01

    The Qingzhou Ship Channel Bridge of the Hong Kong-Zhuhai-Macao Bridge is a steel box girder cable-stayed bridge with double pylons and double cable planes.In the design of the bridge,a variety of the new materials,new techniques and new workmanships have been applied.In this paper,the engineering characteristics and key techniques of the bridge are summarized.On the bridge,the steel box girders of the same structural types of the adjacent non-navigable span bridges are fully used as the counterweight and on the outer side spans of the bridge,the stay cables are not installed.The arrangement of the bridge in such a way is well appropriate to the local conditions of the bridge site and has notable comprehensive advantage.The structural support system of the bridge is the three-way system that can ensure the structural performance of the whole bridge to be optimal.The pylons have the crisscross steel struts of the “Chinese Knot” configuration,which are connected with the concrete pylon columns via the connecting boxes in a combined force transmitting mode of “ compression-shear” and the performance of the steel struts and connection is safe and reliable.The foundations for the bridge are the composite piles of variable diameter steel pipes and together with the reinforced concrete in the steel pipes,the composite sections of the piles that are to jointly bear the loads and are cost-saving and rational are formed.The pier shafts are formed by the precast segments.The segments are installed at the site and are connected each other by the φ75 mm thick prestressing bars.The steel box girders are of the optimized streamlined flat sections topped with the orthotropic steel deck plates and the fatigue performance of the girders are quite superior.The stay cables are the ones made up of the parallel steel wires and having tensile strength of 1 860 MPa.%港珠澳大桥青州航道桥为双塔双索面钢箱梁斜拉桥,该桥设计采用了多项新材料、新技术

  14. Seismic vulnerability analysis of regular continuous girder bridges%规则连续梁桥地震易损性研究

    Institute of Scientific and Technical Information of China (English)

    张菊辉; 管仲国

    2014-01-01

    Structural performance indices for regular continuous girder bridges under different damage states were discussed based on the displacement ductility ratio.On the OpenSees platform,a structural dynamic analysis model was established by using nonlinear fiber beam elements.100 earthquake ground motion records were selected,and the nonlinear time-history analysis was performed,thus the fragility curves under different damage states were constructed. Through parametric analysis,the effects of pier height,bearing types and transverse reinforcement ratios on the fragility curves were studied.The results show that the development degree of ductility of the continuous bridge has a great effect on the structural seismic vulnerability.The fragility curves obtained under minor damage and moderate damage seem to be very close;while under extensive damage,the bridge shows a good performance against earthquake forces.With the increase of pier height,the lower level of damage probability of the structure is observed;meanwhile,the improvement in the fragility by using the plate rubber bearings is excellent for a short-pier bridge,but very limited for a high-pier one. The effect of increasing the transverse reinforcement ratio on fragility curves can be neglected for structural damage in early stage,but it can significantly increase the structural capacity from collapse.%基于位移延性比探讨规则连续梁桥在不同损伤状态下的结构性能控制指标;基于OpenSees平台采用纤维模型建立结构动力分析模型,选取100条强震记录通过非线性时程反应分析计算结构地震易损性曲线。研究不同墩高、支座形式及配箍率对结构地震易损性影响,结果表明,连续梁桥的地震易损性受延性发育程度影响较大,发生中等与轻微破坏概率较相近,对严重破坏有较好的耐损性;结构耐损性随墩高的增大而增加;采用板式橡胶支座可显著提高矮墩桥梁的耐损性,对

  15. Architectural engineering of FRP bridges

    OpenAIRE

    Smits, J.E.P.

    2014-01-01

    This paper deals with the use of Fibre Reinforced Polymers (FRP's) in architectural and structural bridge design. The challenges and opportunities that come with this relatively new material are discussed. An inventory is made of recent engineers' solutions in FRP, followed by a discussion on architectural application of FRP's derived from the authors architectural practice.

  16. Bridge Aesthetics and Structural Honesty

    DEFF Research Database (Denmark)

    Gimsing, Niels Jørgen

    1999-01-01

    In bridges the overall form must be chosen with due respect to the transmission of forces if efficient structures shall be created, The design must therefore be governed by experienced structural engineers - in some cases assisted by aesthetic advisers on specific issues. Some basic requirements...

  17. Intercellular bridges in vertebrate gastrulation.

    Directory of Open Access Journals (Sweden)

    Luca Caneparo

    Full Text Available The developing zebrafish embryo has been the subject of many studies of regional patterning, stereotypical cell movements and changes in cell shape. To better study the morphological features of cells during gastrulation, we generated mosaic embryos expressing membrane attached Dendra2 to highlight cellular boundaries. We find that intercellular bridges join a significant fraction of epiblast cells in the zebrafish embryo, reaching several cell diameters in length and spanning across different regions of the developing embryos. These intercellular bridges are distinct from the cellular protrusions previously reported as extending from hypoblast cells (1-2 cellular diameters in length or epiblast cells (which were shorter. Most of the intercellular bridges were formed at pre-gastrula stages by the daughters of a dividing cell maintaining a membrane tether as they move apart after mitosis. These intercellular bridges persist during gastrulation and can mediate the transfer of proteins between distant cells. These findings reveal a surprising feature of the cellular landscape in zebrafish embryos and open new possibilities for cell-cell communication during gastrulation, with implications for modeling, cellular mechanics, and morphogenetic signaling.

  18. Noise Considerations in Resistance Bridges

    DEFF Research Database (Denmark)

    Diamond, Joseph M.

    1963-01-01

    A signal-to-noise analysis is made of the Wheatstone bridge, where the unknown and standard resistors may be at different temperatures, a situation which occurs in resistance thermometry. The limiting condition is assumed to be dissipation in the unknown resistor. It is shown that the ratio arms ...

  19. The Wien Bridge Oscillator Family

    DEFF Research Database (Denmark)

    Lindberg, Erik

    2006-01-01

    A tutorial in which the Wien bridge family of oscillators is defined and investigated. Oscillators which do not fit into the Barkhausen criterion topology may be designed. A design procedure based on initial complex pole quality factor is reported. The dynamic transfer characteristic...

  20. Architectural engineering of FRP bridges

    NARCIS (Netherlands)

    Smits, J.E.P.

    2014-01-01

    This paper deals with the use of Fibre Reinforced Polymers (FRP's) in architectural and structural bridge design. The challenges and opportunities that come with this relatively new material are discussed. An inventory is made of recent engineers' solutions in FRP, followed by a discussion on archit

  1. History of cable-stayed bridges

    DEFF Research Database (Denmark)

    Gimsing, Niels Jørgen

    1999-01-01

    The principle of supporting a bridge deck by inclined tension members leading to towers on either side of the span has been known for centuries. However, the real development of cable-stayed bridges did not begin before the 1950s. Since then the free span has been increased from 183 m...... in the Strömsund Bridge (from 1955) to 890 m in the Tatara Bridge (from 1999)....

  2. Building Bridges One Line at a Time

    Science.gov (United States)

    Grigsby, Cathy Murray

    2012-01-01

    In this article, first-grade students were taught the different kinds of lines that were part of the construction of various bridges--the curved lines of the arches of stone bridges, straight lines connecting the cables of a suspension bridge, vertical lines, horizontal lines, and so on. They gained practice in drawing structures and in fine brush…

  3. Comparison between Modern Violin Bridge and Baroque Violin Bridge by Photoelastic Observation and Frequency Analysis

    Science.gov (United States)

    Matsutani, Akihiro

    2004-05-01

    A comparison between the modern bridge and the baroque bridge of the violin by photoelastic observation was carried out. The relationship between the stress part and the hole is symmetric in the modern and baroque bridges. The measured spectral envelopes of baroque bridges are similar to those of modern bridges in D- or G-strings, and have peaks at a frequency higher than those of modern bridges in E-string. The visualization method as used in this study may provide hints for the design of violin bridges.

  4. Beginning Course Surveys: Bridges for Knowing and Bridges for Being

    Directory of Open Access Journals (Sweden)

    David Starr-Glass

    2011-06-01

    Full Text Available The use of a participant survey, administered at the outset of an online course, can provide information useful in the management of the learning environment and in its subsequent redesign. Such information can clarify participants’ prior experience, expectations, and demographics. But the very act of enquiring about the learner also signals the instructor’s social presence, relational interest, and desire to enter into an authentic dialogue. This study examines the use of participant surveys in online management courses. The first section discusses the informational bridges that this instrument provides. The second section considers survey responses to open-ended questions dealing with student sentiments. This analysis suggests that the survey plays a valuable part in accentuating social presence and in initiating relational bridges with participants.

  5. ESTIMATION OF ECONOMIC EXPEDIENCY OF «BRIDGE-PRE-BRIDGE TERRITORY» SYSTEM

    Directory of Open Access Journals (Sweden)

    A. A. Lapko

    2008-01-01

    Full Text Available The paper considers principles that form «Bridge-Pre-Bridge Territory» system. The method is proposed for calculation of expenses on technical research for development of projects on usage of pre-bridge territories. Usage of site class number for natural conditions makes it possible to estimate investment attractiveness of «Bridge-Pre-Bridge Territory» system.

  6. 33 CFR 115.70 - Advance approval of bridges.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Advance approval of bridges. 115... BRIDGES BRIDGE LOCATIONS AND CLEARANCES; ADMINISTRATIVE PROCEDURES § 115.70 Advance approval of bridges. (a) The General Bridge Act of 1946 requires the approval of the location and plans of bridges...

  7. Performance analysis of LAN bridges and routers

    Science.gov (United States)

    Hajare, Ankur R.

    1991-01-01

    Bridges and routers are used to interconnect Local Area Networks (LANs). The performance of these devices is important since they can become bottlenecks in large multi-segment networks. Performance metrics and test methodology for bridges and routers were not standardized. Performance data reported by vendors is not applicable to the actual scenarios encountered in an operational network. However, vendor-provided data can be used to calibrate models of bridges and routers that, along with other models, yield performance data for a network. Several tools are available for modeling bridges and routers - Network II.5 was used. The results of the analysis of some bridges and routers are presented.

  8. Problems associated with nondestructive evaluation of bridges

    Science.gov (United States)

    Prine, David W.

    1995-05-01

    The US has 542,000 bridges that consume billions of dollars per year in construction, rehabilitation, and maintenance funds and which are the lifelines of US commerce. The 1992 ISTEA (Intermodal Surface Transportation Efficiency Act) mandates the implementation of a quantitative computerized bridge management system by 1996. A prime need of such a system are quantitative bridge inspection methods to feed accurate reliable condition information to the huge database of bridges. Nondestructive evaluation (NDE) will fill a critical need in the implementation of effective bridge management. However, many serious barriers exist to the widespread routine application of this technology to bridges. This paper provides an overview of the typical problems associated with applying NDE to bridges.

  9. Parabolic metamaterials and Dirac bridges

    Science.gov (United States)

    Colquitt, D. J.; Movchan, N. V.; Movchan, A. B.

    2016-10-01

    A new class of multi-scale structures, referred to as `parabolic metamaterials' is introduced and studied in this paper. For an elastic two-dimensional triangular lattice, we identify dynamic regimes, which corresponds to so-called `Dirac Bridges' on the dispersion surfaces. Such regimes lead to a highly localised and focussed unidirectional beam when the lattice is excited. We also show that the flexural rigidities of elastic ligaments are essential in establishing the `parabolic metamaterial' regimes.

  10. Severe ASR damaged concrete bridges

    DEFF Research Database (Denmark)

    Antonio Barbosa, Ricardo; Gustenhoff Hansen, Søren

    2015-01-01

    Technical University of Denmark (DTU) and University of Southern Denmark (SDU) have conducted several full-scale experiments with severe ASR deteriorated bridges. This paper presents few and preliminary results from both the shear tests and the measuring of the material properties. The shear test...... show that the shear capacity is almost unaffected of ASR despite significant reduction in compressive concrete strength. Furthermore, measurements show a significant tensile reinforcement strain developed due to ASR expansion....

  11. Inspection Strategies for Concrete Bridges

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Thoft-Christensen, Palle

    1989-01-01

    In this paper an optimal inspection strategy for concrete bridges based on periodic routine and detailed inspections is presented. The failure mode considered is corrosion of the reinforcement due to chlorides. A simple modelling of the corrosion and of the inspection strategy is presented....... The optimal inspection strategy is determined from an optimization problem, where the design variables are time intervals between detailed inspections and the concrete cover. The strategy is illustrated on a simple structure, namely a reinforced concrete beam....

  12. Cochleates bridged by drug molecules.

    Science.gov (United States)

    Syed, Uwais M; Woo, Amy F; Plakogiannis, Fotios; Jin, Tuo; Zhu, Hua

    2008-11-03

    A new type of cochleate, able to microencapsulate water-soluble cationic drugs or peptides into its inter-lipid bi-layer space, was formed through interaction between negatively charged lipids and drugs or peptides acting as the inter-bi-layer bridges instead of multi-cationic metal ions. This new type of cochleate opened up to form large liposomes when treated with EDTA, suggesting that cationic organic molecules can be extracted from these cochleates in a way similar to multivalent metal ions from metal ion-bridged cochleates. Cochleates can be produced in sub-micron size using a method known as "hydrogel isolated cochleation" or simply by increasing the ratio of multivalent cationic peptides over negatively charged liposomes. When nanometer-sized cochleates and liposomes containing the same fluorescent labeled lipid component were incubated with human fibroblasts cells under identical conditions, cells exposed to cochleates showed bright fluorescent cell surfaces, whereas those incubated with liposomes did not. This result suggests that cochleates' edges made them fuse with the cell surfaces as compared to edge free liposomes. This mechanism of cochleates' fusion with cell membrane was supported by a bactericidal activity assay using tobramycin cochleates, which act by inhibiting intracellular ribosomes. Tobramycin bridged cochleates in nanometer size showed improved antibacterial activity than the drug's solution.

  13. 郑州市解放路跨线桥主桥设计与施工%Design and Construction of Main Bridge of Jiefang Road Overpass Bridge in Zhengzhou City

    Institute of Scientific and Technical Information of China (English)

    申国朝

    2012-01-01

    The main bridge of the Jiefang Road Overpass Bridge in Zhengzhou City is a cable-stayed bridge with twin pylons, single cable plane and with span arrangement (106 + 248 + 106) m and the bridge employs the structural system of rigid fixity of its pylons and main girder. The main girder of the bridge is of the prestressed concrete triple-cell single box of quasi-triangle section and has a 62 m long variable width portion at the side span on the west side. On both sides of a pylon, 15 pairs of stay cables made up of the low relaxation and high-strength galvanized parallel steel wires are arranged. The pylons are the concrete solid single-column ones of H-shape sections and the main piers are the vase shape hollow reinforced concrete structures supported on the frictional group bored pile foundations. The software Bridge Doctor V3. 03, MIDAS Civil and ANSYS were used to respectively build the plane finite element model for the bridge and the plane link and spatial plate-shell finite element models for the variable width portion. With these models, the global static force of the bridge and the force conditions of the portion were analyzed. In addition, a 1: 4 model for the variable width portion was also designed and made to carry out the model test. The results of the finite element analysis and model test showed that the force conditions of various parts of the bridge could meet the requirements in the codes. The part of the bridge spanning the passenger dedicated railway line on the east side was constructed by the rotation erection while the part of the bridge spanning the freight railway line on the west side was constructed by the covered form traveler.%郑州市解放路跨线桥主桥为双塔单索面斜拉桥,跨径布置为(106+248+106)m,采用塔、梁固结体系.该桥主梁为预应力混凝土单箱三室准三角形截面,西侧边跨设62 m长的变宽段.每个桥塔两侧布置15对斜拉索,斜拉索采用低松弛镀锌高强平行钢丝.桥塔采

  14. Salt bridges: geometrically specific, designable interactions.

    Science.gov (United States)

    Donald, Jason E; Kulp, Daniel W; DeGrado, William F

    2011-03-01

    Salt bridges occur frequently in proteins, providing conformational specificity and contributing to molecular recognition and catalysis. We present a comprehensive analysis of these interactions in protein structures by surveying a large database of protein structures. Salt bridges between Asp or Glu and His, Arg, or Lys display extremely well-defined geometric preferences. Several previously observed preferences are confirmed, and others that were previously unrecognized are discovered. Salt bridges are explored for their preferences for different separations in sequence and in space, geometric preferences within proteins and at protein-protein interfaces, co-operativity in networked salt bridges, inclusion within metal-binding sites, preference for acidic electrons, apparent conformational side chain entropy reduction on formation, and degree of burial. Salt bridges occur far more frequently between residues at close than distant sequence separations, but, at close distances, there remain strong preferences for salt bridges at specific separations. Specific types of complex salt bridges, involving three or more members, are also discovered. As we observe a strong relationship between the propensity to form a salt bridge and the placement of salt-bridging residues in protein sequences, we discuss the role that salt bridges might play in kinetically influencing protein folding and thermodynamically stabilizing the native conformation. We also develop a quantitative method to select appropriate crystal structure resolution and B-factor cutoffs. Detailed knowledge of these geometric and sequence dependences should aid de novo design and prediction algorithms.

  15. 汶川百花大桥震害分析与抗震性能研究%Analysis of seismic damage and aseismic behavior of Wenchuan Baihua Bridge

    Institute of Scientific and Technical Information of China (English)

    雷俊卿; 宋力勋

    2012-01-01

    以遭到严重震害的汶川百花大桥为研究对象,从抗震设计的角度出发,用反应谱法和时程法进行了第一级设防水准(E1)地震作用下的弹性分析,用非线性时程法进行了第二级设防水准(E2)地震作用下的弹塑性分析,并综合分析了该桥的震害原因和抗震性能,为同类桥梁的设计提供参考和借鉴.分析结果表明:双柱式柔性墩的采用导致该桥整体刚度较小;桥墩纵筋和箍筋的配置不足导致了E1地震下的承载力不足,而E2地震下的塑性变形是满足要求的;固定墩处支座设置和系梁布置的不合理导致了固定墩左墩柱受到严重破坏;第五和第六联之间刚度差别较大而牛腿(悬臂支托)的支承长度过小,导致该牛腿处发生了落梁破坏.%Wenchuan Baihua Bridge, which was seriously damaged in the earthquake, was chosen as the object of study. Elastic analysis under earthquake action El was performed with both response spectrum method and time-history method,and elastoplastic analysis under earthquake action E2 was performed with nonlinear time-history method. In the end, causes of the damage and aseismic behavior of the bridge were summarized in order to provide design references for similar bridges. The studies show that: l)the use of double-columns flexible piers decreased the integral stiffness; 2)the deficiency of longitudinal bar and stirrup in the piers leads to the low bearing capacity under E1, while the plastic deformation under E2 can meet the standard; 3) the unreasonable layout of bearings and tie beams causes the severe damage of the left column of the fixed piers; 4)the small bearing length of the bracket, together with the big stiffness gap between the fifth and sixth continuous beam, lead to the falling down of the superstructure.

  16. 对连续梁桥减隔震支座抗震性能的比较分析%Seismic Isolation Bearing On the Comparative Analysis of the Seismic Performance for Continuous Beam Bridge

    Institute of Scientific and Technical Information of China (English)

    史康; 全健; 王福敏; 耿波

    2014-01-01

    以厦漳跨海大桥北汊南引桥为依托,采用有限元非线性时程分析方法,比较分析了铅芯橡胶支座和盆式橡胶支座对高烈度地区大跨径连续箱梁桥的抗震影响。研究结果表明:铅芯橡胶支座增加了结构在地震作用下的振动周期和主梁梁端位移,减小了固定墩的受力。相比盆式橡胶支座,铅芯橡胶支座可以使主梁梁端位移增加20%~200%,固定墩内力减小36%~80%。说明铅芯橡胶支座能够通过增加主梁位移达到减小桥墩受力的效果,隔震效果明显。该研究成果可为同类型桥梁的抗震设计提供参考。%Based on north south approach spans of Xiamen -zhangzhou cross-sea bridge by using the finite element nonlinear a-nalysis method, the seismic impact is compared between lead -rubber bearing and pot rubber bearing on the long span box girder bridges in high-intensity areas .The results show that the lead -rubber bearing can increase the vibration period and displacement of main beam in earthquake , reduce the force of fixed piers .Compared with pot rubber bearing , adopting lead-rubber bearing can in-crease the end displacement of main grider by 20%to 200%, meanwhile decrease internal force for fixed piers by 36%to 80%.The isolation effect is obvious that lead -rubber bearings can reduce the pier force by increasing the displacement of main beam .The re-search results provide a reference for the same type of bridge seismic design .

  17. Sensitive Analysis on Seismic Response of Simply Supported Box Girder Bridge on High Speed Railway Using Friction Pendulum Bearings and U-shaped Steel Combined Earthquake Protection Device%采用摩擦摆支座及U型钢防落梁装置的高速铁路简支箱梁桥地震响应敏感性分析

    Institute of Scientific and Technical Information of China (English)

    臧晓秋; 曹志峰; 吴成亮

    2016-01-01

    以高速铁路简支箱梁桥隔震研究为例,建立了采用摩擦摆支座与 U 型钢防落梁装置组合地震保护方案的全桥地震响应分析模型,针对支座位移、墩底剪力、墩底弯矩等地震响应,考虑了场地类别、桥墩高度、桥梁跨数、桥梁跨度、激励方向等影响因素,并根据各因素选定的水平级别,实施了混合正交试验,再应用极差分析方法对支座位移、墩底剪力、墩底弯矩等地震响应进行了影响因素的敏感性分析,明确了各因素对相关响应量影响的主次情况,为高速铁路简支箱梁桥隔震研究及优化设计奠定了基础。%In this paper,the seismic isolation of simply supported box girder bridges on high speed railway was studied. A bridge model with friction pendulum bearings and a U-shaped steel combined earthquake protection device was built for seismic response analysis,including the seismic response of bearing displacement,and shear and moment at the pier bottom. Multiple factors including site types,pier height,number of bridge spans,bridge span length and excitation direction were considered. A mixed orthogonal test was carried out according to the selected level of each factor. Using range analysis method,sensitivity analysis of each factor was carried out on the seismic response of bearing displacement,and shear and moment at the pier bottom. The primary and secondary cases of the impact of various factors on the relevant response were analyzed. It may provide guidelines for seismic isolation and design optimization of simply supported box girder bridges on high speed railway.

  18. 地震作用下中等跨径RC连续梁桥系统易损性研究%Study on system vulnerability of medium span reinforced concrete continuous girder bridge under earthquake excitation

    Institute of Scientific and Technical Information of China (English)

    李立峰; 吴文朋; 黄佳梅; 王连华

    2012-01-01

    Medium span multi-span continuous RC bridges,whose main failure modes are reflected in piers,abutments or bearings,are widely used in China.One common continuous girder bridge is taken as the analytical model;uncertainties in the strength of material and the weight of superstructure are considered,then a set of 10 nominally identical but statistically different bridge samples are developed for the bridge using the Latin hypercube sampling technique.100 earthquake records are chosen from PEER according to the site condition of bridge to account for the uncertainty of ground motions,and then combined randomly with 10 bridge samples.Then,a series of nonlinear time-history analyses are conducted to obtain the responses of structure,and four limit states for different components are defined.vunerability curves of piers,abutments and bearings are obtained utilizing the traditional reliability and probability tools,and furthermore the system vulnerability of structure is studied using the joint failure probability method.The results show that the bearings,especially the active bearing of abutment,are more vulnerable than the column piers and the abutments.The failure probability of bridge system,which is calculated using the first-order and the second-order reliability principles,is larger than those of structural members,indicating that it is more reasonable to assess the seismic behavior of bridge basing on the system vulnerability.%中等跨径混凝土连续梁桥是一种广泛应用的桥梁结构形式,地震作用下该类桥梁的破坏主要体现在桥墩、桥台和支座位置。以一典型多跨连续梁桥为例,考虑材料强度和上部结构容重等不确定性因素的影响,运用拉丁超立方抽样方法建立了10个桥梁样本。根据场地类型从PEER强震数据库中选取100条地震波来模拟地震动的不确定性,并与10个桥梁样本随机组合。对结构进行非线性时程分析后得到结构的响应,并分别定义了

  19. Evaluation method research on prestressed concrete bridges

    Institute of Scientific and Technical Information of China (English)

    HUANG Qiao; LIN Yang-zi; REN Yuan

    2008-01-01

    Considering the construction features of prestressed concrete bridge, the comprehensive evaluation method about the bridge damage conditions are studied. Particular attentions are paid on establishing a multi-level evaluation model for damaged prestressed concrete bridge, and the evaluation indices of the model as well as the rating standards are defined in the model. A normal relative function about the evaluation indices of each element is developed to calculate the relative degree, and for each element which is no sub-level elements. When evaluating the elements in sub-item level or index level of the model, the weights of elements that are pertained to one element are adopted, taking account of their deterioration degree. At the same time, the dam-age conditions of bridge are characterized by relative degree, element evaluation scale and structural technology mark of bridge ,so it agrees with Code for Maintenance of Highway Bridges and Culvers.

  20. Study on structural system of Sutong Bridge

    Institute of Scientific and Technical Information of China (English)

    Zhang Xigang; Pei Minshan; Yuan Hong; Xu Liping; Zhu Bin

    2009-01-01

    Sutong Bridge, whose layout is [ (100 + 100 + 300) + 1 088 + ( 300 + 100 + 100) ] m, marks the largest span of cable-stayed bridges in the world. The complex natural condition at the bridge site and the strict requirements for resistance of wind and seismic action make it crucial to choose a favorable structural system to assure the function and safety of the bridge. The comparison among several optional structural systems for Sutong Bridge is illustrated. After detailed analysis is carried out for viscous damper and hydraulic buffer, super liquid viscous damper with additional displacement limitation is designed for the first application in bridge engineering. The parameters for the damper is analyzed and studied and the dampers are installed suecessfuUy after quality tests.

  1. New technological approach in reconstructing Hanshin expressway. Base isolation for continuous rigid frame bridge; Hanshin kosoku doro fukkyu deno aratana kokoromi. Rittai ramen kyokyaku kabu menshinkyo wo chushin to shite

    Energy Technology Data Exchange (ETDEWEB)

    Morikawa, H. [Kobe University, Kobe (Japan). Faculty of Engineering

    1996-09-15

    This paper presents new technological approach in reconstructing Hanshin expressway damaged by Hyogo-ken Nanbu earthquake. The expressway of Benten section was composed of 6 three-span continuous RC floor slab girders supported by RC single columns, and 2 simple girders. Among them, 3 girders fell and 5 girders were largely damaged. As the study result of various structures for reconstruction, the 19-span continuous steel plate deck rigid frame bridge was adopted which is supported by steel piers with plane aseismic base isolation structure first in the world. Static and dynamic analyses of 3-D model were carried out to evaluate structure characteristics. The result of static analysis revealed that pile reaction forces are allowable, and horizontal forces due to earthquake or temperature at the bottom of piers considerably decrease. The result of eigenvalue analysis revealed that all of preferential lower- order modes are horizontal mode, and their frequencies are as low as 0.7Hz. The designed damping factor of aseismic bearings was estimated to be 15% or more. 9 figs., 1 tab.

  2. Bridge engineering handbook construction and maintenance

    CERN Document Server

    Chen, Wai-Fah

    2014-01-01

    Over 140 experts, 14 countries, and 89 chapters are represented in the second edition of the Bridge Engineering Handbook. This extensive collection highlights bridge engineering specimens from around the world, contains detailed information on bridge engineering, and thoroughly explains the concepts and practical applications surrounding the subject.Published in five books: Fundamentals, Superstructure Design, Substructure Design, Seismic Design, and Construction and Maintenance, this new edition provides numerous worked-out examples that give readers step-by-step design procedures, includes c

  3. Analysis of liquid bridge between spherical particles

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A pair of central moving spherical particles connected by a pendular liquid bridge with interstitial Newtonian fluid is often encountered in pariculate coalescence process. In this paper, by assuming perfect-wet condition, the effects of liquid volume and separation distance on static liquid bridge are analyzed, and the relation between rupture energy and liquid bridge volume is also studied. These points would be of significance in industrial processes related to adhesive particles.

  4. Bridge Engineering-Oriented Parametric Model

    Institute of Scientific and Technical Information of China (English)

    周凌远; 李乔

    2004-01-01

    A new model is proposed to improve the efficiency of structural modeling. In this model, the bridge structural components are expressed with component description, parametric description and geometric description in a software system. This model provides both convenience and flexibility for users in structural modeling process. The object-oriented method is applied in the model implementation. A bridge analysis preprocessor is developed on the basis of this model. It provides an effective way for bridge modeling.

  5. Dynamics and Statics of Nonaxisymmetric Liquid Bridges

    Science.gov (United States)

    Alexander, J. Iwan D.; Resnick, Andrew H.; Slobozhanin, L. A.

    1996-01-01

    Theoretical and experimental investigation of the stability of nonaxisymmetric and nonaxisymmetric bridges contained between equal and unequal radii disks as a function of Bond and Weber number with emphasis on the transition from unstable axisymmetric to stable nonaxisymmetric shapes, are conducted. Numerical analysis of the stability of nonaxisymmetric bridges between unequal disks for various orientations of the gravity vector is performed. Experimental and theoretical investigation of large (nonaxisymmetric) oscillations and breaking of liquid bridges are also conducted.

  6. Mathematical Modelling of Bridges with SAP2000

    OpenAIRE

    Maraž, Miha

    2006-01-01

    The present work describes a relatively new programme module, which is enhanced in the recently released versions of SAP2000 software. The new module, called Bridge Modeler, is intended for simple, parametric mathematical modelling of bridges. The modelling procedure is explained on a test case through the steps of a user-friendly Bridge Wizard. For each step, we described the basic principles and the application possibilities as well as some limitations. We also explained two types of analys...

  7. Buddha and the bridging relations.

    Science.gov (United States)

    Banerjee, Rahul

    2008-01-01

    The chapter reviews a classical Indian model of consciousness found in the Abhidhamma, a collection of seven treatises in the Pali Canon Tipitaka. The model was based on observations made during advanced vipassana practice, a first-person method taught by the Buddha. The climax of the model consists in the elucidation of 24 'Bridging Relations' causally linking the stream of consciousness, its contents and associated physical events. Review of such a model based on a specialized first-person technique could prove to be a resource of useful ideas providing directions for further research.

  8. Family Medicine: Bridge to Life.

    Science.gov (United States)

    Luz, Clare

    2016-01-01

    Reflecting on the suicide of a close friend, this essay explores what comprises, and inspires a will to live, and how those in Family Medicine can address suicide risk even in the face of debilitating or terminal illness. Research indicates that the will to live is a measurable indicator of general well-being, distinct from depression, and an important predictor of a person's motivation to "hold on to life". As such, understanding what is at the heart of a desire to live should alter clinical practice. This essay offers ideas for ways in which to create bridges for patients that could help sustain life.

  9. Nanoclusters a bridge across disciplines

    CERN Document Server

    Jena, Purusottam

    2010-01-01

    This comprehensive book on Nanoclusters comprises sixteen authoritative chapters written by leading researchers in the field. It provides insight into topics that are currently at the cutting edge of cluster science, with the main focus on metal and metal compound systems that are of particular interest in materials science, and also on aspects related to biology and medicine. While there are numerous books on clusters, the focus on clusters as a bridge across disciplines sets this book apart from others. Delivers cutting edge coverage of cluster science Covers a broad range of topics in

  10. A bridge to advanced mathematics

    CERN Document Server

    Sentilles, Dennis

    2011-01-01

    This helpful workbook-style ""bridge"" book introduces students to the foundations of advanced mathematics, spanning the gap between a practically oriented calculus sequence and subsequent courses in algebra and analysis with a more theoretical slant. Part 1 focuses on logic and number systems, providing the most basic tools, examples, and motivation for the manner, method, and concerns of higher mathematics. Part 2 covers sets, relations, functions, infinite sets, and mathematical proofs and reasoning. Author Dennis Sentilles also discusses the history and development of mathematics as well a

  11. Review of Energy Harvesters Utilizing Bridge Vibrations

    Directory of Open Access Journals (Sweden)

    Farid Ullah Khan

    2016-01-01

    Full Text Available For health monitoring of bridges, wireless acceleration sensor nodes (WASNs are normally used. In bridge environment, several forms of energy are available for operating WASNs that include wind, solar, acoustic, and vibration energy. However, only bridge vibration has the tendency to be utilized for embedded WASNs application in bridge structures. This paper reports on the recent advancements in the area of vibration energy harvesters (VEHs utilizing bridge oscillations. The bridge vibration is narrowband (1 to 40 Hz with low acceleration levels (0.01 to 3.8 g. For utilization of bridge vibration, electromagnetic based vibration energy harvesters (EM-VEHs and piezoelectric based vibration energy harvesters (PE-VEHs have been developed. The power generation of the reported EM-VEHs is in the range from 0.7 to 1450000 μW. However, the power production by the developed PE-VEHs ranges from 0.6 to 7700 μW. The overall size of most of the bridge VEHs is quite comparable and is in mesoscale. The resonant frequencies of EM-VEHs are on the lower side (0.13 to 27 Hz in comparison to PE-VEHs (1 to 120 Hz. The power densities reported for these bridge VEHs range from 0.01 to 9539.5 μW/cm3 and are quite enough to operate most of the commercial WASNs.

  12. CONDITION RATING SYSTEM FOR THAILAND'S CONCRETE BRIDGES

    Directory of Open Access Journals (Sweden)

    Bonaventure H.W. Hadikusumo

    2010-06-01

    Full Text Available The Bridge Management System is designed to maximise use of available data and determine the optimal strategy to perform necessary improvements to bridges in the most cost-effective manner. This paper provides a condition rating system to meet the requirements of Thailand’s Department of Highways (DOH. A rating system to assess the existing condition of bridges is proposed. Segmental inspection is developed to execute efficient element-level evaluations and collect data that demonstrate deterioration patterns in bridge elements. The paper also describes inspection procedures for field survey execution, which enables observed distresses at the level of sub-elements or members to be allocated. Recommendations from bridge experts reveal that the proposed rating system is robust, implementable in actual practice, and suitable for efficient application in evaluating the nation’s concrete highway bridges. Although the bridge condition rating was developed in response to the specific characteristics of Thailand’s bridges, the proposed methodology can easily be extended to other bridge agencies.

  13. A data management infrastructure for bridge monitoring

    Science.gov (United States)

    Jeong, Seongwoon; Byun, Jaewook; Kim, Daeyoung; Sohn, Hoon; Bae, In Hwan; Law, Kincho H.

    2015-04-01

    This paper discusses a data management infrastructure framework for bridge monitoring applications. As sensor technologies mature and become economically affordable, their deployment for bridge monitoring will continue to grow. Data management becomes a critical issue not only for storing the sensor data but also for integrating with the bridge model to support other functions, such as management, maintenance and inspection. The focus of this study is on the effective data management of bridge information and sensor data, which is crucial to structural health monitoring and life cycle management of bridge structures. We review the state-of-the-art of bridge information modeling and sensor data management, and propose a data management framework for bridge monitoring based on NoSQL database technologies that have been shown useful in handling high volume, time-series data and to flexibly deal with unstructured data schema. Specifically, Apache Cassandra and Mongo DB are deployed for the prototype implementation of the framework. This paper describes the database design for an XML-based Bridge Information Modeling (BrIM) schema, and the representation of sensor data using Sensor Model Language (SensorML). The proposed prototype data management framework is validated using data collected from the Yeongjong Bridge in Incheon, Korea.

  14. Assessment of the Reliability of Concrete Bridges

    DEFF Research Database (Denmark)

    Middleton, C. R.; Thoft-Christensen, Palle

    a significant shift in emphasis for the highways authorities around the world away from the design of new structures over to maintaining the existing infrastructure. As a result, bridge owners are seeking improved ways of inspecting, assessing, maintaining and repairing their existing stock of bridges...... in the wake of ever increasing traffic loads and volumes, and an ageing population of bridges subject to various mechanisms of deterioration. The goal is to optimise the allocation of limited resources whilst maintaining their bridges in a safe and serviceable condition. Reliability analysis is one tool being...

  15. John Pier, Configurazioni narrative

    Directory of Open Access Journals (Sweden)

    Alessandra Diazzi

    2009-06-01

    Full Text Available Il presente lavoro si muove in direzione di una narratologia intertestuale che integri una riflessione semiotica e strumenti di logica, ponendo al centro il concetto di «configurazione» quale modello di comprensione (Mink, Ricoeur. Il concetto di «sceneggiature intertestuali» permette di accostarsi all‘atto di lettura interpretandolo come procedimento di abduzione, attraverso cui il Lettore Modello (Eco trova nella propria enciclopedia intertestuale le cosiddette «sceneggiature» ossia «strutture di base» più o meno riconoscibili in ogni racconto. Tramite una lettura di Lolita si giunge a delineare l‘atto interpretativo come un procedimento abduttivo in cui ricorrono «sceneggiature intertestuali», potendo così individuare nel testo quei percorsi, spesso latenti, che una lettura critica deve essere capace non solo di seguire ma anche di tracciare.

  16. 23 CFR 650.409 - Evaluation of bridge inventory.

    Science.gov (United States)

    2010-04-01

    ... 23 Highways 1 2010-04-01 2010-04-01 false Evaluation of bridge inventory. 650.409 Section 650.409... Evaluation of bridge inventory. (a) Sufficiency rating of bridges. Upon receipt and evaluation of the bridge inventory, a sufficiency rating will be assigned to each bridge by the Secretary in accordance with...

  17. 23 CFR 650.807 - Bridges requiring a USCG permit.

    Science.gov (United States)

    2010-04-01

    ... 23 Highways 1 2010-04-01 2010-04-01 false Bridges requiring a USCG permit. 650.807 Section 650.807... BRIDGES, STRUCTURES, AND HYDRAULICS Navigational Clearances for Bridges § 650.807 Bridges requiring a USCG... improvement or construction of a bridge over navigable waters except for the exemption exercised by FHWA...

  18. 33 CFR 118.65 - Lights on fixed bridges.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Lights on fixed bridges. 118.65 Section 118.65 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.65 Lights on fixed bridges. (a) Each fixed bridge span over a...

  19. 33 CFR 118.70 - Lights on swing bridges.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Lights on swing bridges. 118.70 Section 118.70 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.70 Lights on swing bridges. (a) Swing span lights on through bridges....

  20. 33 CFR 118.85 - Lights on vertical lift bridges.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Lights on vertical lift bridges... BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.85 Lights on vertical lift bridges. (a) Lift span lights. The vertical lift span of every vertical lift bridge shall be lighted so that the center of...

  1. Finite element of multilayer surfacing systems on orthotropic steel bridges

    NARCIS (Netherlands)

    Li, J.; Liu, X.; Scarpas, A.; Tzimiris, G.

    2013-01-01

    Light weight orthotropic steel bridge decks have been widely utilized for bridges in seismic zones, movable bridges and long span bridges. In the last three decades, severe problems were reported in relation to asphaltic surfacing materials on orthotropic steel deck bridges. Earlier investigations h

  2. Light-weight aluminium bridges and bridge decks. An overview of recent applications

    NARCIS (Netherlands)

    Maljaars, J.; Soetens, F.; Kluyver, D. de

    2008-01-01

    The last decades have shown a large increase in the application of aluminium alloys for light-weight bridges. For bridge construction, aluminium alloys have some specific advantages, but also some points of attention. This paper deals with some recent projects of aluminium bridges, and for these pro

  3. The Bridge of Mandolin County

    Science.gov (United States)

    Lantz, Juliette M.; Feindt, Jenny E.; Lewellyn, Eric P. B.; Walczak, Mary M.

    1999-12-01

    The Bridge of Mandolin County is a case designed to teach the general chemistry principles of molar mass, ions and aqueous reactions, solubility rules, and inorganic nomenclature. Through the instructor-facilitated class discussion, students consider the options before the Mandolin Town Council regarding deicing the newly constructed bridge connecting Mandolin with a large nearby city. The students must decipher contradictory claims made on behalf of sodium chloride, the traditional deicer, and calcium magnesium acetate, a new environmentally friendly deicer, to arrive at the most cost-effective and environmentally appropriate deicing product. As they work through the analysis they raise questions that can be addressed in a laboratory setting. Four optional role-playing experiments are included, which can be used by the students to gather information helpful to resolution of the case. The case is intended to be used over two class periods, with a laboratory period in between, though suggestions for other models are provided. Laboratory procedures include an EDTA titration for Ca2+ and Mg2+, a gravimetric analysis, a qualitative examination of ions and solubility, an introduction to freezing point depression and measurement, and an experimental design activity. This case can also successfully be used without alteration in non-majors chemistry or environmental chemistry courses, or upper-level analytical or environmental chemistry courses.

  4. Global monitoring concept for bridges

    Science.gov (United States)

    Bergmeister, Konrad; Santa, Ulrich

    2000-06-01

    Knowledge of the integrity of in-service structures on a continuous time basis is an ultimate objective for owners and maintenance authorities. The development of a life extension and/or replacement strategy for highway structures is a crucial point in an effective bridge management system. A key component of such a bridge management system is a means of surveillance techniques and determining the condition of an existing structure within the normative and budgetary constraints. Recent advances in sensing technologies and material/structure damage characterization combined with current developments in computations and communications have resulted in a significant interest in developing diagnostic technologies for monitoring the integrity of and for the detection of damages of structures. To identify anomalies and deterioration processes, it is essential to understand the relationships between the signal measurements and the real occurred phenomena. Therefore, the comparison of measured and calculated data in order to tune and validate the mechanical and numerical model assumptions is an integral part of any system analysis. Finally, the interpreted results of all measurements should be the basis for the condition assessment and the safety evaluation of a structure to facilitate replacement and repair decisions.

  5. Bridging history and social psychology

    DEFF Research Database (Denmark)

    Glaveanu, Vlad Petre; Yamamoto, Koji

    2012-01-01

    This special issue aims to bridge history and social psychology by bringing together historians and social psychologists in an exercise of reading and learning from each other’s work. This interdisciplinary exercise is not only timely but of great importance for both disciplines. Social psycholog......This special issue aims to bridge history and social psychology by bringing together historians and social psychologists in an exercise of reading and learning from each other’s work. This interdisciplinary exercise is not only timely but of great importance for both disciplines. Social...... psychologists can benefit from engaging with historical sources by being able to contextualise their findings and enrich their theoretical models. It is not only that all social and psychological phenomena have a history but this history is very much part of present-day and future developments. On the other...... hand historians can enhance their analysis of historical sources by drawing upon the conceptual tools developed in social psychology. They can “test” these tools and contribute to their validation and enrichment from completely different perspectives. Most important, as contributions to this special...

  6. A risk prediction model for the assessment and triage of women with hypertensive disorders of pregnancy in low-resourced settings : the miniPIERS (Pre-eclampsia Integrated Estimate of RiSk) multi-country prospective cohort study

    NARCIS (Netherlands)

    Payne, Beth A.; Hutcheon, Jennifer A.; Ansermino, J. Mark; Hall, David R.; Bhutta, Zulfiqar A.; Bhutta, Shereen Z.; Biryabarema, Christine; Grobman, William A.; Groen, Henk; Haniff, Farizah; Li, Jing; Magee, Laura A.; Merialdi, Mario; Nakimuli, Annettee; Qu, Ziguang; Sikandar, Rozina; Sass, Nelson; Sawchuck, Diane; Steyn, D. Wilhelm; Widmer, Mariana; Zhou, Jian; von Dadelszen, Peter

    2014-01-01

    Background: Pre-eclampsia/eclampsia are leading causes of maternal mortality and morbidity, particularly in low-and middle-income countries (LMICs). We developed the miniPIERS risk prediction model to provide a simple, evidence-based tool to identify pregnant women in LMICs at increased risk of deat

  7. Salt-bridge energetics in halophilic proteins.

    Directory of Open Access Journals (Sweden)

    Arnab Nayek

    Full Text Available Halophilic proteins have greater abundance of acidic over basic and very low bulky hydrophobic residues. Classical electrostatic stabilization was suggested as the key determinant for halophilic adaptation of protein. However, contribution of specific electrostatic interactions (i.e. salt-bridges to overall stability of halophilic proteins is yet to be understood. To understand this, we use Adaptive-Poison-Boltzmann-Solver Methods along with our home-built automation to workout net as well as associated component energy terms such as desolvation energy, bridge energy and background energy for 275 salt-bridges from 20 extremely halophilic proteins. We then perform extensive statistical analysis on general and energetic attributes on these salt-bridges. On average, 8 salt-bridges per 150 residues protein were observed which is almost twice than earlier report. Overall contributions of salt-bridges are -3.0 kcal mol-1. Majority (78% of salt-bridges in our dataset are stable and conserved in nature. Although, average contributions of component energy terms are equal, their individual details vary greatly from one another indicating their sensitivity to local micro-environment. Notably, 35% of salt-bridges in our database are buried and stable. Greater desolvation penalty of these buried salt-bridges are counteracted by stable network salt-bridges apart from favorable equal contributions of bridge and background terms. Recruitment of extensive network salt-bridges (46% with a net contribution of -5.0 kcal mol-1 per salt-bridge, seems to be a halophilic design wherein favorable average contribution of background term (-10 kcal mol-1 exceeds than that of bridge term (-7 kcal mol-1. Interiors of proteins from halophiles are seen to possess relatively higher abundance of charge and polar side chains than that of mesophiles which seems to be satisfied by cooperative network salt-bridges. Overall, our theoretical analyses provide insight into halophilic

  8. 潮白河矮塔斜拉桥健康监测方案设计%Chaobai River Extra-dosed Cable-stayed Bridge Health Monitoring System

    Institute of Scientific and Technical Information of China (English)

    齐钺; 田杰

    2012-01-01

    潮白河大桥为三塔矮塔斜拉桥,矮塔斜拉桥具有结构性能优良,经济指标优异的特点,受力以梁为主,以索为辅.本桥桥宽29.5m,跨径组合为72m+120m+120m+72m=384m,中间桥塔处为梁塔墩固结,两侧桥塔处为梁塔固结.主梁采用单箱3室箱形结构,梁高按照二次抛物线型式渐变.施工监控采集的数据可为后期健康监测系统提供原始指纹信息,本桥健康监测系统可实时掌握大桥运营过程中受力情况.%Chaobai River Bridge is a short-tower cable-stayed bridge that has three towers. Short-tower cable-stayed bridge has excellent structural performance, excellent economic indicators. The load carrying is mainly the beam, assisted by cable. This bridge width is 29.5m, span combination is 72m + 120m+120m+72m=384m, the middle of the bridge towers is the beam tower pier consolidation, both sides of the bridge tower are the beam tower consolidation. The main beam uses a single box with 3 rooms of box structures, the beam height changes gradually in accordance with cubic parabola. The data from construction monitoring can provide the original fingerprint information for post-health monitoring system. The health monitoring system can monster the real-time force in operation.

  9. 关于大跨径连续刚构桥中跨合拢时常见问题的效应验算%The Effect Check of Problems in Closing the Middle Span of Long-Span Continuous Rigid-Frame Bridge

    Institute of Scientific and Technical Information of China (English)

    王洁

    2014-01-01

    The rationality of the force and smoothly of linearity which are high pier and long span continu‐ous rigid-frame bridge to its structure are the control points during the construction of bridge .In order to neglect the structural system of bridge under construction not follow the construction order during the con‐struction of long span bridge .T hese problems usually neglected by the field technical managers ,and these neg‐lected problems can influence the stress of long span rigid frame bridge before closing the span .%高墩大跨径的连续刚构桥对其结构受力的合理性及线性的平顺,成为施工过程中的控制重点。在大跨径桥梁施工过程中常常忽视在建桥梁的结构体系,而没有严格按照施工顺序进行施工。这些常被现场技术管理人员所忽略的问题,通常会影响到大跨径刚构桥在最终合拢前的受力。

  10. 右线盾构穿越人行天桥施工技术%The Right Line of Shield Crossing Pedestrian Bridge Construction Technology

    Institute of Scientific and Technical Information of China (English)

    施钧; 柴金玲

    2015-01-01

    Tong tai road footbridge on the east side tong tai road and golden waterway junc-tion.Due to the bridge pier is located in zhengzhou city rail transit line one is a phase of the convention and exhibition center to the top of the line between the Yellow River east road station right tunnel,subway construction will affect it.Is studied in this paper,its construction technology,the key to the bridge con-struction technology are introduced,namely the footbridge to protect and shield construction.And under the seriously organize the implementation,the mentally incapacitated person Line bridge completed showed that yellow will range right wire shield crossing tong tai road pedestrian bridge construction tech-nology has the scientific nature and rationality.%河南省郑州市地铁一号线,运行区间会展中心至黄河东路右隧道上方是通泰路的人行天桥的桥墩,在进行地铁施工时会对桥墩产生影响。对其施工技术进行了研究,介绍了该天桥的关键施工技术,即人行天桥保护以及盾构施工。并在认真组织实施下,该人行天桥顺利竣工表明,黄会区间右线盾构穿越通泰路人行天桥施工技术具有科学性和合理性。

  11. A Statistical Observation of Crowns and Bridges in 1988 Part 2 : Bridge

    OpenAIRE

    小林, 賢一; 小坂, 茂; 柳田, 史城; 稲生, 衡樹; 大島, 俊明; 高橋, 喜博; 岩井, 啓三; 甘利, 光治; 中根, 卓

    1991-01-01

    A study was made of 207 bridges which had been fabricated for patients at the Prosthodontic Clinic of Matsumoto Dental College during 1988. Some of results were as follows; 1) 47.3% of the patients were males and 52.7% were females. 2) 92.8% of the patients were between 20 and 69 years old. 3) 65.2%of the bridges were fabricated as 3-unit bridges. 4) 77.8% were fabricated as 1-pontic bridges. 5) There were fewer bridge retainers for the lower anterior segment than for other segments. 6) 52.3%...

  12. Heavy Vehicles on Minor Highway Bridges

    DEFF Research Database (Denmark)

    Kirkegaard, Poul Henning; Nielsen, Søren R. K.; Enevoldsen, I.

    the results obtained using the numerical models given in details in "Heavy Vehicles on Minor Highway Bridges : dynamic modelling of vehicles and bridges". The models are established using a ordinary vehicle which consists of a 48 t Scania with a 3 axle tractor and a 3 axle trailer, joined in a flexible hinge...

  13. Passing the Einstein-Rosen bridge

    CERN Document Server

    Katanaev, M O

    2013-01-01

    We relax the requirement of geodesic completeness of a space-time. Instead, we require test particles trajectories to be smooth only in the physical sector. Test particles trajectories for Einstein--Rosen bridge are proved to be smooth in the physical sector, and particles can freely penetrate the bridge in both directions.

  14. COUPLING VIBRATION OF VEHICLE-BRIDGE SYSTEM

    Institute of Scientific and Technical Information of China (English)

    陈炎; 黄小清; 马友发

    2004-01-01

    By applying the sinusoidal wave mode to simulate the rugged surface of bridge deck,accounting for vehicle-bridge interaction and using Euler-Bernoulli beam theory, a coupling vibration model of vehicle-bridge system was developed. The model was solved by mode analyzing method and Runge-Kutta method, and the dynamic response and the resonance curve of the bridge were obtained. It is found that there are two resonance regions, one represents the main resonance while the other the minor resonance, in the resonance curve. The influence due to the rugged surface, the vibration mode of bridge, and the interaction between vehicle and bridge on vibration of the system were discussed. Numerical results show that the influence due to these parameters is so significant that the effect of roughness of the bridge deck and the mode shape of the bridge can't be ignored and the vehicle velocity should be kept away from the critical speed of the vehicle.

  15. Active aerodynamic stabilisation of long suspension bridges

    DEFF Research Database (Denmark)

    Nissen, Henrik Ditlev; Sørensen, Paul Haase; Jannerup, Ole Erik

    2004-01-01

    The paper describes the addition of actively controlled appendages (flaps) attached along the length of the bridge deck to dampen wind-induced oscillations in long suppension bridges. A novel approach using control systems methods for the analysis of dynamic stability is presented. In order to ma...

  16. General framework for bridge life cycle design

    Institute of Scientific and Technical Information of China (English)

    Junhai MA; Airong CHEN; Jun HE

    2009-01-01

    Based on a detailed illustration for bridge life cycle design which comprises the processes of service life design, aesthetics design, performance design, environ-mental and ecological design, inspection, maintenance and repair design as well as cost analysis, this paper presented a general framework for bridge life cycle design comprising three design phases and six design processes.

  17. Re-Assessment of Concrete Bridges

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    In this paper two aspects of re-assessment of the reliability of concrete bridges are discussed namely modelling of the corrosion of reinforcement and updating of uncertain variables. The main reason for deterioration of concrete bridges is corrosion of the reinforcement. Therefore, modelling...

  18. Lifetime Reliability Assessment of Concrete Slab Bridges

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    A procedure for lifetime assesment of the reliability of short concrete slab bridges is presented in the paper. Corrosion of the reinforcement is the deterioration mechanism used for estimating the reliability profiles for such bridges. The importance of using sensitivity measures is stressed. Fi...

  19. Precast Pearl-Chain concrete arch bridges

    DEFF Research Database (Denmark)

    Halding, Philip Skov; Hertz, Kristian Dahl; Schmidt, Jacob Wittrup

    2015-01-01

    A Pearl-Chain Bridge is a closed-spandrel arch bridge consisting of a number of straight pre-fabricated so called Super-Light Deck elements put together in an arch shape by post-tensioning cables. Several Pearl-Chain arches can be positioned adjacent to each other by a crane to achieve a bridge...... the technology was used. We also study other important components and details in the Pearl-Chain Bridge concept and review the effects of different types of loads. A theoretical case study of a circular 30 m span Pearl-Chain Bridge is presented showing the influence of a number of parameters: The number of post-tensioning......, and gives a large positive bending moment below the load and a smaller negative bending moment in the unloaded side. When the Pearl-Chain Bridge concept is compared to other pre-fabricated arch bridge solutions we find a number of advantages when using Pearl-Chain Bridges: Straight elements, combination...

  20. 应用车辆-道岔-桥梁耦合动力学分析道岔-桥梁合理相对位置%Vehicle-turnout-bridge Coupling Dynamics Analysis for Turnout-bridge Relative Position

    Institute of Scientific and Technical Information of China (English)

    伍曾; 刘学毅; 王平

    2011-01-01

    为确定道岔、桥梁的合理相对位置,深入研究快速及高速行车条件下车辆-道岔-桥梁的动态相互作用,将车辆、道岔区轨道和桥梁作为一个整体,建立车辆-道岔-桥梁耦合系统动力分析模型,用数值模拟的方法计算分析高速行车条件下道岔区轨道、车辆与连续桥梁结构的动力特性及行车安全性和舒适性.以车速350 km/h通过18号国产道岔,岔桥相对位置为尖轨尖端分别位于桥跨1/4、跨中、3/4跨及墩上,通过计算出的尖轨和心 轨开口量、尖轨和心轨动应力、车体振动加速度、减载率、脱轨系数、舒适性、桥梁振幅、振动加速度和梁端转角等动力响应,确定在车辆-道岔-桥梁耦合动力条件下4×32 m连续梁桥的合理岔桥相对位置.计算结果表明,18号国产道岔铺设于4×32 m连续梁桥上时,道岔尖轨尖端位于1/4跨时综合动力效果较佳.%Dynamical vehicle-turnout-bridge interaction was studied to determine the rational relative position of the turnout and bridge. The dynamic model of the vehicle-turnout-bridge coupling system was established, and the numerical simulation method was applied to analyze the dynamic characteristics of the vehicle-turnout-continuous bridge structure and the safety and comfort of trains running at high speeds. Assume that the train runs at the speed of 350 km/h through China-made Turnout No. 18 and the toe of switch rail was placed at the 1/4 span,mid-span,3/4 span and the top of the pier respectively. The turnout-bridge relative position for the 4×32 m continuous bridge under the action of dynamic coupling of the vehicle-turnout-bridge structure was determined by calculating the train running safety, ride comfort, vibration acceleration of vehicle body, dynamic stresses and displacements of switch rail and nose rail,load reducing rate,derailment coefficient, vibration amplitude and acceleration of bridge, and so on. The calculation results show that

  1. Design of Concrete Self-Anchored Suspension Bridge of Wusong Bridge in Jilin City%吉林市雾凇大桥混凝土自锚式悬索桥设计

    Institute of Scientific and Technical Information of China (English)

    张伟; 唐贺强; 宁伯伟

    2011-01-01

    The main bridge of the Wusong Bridge in Jilin City is a 5-span continuous concrete self-anchored suspension bridge with span arrangement (35+68+150+68+35) m. A summarized account of the design and calculation of the main bridge is presented herewith. On the bridge, the transverse and vertical bearings and the longitudinal dampers are arranged in between the stiffening girder and towers. The girder is of a concrete 3-cell single box section, the depth of a typical segment of the girder is 2.5 m and towards the anchorage sections at the side spans, the segments of the girder gradually change into a depth of 6.5 m. A tower of the bridge is a concrete portal frame structure that is 54 m in height and the tower columns and the cross beams on the towers are all of rectangular hollow sections. Beneath a tower pier are the pile caps of separation type and each pile cap is supported by 9 nos. of Φ2.0 m bored piles. The main cables are respectively made up of Φ5.1 mm galvanized high strength steel wires and the hanger cables are of Φ7.0 mm low relaxation galvanized high strength parallel steel wires. In the design, the finite element software MIDAS Civil 2006, the nonlinear analysis software BNLAS for suspension bridge and the plane program SCDS are employed to calculate and analyze the bridge. The results of the calculation and analysis indicate that all checking calculation made for the bridge can conform to the relevant requirements in the codes.%吉林市雾凇大桥主桥为(35+68+150+68+35)m五跨连续混凝土自锚式悬索桥,综述该桥主桥设计与计算.该桥塔梁间设置横、竖向支座和纵向阻尼器;加劲梁采用单箱三室混凝土截面,标准段梁高2.5 m,在边跨锚固段渐变至6.5 m;桥塔采用门形框架混凝土结构,高54 m,塔身及横梁均采用矩形空心截面;桥塔墩下部采用分离式承台,单个承台布置9根φ2.0 m钻孔灌注桩;主缆采用φ5.1 mm镀锌高强钢丝,吊索采用φ7.0 mm低松弛镀锌高强

  2. FRP 加固 RC 连续梁桥抗震性能试验研究%Tests for aseismic performances of a RC continuous girder bridge retrofitted by FRP jacket

    Institute of Scientific and Technical Information of China (English)

    林元铮; 田石柱

    2016-01-01

    Taking a reinforced concrete continuous girder bridge as the study object,retrofitting the plastic region of piers with FRP jacket,the aseismic performances of the bridge structure were studied with hybrid tests.The fixed pier bearing most seismic action was taken as a test element and physically tested in a lab while the other parts of the bridge structure were taken as calculation elements and simulated numerically with OpenSees.After integrating and combining different parts with the hybrid test platform--OpenFresco,the dynamic responses of the overall bridge structure under seismic action were obtained.At last,the test results and Open Sees finite element analysis ones were compared.The results showed that the aseismic performances of the RC continuous girder bridge can be improved effectively after retrofitted with FRP jacket,and the test results agree well with those of finite element analysis.%以某钢筋混凝土连续梁桥作为研究对象,对其桥墩进行了塑性铰区的 FRP 抗震加固,采用混合试验技术研究了该桥梁结构的抗震性能。将连续梁桥结构承担主要地震作用的固定墩作为试验单元,进行真实的物理试验;将桥梁结构其余部分作为计算单元通过有限元软件 OpenSees 进行模拟,通过 OpenFresco 混合试验平台集成协调,完成了该连续梁桥的抗震混合试验。最后将试验结果与 OpenSees 有限元分析结果进行了对比。研究结果表明,FRP 抗震加固能够有效改善桥梁的抗震性能;试验结果与有限元分析结果吻合较好。

  3. The I-35W bridge Project Website

    DEFF Research Database (Denmark)

    Kampf, Constance

    How can websites be used to rebuild trust?  In August 2007, the Interstate Highway 35-W bridge in Minneapolis, MN collapsed during rush hour.  Although many people were rescued and casualties were as limited as could be expected due to quick and effective intervention, the image of a major bridge...... collapsing during rush hour damaged the Minnesota Department of Transportation's reputation and resulted in the loss of public trust for the organization.  The ensuing bridge reconstruction project included a project website intended to rebuild this trust through transparency, community involvement......, and the use of multimodal features.  This paper looks at the I35-W bridge reconstruction project in Minneapolis through web-based communication by the Minnesota Department of Transportation (MnDOT) about the project. The MnDOT bridge reconstruction website will be examined using a combination of 1). Weick...

  4. Seismic response of steel suspension bridge

    Energy Technology Data Exchange (ETDEWEB)

    McCallen, D.B. [Lawrence Livermore National Lab., CA (United States); Astaneh-Asl, A. [California Univ., Berkeley, CA (United States). Dept. of Civil and Environmental Engineering

    1996-11-01

    Performing accurate, realistic numerical simulations of the seismic response of long-span bridges presents a significant challenge to the fields of earthquake engineering and seismology. Suspension bridges in particular represent some of the largest and most important man-made structures and ensuring the seismic integrity of these mega-structures is contingent on accurate estimations of earthquake ground motions and accurate computational simulations of the structure/foundation system response. A cooperative, multi-year research project between the Univ. of California and LLNL was recently initiated to study engineering and seismological issues essential for simulating the response of major structures. Part of this research project is focused on the response of the long-span bridges with the San Francisco-Oakland Bay Bridge serving as a case study. This paper reports on the status of this multi-disciplinary research project with emphasis on the numerical simulation of the transient seismic response of the Bay Bridge.

  5. Optimum Maintenance Strategies for Highway Bridges

    DEFF Research Database (Denmark)

    Frangopol, Dan M.; Thoft-Christensen, Palle; Das, Parag C.;

    As bridges become older and maintenance costs become higher, transportation agencies are facing challenges related to implementation of optimal bridge management programs based on life cycle cost considerations. A reliability-based approach is necessary to find optimal solutions based on minimum...... expected life-cycle costs or maximum life-cycle benefits. This is because many maintenance activities can be associated with significant costs, but their effects on bridge safety can be minor. In this paper, the program of an investigation on optimum maintenance strategies for different bridge types...... is described. The end result of this investigation will be a general reliability-based framework to be used by the UK Highways Agency in order to plan optimal strategies for the maintenance of its bridge network so as to optimize whole-life costs....

  6. Building bridges … and accelerators

    CERN Multimedia

    2009-01-01

    Lyn Evans, the LHC project leader, was awarded an honorary doctorate from the University of Geneva (UNIGE) to celebrate his role not just in building accelerators, but also in building bridges between nations. He was one of four notables honoured at the event on Friday 5 June, coinciding with the University’s 450th Anniversary. Lyn Evans arriving at the ceremony with Archbishop Desmond Tutu. "It was a big surprise when I found out I’d been nominated," recounts Evans, "but it was an even bigger surprise to find out with whom I’d been nominated". At the ceremony Evans was awarded the honorary doctorate along with three others: Archbishop Desmond Tutu, who was acclaimed for his fight against apartheid in South Africa, Mary Robinson, first woman president of Ireland and former United Nations’ high commissioner of human rights, and Pascal Lamy, Director-General of the World Trade Organization. The award ceremony, known as the �...

  7. Application of Climbing Form Technology in Bridge Construction%爬模技术在桥梁施工中的应用

    Institute of Scientific and Technical Information of China (English)

    何忠舟

    2014-01-01

    以某大桥高墩施工为例,分别针对爬模系统的组成、塔身爬模施工工艺以及爬模系统的特点进行了详细探讨,指出了液压爬模的施工要点,包括液压爬模系统技术参数、液压爬模系统的安装施工、主塔液压爬模施工,可为同类桥梁施工提供借鉴。%Taking the high pier construction of a bridge as an example, the paper discusses the composing of climbing form system, the climbing form construction technique of tower body, and the characteristics of climbing form system in detail, points out the key points of hydraulic climbing form construction includ-ing technical parameters of hydraulic climbing form system, the installation and construction of hydraulic climbing form system, and the climbing form construction of the main tower, which can provide references for the construction of similar bridges.

  8. 跨多股道钢箱梁天桥的结构设计%The Structural Design of Steel Box Girder Pedestrian Bridge Crossing Multiple Railways

    Institute of Scientific and Technical Information of China (English)

    沈耀海

    2011-01-01

    结合西部某新建火车站进站人行天桥工程实例,分析了设计和施工的多种控制条件,论证了主梁采用钢箱梁结构的合理性.通过有限元分析和动力特性计算可知,结构设计的控制因素为竖向自振频率,采用中墩与主梁固结的连接方式可以有效地调整结构竖向自振频率.%Based on the project case of one pedestrian bridge in one new constructed railway station at west China, many controlled conditions are analyzed about structural design and engineering construction, and the rationalitles of steel box girder bridge adopted in the design are also demonstrated. It is learned from finite - element analysis and dynamic characteristics calculation that the control factor of structural design is vertical vibration frequency, which can be improved effectively by means of fixed connection between central pier and steel box girder.

  9. Earthquake Response Analysis of High Pier and Upper Auxiliary Structure%高闸墩及其上部附属结构地震响应分析

    Institute of Scientific and Technical Information of China (English)

    谢义华; 宫必宁; 刘莎

    2013-01-01

    At present, there is less aseismic research on the upper auxiliary structure and has no standards for mention, so it leads to random and empirical knowledge for equivalent static calculation. Dynamic time-history method is applied to calculate pier and frame structures of a hydropower station in the northwestern districts by using ADINA software. And the coupling effect between different structures is discussed under the action of earthquake through dynamic characteristics of different structures and response characteristics at different operating conditions. The results show that under the action of earthquake, pier and frame structures with mutational mass and stiffness in vertical direction produce structural damages like whiplash effect easily. So this phenomenon must be taken a special attention when designing.%鉴于我国对上部附属结构抗震研究较少,规范中也未专门提及,由此导致设计人员进行等效静力计算时带有一定的随意性和经验性.借助有限元软件ADINA,利用动力时程分析法计算了西北地区某水电站的闸墩和框架结构,并通过各结构的动力特性和不同工况下的响应特点,探讨了地震作用下结构之间的耦联作用.结果表明,在地震作用时,质量和刚度沿竖向均存在明显突变的高闸墩和框架结构易产生类鞭梢效应的结构破坏,设计时应引起格外重视.

  10. Oscillations in a sunspot with light bridges

    CERN Document Server

    Yuan, Ding; Huang, Zhenghua; Li, Bo; Su, Jiangtao; Yan, Yihua; Tan, Baolin

    2014-01-01

    Solar Optical Telescope onboard Hinode observed a sunspot (AR 11836) with two light bridges (LBs) on 31 Aug 2013. We analysed a 2-hour \\ion{Ca}{2} H emission intensity data set and detected strong 5-min oscillation power on both LBs and in the inner penumbra. The time-distance plot reveals that 5-min oscillation phase does not vary significantly along the thin bridge, indicating that the oscillations are likely to originate from the underneath. The slit taken along the central axis of the wide light bridge exhibits a standing wave feature. However, at the centre of the wide bridge, the 5-min oscillation power is found to be stronger than at its sides. Moreover, the time-distance plot across the wide bridge exhibits a herringbone pattern that indicates a counter-stream of two running waves originated at the bridge sides. Thus, the 5-min oscillations on the wide bridge also resemble the properties of running penumbral waves. The 5-min oscillations are suppressed in the umbra, while the 3-min oscillations occupy...

  11. Signal and noise in bridging PCR

    Directory of Open Access Journals (Sweden)

    Thaler David S

    2002-07-01

    Full Text Available Abstract Background In a variant of the standard PCR reaction termed bridging, or jumping, PCR the primer-bound sequences are originally on separate template molecules. Bridging can occur if, and only if, the templates contain a region of sequence similarity. A 3' end of synthesis in one round of synthesis that terminates in this region of similarity can prime on the other. In principle, Bridging PCR (BPCR can detect a subpopulation of one template that terminates synthesis in the region of sequence shared by the other template. This study considers the sensitivity and noise of BPCR as a quantitative assay for backbone interruptions. Bridging synthesis is also important to some methods for computing with DNA. Results In this study, BPCR was tested over a 328 base pair segment of the E. coli lac operon and a signal to noise ratio (S/N of approximately 10 was obtained under normal PCR conditions with Taq polymerase. With special precautions in the case of Taq or by using the Stoffel fragment the S/N was improved to 100, i.e. 1 part of cut input DNA yielded the same output as 100 parts of intact input DNA. Conclusions In the E. coli lac operator region studied here, depending on details of protocol, between 3 and 30% per kilobase of final PCR product resulted from bridging. Other systems are expected to differ in the proportion of product that is bridged consequent to PCR protocol and the sequence analyzed. In many cases physical bridging during PCR will have no informational consequence because the bridged templates are of identical sequence, but in a number of special cases bridging creates, or, destroys, information.

  12. 大桥深水基础方案设计与施工及经济性研究%Study of Design Solutions, Construction and Economy of Deepwater Foundations for Major Bridges

    Institute of Scientific and Technical Information of China (English)

    杨进

    2011-01-01

    大桥深水基础方案设计在技术上如能很好地与环境相适应,可以达到经济上更合理,现以2座大桥基础工程实例进行分析.肇庆西江公铁两用大桥水中4号墩基础外形与高承台管柱基础基本相似,采用全钢外壳,由于在施工中无需承受震动打桩机的强力冲击,所以结构截面比较轻型,用钢量并不高,且有相当一部分系使用后可以回收的常备式杆件,故在经济上更具优势而且工期也短.泰州长江公路大桥中塔沉井基础高76 m,分为12节,沉井平面布置12个大井孔,与当时在长江中习惯采用的大直径深钻孔集群桩基础方案相比,该沉井基础在材料上更节省,工艺上更简单,且在受力性能和经济性方面明显占优,具有明显的技术优势.%If the design solutions of deepwater foundations for major bridges can technically accommodate very well the environment where the foundations are located, the solutions will be economically still more rational. The practical examples of the foundations of two major bridges are cited herewith and analyzed. The outline of the foundation for in-water Pier No. 4 of Zhaoqing Xijiang River Rail-cum-Road Bridge, used with complete steel shell, is basically similar to the foundation of the cylindrical shafts with elevated pier base. The structural cross section of the foundation for the pier is rather light and the usage amount of steel is not great because the foundation does not have to sustain strong impact from vibro-pile driver in the construction and moreover, a considerable part of the common members for the foundation is recyclable after usage and the foundation therefore is economically advantageous and the working time schedule is short as well. The caisson foundation, 76 m in height, for intermediate tower of Taizhou Changjiang River Highway Bridge is composed of 12 lifts and has 12 big wells arranged in plan of the caisson. In comparison to the large diameter and deep hole group

  13. 粉房湾长江大桥船撞风险分析与设防标准研究%Risk Analysis and Protection Criteria Study of Ship Collision of Fenfangwan Changjiang River Bridge

    Institute of Scientific and Technical Information of China (English)

    耿波; 徐龙

    2012-01-01

    为确定粉房湾长江大桥设防船撞力标准,采用美国AASHTO规范方法和三概率参数积分路径方法对该桥进行船撞风险分析,计算桥梁的碰撞概率和年倒塌频率,并与可接受的风险准则进行比较;确定船撞设计代表船型,采用LS-DYNA软件对船舶碰撞桥梁进行数值模拟分析.分析结果表明:该桥在2010年、2020年和2050年通航密度下的船撞风险分别为4.05×10-6、2.02×10-5、7.06×10-5;P3、P4主墩的船撞设计代表船型均为5 000吨级;近期P3、P4主墩的设防船撞力可分别取38.68 MN和27.57 MN,远期可分别取38.68 MN和24.19 MN,P3、P4主墩抗力均满足船撞设防标准.%To determine the protection criteria for ship collision forces of Fenfangwan Changjiang River Bridge, the ship collision risk of the bridge was analyzed, the collision probability and the annual bridge collapse probability were calculated by the AASHTO method'and the three-probability parameter integral path method, and the analysis and calculation were compared to the acceptable risk criteria. The representative types of ships used for the ship collision design were determined and the software LS-DYNA was used to carry out numerical simulation of the ships colliding against the bridge. The results of the analysis indicate that the ship collision risk of the bridge under the shipping-density in the years 2010, 2020 and 2050 are respectively 4. 05 X 10-6 , 2. 02 × 10-5 and 7. 06 × 10-5. The representative types of the ships colliding against the main piers P3 and P4 of the bridge are of the 5 000 tonnage, the ship collision force protection of the piers in the near future can be determined as 38. 68 MN and 27. 57 MN and in the far future can be 38. 68 MN and 24. 19 MN, which will all satisfy the protection criteria of the ship collision of the piers.

  14. Building the clinical bridge: an Australian success.

    Science.gov (United States)

    Wallis, Marianne; Chaboyer, Wendy

    2012-01-01

    Nursing effectiveness science includes primary, secondary, and translational, clinically focused research activities which aim to improve patient or client outcomes. It is imperative, for the successful conduct of a program of nursing effectiveness science, that a clinical bridge is established between academic and healthcare service facilities. An Australian example of the development of a robust clinical bridge through the use of jointly funded positions at the professorial level is outlined. In addition, an analysis of the practical application of Lewin's model of change management and the contribution of both servant and transformational leadership styles to the bridge building process is provided.

  15. Building the Clinical Bridge: An Australian Success

    Directory of Open Access Journals (Sweden)

    Marianne Wallis

    2012-01-01

    Full Text Available Nursing effectiveness science includes primary, secondary, and translational, clinically focused research activities which aim to improve patient or client outcomes. It is imperative, for the successful conduct of a program of nursing effectiveness science, that a clinical bridge is established between academic and healthcare service facilities. An Australian example of the development of a robust clinical bridge through the use of jointly funded positions at the professorial level is outlined. In addition, an analysis of the practical application of Lewin’s model of change management and the contribution of both servant and transformational leadership styles to the bridge building process is provided.

  16. Asymptotics of a horizontal liquid bridge

    Science.gov (United States)

    Haynes, M.; O'Brien, S. B. G.; Benilov, E. S.

    2016-04-01

    This paper uses asymptotic techniques to find the shape of a two dimensional liquid bridge suspended between two vertical walls. We model the equilibrium bridge shape using the Laplace-Young equation. We use the Bond number as a small parameter to deduce an asymptotic solution which is then compared with numerical solutions. The perturbation approach demonstrates that equilibrium is only possible if the contact angle lies within a hysteresis interval and the analysis relates the width of this interval to the Bond number. This result is verified by comparison with a global force balance. In addition, we examine the quasi-static evolution of such a two dimensional bridge.

  17. Calculations in bridge aeroelasticity via CFD

    Energy Technology Data Exchange (ETDEWEB)

    Brar, P.S.; Raul, R.; Scanlan, R.H. [Johns Hopkins Univ., Baltimore, MD (United States)

    1996-12-31

    The central focus of the present study is the numerical calculation of flutter derivatives. These aeroelastic coefficients play an important role in determining the stability or instability of long, flexible structures under ambient wind loading. A class of Civil Engineering structures most susceptible to such an instability are long-span bridges of the cable-stayed or suspended-span variety. The disastrous collapse of the Tacoma Narrows suspension bridge in the recent past, due to a flutter instability, has been a big impetus in motivating studies in flutter of bridge decks.

  18. Gust loading on streamlined bridge decks

    DEFF Research Database (Denmark)

    Larose, Guy; Mann, Jakob

    1998-01-01

    The current analytical description of the buffeting action of wind on long-span bridges is based on the strip assumption. However, recent experiments on closed-box girder bridge decks have shown that this assumption is not valid and is the source of an important part of the error margin...... of the analytical prediction methods. In this paper, an analytical model that departs from the strip assumption is used to describe the gust loading on a thin airfoil. A parallel is drawn between the analytical model and direct measurements of gust loading on motionless closed-box girder bridge decks. Empirical...

  19. Transformation of the bridge during drop separation

    Science.gov (United States)

    Chashechkin, Yu. D.; Prokhorov, V. E.

    2016-05-01

    The geometry of flows during separation of pendant drops of liquids with significantly different physical properties (alcohol, water, glycerin, oil) has been studied by high-speed video recording. The dynamics of the processes involving the formation of bridges of two characteristic shapes—slightly nonuniform in thickness and with thinning of the upper and lower ends—has been investigated. It has been shown that the shape change of the separated bridge has a number of stages determined by the properties of the liquid. As a result, the bridge is transformed into a small drop—a satellite drop.

  20. Closure technique for the hybrid girder cable stayed bridge of Edong Bridge

    Institute of Scientific and Technical Information of China (English)

    Liu Minghu; Tan Hao; Xu GuoPing; Zhao Canhui

    2012-01-01

    Based on Edong Yangtze River Bridge, which is the second longest hybrid girder cable stayed bridge with 926 m long main span, the influencing factors and crucial techniques of the main span closure method for long span hybrid girder cable stayed bridge are studied. After theoretical analysis, numerical evaluation and practical test, the loading assistant closure method is employed in Edong Yangtze River Bridge. The loading assistant closure method, with better thermal adaptability and less influence on bridge line and the forced status, can meet the requirements of the unstressed state control method. Based on the mentioned advantages, the loading assistant closure method is applicable to long span hybrid girder cable stayed bridges. The conclusion can provide a reference for the further design of the similar brid~es.

  1. 后牙氧化锆全瓷桥的临床应用分析%Clinical analysis of All-ceramic bridges with Zirconia-base in posterior teeth repairing

    Institute of Scientific and Technical Information of China (English)

    彭利辉; 钟爱喜; 潘小波; 刘光雪; 李荣婷

    2011-01-01

    Objective To explore the effects of All-ceramic bridges with Zirconia-base in posterior teeth repairing. Methods 31 patients with 1 or 2 missing posterior teeth were restored with Zirconia-base All-ceramic bridges.and followed up 1 to 2 years. Results 30 bridges were sealed and had good retentive power.those all reached class A in marginal integrity,crown coloring,pier periodontal pocket aspects,without loosing and shedding,1 bridge was fracture and shedded,the succeed rate is 96.77. Conclusion Zirconia-base All-ceramic bridges may be used in the repairing of 1 or 2 missing posterior teeth,and the repairing effect is fine.%目的:探讨氧化锆全瓷桥在1~2颗后牙缺失固定修复中的应用.方法:选择31例单颗或2颗后牙缺失患者行氧化锆全瓷桥的固定修复、现察1~2年.结果:除1例(3单位桥)在修复1年后桥体折断并脱落,其余修复体修复效果良好,在边缘密合度、冠染色、基牙牙周袋方面均迭A级,修复体未见脱落及松动,成功率达96,77%.结论:氧化锆全瓷桥可用于1~2颗后牙缺失的3~5单位的固定桥修复,效果良好.

  2. Diode-quad bridge circuit means

    Science.gov (United States)

    Harrison, D. R.; Dimeff, J. (Inventor)

    1975-01-01

    A transducer and frequency discriminator circuit is described including a four-terminal circulating diode bridge, a first pair of capacitors connected in series across two terminals of the bridge, and a second pair of capacitors, or other impedance elements, connected in series across the other two terminals of the bridge. A source of balanced alternating electrical energy for energizing the circuit is coupled between the commonly connected plates of the first pair of capacitors and the commonly connected plates of the second pair of capacitors. Due to the operation of the diode bridge, the sum of the resultant charges developed on the first pair of capacitors is proportional to the relationship between the respective capacitors of the second pair, and consequently, an output voltage taken across the first pair of capacitors will be proportional to that relationship.

  3. Allegheny County-Owned Bridges Points

    Data.gov (United States)

    Allegheny County / City of Pittsburgh / Western PA Regional Data Center — This dataset shows the location of bridges owned by Allegheny County as centroids. If viewing this description on the Western Pennsylvania Regional Data Center’s...

  4. Allegheny County-Owned Bridges Centerlines

    Data.gov (United States)

    Allegheny County / City of Pittsburgh / Western PA Regional Data Center — This dataset shows the bridges owned by Allegheny County. If viewing this description on the Western Pennsylvania Regional Data Center’s open data portal...

  5. Relaxation of liquid bridge after droplets coalescence

    Directory of Open Access Journals (Sweden)

    Jiangen Zheng

    2016-11-01

    Full Text Available We investigate the relaxation of liquid bridge after the coalescence of two sessile droplets resting on an organic glass substrate both experimentally and theoretically. The liquid bridge is found to relax to its equilibrium shape via two distinct approaches: damped oscillation relaxation and underdamped relaxation. When the viscosity is low, damped oscillation shows up, in this approach, the liquid bridge undergoes a damped oscillation process until it reaches its stable shape. However, if the viscous effects become significant, underdamped relaxation occurs. In this case, the liquid bridge relaxes to its equilibrium state in a non-periodic decay mode. In depth analysis indicates that the damping rate and oscillation period of damped oscillation are related to an inertial-capillary time scale τc. These experimental results are also testified by our numerical simulations with COMSOL Multiphysics.

  6. Wheatstone bridge technique for magnetostriction measurements.

    Science.gov (United States)

    Sullivan, M

    1980-03-01

    A basic Wheatstone bridge, with additional electronic instrumentation, has been used in the measurement of magnetostriction. This method allows a resolution of approximately 10% on measurements of magnetostrictions less than 0.75 parts per million.

  7. VT Short Structures - Bridges and Culverts

    Data.gov (United States)

    Vermont Center for Geographic Information — Inspection data for structures (bridge and culvert) between 6 feet and 20 feet in length inspected on State road system. Stewards: Information Technology, Data...

  8. VT Long Structures - Bridges and Culverts

    Data.gov (United States)

    Vermont Center for Geographic Information — Inspection data for structures (bridge and culvert) greater than 20 feet in length inspected on both State and local road systems. Stewards: Information Technology,...

  9. Active Control of Long Bridges Using Flaps

    DEFF Research Database (Denmark)

    Hansen, H. I.; Thoft-Christensen, Palle

    The main problem in designing ultra-long span suspension bridges is flutter. A solution to this problem might be to introduce an active flap control system to increase the flutter wind velocity. The investigated flap control system consists of flaps integrated in the bridge girder so each flap...... is the streamlined part of the edge of the girder. Additional aerodynamic derivatives are shown for the flaps and it is shown how methods already developed can be used to estimate the flutter wind velocity for a bridge section with flaps. As an example, the flutter wind velocity is calculated for different flap...... configurations for a bridge section model by using aerodynamic derivatives for a flat plate. The example shows that different flap configurations can either increase or decrease the flutter wind velocity. for optimal flap configurations flutter will not occur....

  10. Pilot testing of a hydraulic bridge exciter

    Directory of Open Access Journals (Sweden)

    Andersson Andreas

    2015-01-01

    Full Text Available This paper describes the development of a hydraulic bridge exciter and its first pilot testing on a full scale railway bridge in service. The exciter is based on a hydraulic load cylinder with a capacity of 50 kN and is intended for controlled dynamic loading up to at least 50 Hz. The load is applied from underneath the bridge, enabling testing while the railway line is in service. The system is shown to produce constant load amplitude even at resonance. The exciter is used to experimentally determine frequency response functions at all sensor locations, which serve as valuable input for model updating and verification. An FE-model of the case study bridge has been developed that is in good agreement with the experimental results.

  11. Practical Approach to Fragility Analysis of Bridges

    Directory of Open Access Journals (Sweden)

    Yasamin Rafie Nazari

    2012-12-01

    Full Text Available Damages during past earthquakes reveal seismic vulnerability of bridge structures and the necessity of probabilistic approach toward seismic performance evaluation of bridges and its interpretation in terms of decision variables such as repair cost, downtime and life loss. This Procedure involves hazard analysis, structural analysis, damage analysis and loss analysis. The purpose of present study is reviewing different methods developed to derive fragility curves for damage analysis of bridges and demonstrating a simple procedure for fragility analysis using Microsoft Office Excel worksheet to reach probability of occurring predefined level of damage due to different levels of seismic demand parameters. The input of this procedure is the intensity of ground motion and the output is an appropriate estimate of the expected damage. Different observed damages of the bridges are discussed and compared the practical definition of damage states. Different methods of fragility analyses are discussed and a practical step by step example is illustrated.

  12. Identifying hidden sexual bridging communities in Chicago.

    Science.gov (United States)

    Youm, Yoosik; Mackesy-Amiti, Mary Ellen; Williams, Chyvette T; Ouellet, Lawrence J

    2009-07-01

    Bridge populations can play a central role in the spread of human immunodeficiency virus (HIV) by providing transmission links between higher and lower prevalence populations. While social network methods are well suited to the study of bridge populations, analyses tend to focus on dyads (i.e., risk between drug and/or sex partners) and ignore bridges between distinct subpopulations. This study takes initial steps toward moving the analysis of sexual network linkages beyond individual and risk group levels to a community level in which Chicago's 77 community areas are examined as subpopulations for the purpose of identifying potential bridging communities. Of particular interest are "hidden" bridging communities; that is, areas with above-average levels of sexual ties with other areas but whose below-average AIDS prevalence may hide their potential importance for HIV prevention. Data for this analysis came from the first wave of recruiting at the Chicago Sexual Acquisition and Transmission of HIV Cooperative Agreement Program site. Between August 2005 through October 2006, respondent-driven sampling was used to recruit users of heroin, cocaine, or methamphetamine, men who have sex with men regardless of drug use, the sex partners of these two groups, and sex partners of the sex partners. In this cross-sectional study of the sexual transmission of HIV, participants completed a network-focused computer-assisted self-administered interview, which included questions about the geographic locations of sexual contacts with up to six recent partners. Bridging scores for each area were determined using a matrix representing Chicago's 77 community areas and were assessed using two measures: non-redundant ties and flow betweenness. Bridging measures and acquired immunodeficiency syndrome (AIDS) case prevalence rates were plotted for each community area on charts representing four conditions: below-average bridging and AIDS prevalence, below-average bridging and above

  13. 49 CFR 237.33 - Content of bridge management programs.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Content of bridge management programs. 237.33... Content of bridge management programs. Each bridge management program adopted in compliance with this part... spans, span lengths, and all other information necessary to provide for the management of bridge...

  14. 23 CFR 650.705 - Application for discretionary bridge funds.

    Science.gov (United States)

    2010-04-01

    ... TRAFFIC OPERATIONS BRIDGES, STRUCTURES, AND HYDRAULICS Discretionary Bridge Candidate Rating Factor § 650... cost, current average daily truck traffic and a narrative describing the existing bridge, the proposed new or rehabilitated bridge and other relevant factors which the State believes may warrant...

  15. 33 CFR 118.80 - Lights on bascule bridges.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Lights on bascule bridges. 118.80 Section 118.80 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.80 Lights on bascule bridges. (a) Lift span lights. Each lift span...

  16. 33 CFR 118.90 - Bridges crossing channel obliquely.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Bridges crossing channel obliquely. 118.90 Section 118.90 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.90 Bridges crossing channel obliquely....

  17. 23 CFR 650.809 - Movable span bridges.

    Science.gov (United States)

    2010-04-01

    ... 23 Highways 1 2010-04-01 2010-04-01 false Movable span bridges. 650.809 Section 650.809 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENGINEERING AND TRAFFIC OPERATIONS BRIDGES, STRUCTURES, AND HYDRAULICS Navigational Clearances for Bridges § 650.809 Movable span bridges. A fixed...

  18. Detection of salt bridges to lysines in solution in barnase

    DEFF Research Database (Denmark)

    Hansen, Poul Erik; Williamson, Michael P.; Hounslow, Andrea M.

    2013-01-01

    We show that salt bridges involving lysines can be detected by deuterium isotope effects on NMR chemical shifts of the sidechain amine. Lys27 in the ribonuclease barnase is salt bridged, and mutation of Arg69 to Lys retains a partially buried salt bridge. The salt bridges are functionally important....

  19. Inspection Based Evaluation of a Danish Road Bridge

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    In this paper it is shown how an inspection-based evaluation of a Danish road bridge may be performed using the BRIDGE1 and BRIDGE2 bridge management systems produced within the EC-supported research programme "Assessment of Performance and Optimal Strategies for Inspection and Maintenance...

  20. Micromechanical model of cross-over fibre bridging - Prediction of mixed mode bridging laws

    DEFF Research Database (Denmark)

    Sørensen, Bent F.; Gamstedt, E.K.; Østergaard, Rasmus Christian;

    2008-01-01

    on the observed bridging mechanism, a micromechanical model is developed for the prediction of macroscopic mixed mode bridging laws (stress-opening laws). The model predicts a high normal stress for very small openings, decreasing rapidly with increasing normal and tangential crack opening displacements......The fracture resistance of fibre composites can be greatly enhanced by crack bridging. In situ observations of mixed mode crack growth in a unidirectional carbon-fibre/epoxy composite reveal crack bridging by single fibres and by beam-like ligaments consisting of several fibres. Based...

  1. Thermal Bridge Effects in Walls Separating Rowhouses

    DEFF Research Database (Denmark)

    Rose, Jørgen

    1997-01-01

    In this report the thermal bridge effects at internal wall/roof junctions in rowhouses are evaluated. The analysis is performed using a numerical calculation programme, and different solutions are evaluated with respect to extra heat loss and internal surface temperatures.......In this report the thermal bridge effects at internal wall/roof junctions in rowhouses are evaluated. The analysis is performed using a numerical calculation programme, and different solutions are evaluated with respect to extra heat loss and internal surface temperatures....

  2. Heavy Vehicles on Minor Highway Bridges

    DEFF Research Database (Denmark)

    Nielsen, Søren R. K.; Kirkegaard, Poul Henning; Enevoldsen, I.

    The present paper worked out as a part of a research project on "Dynamic amplification factor of vehicle loadings on smaller bridges" establishes a two-dimensional spectral description of the road roughness surface based on measurements from a Danish road using so-called Profilograph used by Danish...... to the bridge and the stochastic nature of the surface roughness are included into the model....

  3. Earthquake Resistance of Integral Abutment Bridges

    OpenAIRE

    2009-01-01

    intermediate length bridges. Integral abutment construction eliminates joints and bearings which reduce long-term maintenance costs. However, in the absence of joints and bearings, the bridge abutments and foundations must be able to accommodate lateral movements from thermal expansion and contraction of the superstructure and from seismic events. Previous research has focused on the response to thermal expansion and contraction. The current research examines the response of integral abutment...

  4. Arch bridges – unlocking their potential

    OpenAIRE

    Long, Adrian; Nanukuttan, Sreejith

    2016-01-01

    Arch bridges are strong, durable, aesthetically pleasing and require little maintenance but very few have been built since the early 1900s. However, this trend has changed as more than 60 FlexiArch bridges have been installed since the system was launched in 2007. The FlexiArch uses precast concrete voussoirs, requires neither corrodible reinforcement, nor centring, can be installed in hours and is contractor friendly. Details of this innovative method of construction and installation of arch...

  5. External Prestressing Bridge Reinforcement Technology Review

    Directory of Open Access Journals (Sweden)

    Zhu Hanbing

    2015-01-01

    Full Text Available Externally prestressed bridge can not only limit and reduce the cracks and deformation of the structure, improve the rigidity and bearing capacity of structure, improve the stress state of structure, but also have less interference for bridge operation when it is operating and have the good economic efficiency. This paper introduces the advantages and disadvantages of external prestressed strengthening technique, its calculation theory and construction technology described in detail, and finally the paper discusses the deficiency of existing research.

  6. Study of Parameters Influencing Load Bearing Performance of No .0 Block in PC Continuous Box Girder Bridge%PC连续箱梁桥0号块受力性能的影响参数分析

    Institute of Scientific and Technical Information of China (English)

    熊敏; 胡峰强; 邱衍坚; 徐义标; 冯小毛; 刘蕙婷

    2016-01-01

    To study the load bearing performance of No .0 blocks in the superstructure of PC continuous box beam bridge ,a PC continuous box beam bridge with span arrangement of (55+90+90+55) m was taken as the study background .The spatial finite element model of the No .0 block was established to study the variation of parameters on the load bearing capacity of No .0 block ,including the height of the piers ,prestressing loss along the prestressing tendons and the constraints of the bearings .And the features of the spatial stress of the No .0 block during the lon‐gest cantilever construction stage and in the completed bridge state were analyzed .The results of the analysis indicate that the stress in the intersection of the bottom slab of the No .0 block box beam and the bearings is prone to the influence of pier height ,therefore ,the influence of piers should be taken into account during the model establishment ,and pier heights can choose one time of the beam depth to simplify the process .The surrounding prestressing distribution exerts signifi‐cant influence on the load bearing capacity of No .0 block .During the operation period ,if the stress local distortion of the No .0 block at the bearings is not considered ,the fixed constraints can be used to replace the real bearings in the stress calculation of No .0 block as a simplified treat‐ment .At the locations where constant cross section of the diaphragm showing abrupt change ,the main tensile stress in the No .0 block will exceed the values prescribed in the code .%为研究PC连续箱梁桥0号块建模参数对其受力性能的影响程度,以选取合理的建模参数,以某跨度为(55+90+90+55) m的PC连续箱梁桥为工程背景,建立0号块空间有限元模型,分析不同桥墩高度、预应力筋沿程预应力损失、支座约束等参数下0号块受力性能的变化规律,以及最大悬臂施工阶段和成桥阶段0号块的空间应力特点。分析结果表明:0

  7. Framework for Bridges Maintenance in Egypt

    Directory of Open Access Journals (Sweden)

    Hesham Abd Elkhalek

    2016-01-01

    Full Text Available The traditional approaches for bridges maintenance is proven to be inefficient as they lead to random way of spending maintenance budget and deteriorating bridge conditions. In many cases, maintenance activities are performed due to user complaints. The objective of this paper is to develop a practical and reliable framework to manage the maintenance and repair activities of Bridges network in Egypt considering performance and budget limits. The model solves an optimization problem that maximizes the average condition of the network given the limited budget using Genetic Algorithm (GA. The main tasks of the system are bridge inventory, condition assessment, deterioration using markov model, and maintenance optimization. The developed model takes into account multiple parameters including serviceability requirements, budget allocation, element importance on structural safety and serviceability, bridge impact on network, and traffic. A questionnaire is conducted to complete the research scope. The proposed model is implemented in software, which provides a friendly user interface. The results of the framework are multi – year maintenance plan for the entire network for up to five years. A case study is presented for validating and testing the model with Data collected from “General Authority for Roads, Bridges and Land Transport” in Egypt.

  8. I-5/Gilman advanced technology bridge project

    Science.gov (United States)

    Lanza di Scalea, Francesco; Karbhari, Vistasp M.; Seible, Frieder

    2000-04-01

    The UCSD led I-5/Gilman Advanced Technology Bridge Project will design and construct a fully functional traffic bridge of advanced composite materials across Interstate 5 in La Jolla, California. Its objective is to demonstrate the use of advanced composite technologies developed by the aerospace industry in commercial applications to increase the life expectancy of new structures and for the rehabilitation of aging infrastructure components. The structure will be a 450 ft long, 60 ft wide cable-stayed bridge supported by a 150 ft A-frame pylon with two vehicular lanes, two bicycle lanes, pedestrian walkways and utility tunnels. The longitudinal girders and pylon will be carbon fiber shells filled with concrete. The transverse deck system will consist of hollow glass/carbon hybrid tubes and a polypropylene fiber reinforced concrete deck with an arch action. Selected cables will be composite. The bridge's structural behavior will be monitored to determine how advanced composite materials perform in civil infrastructure applications. The bridge will be instrumented to obtain performance and structural health data in real time and, where possible, in a remote fashion. The sensors applied to the bridge will include electrical resistance strain gages, fiberoptic Bragg gratings and accelerometers.

  9. Calculation analysis on portal frame pier structure of expressway reconstruction and extension%改扩建高速公路门架墩结构计算分析

    Institute of Scientific and Technical Information of China (English)

    郜小兴; 晏炳科

    2012-01-01

    通过对某改扩建高速公路门架墩结构的有限元计算分析,总结了其结构受力特点,并对考虑和不考虑桩基参与受力两种情况下的门架墩计算结果进行了探讨,进而得出了一些有指导意义的结论。%Through the finite element calculation analysis on a portal frame pier structure of expressway reconstruction and extension,this paper summarized the force characteristics of this structure,and discussed the calculation results of portal frame pier under considering and not considering pile foundation in force two situations,and then gained some instructive conclusions.

  10. A Tale of Five Bridges; the use of GNSS for Monitoring the Deflections of Bridges

    Science.gov (United States)

    Roberts, Gethin Wyn; Brown, Christopher J.; Tang, Xu; Meng, Xiaolin; Ogundipe, Oluropo

    2014-11-01

    The first Bridge Monitoring surveying was carried out in 1996 by the authors, through attaching Ashtech ZXII GPS receivers onto the Humber Bridge' parapet, and gathering and further analysing the resulting 1 Hz RTK GPS data. Various surveys have subsequently been conducted on the Humber Bridge, the Millennium Bridge, the Forth Road Bridge, the Severn Suspension Bridge and the Avonmouth Viaduct. These were all carried out using survey grade carrier phase/pseudorange GPS and later GNSS receivers. These receivers were primarily dual frequency receivers, but the work has also investigated the use of single frequency receivers, gathering data at 1 Hz, 10 Hz, 20 Hz and even 100 Hz. Various aspects of the research conducted are reported here, as well as the historical approach. Conclusions are shown in the paper, as well as lessons learnt during the development of this work. The results are compared to various models that exist of the bridges' movements, and compare well. The results also illustrate that calculating the frequencies of the movements, as well as looking at the magnitudes of the movements, is an important aspect of this work. It is also shown that in instances where the magnitudes of the movements of the bridge under investigation are small, it is still possible to derive very accurate frequencies of the movements, in comparison to the existing models.

  11. Role of multiprotein bridging factor 1 in archaea: bridging the domains?

    NARCIS (Netherlands)

    Koning, de B.; Blombach, F.; Wu Hao,; Brouns, S.J.J.; Oost, van der J.

    2009-01-01

    MBF1 (multiprotein bridging factor 1) is a highly conserved protein in archaea and eukaryotes. It was originally identified as a mediator of the eukaryotic transcription regulator BmFTZ-F1 (Bombyx mori regulator of fushi tarazu). MBF1 was demonstrated to enhance transcription by forming a bridge bet

  12. 横风对货车通过高墩桥梁行车安全性的影响分析%The Running Safety Analysis of Freight Trains Passing on the High Pier Bridge to Cross Wind Loads

    Institute of Scientific and Technical Information of China (English)

    凌知民; 高碧波; 项海帆

    2007-01-01

    在对国内外研究成果进行简要介绍和分析的基础上,本文按一系悬挂和变摩擦阻尼建立货车的动力计算模型;轮轨作用力采用Kalker的线性接触理论并按Vermeulen-Jnhnson的非线性理论对其进行修正的方法;作为车桥系统外部激励的抖振力的时域随机风荷载按Shinozuka理论进行模拟.以某高墩连续梁刚构桥为对象,对考虑横风作用时货车的行车安全性进行了对比分析.计算结果表明:在横风作用时,背风侧的脱轨系数和轮轨作用力增加,轮重减载率减小,迎风侧的脱轨系数和轮轨作用力有所减小,轮重减载率增加;与无风时相比,横风的作用将导致车辆的行车安全性较为不利,这一结论与文献[2]的试验结果基本一致.

  13. 谷拉河大桥墩液压自爬模施工受力分析%The Construction Stress Analysis of Hydraulic Creep Form in the Bridge Pier of River Gula

    Institute of Scientific and Technical Information of China (English)

    崔凌岳

    2007-01-01

    桥梁的高桥墩施工属于特种结构施工范畴,现场施工方案的选择一直以来偏重于经验而忽视施工受力分析.本文基于工程实例,给出了桥梁高墩身施工选用液压自爬模完整的施工受力计算过程,且已成功地应用于工程实践,可供类似特种结构施工参考.

  14. 谷拉河大桥混凝土薄壁空心墩爬模施工技术%Construction Technique of Climbing Forms for the Thin-Walled, Hollow Piers of the Gula River Bridge

    Institute of Scientific and Technical Information of China (English)

    彭彦彬; 张彦光

    2005-01-01

    高桥墩施工是大桥施工的重点和难点,合理选择施工方法是成功的关键.介绍桥墩施工的基本方法及各自的特点,并着重介绍液压自动爬升模板的构造、施工工艺、关键技术及该施工方法的特点.实践表明,液压自动爬升模板系统施工速度快,施工质量好,作业安全,能节省大量的模板拆、装工作,经济效益高,是一种很有发展前途的高桥墩及其他高大建筑施工的新型模板系统,具有较高的推广价值.

  15. 桥梁单墩不同侧向力分布模式Pushover分析方法%Pushover analysis of different distribute lateral load patterns for seismic assessment of bridge piers

    Institute of Scientific and Technical Information of China (English)

    盛光祖; 李建中; 陈亮

    2010-01-01

    Pushover分析使用一定分布模式的递增水平侧向力代表地震作用下结构惯性力的分布,分布模式的不同会直接影响Pushover分析的结果,尤其是结构高阶振型影响显著时,因此侧向力分布的选取是Pushover分析中的一个关键问题.通过选取7条强震地震波,对比了典型地震波下非线性时程分析(IDA)和采用4种不同侧向力分布模式的Pushover分析的15m、30m和60m墩的地震反应.并从总体、构件和截面三个层面对各种模式Pushover分析进行评价,分析其适用性.研究表明结构进入非线性和高阶振型影响显著时,自适应侧向力模式较其他模式Pushover分析结果更接近IDA分析结果.

  16. Modified Modal Pushover Method Applied to Seismic Analysis of High-Pier Bridge%改进模态pushover法应用于高墩桥梁抗震分析

    Institute of Scientific and Technical Information of China (English)

    龙晓鸿; 潘玲; 陈恩友; 陈宏伟

    2008-01-01

    国内外尚缺乏针对高墩桥梁抗震的设计方法.介绍了模态pushover分析方法与能力谱法相结合后的改进模态pushover分析方法,并以实例进行高阶振型对高墩桥梁抗震能力的影响分析.将其计算结果与常规加载的pushover分析方法的计算结果进行比较,分析表明在高墩桥梁中不能忽略高阶振型的影响.

  17. Natural vibration dynamics of Rainbow Bridge, Utah

    Science.gov (United States)

    Moore, J. R.; Thorne, M. S.; Wood, J. R.; Doyle, S.; Stanfield, E.; White, B.

    2015-12-01

    We measured resonant frequencies of Rainbow Bridge, Utah, one of the world's longest rock spans, during a field experiment recording ambient vibration data. Measurements were generated over 20 hours on March 23-24, 2015 using two broadband three-component seismometers placed on the bridge, and compared to concurrent data from nearby reference stations 20 and 220 m distant. We identified seven distinct modes of vibration for Rainbow Bridge between 1 and 6 Hz. Data for each resonant frequency was then analyzed to determine the frequency-dependent polarization vector in an attempt to clarify mode shapes; e.g. the fundamental mode represents out-of-plane horizontal flexure. We compared experimental data to results of 3D numerical modal analysis, using a new photogrammetric model of Rainbow Bridge generated in this study imported into COMSOL Multiphysics. Results compare well with measured data for seven of the first eight modeled modes, matching vibrational frequencies and polarization orientations generally within 10%. Only predicted mode 6 was not explicitly apparent in our experimental data. Large site-to-reference spectral ratios resolved from experimental data indicate high amplification on the bridge as compared to nearby bedrock.

  18. A probabilistic bridge safety evaluation against floods.

    Science.gov (United States)

    Liao, Kuo-Wei; Muto, Yasunori; Chen, Wei-Lun; Wu, Bang-Ho

    2016-01-01

    To further capture the influences of uncertain factors on river bridge safety evaluation, a probabilistic approach is adopted. Because this is a systematic and nonlinear problem, MPP-based reliability analyses are not suitable. A sampling approach such as a Monte Carlo simulation (MCS) or importance sampling is often adopted. To enhance the efficiency of the sampling approach, this study utilizes Bayesian least squares support vector machines to construct a response surface followed by an MCS, providing a more precise safety index. Although there are several factors impacting the flood-resistant reliability of a bridge, previous experiences and studies show that the reliability of the bridge itself plays a key role. Thus, the goal of this study is to analyze the system reliability of a selected bridge that includes five limit states. The random variables considered here include the water surface elevation, water velocity, local scour depth, soil property and wind load. Because the first three variables are deeply affected by river hydraulics, a probabilistic HEC-RAS-based simulation is performed to capture the uncertainties in those random variables. The accuracy and variation of our solutions are confirmed by a direct MCS to ensure the applicability of the proposed approach. The results of a numerical example indicate that the proposed approach can efficiently provide an accurate bridge safety evaluation and maintain satisfactory variation.

  19. Using rotating liquid bridges as accelerometers

    Energy Technology Data Exchange (ETDEWEB)

    Montanero, J.M. [Universidad de Extremadura, Badajoz (Spain). Dept. de Electronica e Ingenieria Electromecanica; Cabezas, G.; Acero, J.; Zayas, F.

    1999-07-01

    Liquid bridges have recently been proposed as fluid accelerometers that could be used to measure very small inertial forces under microgravity conditions [Meseguer et al., microgravity sci. technol. IX/2 (1996)]. The essential idea is to infer the values of such inertial forces from the liquid bridge interface contour, whose shape obviously depends on the values of such forces (apart from the bridge volume and the geometry of the supporting disks). Following a similar procedure, in this paper we explore the use of rotating axisymmetric liquid bridges to measure the residual axial gravity and the rotation rate of the liquid bridge regarded as a solid body. In light off the difficulties involved in performing experiments on Earth, the role of empirical data is played by an accurate numerical solution of the Young-Laplace equation. The values of both the axial gravity and angular speed are obtained by fitting the approximate analytical expressions derived in this paper to the numerical solution of the Young-Laplace equation. The comparison between the predicted and actual values of the variables of interest shows a satisfactory agreement, supporting the suitability of the procedure. (orig.)

  20. 高瓦斯矿井高水材料充填墩柱沿空留巷技术%Gateway Retained Along Goaf Technology with Pier Pillar Backfilled with High Water Material in High Gassy Mine

    Institute of Scientific and Technical Information of China (English)

    史国跃

    2014-01-01

    In order to improve a high timber consumption,high labor intensity,complicated construction and low support strength of the timber pack gateway retained along the goaf,a high water material was applied to backfill the pier pillar for the gateway retained along the goaf technology in Gaohe Mine and the industrial trial was conducted in No. E1302 air return gateway.The results showed that the max convergence between the roof and floor of the timber pack gateway retained along the goaf was 286 mm,the max convergence between the roof and floor of the gateway retained along the goaf with the pier pillar backfilled with the high water material was 188 mm and the max deformation value of the pier pillar was 65 mm.The construction technology of the gateway retained along the goaf with the pier pillar backfilled with the high water material was simple.The compressive strength of the pier pillar was high and could control the deformation of the surrounding rock.Meanwhile,the ventilation cross section enlarged of the mine roadway would be favorable for the ventilation gas discharging and could prevent the gas accident occurred in the mine.%为了改善木垛沿空留巷木料消耗量大、劳动强度高、施工复杂、支护强度较低的问题,高河煤矿采用了高水材料充填墩柱沿空留巷技术,并在E1302回风巷进行了工业性试验。结果表明:木垛沿空留巷顶底板最大移近量为286 mm,采用高水材料充填墩柱沿空留巷技术顶底板最大移近量为188 mm,墩柱最大变形量为65 mm,高水材料充填墩柱沿空留巷技术施工工艺简单、墩柱抗压强度大,可有效控制围岩变形,同时增大巷道通风断面有利于风排瓦斯,防止矿井发生瓦斯事故。

  1. A risk prediction model for the assessment and triage of women with hypertensive disorders of pregnancy in low-resourced settings: the miniPIERS (Pre-eclampsia Integrated Estimate of RiSk multi-country prospective cohort study.

    Directory of Open Access Journals (Sweden)

    Beth A Payne

    2014-01-01

    Full Text Available Pre-eclampsia/eclampsia are leading causes of maternal mortality and morbidity, particularly in low- and middle- income countries (LMICs. We developed the miniPIERS risk prediction model to provide a simple, evidence-based tool to identify pregnant women in LMICs at increased risk of death or major hypertensive-related complications.From 1 July 2008 to 31 March 2012, in five LMICs, data were collected prospectively on 2,081 women with any hypertensive disorder of pregnancy admitted to a participating centre. Candidate predictors collected within 24 hours of admission were entered into a step-wise backward elimination logistic regression model to predict a composite adverse maternal outcome within 48 hours of admission. Model internal validation was accomplished by bootstrapping and external validation was completed using data from 1,300 women in the Pre-eclampsia Integrated Estimate of RiSk (fullPIERS dataset. Predictive performance was assessed for calibration, discrimination, and stratification capacity. The final miniPIERS model included: parity (nulliparous versus multiparous; gestational age on admission; headache/visual disturbances; chest pain/dyspnoea; vaginal bleeding with abdominal pain; systolic blood pressure; and dipstick proteinuria. The miniPIERS model was well-calibrated and had an area under the receiver operating characteristic curve (AUC ROC of 0.768 (95% CI 0.735-0.801 with an average optimism of 0.037. External validation AUC ROC was 0.713 (95% CI 0.658-0.768. A predicted probability ≥25% to define a positive test classified women with 85.5% accuracy. Limitations of this study include the composite outcome and the broad inclusion criteria of any hypertensive disorder of pregnancy. This broad approach was used to optimize model generalizability.The miniPIERS model shows reasonable ability to identify women at increased risk of adverse maternal outcomes associated with the hypertensive disorders of pregnancy. It could be

  2. Seasonal variation and potential sources of Cryptosporidium contamination in surface waters of Chao Phraya River and Bang Pu Nature Reserve pier, Thailand.

    Science.gov (United States)

    Koompapong, Khuanchai; Sukthana, Yaowalark

    2012-07-01

    Using molecular techniques, a longitudinal study was conducted with the aims at identifying the seasonal difference of Cryptosporidium contamination in surface water as well as analyzing the potential sources based on species information. One hundred forty-four water samples were collected, 72 samples from the Chao Phraya River, Thailand, collected in the summer, rainy and cool seasons and 72 samples from sea water at Bang Pu Nature Reserve pier, collected before, during and after the presence of migratory seagulls. Total prevalence of Cryptosporidium contamination in river and sea water locations was 11% and 6%, respectively. The highest prevalence was observed at the end of rainy season continuing into the cool season in river water (29%) and in sea water (12%). During the rainy season, prevalence of Cryptosporidium was 4% in river and sea water samples, but none in summer season. All positive samples from the river was C. parvum, while C. meleagridis (1), and C. serpentis (1) were obtained from sea water. To the best of our knowledge, this is the first genetic study in Thailand of Cryptosporidium spp contamination in river and sea water locations and the first report of C. serpentis, suggesting that humans, household pets, farm animals, wildlife and migratory birds may be the potential sources of the parasites. The findings are of use for implementing preventive measures to reduce the transmission of cryptosporidiosis to both humans and animals.

  3. A monk which celebrates, prays, teaches, corrects. The poetry of St. Peter Damian Un monaco che celebra, prega, insegna, corregge. La poetica di san Pier Damiani

    Directory of Open Access Journals (Sweden)

    Ugo Facchini

    2010-06-01

    Full Text Available To speak of St. Peter Damian's poetry is not easy, there are many literary genres, different contexts, among which the liturgy stands out, but there are also lyrics related to monastic life, and to the controversial ills' corrections of the Church of his time, such as simony and nicolaism. The complete edition published in 2007, that is the result of a long process of critical and theological research, wants to be a new way of approaching the poetry of the saint, trying to underline the sources, the occasion for the composition and finally to provide an additional seat contribution to approach ever more fully to his great personality.

    Parlare della poetica di san Pier Damiani non è facile, tanti i generi letterari, diversi i contesti fra i quali primeggia quello liturgico, ma anche poesie in versi legate alla vita monastica, alla correzione polemica dei mali della Chiesa del suo tempo, come la simonia e il nicolaismo. L'edizione integrale apparsa nel 2007, frutto di un lungo percorso di ricerca critica e teologica, vuole essere un modo nuovo di accostare la produzione poetica del santo cercando di evidenziare le fonti, l'occasione per la composizione e in ultima sede fornire un ulteriore contributo per accostarne sempre più pienamente la grande personalità.

  4. 大跨度连续下承式钢箱拱桥设计%Design of Long-Span Continuous Through Type Steel Box Arch Bridge

    Institute of Scientific and Technical Information of China (English)

    李国普; 李斐然

    2016-01-01

    为满足桥梁的景观和功能要求,小浪底坝后保护区交通桥上部结构采用(95+152+95) m三跨连续下承式钢箱拱结构。主梁为预应力混凝土π形梁,采用钢管桩+贝雷梁法施工。拱肋为钢箱提篮拱,结构用钢采用Q345D钢板,先工厂预制再现场焊接成型。吊索采用7根φ15.2环氧喷涂无粘结钢绞线,缠包后热挤HDPE ,抗拉强度标准值1860 M Pa。下部结构采用柱式台、倒V形实体薄壁墩、高桩承台、钻孔灌注桩基础。采用非线性程序TDV进行计算分析,结果表明,该桥的强度、刚度和稳定性以及抗震性能均满足规范要求。%To meet the landscape and function requirements proposed , the transportation bridge in the conservation area behind the Xiaolangdi Dam adopts a three‐span continuous through type steel box arch bridge structure with span arrangement of (95+152+95) m .The main girder is the prestressed concrete π‐shaped girder ,constructed by the combined use of steel tube piles and bailey truss .T he arch ribs are the steel box basket handle arches .T he predominant material used for the structure is the Q345D steel plate ,and all the components are prefabricated in the factory and transported to the bridge site for welding to take shape .Each hanger consists of 7φ15 .2 epoxy non‐binding steel strands ,extruded with HDPE after wrapping .The hanger has a standard tensile strength of 1 860 MPa .The substructure of the bridge incorporates column‐type abutments ,in‐versed V‐shaped solid thin‐wall piers ,high‐rise pile caps and bored piles .The non‐linear program TDV was used to do calculation .The results of the calculation demonstrate that the strength ,ri‐gidity ,reliability and anti‐seismic performance of the bridge all meet the code requirements .

  5. Study on restrainer design method for continuous bridges%连续梁桥缆索限位器设计方法

    Institute of Scientific and Technical Information of China (English)

    张华; 李建中; 彭天波

    2013-01-01

    The method to define the maximum available relative displacement (MARD) of girder bridges is presented first. Based on the existing restrainer design methods for in-span hinges of frame bridges, different simplified mechanical models are proposed according to the different characteristics and positions of the expansions of continuous bridges with laminated rubber bearings. The nonlinear properties of sliding between laminated rubber bearings and main girders, restrainers and expansion gap are included in the simplified models. The restrainer design method for each simplified model is proposed. The effectiveness of the design methods is verified by designing restrainers for an example bridge. The results from nonlinear time history analysis show that restrainers determined by the methods perform well and effectively prevent unseating of the bridge. Meanwhile the seismic demands of the piers with restrainers are increased.%首先提出了梁桥有效搭接长度的确定方法.在参考国外缆索限位器设计方法的基础上,针对采用板式橡胶支座的连续梁桥,根据不同伸缩缝位置的约束特点,提出了对应的简化力学分析模型.简化模型考虑了板式橡胶支座滑动、缆索限位器和伸缩缝约束作用的非线性特性,在此基础上提出了不同伸缩缝位置处相应的缆索限位器设计方法.采用该方法对某桥进行了缆索限位器设计,并用非线性时程分析方法对限位器设计方法的有效性进行了评估.结果表明,所提设计方法能够有效地设计约束伸缩缝处墩梁相对位移的缆索限位器刚度,但设置缆索限位器后过渡墩的抗震要求有一定的增加.

  6. Design of Welded Turnout Bridge on Taiyuan-Zhongwei-Yinchuan Railway%太中银铁路无缝线路道岔桥梁设计

    Institute of Scientific and Technical Information of China (English)

    左家强

    2014-01-01

    太原至中卫至银川铁路文水至靖边段位于吕梁山脉及陕北黄土高原,设计速度200 km/h,铺设跨区间无缝线路有砟轨道。为适应复杂的地形,共有3个车站的4座桥上设置了道岔。桥梁设计时结合具体情况,采用了不同的桥式方案及施工方法。各桥的孔跨布置满足无缝线路道岔的布设原则;对道岔梁采用结构设计软件进行分析,各项指标能满足无缝线路道岔的变形要求。并解决了预应力混凝土箱梁顶板大悬臂剪力滞效应、道岔梁桥墩及基础纵向总刚度与无缝线路道岔受力适应性、桥面及底板变宽连续箱梁支座横向布置等技术难题。经实际运营检验,能保证列车通过时的安全性、舒适性和平稳性。%Wenshui-Jingbian line of Taiyuan-Zhongwei-Yinchuan railway,a ballast jointless track with designed speed of 200 km/h,goes through Luliang Mountains and northern Shanxi Loess Plateau.In order to adapt to the complex terrain, turnouts were installed on four bridges near three stations.Combined with the specific circumstances of each project site, the bridges were designed using different structures and construction methods.The arrangement of spans for each bridge meets the laying principles of welded turnout.MIDAS and BSAS software is employed to ensure analysis for each turnout girder.All indexes met the requirements of the deformation of welded turnout while addressing the shear lag effect on top plate large cantilever of pre-stressed concrete box,adaptability of turnout girder piers and the total longitudinal stiffness of base to welded turnout stress,lateral arrangement of bridge floor and continuous box girders with widened baseboard as well as other technical problems.The actual operation indicates the bridges can ensure a safe,comfortable and smooth running.

  7. Heavy Vehicles on Minor Highway Bridges

    DEFF Research Database (Denmark)

    Kirkegaard, Poul Henning; Nielsen, Søren R. K.; Enevoldsen, I.

    of heavier trucks moving at larger speeds, and partly because the authorities want to permit transportation of special heavy goods at a larger part of the road net. These needs will in many cases cause the strengthening of the bridges becomes necessary. In order to keep the expenses of such strengthening...... projects at a minimum, it is necessary to perform accurate estimates of the dynamic amplification factor (defined as the dynamic load effect divided by the static load effect from the vehicles), so this quantity is neither over- nor underestimated. The principal aims of the present paper are to establish...... the numerical models for the mathematical models of the vehicles and the bridge from which the load amplification factors can be estimated assuming that the dynamic parameters of the vehicles and the modal parameters of the bridge are known....

  8. Ergonomic aspects of automation in navigation bridges.

    Science.gov (United States)

    Lazet, A; Walraven, P L

    1971-06-01

    New ergonomic questions arise from the tendency toward increasing automation in maritime operations. Direct control of engines and rudder from the bridge promises improved ship control, provided that the operator can really exploit the technical improvements. To make such direct control most efficient, good ergonomic design is essential. A series of designs of navigation bridges is used to illustrate typical problems and situations. The building of full scale mock-ups of complete bridges is essential in order to handle the design as an integrated problem and to simulate the work situation. Such static mock-ups have been shown to be extremely useful in the discussion between builder, future user and adviser. An extension to dynamic simulation is necessary in order to study the actual work conditions in a new design.

  9. Influence of Icing on Bridge Cable Aerodynamics

    DEFF Research Database (Denmark)

    Koss, Holger; Frej Henningsen, Jesper; Olsen, Idar

    2013-01-01

    In recent years the relevance of ice accretion for wind-induced vibration of structural bridge cables has been recognised and became a subject of research in bridge engineering. Full-scale monitoring and observation indicate that light precipitation at moderate low temperatures between zero and -5......°C may lead to large amplitude vibrations of bridge cables under wind action. For the prediction of aerodynamic instability quasi-steady models have been developed estimating the cable response magnitude based on structural properties and aerodynamic force coefficients for drag, lift and torsion....... The determination of these force coefficients require a proper simulation of the ice layer occurring under the specific climatic conditions, favouring real ice accretion over simplified artificial reproduction. The work presented in this paper was performed to study the influence of ice accretion on the aerodynamic...

  10. Stability of dynamic response of suspension bridges

    Science.gov (United States)

    Capsoni, Antonio; Ardito, Raffaele; Guerrieri, Andrea

    2017-04-01

    The potential occurrence of internal parametric resonance phenomena has been recently indicated as a potential contributory cause of the appearance of critical dynamic states in long-span suspension bridges. At the same time, suspension bridges, in view of their flexibility, are prone to aeroelastic response, such as vortex shedding, torsional divergence and flutter. In this paper, a non-linear dynamic model of a suspension bridge is devised, with the purpose of providing a first attempt toward a unified framework for the study of aeroelastic and internal resonance instabilities. Inspired by the pioneering work of Herrmann and Hauger, the analyses have been based on a linearized formulation that is able to represent the main structural non-linear effects and the coupling given by aerodynamic forces. The results confirm that the interaction between aeroelastic effects and non-linear internal resonance leads to unstable conditions for wind speeds which can be lower than the critical threshold for standard aeroelastic predictions.

  11. Building bridges within the bacterial chromosome.

    Science.gov (United States)

    Song, Dan; Loparo, Joseph J

    2015-03-01

    All organisms must dramatically compact their genomes to accommodate DNA within the cell. Bacteria use a set of DNA-binding proteins with low sequence specificity called nucleoid-associated proteins (NAPs) to assist in chromosome condensation and organization. By bending or bridging DNA, NAPs also facilitate chromosome segregation and regulate gene expression. Over the past decade, emerging single-molecule and chromosome conformation capture techniques have investigated the molecular mechanisms by which NAPs remodel and organize the bacterial chromosome. In this review we describe how such approaches reveal the biochemical mechanisms of three NAPs that are believed to facilitate DNA bridging: histone-like nucleoid structuring protein (H-NS), ParB, and structural maintenance of chromosomes (SMC). These three proteins form qualitatively different DNA bridges, leading to varied effects on transcription and chromosome segregation.

  12. Fast Hough transform for automatic bridge extraction

    Science.gov (United States)

    Hao, Qiwei; Chen, Xiaomei; Ni, Guoqiang; Zhang, Huaili

    2008-03-01

    In this paper, a new method to recognize bridge in the complicated background is presented. The algorithm takes full advantages of the characteristics of the bridge image. Firstly, the image is preprocessed and the object edges are extracted. Then according to the limitations of traditional Hough transform (HT), the extraction method of the image line segment characteristic of HT is improved, which eliminates spurious peaks on the basis of global and local thresholds, discriminates the position relation between two straight line segments, and merges segments with near endpoints, etc. Experiments show that this algorithm is more precise and efficient than traditional HT, moreover it can provide a complete description of the bridge in a complicated background.

  13. MINERAL BRIDGES OF NACRE AND ITS EFFECTS

    Institute of Scientific and Technical Information of China (English)

    宋凡; 白以龙

    2001-01-01

    Nacre, or mother-of-pearl, is a kind of composites of aragonite platelets sandwiched between organic materials. Its excellent mechanical properties are thought to stem from the microarchitecture that is traditionally described as a "brick and mortar" arrangement. In this paper, a new microstructure, referred to as mineral bridge in the biomineralization, is directly observed in the organic matrix layers (mortar) of nacre. This is an indication that the organic matrix layer of nacre should be treated as a three-dimensional interface and the microarchitecture of nacre ought to be considered as a "brick-bridge-mortar" structure rather than the traditional one. Experiments and analyses show that the mineral bridges not only improve the mechanical properties of the organic matrix layers but also play an important role in the pattern of the crack extension in nacre.

  14. Operational modal analysis of road-rail bridge

    OpenAIRE

    Cardoso M.; Sampaio R. A. C.; de Souza R. M.; Silva E.

    2015-01-01

    In this paper, we describe an Operational Modal Analysis (OMA) of the Bridge over the Tocantins River, a composite road-rail bridge located in the city of Marabá, state of Pará, northern Brazil. The bridge is part of the Carajás Railway, which is used by VALE Company to transport iron ore from “Serra dos Carajás”, the largest mineral reserve of the planet. The bridge has a length of 2310m, being the second longest road-rail bridge in Brazil. The study focused on the bridge central span (with ...

  15. Dragon bridge - the world largest dragon-shaped (ARCH steel bridge as element of smart city

    Directory of Open Access Journals (Sweden)

    Chinh Luong Minh

    2016-01-01

    Full Text Available Dragon Bridge - The world’s largest dragon-shaped steel bridge, with an installation cost of $85 million USD, features 6 lanes for two separate directions, 666 meters of undulating steel in the shape of a dragon in the Ly Dynasty, the symbol of prosperity in Vietnamese culture. This unique and beautifully lit bridge, which also breathes fire and sprays water. It’s the purposeful integration of the lighting hardware articulates the dragon’s form, and the fire-breathing dragon head. This project transcends the notion of monumental bridge with dynamic colour-changing lighting, creating an iconic sculpture in the skyline that is both reverent and whimsical. The signature feature of the bridge was the massive undulating support structure resembling a dragon flying over the river. The dragon is prominent in Vietnamese culture as a symbol of power and nobility. Dragon Bridge stands out as a model of innovation. It has received worldwide attention in the design community and from the global media for its unique arch support system. Dragon Bridge serves as an example of how aesthetic quality of a design can serve cultural, economic and functional purposes. The article presents design solutions of the object and the evaluation of the technical condition before putting the facility into service.

  16. The seismic response of concrete arch bridges (with focus on the Bixby Creek bridge Carmel, California)

    Energy Technology Data Exchange (ETDEWEB)

    Hoehler, M; McCallen, D; Noble, C

    1999-06-01

    The analysis, and subsequent retrofit, of concrete arch bridges during recent years has relied heavily on the use of computational simulation. For seismic analysis in particular, computer simulation, typically utilizing linear approximations of structural behavior, has become standard practice. This report presents the results of a comprehensive study of the significance of model sophistication (i.e. linear vs. nonlinear) and pertinent modeling assumptions on the dynamic response of concrete arch bridges. The study uses the Bixby Creek Bridge, located in California, as a case study. In addition to presenting general recommendations for analysis of this class of structures, this report provides an independent evaluation of the proposed seismic retrofit for the Bixby Creek Bridge. Results from the study clearly illustrate a reduction of displacement drifts and redistribution of member forces brought on by the inclusion of material nonlinearity. The analyses demonstrate that accurate modeling of expansion joints, for the Bixby Creek Bridge in particular, is critical to achieve representative modal and transient behavior. The inclusion of near-field displacement pulses in ground motion records was shown to significantly increase demand on the relatively softer, longer period Bixby Creek Bridge arch. Stiffer, shorter period arches, however, are more likely susceptible to variable support motions arising from the canyon topography typical for this class of bridges.

  17. Extracorporeal Life Support Bridge to Ventricular Assist Device: The Double Bridge Strategy.

    Science.gov (United States)

    Marasco, Silvana F; Lo, Casey; Murphy, Deirdre; Summerhayes, Robyn; Quayle, Margaret; Zimmet, Adam; Bailey, Michael

    2016-01-01

    In patients requiring left ventricular assist device (LVAD) support, it can be difficult to ascertain suitability for long-term mechanical support with LVAD and eventual transplantation. LVAD implantation in a shocked patient is associated with increased morbidity and mortality. Interest is growing in the utilization of extracorporeal life support (ECLS) as a bridge-to-bridge support for these critically unwell patients. Here, we reviewed our experience with ECLS double bridging. We hypothesized that ECLS double bridging would stabilize end-organ dysfunction and reduce ventricular assist device (VAD) implant perioperative mortality. We conducted a retrospective review of prospectively collected data for 58 consecutive patients implanted with a continuous-flow LVAD between January 2010 and December 2013 at The Alfred Hospital, Melbourne, Victoria, Australia. Twenty-three patients required ECLS support pre-LVAD while 35 patients underwent LVAD implantation without an ECLS bridge. Preoperative morbidity in the ECLS bridge group was reflected by increased postoperative intensive care duration, blood loss, blood product use, and postoperative renal failure, but without negative impact upon survival when compared with the no ECLS group. ECLS stabilization improved end-organ function pre-VAD implant with significant improvements in hepatic and renal dysfunction. This series demonstrates that the use of ECLS bridge to VAD stabilizes end-organ dysfunction and reduces VAD implant perioperative mortality from that traditionally reported in these "crash and burn" patients.

  18. Stability of a liquid bridge under vibration

    Science.gov (United States)

    Benilov, E. S.

    2016-06-01

    We examine the stability of a vertical liquid bridge between two vertically vibrating, coaxial disks. Assuming that the vibration amplitude and period are much smaller than the mean distance between the disks and the global timescale, respectively, we employ the method of multiple scales to derive a set of asymptotic equations. The set is then used to examine the stability of a bridge of an almost cylindrical shape. It is shown that, if acting alone, gravity is a destabilizing influence, whereas vibration can weaken it or even eliminate altogether. Thus, counter-intuitively, vibration can stabilize an otherwise unstable capillary structure.

  19. A Bridge Deflection Monitoring with GPS

    Science.gov (United States)

    Figurski, M.; Gałuszkiewicz, M.; Wrona, M.

    2007-01-01

    This paper introduces results of investigation carried on by The Applied Geomatics Section in Military University of Technology. Research includes possibilities of monitoring dynamic behavior of a bridge using high rate GPS data. Whole event was executed with collaboration of The Road and Bridge Management and The Warsaw Geodesy Company. Interdisciplinary approach with this project allows authors to get reliable information about investigating constructions and their respond for true traffic loading detected by GPS receivers. Way of compute data and used software (TRACK) are also shown in this paper.

  20. Planar Hall effect bridge magnetic field sensors

    DEFF Research Database (Denmark)

    Henriksen, A.D.; Dalslet, Bjarke Thomas; Skieller, D.H.

    2010-01-01

    Until now, the planar Hall effect has been studied in samples with cross-shaped Hall geometry. We demonstrate theoretically and experimentally that the planar Hall effect can be observed for an exchange-biased ferromagnetic material in a Wheatstone bridge topology and that the sensor signal can...... be significantly enhanced by a geometric factor. For the samples in the present study, we demonstrate an enhancement of the sensor output by a factor of about 100 compared to cross-shaped sensors. The presented construction opens a new design and application area of the planar Hall effect, which we term planar...... Hall effect bridge sensors....

  1. Analysis of Biaxially Stressed Bridge Deck Plates

    DEFF Research Database (Denmark)

    Jönsson, Jeppe; Bondum, Tommi Højer

    2012-01-01

    The ultimate state analysis of bridge deck plates at the intersection zone between main girders and transverse beams is complicated by biaxial membrane stresses, which may be in compression or tension in either direction depending on the bridge configuration and the specific location. This paper...... presents a detailed investigation of the ultimate capacity of simply supported plates subjected to biaxial loads. The full interaction domain of combinations of compressive and tensile loads has been investigated including a large number of imperfections. It was found that non-standard imperfection modes...

  2. Construction Technology of Long Span Bridges

    DEFF Research Database (Denmark)

    Gimsing, Niels Jørgen

    2000-01-01

    A large variety of construction methods are used during construction of major bridges, and in many cases the final structural system must be chosen with due respect to the construction process. Today the preferred construction methods are: the free-cantilever method, the launching method and the ......A large variety of construction methods are used during construction of major bridges, and in many cases the final structural system must be chosen with due respect to the construction process. Today the preferred construction methods are: the free-cantilever method, the launching method...

  3. 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

  4. V. Tormis: "Bridge of Song / Brian Hunt

    Index Scriptorium Estoniae

    Hunt, Brian

    1997-01-01

    Uuest heliplaadist "V. Tormis: "Bridge of Song" - Bridge of Song; Singing aboard ship; Brides Farewell; Kihnu Island Wedding Songs; 17 Estonian Wedding Songs; Three Estonian Game Songs; Four Estonian Lullabies. Estonian Radio Choir / Toomas Kapten. Finlandia 4509 96937-2; 56:52 DDD; "People of Kalevala" - God protect us from war; Vespian Winter; Eagle Flew From the North East; Plague Memory; Vainamoinen's Words of Wisdom; The Seventeenth Rune of Kalevala. National Male Choir of Estonia. Finlandia 0630 12245-2; 56:52 DDD

  5. Composite timber-concrete road bridge structure

    Directory of Open Access Journals (Sweden)

    Stojić Dragoslav

    2007-01-01

    Full Text Available This work presents preliminary design of the road bridge made of laminated timber. The supporting system of the main bearing elements is made of the laminated timber in the system of arch with three joints; the bridge slab is designed as continuous slab, made of nine equal fields; each pair is made as composite timber-concrete beam, where the road slab is made of concrete and the needle pieces are made of timber. Fundament is based on HW piles. All the elements are designed to Eurocode.

  6. Planar Hall effect bridge magnetic field sensors

    Science.gov (United States)

    Henriksen, A. D.; Dalslet, B. T.; Skieller, D. H.; Lee, K. H.; Okkels, F.; Hansen, M. F.

    2010-07-01

    Until now, the planar Hall effect has been studied in samples with cross-shaped Hall geometry. We demonstrate theoretically and experimentally that the planar Hall effect can be observed for an exchange-biased ferromagnetic material in a Wheatstone bridge topology and that the sensor signal can be significantly enhanced by a geometric factor. For the samples in the present study, we demonstrate an enhancement of the sensor output by a factor of about 100 compared to cross-shaped sensors. The presented construction opens a new design and application area of the planar Hall effect, which we term planar Hall effect bridge sensors.

  7. Fasting style collapse of a multi-span arch bridge analyze the causes of the box%某多跨空腹式箱形拱桥倒塌成因分析

    Institute of Scientific and Technical Information of China (English)

    饶奇志; 易汉斌; 俞博

    2014-01-01

    In this paper, a box-shaped multi-span arch bridge collapsed fasting accident, for example, ana-lyze the causes of its collapse. First, the bridge collapse accident scene investigation, proved a bit of geologi-cal bridge pier foundation and Conditions; secondly, according to the findings of the arch structure was seized count;moreover, considering the effect of cutting down on the pile bearing capacity of the river bed;the results show that under the riverbed leads to the bridge substructure cut transition from low pile platform for high pile caps, this time the stakes withstand compressive stress is greater than its carrying capacity, the stakes can not bear the weight of the upper structure, leading to the occurrence of arch collapsed.%本文以某多跨空腹式箱形拱桥倒塌事故为例,对其倒塌成因进行了分析。首先,对桥梁倒塌事故现场进行了调查,探明了桥墩基础及桥位地质条件情况;其次,根据调查结果对拱桥结构进行了检算;此外,考虑了河床下切对桩基承载力的影响;分析结果表明,河床下切导致该桥下部结构从低桩承台转变为高桩承台,此时木桩承受的压应力大于其承载能力,木桩已经不能承担上部结构自重的作用,导致拱桥发生倒塌。

  8. Experimental investigation of different fill materials in arch bridges with particular focus on Pearl-Chain Bridges

    DEFF Research Database (Denmark)

    Lund, Mia Schou Møller; Hansen, Kurt Kielsgaard; Hertz, Kristian Dahl

    2016-01-01

    Pearl-Chain Bridge technology is a recently developed prefabricated arch solution for road and railway bridges allowing faster, more environmentally friendly, and cheaper bridge construction. This study compared the strength and durability properties of three different types of fill material...... to find the most optimal fill for Pearl-Chain Bridges. Sub-base gravel, cement-stabilized gravel, and pervious concrete were tested with respect to compressive strength, stiffness, splitting tensile strength, permeability, freeze–thaw durability, and shrinkage. This paper summarizes the advantages...... and disadvantages of implementing the different types of fill material in arch bridges, particularly in Pearl-Chain Bridges....

  9. Bridge Influence Line Estimation for Bridge Weigh-in-Motion System

    OpenAIRE

    Ieng, Sio Song

    2015-01-01

    This paper presents an algorithm that estimates the influence line (IL) of a bridge using data collected when trucks pass over the sensors installed in the bridge. The algorithm is tested with data collected from the Millau Viaduct in France using a bridge weigh-in-motion (B-WIM) device. The algorithm uses the maximum likelihood estimation (MLE) and is compared with an old algorithm. The algorithm is more robust because it takes into account many signals for the estimation of the IL.

  10. Research on the Construction Scheme of the Bridge Foundation in Deep Water in the Three Gorges Reservoir%三峡库区某大桥深水基础施工方案研究

    Institute of Scientific and Technical Information of China (English)

    秦清波; 王哲; 刘合耀

    2014-01-01

    某大桥位于三峡库区,桥址所在河谷呈“U”形。桥型设计为预应力混凝土连续刚构,主墩基础采用高桩承台基础。由于三峡水库从2009年开始正式蓄水,水库常年蓄水位在145~175 m之间变化,变幅达30 m,在水库里进行大型桥梁的基础施工存在水深大、施工期水位变幅大等困难。大桥在水库高水位时(长江枯水期)采用固定式施工平台施工桩基础,在低水位时(长江汛期)下放钢吊箱围堰施工承台及桥墩。该方案安全性高,经济性好,工期短且易于保证。%A bridge is located in the Three Gorges Reservoir,where the valley showsUType.The bridge is designed as prestressed concrete continuous rigid frame.The main pier foundation is high pile foundation.Because the Three Gorges Reservoir started water storage in 2009,and the perennial water level varies from 145 to 175m with a variation of 30m,there are difficulties in foundation con-struction of large bridges in the reservoir with great water depth and large variation range of water level in construction period.The pile foundation is constructed in the high water level of reservoirs (the Yangtze River during dry season)using a fixed type construction platform,and the cap and pier is constructed in the low water level (the Yangtze River flood)using steel suspension box cofferdam.The scheme has high security,good economy,and short construction period and is easy to be guaranteed.

  11. Violin bridge mobility analysis under in-plane excitation.

    Science.gov (United States)

    Zhang, Cheng-Zhong; Zhang, Guang-Ming; Ye, Bang-Yan; Liang, Li-Dong

    2013-11-08

    The vibration of a violin bridge is a dynamic contact vibration with two interfaces: strings-bridge, and bridge feet-top plate. In this paper, the mobility of an isolated bridge under in-plane excitation is explored using finite element modeling based on the contact vibration model. Numerical results show that the dynamic contact stiffness in the two contact interfaces has a great impact on the bridge mobility. A main resonance peak is observed in the frequency range of 2-3 kHz in the frequency response of the isolated bridge when the contact stiffness is smaller than a critical threshold. The main resonance peak frequency is affected by the contact stiffness as well. In order to verify the numerical findings, a novel experimental system is then designed on the basis of a piezoelectric dynamometer for bridge mobility analysis. Experimental results confirm the impact of the dynamic contact stiffness on the bridge mobility.

  12. Foot force models of crowd dynamics on a wobbly bridge

    CERN Document Server

    Belykh, Igor; Belykh, Vladamir

    2016-01-01

    Modern pedestrian and suspension bridges are designed using industry-standard packages, yet disastrous resonant vibrations are observed, necessitating multi-million dollar repairs. Recent examples include pedestrian induced vibrations during the openings of the Solf\\'erino Bridge in Paris in 1999 and the increased bouncing of the Squibb Park Bridge in Brooklyn in 2014. The most prominent example of an unstable lively bridge is the London Millennium Bridge which started wobbling as a result of pedestrian-bridge interactions. Pedestrian phase-locking due to footstep phase adjustment, is suspected to be the main cause of its large lateral vibrations; however, its role in the initiation of wobbling was debated. In this paper, we develop foot force models of pedestrians' response to bridge motion and detailed, yet analytically tractable models of crowd phase-locking. We use bio-mechanically inspired models of crowd lateral movement to investigate to what degree pedestrian synchrony must be present for a bridge to ...

  13. CDC WONDER: Population - Bridged-Race July 1st Estimates

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Population - Bridged-Race July 1st Estimates online databases report bridged-race population estimates of the July 1st resident population of the United States,...

  14. Hydraulic bridges in unsaturated coarse granular media: Influence of bridge size and conductivity on flow through clasts

    Science.gov (United States)

    Jayakody, Jeevan A.; Nicholl, Michael J.

    2016-10-01

    Unsaturated flow in coarse granular media must pass through hydraulic bridges (e.g., pendular water, porous connections) that form a physical connection between adjoining clasts. Previous studies suggest that volumetric flow through a porous clast (Q) will be linearly dependent on the cross-sectional area of the hydraulic bridges, and understate the importance of bridge conductivity. Numerical simulations were performed to explore steady-state flow through a spherical clast with identical bridges located at the top and bottom. The cross-sectional area of the bridges relative to that of the clast (Ar) was varied across six orders of magnitude. The ratio of hydraulic conductivity between bridges and clasts (Kb/Kc) was varied across 12 orders of magnitude to consider resistive, neutral, and conductive bridges. Results show that hydraulic bridges place a primary control on both Q and flux distribution within the clast. For neutral and conductive bridges (Kb/Kc ≥1), Ar is the dominant factor in determining Q, while Kb/Kc is the primary control for resistive bridges (Kb/Kc < 1). For all bridges, Q shows a non-linear dependency on both Ar and Kb/Kc. The intra-clast flow distribution shifts outwards as Ar increases. Conductive bridges promote this process and resistive bridges impede it.

  15. Steel plate reinforcement of orthotropic bridge decks

    NARCIS (Netherlands)

    Teixeira de Freitas, S.

    2012-01-01

    The PhD research is focused on the reinforcement of fatigue cracked orthotropic steel bridge decks (OBD) by adding a second steel plate to the existing deck. The main idea is to stiffen the existing deck plate, which will reduce the stresses at the fatigue sensitive details and extend the fatigue li

  16. LPN/ADN Bridge Course. Instructor's Guide.

    Science.gov (United States)

    Barrett, Jan; And Others

    This curriculum guide has been constructed in order to bridge the skills gap between licensed practical nursing (LPN) programs and associate degree nursing (ADN) programs in Missouri. The curriculum was developed through a cooperative effort by persons from both sectors. The curriculum contains four major units, each consisting of several lessons,…

  17. Images Bridging Home and Academic Cultures.

    Science.gov (United States)

    Andres, Sophia

    Often students are unable to draw upon their personal worlds and individual experiences to enrich their writing, suggesting a disparity between home and academic cultures. In light of this apparent disparity, teachers must try to bridge the gap, a task that is possible when the teacher focuses on the germinal, emotional, and unifying qualities of…

  18. The mechanics of ship impacts against bridges

    DEFF Research Database (Denmark)

    Pedersen, Preben Terndrup; Zhang, Shengming

    1998-01-01

    a glancing blow between the ship and the bridge structure. This model is based on rigid body mechanics and well suited for inclusion in a probabilistic analysis procedure. Finally, some empirical expressions are presented which relate the energy absorbed by crushing of ship structures to the maximum impact...

  19. Bridging the digital divide with mobile services

    CERN Document Server

    Yelton, Andromeda

    2013-01-01

    In this issue of Library Technology Reports, Andromeda Yelton shows how libraries can build on the breadth of this population to help bridge the digital divide and provide even greater access to information. Yelton breaks down the demographics of mobile internet users, provides examples of how different libraries are reaching out to these populations, and suggests what the future may hold for this trend.

  20. New Program Builds Bridges for Hearing Impaired.

    Science.gov (United States)

    Johnson, Jeannie

    1998-01-01

    Describes a new approach to teaching English-as-a-Second-Language to New Mexico elementary school students who have hearing impairments and whose dominant language is American Sign Language (ASL). These students must first acquire ASL as a bridge to learning English. Then, using the bilingual approach, they are able to focus on English literacy.…

  1. Ergonomic aspects of automation in navigation bridges

    NARCIS (Netherlands)

    Lazet, A.; Walraven, P.L.

    1971-01-01

    New ergonomic questions arise from the tendency toward increasing automation in maritime operations. Direct control of engines and rudder from the bridge promises improved ship control, provided that the operator can really exploit the technical improvements. To make such direct control most efficie

  2. Fiber reinforced polymer composites for bridge structures

    Directory of Open Access Journals (Sweden)

    Alexandra CANTORIU

    2013-12-01

    Full Text Available Rapid advances in construction materials technology have led to the emergence of new materials with special properties, aiming at safety, economy and functionality of bridges structures. A class of structural materials which was originally developed many years ago, but recently caught the attention of engineers involved in the construction of bridges is fiber reinforced polymer composites. This paper provides an overview of fiber reinforced polymer composites used in bridge structures including types, properties, applications and future trends. The results of this study have revealed that this class of materials presents outstanding properties such as high specific strength, high fatigue and environmental resistance, lightweight, stiffness, magnetic transparency, highly cost-effective, and quick assembly, but in the same time high initial costs, lack of data on long-term field performance, low fire resistance. Fiber reinforced polymer composites were widely used in construction of different bridge structures such as: deck and tower, I-beams, tendons, cable stands and proved to be materials for future in this field.

  3. Aeroelastic Stability of Suspension Bridges using CFD

    DEFF Research Database (Denmark)

    Stærdahl, Jesper Winther; Sørensen, Niels; Nielsen, Søren R.K.

    2007-01-01

    In recent years large span suspension bridges with very thin and slender profiles have been built without proportional increasing torsional and bending stiffness. As a consequence large deformations at the mid-span can occur with risk of aeroelastic instability and structural failure. Analysis...

  4. Bridge monitoring using heterogeneous wireless sensor network

    Science.gov (United States)

    Haran, Shivan; Kher, Shubhalaxmi; Mehndiratta, Vandana

    2010-03-01

    Wireless sensor networks (WSN) are proving to be a good fit where real time monitoring of multiple physical parameters is required. In many applications such as structural health monitoring, patient data monitoring, traffic accident monitoring and analysis, sensor networks may involve interface with conventional P2P systems and it is challenging to handle heterogeneous network systems. Heterogeneous deployments will become increasingly prevalent as it allows for systems to seamlessly integrate and interoperate especially when it comes to applications involving monitoring of large infrastructures. Such networks may have wireless sensor network overlaid on a conventional computer network to pick up data from one distant location and carry out the analysis after relaying it over to another distant location. This paper discusses monitoring of bridges using WSN. As a test bed, a heterogeneous network of WSN and conventional P2P together with a combination of sensing devices (including vibration and strain) is to be used on a bridge model. Issues related to condition assessment of the bridge for situations including faults, overloads, etc., as well as analysis of network and system performance will be discussed. When conducted under controlled conditions, this is an important step towards fine tuning the monitoring system for recommendation of permanent mounting of sensors and collecting data that can help in the development of new methods for inspection and evaluation of bridges. The proposed model, design, and issues therein will be discussed, along with its implementation and results.

  5. Circuit bridging of components by smoke

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, T.J.; Nowlen, S.P.; Anderson, D.J. [Sandia National Labs., Albuquerque, NM (United States)

    1996-10-01

    Smoke can adversely affect digital electronics; in the short term, it can lead to circuit bridging and in the long term to corrosion of metal parts. This report is a summary of the work to date and component-level tests by Sandia National Laboratories for the Nuclear Regulatory Commission to determine the impact of smoke on digital instrumentation and control equipment. The component tests focused on short-term effects such as circuit bridging in typical components and the factors that can influence how much the smoke will affect them. These factors include the component technology and packaging, physical board protection, and environmental conditions such as the amount of smoke, temperature of burn, and humidity level. The likelihood of circuit bridging was tested by measuring leakage currents and converting those currents to resistance in ohms. Hermetically sealed ceramic packages were more resistant to smoke than plastic packages. Coating the boards with an acrylic spray provided some protection against circuit bridging. The smoke generation factors that affect the resistance the most are humidity, fuel level, and burn temperature. The use of CO{sub 2} as a fire suppressant, the presence of galvanic metal, and the presence of PVC did not significantly affect the outcome of these results.

  6. Thermal Bridge Effects in Window Grooves

    DEFF Research Database (Denmark)

    Rose, Jørgen

    1997-01-01

    In this report thermal bridge effects in window grooves are analyzed. The analysis is performed using different thicknesses of the window groove insulation, to evaluate what the optimal solution is.All analysis in the report is performed using both 2- and 3-dimensional numerical analysis....

  7. Nondestructive evaluation inspection of the Arlington Memorial Bridge using a robotic assisted bridge inspection tool (RABIT)

    Science.gov (United States)

    Gucunski, Nenad; Boone, Shane D.; Zobel, Rob; Ghasemi, Hamid; Parvardeh, Hooman; Kee, Seong-Hoon

    2014-04-01

    The information presented in this report provides a detailed assessment of the condition of the Arlington Memorial Bridge (AMB) deck. The field-data collection was obtained by both the RABIT™ Bridge Inspection Tool and a number of semi-automated non-destructive evaluation (NDE) tools. The deployment of the semi-automated NDE tools was performed to inspect the AMB deck condition and also to validate data obtained by the RABIT™ Bridge Inspection Tool. Data mining and analysis were accomplished through enhanced data interpretation and visualization capabilities using advanced data integration, fusion, and 2D rendering. One of the major challenges that the research team had to overcome in assessing the condition of the AMB deck was the presence of an asphalt overlay on the entire bridge deck.

  8. Railroad Bridges in Louisiana, Geographic NAD83, FEMA (1997) [railroad_bridges_FEMA_1997

    Data.gov (United States)

    Louisiana Geographic Information Center — This is is a point dataset for the locations and attributes of 32 Louisiana railroad bridges. The attributes include city (nearest?), county (sic), routefrom (city),...

  9. Performance Assessment of Bridges Using GPS: The Juarez Bridge in Culiacan, Mexico

    Science.gov (United States)

    Vazquez, G. E.; Gaxiola-Camacho, J. R.; Trejo, M.; Echagaray, J.; Guzman, G. M.

    2015-12-01

    Performance assessment of bridges has become very important during recent years. Bridges around the world are aging, leading to the incorporation of efficient, reliable, and economic evaluation procedures. These techniques must assess properly the performance of bridges under several loading conditions in a real manner, representing the physics of the problem. Among several approaches, Global Positioning System (GPS) can be intelligently used for the performance evaluation of bridges. We focused on GPS, since it naturally produces position estimates as compared to seismic instruments that record either velocity or acceleration, and thus require an integration. There are several reasons that make the Juarez Bridge a case of study for evaluation: it is approximately 45 years old, it is a reinforced concrete structure, it connects two significant zones of the city, and its spans is closely to 200 meters long. In addition, thousands of vehicles and pedestrians use the Juarez Bridge every day, which make feasible the GPS performance assessment. Hence, in order to produce optimal position estimates, GPS data were collected during two consecutive hours at three different periods of the day for a whole week (Monday through Sunday), to represent three critical limit states of the bridge (mid-span and end-spans). GPS data were processed using the GAMIT/GLOBK software, considering 1-second sampling rate, 15-degree cutoff angle, ionosphere-free double-differenced (DD) carrier phase method, and precise final orbits disseminated by IGS (International GNSS Service). The displacements obtained from the above discussed procedure are compared with allowable values documented in bridge construction manuals. Reliability theory was used to evaluate the probability of failure of the bridge for the three periods of the day. In addition, a conclusion was made about the most risky day of the week for the use of the Juarez Bridge. It is expected that the results from the proposed research

  10. Ambient Response Analysis of the Great Belt Bridge

    DEFF Research Database (Denmark)

    Brincker, Rune; Frandsen, J. B.; Andersen, P.

    2000-01-01

    In this paper an ambient response analysis of the Great Belt Bridge is presented. The Great Belt Bridge is one of the largest suspension bridges in the world, and the analysis was carried out in order to investigate the possibilities of estimating reliable damping values from the ambient response...

  11. Resin-Bonded Bridges in vitro and in vivo

    NARCIS (Netherlands)

    Veen, Johannes Hilbrandt van der

    1988-01-01

    In this thesis in vitro and in vivo studies on the clinical application of resin-bonded bridges are described and discussed. The development of different types of resin-bonded bridges is described in chapter 1. The bridges are often made by boding a cast metal retainer fitted with and artificial too

  12. Renovation techniques for fatigue cracked orthotropic steel bridge decks

    NARCIS (Netherlands)

    de Jong, F.B.P.

    2007-01-01

    This dissertation presents the research into renovation techniques for orthotropic steel bridge decks. These techniques are needed to solve fatigue problems in the decks of these bridges, as several fatigue cracks have been detected in the deck structure of these bridges the last decade. A well-know

  13. A calculation model for the noise from steel railway bridges

    NARCIS (Netherlands)

    Janssens, M.H.A.; Thompson, D.J.

    1996-01-01

    The sound level of a train crossing a steel railway bridge is usually about 10 dB higher than on plain track. In the Netherlands there are many such bridges which, for practical reasons, cannot be replaced by more intrinsically quiet concrete bridges. A computational model is described for the estim

  14. Dynamic Vehicle Impact for Safety Assessment of Bridges

    DEFF Research Database (Denmark)

    Kirkegaard, Poul Henning; Nielsen, Søren R. K.; Enevoldsen, I.

    In this paper the dynamic amplification of vehicle load at minor highway bridges is considered for safety assessment of the load carrying capacity of bridges. The considered case is the most critical for bridges, i.e. the simultaneous passage of two heavy trucks. A short description...

  15. 33 CFR 115.50 - Application for bridge permits.

    Science.gov (United States)

    2010-07-01

    ... authority not necessary. Coast Guard approval of the location and plans for construction or modification of a bridge or causeway is not required for any bridge or causeway over waters which are not subject to... (historic use). This provision does not apply to bridges which connect the United States with any...

  16. Future Trends in Reliability-Based Bridge Management

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    Future bridge management systems will be based on simple stochastic models predicting the residual strength of structural elements. The current deterministic management systems are not effective in optimizing e.g. the life cycle cost of a bridge or a system of bridges. A number of important factors...

  17. 21 CFR 872.3770 - Temporary crown and bridge resin.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Temporary crown and bridge resin. 872.3770 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3770 Temporary crown and bridge resin. (a) Identification. A temporary crown and bridge resin is a device composed of a material, such...

  18. Seismic Performance of Multi-Span RC Railway Bridges

    DEFF Research Database (Denmark)

    Georgakis, Christos; Barrau, Xavier

    2008-01-01

    Presently, there is no clear method for determining the optimal railway bridge design for a particular ground type and expected seismic intensity. Four main types of RC bridge dominate the current multi-span railway bridge design trends – the Simply Supported Beam, Continuous Box-Girder (CBG), CBG...

  19. Reduction of Impact Noise of Trams on a Major Bridge

    NARCIS (Netherlands)

    Dittrich, M.G.; Bosshaart, C.; Wessels, P.W.

    2015-01-01

    As part of a recent renovation of the Erasmus bridge in Rotterdam, improvements were made to reduce impact noise caused by trams passing a series of rai! joints. The bridge inciudes several different sections inciuding a bascule bridge and is in an inner city tocation with new adjacent apartment bui

  20. Improving the Dynamics of Suspension Bridges using Active Control Systems

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    Improving the dynamics of suspension bridge using active control is discussed in this paper. The main dynamic problem with long suspension bridges is the aeroelastic phenomenon called flutter. Flutter oscillations of a bridge girder is a stability problem and the oscillations are perpendicular...