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Sample records for twelve-span viaduct aashto

  1. AASHTO transportation asset management guide : a focus on implementation executive summary.

    Science.gov (United States)

    2013-06-01

    This AASHTO Transportation Asset Management Executive Summary serves as a companion to the AASHTO Transportation : Asset Management GuideA Focus on Implementation, which takes as a starting point the Transportation : Asset Management Guide publish...

  2. Safety assessment of existing highway bridges and viaducts

    NARCIS (Netherlands)

    Maljaars, J.; Steenbergen, R.; Abspoel, L.; Kolstein, M.H.

    2012-01-01

    The assessment of the structural safety of existing br idges and viaducts becomes increasingly important in many countries owing to an increase in traffic loads. Most existing standards, however, are developed for the design of new structures. For this reason, an assessment method for determining

  3. AUTOMATIC EXTRACTION AND TOPOLOGY RECONSTRUCTION OF URBAN VIADUCTS FROM LIDAR DATA

    Directory of Open Access Journals (Sweden)

    Y. Wang

    2015-08-01

    Full Text Available Urban viaducts are important infrastructures for the transportation system of a city. In this paper, an original method is proposed to automatically extract urban viaducts and reconstruct topology of the viaduct network just with airborne LiDAR point cloud data. It will greatly simplify the effort-taking procedure of viaducts extraction and reconstruction. In our method, the point cloud first is filtered to divide all the points into ground points and none-ground points. Region growth algorithm is adopted to find the viaduct points from the none-ground points by the features generated from its general prescriptive designation rules. Then, the viaduct points are projected into 2D images to extract the centerline of every viaduct and generate cubic functions to represent passages of viaducts by least square fitting, with which the topology of the viaduct network can be rebuilt by combining the height information. Finally, a topological graph of the viaducts network is produced. The full-automatic method can potentially benefit the application of urban navigation and city model reconstruction.

  4. Adaptation of AASHTO Pavement Design Guide for Local Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Hajek, J.J. [Applied Research Associates Inc., Toronto, ON (Canada)

    2001-07-01

    The methodology used to adapt the 1993 AASHTO Guide for Design of Pavement Structures to Ontario conditions was described. The guide expresses the effect of traffic loads on pavement performance using the concept of axle Load Equivalency Factors (LEF). LEF is regarded as a pavement damage factor assigned to each specific load and axle configuration. The size of LEF is related to the damage that is expected to occur from a standard load of 80 kN carried by a single axle with dual tires. The factors are summarized to yield the number of Equivalent Single Axle Loads (ESALs) a pavement is expected to sustain during its life. A summary was also provided of the additional work done to prepare for the transition to the proposed mechanistically-based 2002 AASHTO Guide. The paper focused only on the design of flexible pavements in terms of load characterization using equivalent single axle loads along with axle load spectra, below grade and material characterization, plus initial and terminal serviceability and reliability. The AASHTO Guide uses two parameters to deal with design reliability: design reliability level and overall standard deviation. Data collected on Ontario highway pavements and materials was used for assessing the design inputs. Other data was also collected from research and development studies, laboratory experiments, and from a survey of experienced pavement design engineers. The end result was a new grouping of Ontario soils for pavement design, recommended values for the resilient modulus of below grade soils, recommendations for structural layer coefficients for Ontario pavement materials and recommendations for the initial pavement serviceability based on Ontario smoothness specifications. Results of calibration and verification processes indicate that for new flexible pavements, the AASHTO-Ontario model is in good agreement with the observed results. It was recommended that the calibration and verification of the AASHTO-Ontario model should be a

  5. Natural frequencies of a flat viaduct road part simply supported on ...

    Indian Academy of Sciences (India)

    Viaduct roads have wide application in big cities with high traffic ... the solutions of plates that have various boundary conditions, numerical methods must be .... algorithm, in the most general condition, we get output and hidden layer equations ...

  6. Engineering properties of stabilized subgrade soils for implementation of the AASHTO 2002 pavement design guide.

    Science.gov (United States)

    2009-06-01

    A comprehensive laboratory study was undertaken to determine engineering properties of cementitiously stabilized common subgrade soils in Oklahoma for the design of roadway pavements in accordance with the AASHTO 2002 Mechanistic-Empirical Pavement D...

  7. Vibration Monitoring of a Large Scale Heavy Haul Railway Viaduct

    Directory of Open Access Journals (Sweden)

    Busatta Fulvio

    2015-01-01

    Full Text Available In South Africa, heavy haul railway transport was introduced in the mid-1970s for the Iron Ore and the Coal Export lines. In recent decades, the expansion of existing mines, new markets and the competition of iron ore- and coal-exporting countries have led owners and operators to progressively increase the capacity of the export lines. On the one hand, operational efficiencies have been improved; on the other hand, a significant increase of the rail traffic has been experienced. Thus, bridges along the export lines are now crossed by heavier and longer trains with more frequent train passages than in the past. Increasing train loading might lead to significant consequences on structures such as dynamic amplifications and reduction of service life due to fatigue. Hence dynamic assessment and monitoring of the structural condition of bridges under actual train loading are becoming more relevant to support decision making processes. The paper presents the investigations carried out on the Olifants River Viaduct, a critical structure along the Iron Ore Export Line, in order to implement a state-of-the-art vibration monitoring system.

  8. Re-evaluation of the AASHTO-flexible pavement design equation with neural network modeling.

    Science.gov (United States)

    Tiğdemir, Mesut

    2014-01-01

    Here we establish that equivalent single-axle loads values can be estimated using artificial neural networks without the complex design equality of American Association of State Highway and Transportation Officials (AASHTO). More importantly, we find that the neural network model gives the coefficients to be able to obtain the actual load values using the AASHTO design values. Thus, those design traffic values that might result in deterioration can be better calculated using the neural networks model than with the AASHTO design equation. The artificial neural network method is used for this purpose. The existing AASHTO flexible pavement design equation does not currently predict the pavement performance of the strategic highway research program (Long Term Pavement Performance studies) test sections very accurately, and typically over-estimates the number of equivalent single axle loads needed to cause a measured loss of the present serviceability index. Here we aimed to demonstrate that the proposed neural network model can more accurately represent the loads values data, compared against the performance of the AASHTO formula. It is concluded that the neural network may be an appropriate tool for the development of databased-nonparametric models of pavement performance.

  9. Natural frequencies of a flat viaduct road part simply supported on ...

    Indian Academy of Sciences (India)

    The low weight of steel structures however causes problems such as vibration and noise. There is increasing demand especially in populated areas to suppress vibration and noise on highway roads for reducing noise-related environmental pollution. In this study, bending vibrations of rectangular plate viaduct roads, which ...

  10. Repair and Protection of Small Railway Viaduct with Jammed Span at the Mining Influence

    Science.gov (United States)

    Bętkowski, Piotr

    2017-10-01

    This paper is about the maintenance of bridge objects on mining areas. Based on several years of observation is shown as functional parameters and technical conditions were deteriorated. As a result of the mining area deformations appeared among others following damages: block of bearings, jam of span, cracks on the abutments. The article describes series of clever maintenance repairs (such as the restoration of displacement freedom on non-standard tangent bearings) which enabled the exploitation of the viaduct without interruptions of railway communication. The region of the bridge is planned to further mining activities, which prejudged, that a repair of the viaduct was necessary to realization. The article discusses the predicted mining area deformation and analyses their influence on the bridge structure. Repair of the viaduct is a comprehensive example of the mining facility protection with the restoration of the expansion joints, bearings replacement, widening benches under bearings, stitching cracks and strengthening abutments, recreating the isolation and the drainage system damaged by mining influences, performance strut in the foundation level. An important element in determining the durability of repair is the selection of appropriate materials and repair technology, which is analysed in the article. All of these tasks completed in less than four months. Article illustrates the photo documentation made before and after repairs and technical drawings that show the range of the repairs.

  11. Evaluasi Struktural Perkerasan Kaku Menggunakan Metoda AASHTO 1993 dan Metoda AUSTROADS 2011 Studi Kasus : Jalan Cakung-Cilincing

    Directory of Open Access Journals (Sweden)

    Shinta Rahmalia Irawan

    2017-08-01

    Full Text Available Cakung-Cilincing Jakarta National Road Section has very rapid traffic load for rigid pavement. The purpose of this study are determining overlay thickness and choosing suitable method for implementation. AASHTO 1993 and AUSTROADS 2011 method are used in this study and using on Falling Weight Deflectometer (FWD data. This study shows that value of Concrete Elasticity Modulus less than 3 million, then this rigid pavement is severely damaged. Based on AASHTO 1993 Method analysis, it needs 11 cm for flexible overlay and 12 cm for rigid overlay on lane 1 with 59% remaining life and lane 2 with 53% remaining life. AUSTROADS 2011 Methods use only FWD data and for overlay thickness determination is use new pavement analysis. Analysis using AUSTROADS 2011 Methods shows that flexible overlay requirement is 24 cm and rigid overlay requirement is 18.50 cm. Comparation between these two methods shows that AASHTO 1993 Method Analysis produce less overlay thickness than AUSTROADS 2011 Methods.

  12. Evaluasi Struktural Perkerasan Lentur Menggunakan Metode AASHTO 1993 dan Metode Bina Marga 2013 Studi Kasus: Jalan Nasional Losari - Cirebon

    Directory of Open Access Journals (Sweden)

    Akhmad Haris Fahruddin Aji

    2015-08-01

    Full Text Available The purpose of of this research is to analyze structural flexible pavement by using Bina Marga 2013 Method and comparing with AASHTO 1993 Method, both of which are part of the non-destructive evaluation methods. Structural evaluation of flexible pavement by AASHTO 1993 Method carried out based on data deflections d1 and d6 of survey FWD (Falling Weight Deflectometer to calculate value of Resilient Modulus of subgrade (MR and Pavement Effective Modulus (EP, and then it used to determine SNeff value (Structural Number Effective, SNf value (Structural Number in the Future, and overlay thickness. While Bina Marga 2013 Method, first step of evaluation is analyzing the choice of treatment which is based on 3 trigger value, ie: Deflection Trigger, IRI Trigger, and Conditions Trigger, then continued by calculation of overlay thickness through mechanistic design approaches with graphics and General Mechanistic Procedure (GMP. Comparison of the two methods shows that overlay thickness calculation of Bina Marga 2013, is thinner than calculation of AASHTO 1993 for the same modeling assumptions, this is because Bina Marga 2013 using the analytical method with the help of CIRCLY programs so that strain stress analysis of structural as a response of pavement can be determined more accurately and represent the actual conditions on site, compared to analytical-empirical method used in AASHTO 1993 Method.

  13. Synthesis and evaluation of lightweight concrete research relevant to the AASHTO LRFD bridge design specifications : potential revisions for definition and mechanical properties.

    Science.gov (United States)

    2012-11-01

    Much of the fundamental basis for the current lightweight concrete provisions in the AASHTO LRFD Bridge : Design Specifications is based on research of lightweight concrete (LWC) from the 1960s. The LWC that was : part of this research used tradition...

  14. Ensaios MSCR segundo as normas ASTM D7405-10a e AASHTO T350-14: um estudo de caso envolvendo ligantes asfálticos modificados

    Directory of Open Access Journals (Sweden)

    Matheus David Inocente Domingos

    2016-12-01

    especially the AC+rubber and the AC+rubber+PPA. The AC+PPA showed low stress sensitivity and the best results for the parameters R and Jnr at 3,200 Pa either in the ASTM or the AASHTO protocols, which justifies its choice as the best formulation. The data from the modified asphalt binders suggest that the change from the ASTM protocol to the AASHTO one is recommended.

  15. Design and construction of the Soegawa viaduct; Soegawa kokakyo no sekkei to seko

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, M.; Sueoka, M. [Japan Highway Public Corporation, Tokyo (Japan); Takahashi, M.; Ito, K. [Kajima Corp., Tokyo (Japan)

    1997-09-30

    This paper describes the precast segment construction of double-span continuous prestressed concrete (PC) box girder with a length of 93 m in the Soegawa Viaduct in Akita Prefecture. The match cast surface of the newly constructed segment is occasionally deformed into arch due to the temperature gradient generated by the hardening heat. To avoid this phenomenon, the minimum segment length more than one-sixth of the segment width of 11.2 m was determined. Compatible type internal/external cable method was adopted for the configuration of PC steel members in the main direction. In this method, steel members for PC were placed outside of concrete as well as inside of concrete. The yard for fabricating segments was made in the back area of abutment of the bridge. Segments fabricated using steel frames were brought in the yard using a crane and stocked. After the support construction, segments were constructed from No.1 segment in order. Since placing accuracy of the whole segments was affected by the placing of the standard segment, the accuracy was improved by the three-dimensional control using surveying equipment. After the construction of segments and tension of PC, the bridge is to be completed in September, 1997. 3 refs., 21 figs., 4 tabs.

  16. Analysis of pavement serviceability for the Aashto Design Method: The Chilean Case

    International Nuclear Information System (INIS)

    Solminihac, Hernan De; Salsilli, R.; Bengoa, E.; Kohler, E.

    2003-01-01

    Serviceability is an indicator that represents the level of service a pavement provides to the users. This subjective opinion is closely related to objective aspects, which can be measured on the pavement's surface. This research aims specifically at relating serviceability results obtained by a 9-member evaluation panel, representing general public as closely as possible to parameters (particularly of roughness) measured within instruments on 30, 25 and 11 road sections of asphalt concrete, Portland cement concrete and asphalt overlay respectively. Results show that prediction of serviceability is quite accurate based on roughness evaluation, while also revealing that, by comparison to studies in more developed countries, Chileans are seemingly more tolerant, in that they assign a somewhat high rating to ride quality. Furthermore, visible distress does not have a significant influence on serviceability values for Chilean users. A ratio between International Roughness Index (IRI) and Serviceability, as defined by AASHTO, was developed and may be used in this design method. Results for the final pavement condition of urban pavements were obtained (IRI-asphalt final=5.9, IRI-concrete final=8.1). (author)

  17. Flexural and Shear Behavior of FRP Strengthened AASHTO Type Concrete Bridge Girders

    Directory of Open Access Journals (Sweden)

    Nur Yazdani

    2016-01-01

    Full Text Available Fiber-reinforced polymers (FRP are being increasingly used for the repair and strengthening of deteriorated or unsafe concrete structures, including structurally deficient concrete highway bridges. The behavior of FRP strengthened concrete bridge girders, including failure modes, failure loads, and deflections, can be determined using an analytical finite element modeling approach, as outlined in this paper. The differences in flexural versus shear FRP strengthening and comparison with available design guidelines are also beneficial to design professionals. In this paper, a common AASHTO type prestressed concrete bridge girder with FRP wrapping was analyzed using the ANSYS FEM software and the ACI analytical approach. Both flexural and shear FRP applications, including vertical and inclined shear strengthening, were examined. Results showed that FRP wrapping can significantly benefit concrete bridge girders in terms of flexure/shear capacity increase, deflection reduction, and crack control. The FRP strength was underutilized in the section selected herein, which could be addressed through decrease of the amount of FRP and prestressing steel used, thereby increasing the section ductility. The ACI approach produced comparable results to the FEM and can be effectively and conveniently used in design.

  18. On the influence of viaduct and ground heating on pollutant dispersion in 2D street canyons and toward single-sided ventilated buildings

    Science.gov (United States)

    This paper employs Computational Fluid Dynamic (CFD) simulations to investigate the influence of ground heating intensities and viaduct configurations on gaseous and particle dispersion within two-dimensional idealized street canyons (typical aspect ratio H/W=1) and their transpo...

  19. Damaged Concrete Viaduct in an Italian Highway: Concrete Characterization and Possible Strengthening Techniques by FRP Applications in Comparison

    Science.gov (United States)

    Tittarelli, Francesca; Ruello, Maria Letizia; Capuani, Domenico; Aprile, Alessandra

    2017-10-01

    The “Fornello” viaduct in the Italian Orte-Ravenna highway (E45) is seriously damaged. In this paper, the concrete of the reinforced slab has been widely characterized to evaluate the level of damage and to identify the causes of degradation. No-destructive tests, as those based on ultrasonic waves, as well as chemical, physical and mechanical destructive tests have been carried out on specimens drawn from deteriorated and not deteriorated zones of the R/C bridge decks. Into the slab thickness, the concentration distribution of main anions has been quantified by ion chromatography. Porosimetry tests have been carried out to detect the resistance to freeze-thaw cycles of cement paste. Possible strengthening techniques by FRP applications have been compared.

  20. Comparison of various methods to determine bulk specific gravity of cores : an investigation of high values using AASHTO T275 - paraffin-coated method.

    Science.gov (United States)

    2012-07-01

    A report from a MoDOT asphalt paving project was that unexpected results were obtained when adhering to the standard for determination of bulk specific gravity of compacted asphalt mixture (Gmb) specimens, AASHTO T 166. The test method requires speci...

  1. Did the suicide barrier work after all? Revisiting the Bloor Viaduct natural experiment and its impact on suicide rates in Toronto.

    Science.gov (United States)

    Sinyor, Mark; Schaffer, Ayal; Redelmeier, Donald A; Kiss, Alex; Nishikawa, Yasunori; Cheung, Amy H; Levitt, Anthony J; Pirkis, Jane

    2017-06-19

    This research aims to determine the long-term impact of the Bloor Street Viaduct suicide barrier on rates of suicide in Toronto and whether media reporting had any impact on suicide rates. Natural experiment. City of Toronto, Canada; records at the chief coroner's office of Ontario 1993-2003 (11 years before the barrier) and 2004-2014 (11 years after the barrier). 5403 people who died by suicide in the city of Toronto. Changes in yearly rates of suicide by jumping at Bloor Street Viaduct, other bridges including nearest comparison bridge and walking distance bridges, and buildings, and by other means. Suicide rates at the Bloor Street Viaduct declined from 9.0 deaths/year before the barrier to 0.1 deaths/year after the barrier (incidence rate ratio (IRR) 0.005, 95% CI 0.0005 to 0.19, p=0.002). Suicide deaths from bridges in Toronto also declined significantly (IRR 0.53, 95% CI 0.40 to 0.71, psuicide at the Bloor Street Viaduct were associated with an increase in suicide-by-jumping from bridges the following year. The current study demonstrates that, over the long term, suicide-by-jumping declined in Toronto after the barrier with no associated increase in suicide by other means. That is, the barrier appears to have had its intended impact at preventing suicide despite a short-term rise in deaths at other bridges that was at least partially influenced by a media effect. Research examining barriers at other locations should interpret short-term results with caution. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  2. Correlation between Wavelength Dispersive X-ray Fluorescence (WDXRF) analysis of hardened concrete for chlorides vs. Atomic Absorption (AA) analysis in accordance with AASHTO T- 260; sampling and testing for chloride ion in concrete and concrete raw mater

    Science.gov (United States)

    2014-04-01

    A correlation between Wavelength Dispersive X-ray Fluorescence(WDXRF) analysis of Hardened : Concrete for Chlorides and Atomic Absorption (AA) analysis (current method AASHTO T-260, procedure B) has been : found and a new method of analysis has been ...

  3. Construction of Pile foundations of Dacheng Viaduct%大成桥高架桥桩基施工

    Institute of Scientific and Technical Information of China (English)

    彭振斌; 刘铁雄

    2001-01-01

    Dacheng viaduct in Ningxiang,Hunan province landed in limestone area with developed Karst and cave-in the surface. Considered the engineering geology condition, a project of hand-dug piles was presented, which was successful through several kinds of special treatment. Among of these, the most length of hand-dug pile was 70.8 meter .So long a pile like this was infrequent in our country.%大成桥高架桥位于宁横公路三标段灰岩区,岩溶发育,地面塌陷严重。综合现场工程地质条件,提出了在采用人工挖孔桩的方案,由于采用了特殊处理措施,取得了较大的成功。其中最深的人工挖孔桩达70.8 m,如此深的人工挖孔桩国内少见。

  4. Non-linear vehicle-bridge-wind interaction model for running safety assessment of high-speed trains over a high-pier viaduct

    Science.gov (United States)

    Olmos, José M.; Astiz, Miguel Á.

    2018-04-01

    In order to properly study the high-speed traffic safety on a high-pier viaduct subject to episodes of lateral turbulent winds, an efficient dynamic interaction train-bridge-wind model has been developed and experimentally validated. This model considers the full wheel and rail profiles, the friction between these two bodies in contact, and the piers P-Delta effect. The model has been used to determine the critical train and wind velocities from which the trains cannot travel safely over the O'Eixo Bridge. The dynamic simulations carried out and the results obtained in the time domain show that traffic safety rates exceed the allowed limits for turbulent winds with mean velocities at the deck higher than 25 m/s.

  5. Influence of the wind direction on the chloride profiles of structures close to the Caribbean Sea. The case of the Turiguanó- Coco Key Viaduct in Cuba

    Directory of Open Access Journals (Sweden)

    Pérez García, E. J.

    2005-03-01

    Full Text Available Interpretation of chlorides profiles is important to predict concrete structures service life, among other factors. However, reported results are, in general, from small specimens exposed to specific atmospheres instead of real structures. The objective of this work was the obtention and interpretation of the chlorides profiles forms from several bridges of the Turiguanó-Coco Key viaduct in Cuba. The results verified data from other authors but on different structural elements and similar atmospheres. The form of the chloride profile for structures similar to those in the viaduct bridges, exposed to tropical marine atmosphere, is consistent and changes in intensity with the winds direction and the blocking to them by parts of the structure. The possible effect of the wet and drying process is also discussed.

    En años recientes se le ha dado importancia a la interpretación de los perfiles de cloruros en el hormigón armado con fines de predicción de vida útil, entre otros. Sin embargo, los datos que se han constatado pertenecen, por lo general, a experimentos sobre probetas que han sido expuestas, por un tiempo determinado, a atmósferas específicas más que a estructuras reales. El objetivo de este trabajo fue la obtención e interpretación de la forma de los perfiles de cloruros de varios puentes del viaducto Turiguanó-Cayo Coco en Cuba. Los resultados ratificaron los datos encontrados por otros autores en otros elementos y ambientes similares, pero en un tipo de estructura diferente. En todos los casos estudiados se pudo verificar que, la forma del perfil de concentración de cloruros para estructuras similares a los puentes del viaducto estudiado expuestas a un ambiente tropical marino, es consistente y cambia de intensidad con la dirección de los vientos y del apantallamiento a los mismos por parte de la estructura y de sus partes. Se discute el posible efecto del mojado y secado.

  6. A High-Speed Target-Free Vision-Based Sensor for Bus Rapid Transit Viaduct Vibration Measurements Using CMT and ORB Algorithms

    Directory of Open Access Journals (Sweden)

    Qijun Hu

    2017-06-01

    Full Text Available Bus Rapid Transit (BRT has become an increasing source of concern for public transportation of modern cities. Traditional contact sensing techniques during the process of health monitoring of BRT viaducts cannot overcome the deficiency that the normal free-flow of traffic would be blocked. Advances in computer vision technology provide a new line of thought for solving this problem. In this study, a high-speed target-free vision-based sensor is proposed to measure the vibration of structures without interrupting traffic. An improved keypoints matching algorithm based on consensus-based matching and tracking (CMT object tracking algorithm is adopted and further developed together with oriented brief (ORB keypoints detection algorithm for practicable and effective tracking of objects. Moreover, by synthesizing the existing scaling factor calculation methods, more rational approaches to reducing errors are implemented. The performance of the vision-based sensor is evaluated through a series of laboratory tests. Experimental tests with different target types, frequencies, amplitudes and motion patterns are conducted. The performance of the method is satisfactory, which indicates that the vision sensor can extract accurate structure vibration signals by tracking either artificial or natural targets. Field tests further demonstrate that the vision sensor is both practicable and reliable.

  7. A Simulation of the Millau Viaduct

    OpenAIRE

    Bergsjö, Cathrina; Pettersson, Marcus

    2016-01-01

    Cable-stayed bridges have become very popular over the last ve decades due totheir aesthetic appeal, structural eciency, the limited amount of material usageand nancial benets. The rapid increase of new techniques creating longer spans,slender decks and more spectacular design has given rise to a major concern ofthe dynamic behavior of cable-stayed bridges. This has resulted in a more carefulmodelling procedure that will represent the reality in the most particular way. Amodel is simply an ap...

  8. Update of bridge design standards in Alabama for AASHTO LRFD seismic design requirements.

    Science.gov (United States)

    2013-11-01

    The Alabama Department of Transportation (ALDOT) has been required to update their bridge design to the LRFD Bridge Design Specifications. This transition has resulted in changes to the seismic design standards of bridges in the state. Multiple bridg...

  9. Hot mix asphalt (HMA) characterization for the 2002 AASHTO design guide.

    Science.gov (United States)

    2008-09-30

    The two study objectives were to conduct dynamic modulus and APA rutting tests of selected Mississippi HMA mixtures. A total of twenty-five mixtures were tested including aggregate combinations of gravel and gravel/limestone; 9.5mm, 12.5mm and 19.0mm...

  10. Kinematic Interaction and Rocking Effects on the Seismic Response of Viaducts on Pile Foundations

    International Nuclear Information System (INIS)

    Dezi, F.; Carbonari, S.; Leoni, G.

    2008-01-01

    This paper is aimed at providing a contribution for a more accurate and effective design of bridges founded on piles. A numerical model is employed herein to determine the stresses and displacements in the piles taking into account soil-foundation-structure interaction. A 3D finite element approach is developed for piles and superstructure whereas the soil is assumed to be a Winkler-type medium. The method is applied to single piers representative for a class of bridges. Varying the soil layers characteristics and the pile spacing (from 3 to 5 diameters), bending and axial stresses along piles as well as the pier base shear are computed. A comparison with respect to a fixed-base model is provided. Special issues such as the contribution of the soil profile, of the local amplification and of the rocking at the foundation level are discussed. Soil-structure interaction is found to be essential for effective design of bridges especially for squat piers and soft soil

  11. Analysis of B-WIM Signals acquired in Millau Orthotropic Viaduct Using Statistical Classification

    OpenAIRE

    IENG, Sio Song; ZERMANE, Abderraouf; SCHMIDT, Franziska; JACOB, Bernard

    2012-01-01

    Les systèmes B-WIM classiques sont généralement fondés sur les travaux de Moses utilisant la notion de la ligne d'influence. Ces systèmes ont été testés avec succès sur les ponts en béton à travers le monde. Ce papier s'intéresse aux travaux de recherche concernant l'utilisation d'un système B-WIM sur le viaduc de Millau qui est un pont à haubans avec une à dalle orthotrope. Nous montrons d'abord qu'un système de B-WIM ne peut pas être utilisé directement sur ce type de pont sans adaptation d...

  12. UJI KOMPARASI PERENCANAAN TEBAL PERKERASAN LENTUR DAN KAKU METODE AASHTO 1993 (STUDI KASUS PROYEK KBK PENINGKATAN JALAN NASIONAL BANYUMANIK BAWEN

    Directory of Open Access Journals (Sweden)

    Totok Apriyatno

    2015-01-01

    Full Text Available KBK project Tujauan Road Improvement Banyumanik - Bawen besides increasing the capacity of the road, also aims to improve the quality of the pavement in the form of rigid pavement in order to overcome the damage to roads, especially in the area of incline / derivatives and around traffic light .. This is because the pavement in regional incline / derivatives or traffic light is always damage in the form of Ruts (groove. This study analyzes the thick rigid pavement CBC project is implemented and compared with if the use is thick flexible pavement (asphalt. In terms of cost requirements and the design life of pavement, the results of this study might be useful for research studies on the next, remembering of several studies found that for the same length, rigid pavement construction costs more expensive than flexible pavement, but the life of the plan rigid pavement longer than flexible pavement. Thick rigid pavement were implemented in this project is 27 cm, while the results of the analysis, using concrete K-350 and a 20-year design life of rigid pavement thickness obtained by 29 cm and when using flexible pavement with a design life of 10 years obtained a total thickness of 47.5 cm consisting of: (a. Surface layer (AC 4 cm, (b. Base layers Over 12 cm, and (c. Under the foundation layers of 31.5 cm.

  13. Transfer and development length of prestressing tendons in full-scale AASHTO prestressed concrete girders using self-consolidating concrete.

    Science.gov (United States)

    2009-03-01

    Self-consolidating concrete (SCC) is a highly workable concrete that flows through densely reinforced or : complex structural elements under its own weight. The benefits of using SCC include: a) Reducing labor costs : by eliminating the need for mech...

  14. Selecting measures to prevent deleterious alkali-silica reaction in concrete : rationale for the AASHTO PP65 prescriptive approach.

    Science.gov (United States)

    2012-10-01

    PP65-11 provides two approaches for selecting preventive measures: (i) a performance approach based on laboratory testing, and (ii) a prescriptive approach based on a consideration of the reactivity of the aggregate, type and size of structure, expos...

  15. Appendix B : small beam tests.

    Science.gov (United States)

    2013-03-01

    The AASHTO LRFD Bridge Design Specifications (2007) require that confinement : reinforcement be placed around prestressing strands in the bottom bulb of pretensioned concrete : beams. Although the AASHTO specifications contain prescriptive requiremen...

  16. Validation of correction factors for concrete coefficient of thermal expansion.

    Science.gov (United States)

    2010-07-01

    To complete the objectives, AASHTO T 366-09 results will be compared to ASHTO TP 60-00 results. The results will then be used as input values for the MEPDG and the results evaluated. : Major changes between AASHTO TP 60-00 and AASHTO T 336-09 will be...

  17. 77 FR 38248 - Passenger Train Emergency Preparedness

    Science.gov (United States)

    2012-06-27

    ... State Highway and Transportation Officials (AASHTO); American Chemistry Council; American Petroleum... Engineers and Trainmen (BLET); Brotherhood of Maintenance of Way Employees Division (BMWED); Brotherhood of...

  18. 77 FR 153 - Passenger Train Emergency Systems II

    Science.gov (United States)

    2012-01-03

    ... Transportation Officials (AASHTO); American Chemistry Council; American Petroleum Institute; American Public...); Association of State Rail Safety Managers (ASRSM); Brotherhood of Locomotive Engineers and Trainmen (BLET...

  19. 77 FR 64249 - Track Safety Standards; Improving Rail Integrity

    Science.gov (United States)

    2012-10-19

    ... Transportation Officials (AASHTO); American Chemistry Council; American Petrochemical Institute; American Public... (ASRSM); BMWED; Brotherhood of Locomotive Engineers and Trainmen (BLET); Brotherhood of Railroad...

  20. Evaluation of Bridges Subjected to Military Loading and Dynamic Hydraulic Effects: Review of Design Regulations, Selection Criteria, and Inspection Procedures for Bridge Railing Systems

    Science.gov (United States)

    2011-08-01

    Figure 11. Potential for wheel , bumper, or hood impact with post (AASHTO 2007). ....................... 102 Figure 12. Post setback criteria (AASHTO 2007...barriers. ................................................................... 88 Table 22. Recommended values for runout lengths...The clear zone may consist of a shoulder, a recoverable slope, a nonrecoverable slope, and/or a clear runout area. Crash tests: Vehicular impact

  1. 23 CFR 973.208 - Indian lands pavement management system (PMS).

    Science.gov (United States)

    2010-04-01

    ... 23 Highways 1 2010-04-01 2010-04-01 false Indian lands pavement management system (PMS). 973.208... PROGRAM Bureau of Indian Affairs Management Systems § 973.208 Indian lands pavement management system (PMS... concepts described in the AASHTO's “Pavement Management Guide.” 1 1 “Pavement Management Guide,” AASHTO...

  2. Rating precast prestressed concrete bridges for shear

    Science.gov (United States)

    2008-12-01

    Shear capacity of real-world prestressed concrete girders designed in the 1960s and 1970s is a concern because : AASHTO Standard Specifications (AASHTO-STD) employed the quarter-point rule for shear design, which is less : conservative for shea...

  3. 23 CFR 500.106 - PMS.

    Science.gov (United States)

    2010-04-01

    ... the “AASHTO Guidelines for Pavement Management Systems.” 1 1 AASHTO Guidelines for Pavement Management... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION TRANSPORTATION INFRASTRUCTURE MANAGEMENT MANAGEMENT AND MONITORING SYSTEMS Management Systems § 500.106 PMS. An effective PMS for Federal-aid highways is a systematic...

  4. Electronic construction collaboration system : phase III.

    Science.gov (United States)

    2011-12-01

    This phase of the electronic collaboration project involved two major efforts: 1) implementation of AEC Sync (formerly known as Attolist), a web-based project management system (WPMS), on the Broadway Viaduct Bridge Project and the Iowa Falls Arch Br...

  5. Sadhana | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    ... Committee on Scientific Values · Project Lifescape · Scientific Data of Public Interest ... Viaduct roads have wide application in big cities with high traffic loads, ... technique, finite elements analysis, experimentally and neural networks (NN).

  6. The Information Manager Vol. 7 (2)2007 28

    African Journals Online (AJOL)

    ezra

    or infrastructures, dams, bridges, viaducts, industrial complexes, etc. are often .... the ability to span large distances with high precision. ... reduce cost. Issues to be considered in designing a ... Unlike a simple amplitude SAR image, which only ...

  7. 55. 鉄道構造物の健全度把握手法の精度向上と有効利用に関する考察(都市施設の防災性向上と許容リスク その1)

    OpenAIRE

    上半, 文昭; 目黒, 公郎; Fumiaki, UEHAN; Kimiro, MEGURO; (財)鉄道総合技術研究所:東京大学生産技術研究所; 東京大学生産技術研究所; Railway Technical Research Institute:Institute of Industrial Science, The University of Tokyo; Institute of Industrial Science, The University of Tokyo

    1999-01-01

    This paper discusses the improvement and effective use of health monitoring technique of railway bridges, using vibration measurement and new numerical model for nonlinear analysis of structures. First, accuracy of the Applied Element Method (AEM), used in this study, is verified through eigen value analysis and seismic response simulation of existing two-storied RC rigid frame viaduct. Next, change of natural frequency of the viaduct due to damage to columns is studied by the AEM. Applicabil...

  8. Sadhana | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Home; Journals; Sadhana. Ahmet Çelık. Articles written in Sadhana. Volume 31 Issue 1 February 2006 pp 9-20. Natural frequencies of a flat viaduct road part simply supported on two ends · İsmail Yüksek Ahmet Çelık Kayhan Gülez · More Details Abstract Fulltext PDF. Viaduct roads have wide application in big cities with ...

  9. Uso de aisladores de base en puentes de concreto simplemente apoyados

    OpenAIRE

    Leocadio Rico Pradilla; Gustavo Chio Cho

    2012-01-01

    The aim of this paper is to present a comparison of the seismic behavior of simply supported concrete bridges by using three types of base isolators, namely high damping rubber bearing (HDRB), lead rubber bearing (LRB) and friction pendulum system (FPS). “La Flora” viaduct is taken as case study; the geometry and the corresponding modeling of such viaduct are defined in sap2000. Additionally, the mechanical properties of three insulators are defined using a bilinear model. An analysis of hist...

  10. The design, construction and Heavy Vehicle Simulator testing results on Roller Compacted Concrete test sections at the CSIR Innovation Site and on a full-scale test road at Rayton

    CSIR Research Space (South Africa)

    Du Plessis, Louw

    2016-09-01

    Full Text Available . AASHTO), which was above the specified South African limit of a minimum CBR of 25 at 95% Mod AASHTO. The density of the subbase was measured with a nuclear density gauge after compaction. The subbase was only compacted to 90.7% Mod AASHTO, 2.3% short... and was concentrated around the shrinkage crack. 6.1.1 Elastic deflection response Figure 1 shows both the surface deflections captured by the joint deflection measuring devices (JDMDs) and multi-depth deflectometers (MDD). MDD 12 and JDMD 1 and 2 were placed...

  11. A static analysis method for barge-impact design of bridges with consideration of dynamic amplification : final report, November 2009.

    Science.gov (United States)

    2009-11-01

    Current practice with regard to designing bridge structures to resist impact loads associated with barge collisions relies upon the : use of the American Association of State Highway and Transportation Officials (AASHTO) bridge design specifications....

  12. Geotechnical LFRD calculations of settlement and bearing capacity of GDOT shallow bridge foundations and retaining walls.

    Science.gov (United States)

    2016-08-09

    The AASHTO codes for Load Resistance Factored Design (LRFD) regarding shallow bridge foundations : and walls have been implemented into a set of spreadsheet algorithms to facilitate the calculations of bearing : capacity and footing settlements on na...

  13. Survey of state funding for public transportation 2010

    Science.gov (United States)

    2010-07-01

    The AASHTO Standing Committee on Public Transportation is pleased to release the Survey of State : Funding for Public Transportation. The survey results reflect Fiscal Year 2008 data. This annual report : provides a snapshot of state-by-state investm...

  14. Advanced bridge safety initiative, task 1 : development of improved analytical load rating procedures for flat-slab concrete bridges - a thesis and guidelines.

    Science.gov (United States)

    2010-01-01

    Current AASHTO provisions for the conventional load rating of flat slab bridges rely on the equivalent strip method : of analysis for determining live load effects, this is generally regarded as overly conservative by many professional : engineers. A...

  15. Effects of increasing the allowable compressive stress at release on the shear strength of prestressed concrete girders.

    Science.gov (United States)

    2008-09-01

    In recent years, several research projects have been conducted to study the feasibility of increasing the allowable : compressive stress in concrete at prestress transfer, currently defined as 0.60f'ci in the AASHTO LRFD Bridge : Design Specification...

  16. Bridge removal plan requirements.

    Science.gov (United States)

    2011-04-15

    This report provides resources that detail specifications and guidelines related to bridge removal plans across the : United States. We have organized the information into three sections: : ! National Guidance : Includes language from AASHTO specific...

  17. Route 139 rehabilitation: Pulaski Skyway contract 2 : technical brief.

    Science.gov (United States)

    2017-06-01

    This study addressed the need for an aesthetically pleasing historic concrete balustrade design alternative for the Pulaski Skyway in Jersey City, Hudson County. In this study, a crashworthy design was developed according to AASHTO Section 13 specifi...

  18. A feasibility study for Arizona's roadway safety management process using the Highway Safety Manual and SafetyAnalyst : final report.

    Science.gov (United States)

    2016-07-01

    To enable implementation of the American Association of State Highway Transportation (AASHTO) Highway Safety Manual using : SaftetyAnalyst (an AASHTOWare software product), the Arizona Department of Transportation (ADOT) studied the data assessment :...

  19. Determination of barge impact probabilities for bridge design.

    Science.gov (United States)

    2016-04-01

    Waterway bridges in the United States are designed to resist vessel collision loads according to design provisions released by the American Association of State : Highway and Transportation Officials (AASHTO). These provisions provide detailed proced...

  20. Enhancement of the FDOT's project level and network level bridge management analysis tools

    Science.gov (United States)

    2011-02-01

    Over several years, the Florida Department of Transportation (FDOT) has been implementing the AASHTO Pontis Bridge Management System to support network-level and project-level decision making in the headquarters and district offices. Pontis is an int...

  1. Evaluation of resistivity meters for concrete quality assurance.

    Science.gov (United States)

    2015-06-01

    This research evaluated a series of MoDOT concrete mixtures to verify existing relationships between surface resistivity (SR), rapid : chloride permeability (RCP), chloride ion diffusion, and the AASHTO penetrability classes. The research also perfor...

  2. Surface resistivity test evaluation as an indicator of the chloride permeability of concrete.

    Science.gov (United States)

    2012-12-01

    Many agencies have adopted the standard tests for electrical : indication of concretes ability to resist chloride ion penetration : (AASHTO T 277 and ASTM C1202), commonly known as the rapid : chloride permeability test (RCPT), in their specificat...

  3. Iowa calibration of MEPDG performance prediction models.

    Science.gov (United States)

    2013-06-01

    This study aims to improve the accuracy of AASHTO Mechanistic-Empirical Pavement Design Guide (MEPDG) pavement : performance predictions for Iowa pavement systems through local calibration of MEPDG prediction models. A total of 130 : representative p...

  4. Iowa calibration of MEPDG performance prediction models : [summary].

    Science.gov (United States)

    2013-06-01

    The latest AASHTOWare DARWin-METM (now referred to as Pavement ME Design), and the Mechanistic-Empirical Pavement Design Guide (MEPDG) (AASHTO 2008) are significantly improved methodologies for the analysis and design of pavement structures. DARWin...

  5. Rock mass classification system : transition from RMR to GSI.

    Science.gov (United States)

    2013-11-01

    The AASHTO LRFD Bridge Design Specifications is expected to replace the rock mass rating : (RMR) system with the Geological Strength Index (GSI) system for classifying and estimating : engineering properties of rock masses. This transition is motivat...

  6. Evidence-based decision making : developing a knowledge base for successful program outcomes in transportation asset management.

    Science.gov (United States)

    2015-12-01

    MAP-21 and AASHTOs framework for transportation asset management (TAM) offer opportunities to use more : rigorous approaches to collect and apply evidence within a TAM context. This report documents the results of a study : funded by the Georgia D...

  7. Highway Safety Manual applied in Missouri - freeway/software : research summary.

    Science.gov (United States)

    2016-03-01

    AASHTOs Highway Safety Manual (HSM) : includes models for freeway segments, speedchange : lanes (transitional area between mainline : and ramps), ramps, and interchange terminals. : These predictive models for freeway : interchanges need to be cal...

  8. Determination of mechanical properties for cement-treated aggregate base : final report.

    Science.gov (United States)

    2017-06-01

    The Virginia Department of Transportation (VDOT) currently follows pavement design procedures for all new and rehabilitated pavements based on the 1993 AASHTO Guide for Design of Pavement Structures. VDOTs Materials Division is in the process of i...

  9. Quick test for durability factor estimation.

    Science.gov (United States)

    2010-03-01

    The Missouri Department of Transportation (MoDOT) is considering the use of the AASHTO T 161 Durability Factor (DF) as an endresult : performance specification criterion for evaluation of paving concrete. However, the test method duration can exceed ...

  10. Evaluation of size effect on shear strength of reinforced concrete ...

    Indian Academy of Sciences (India)

    of the longitudinal and the web reinforcement, shear span-to-depth ratio and the ... A simple equation for predicting the shear strength of reinforced concrete deep ..... AASHTO 2007 LRFD Bridge Design Specifications, American Association of ...

  11. Performance of self-consolidating concrete in prestressed girders.

    Science.gov (United States)

    2010-04-01

    A structural investigation of self-consolidating concrete (SCC) in AASHTO Type I precast, : prestressed girders was performed. Six test girders were subjected to transfer length and : flexural testing. Three separate concrete mixtures, two girders pe...

  12. Appendix G : end region design models.

    Science.gov (United States)

    2013-03-01

    The 2007 AASHTO LRFD Bridge Design Specifications contain prescriptive : requirements for the quantity and placement of confinement reinforcement located in the bottom : flange of pretensioned concrete I-girders. This chapter proposes a rational mode...

  13. An Account of Preliminary Landslide Damage and Losses Resulting from the February 28, 2001, Nisqually, Washington, Earthquake

    Science.gov (United States)

    Highland, Lynn M.

    2003-01-01

    The February 28, 2001, Nisqually, Washington, earthquake (Mw = 6.8) damaged an area of the northwestern United States that previously experienced two major historical earthquakes, in 1949 and in 1965. Preliminary estimates of direct monetary losses from damage due to earthquake-induced landslides is approximately $34.3 million. However, this figure does not include costs from damages to the elevated portion of the Alaskan Way Viaduct, a major highway through downtown Seattle, Washington that will be repaired or rebuilt, depending on the future decision of local and state authorities. There is much debate as to the cause of the damage to this viaduct with evaluations of cause ranging from earthquake shaking and liquefaction to lateral spreading to a combination of these effects. If the viaduct is included in the costs, the losses increase to $500+ million (if it is repaired) or to more than $1+ billion (if it is replaced). Preliminary estimate of losses due to all causes of earthquake damage is approximately $2 billion, which includes temporary repairs to the Alaskan Way Viaduct. These preliminary dollar figures will no doubt increase when plans and decisions regarding the Viaduct are completed.

  14. Earthquake resistant measures of existing structures by TRTA; Eidan chikatetsu ni okeru kisetsu doboku kozobutsu no taishin taisaku

    Energy Technology Data Exchange (ETDEWEB)

    Miyata, N.

    1997-08-10

    Seismic countermeasures for the existing structures are introduced on the main item: reinforcement of open-cut tunnel RC center pillars as well as on reinforcement of rigid frame viaduct pillars and installation of a device for prevention of viaduct falling. First, for reinforcing open-cut tunnel center pillars, design was devised so as to be suitable to construction environment in the subway yard. Important reinforcement materials are steel and filling materials; SS and a self-leveling material for building construction were chosen. The following construction work procedures are explained based on the actual construction: removal of interior materials of existing pillars and measurement of the actual size, high pressure water washing, steel plate fabrication, plate delivery to the yard, installation of steel plates, filler filling, painting. Next, on reinforcement of viaduct pillars on the ground, the reinforcement design concept is basically same as in the open-cut tunnel. Points of difference in design and construction are explained. On the countermeasure for prevention of viaduct falling for girder bridges without the falling prevention, countermeasure investigation and design work or installation work are being carried out. Seismic resistance evaluation and design of existing bridges, and construction work are explained. 13 figs., 1 tab.

  15. Electrical pulses protect concrete

    NARCIS (Netherlands)

    Koleva, D.; Fraaij, A.; Van Kasteren, J.

    2006-01-01

    Even concrete is not as hard as it looks. Sea water, salt on icy roads, and indirectly even carbon dioxide from the air can corrode the steel of the reinforcing bars and so threaten the strength and integrity of a bridge pier, jetty, or viaduct. Dessi Koleva, a chemical engineer from Bulgaria, spent

  16. Structural monitoring of tunnels using terrestrial laser scanning

    NARCIS (Netherlands)

    Lindenbergh, R.C.; Uchanski, L.; Bucksch, A.; Van Gosliga, R.

    2009-01-01

    In recent years terrestrial laser scanning is rapidly evolving as a surveying technique for the monitoring of engineering objects like roof constructions, mines, dams, viaducts and tunnels. The advantage of laser scanning above traditional surveying methods is that it allows for the rapid

  17. If Only it Could Speak

    DEFF Research Database (Denmark)

    Jensen, Ole B.

    2012-01-01

    cleaves its way on the north-south trajectory through the city via raised ramps and elevated sections and carries about 110,000 vehicles a day. One of these sections, the Alaskan Way Viaduct, was built on old seawall structures and created a buffer between the city and the sea at Elliott Bay. The Alaskan...

  18. Analytical Model for Passing Sight Distance Design Criteria of Two-Lane Roads in Sri Lanka

    Directory of Open Access Journals (Sweden)

    Mampearachchi W. K.

    2018-03-01

    Full Text Available For a safe overtaking manoeuvre on two-lane highways, drivers need a sufficient sight distance along the roadway, but it depends on the traffic environment. To provide an adequate Passing Sight Distance (PSD, a number of models have been proposed since the initial model introduced by American Association of State Highways and Transport Officials (AASHTO in 1954. It is a current design practice in Sri Lanka as well, however, not validated for local traffic conditions. This paper will present an alternative PSD model and an evaluation of AASHTO model for national highway design. Experiment was based on GPS data collection. In conclusion, PSD demand was satisfied by AASHTO PSD under mix traffic conditions, but not the safety concerns for speeds greater than 80 km/h, while alternative model successful for all speeds.

  19. Hormigón liviano de alto desempeño - una comparación entre pérdidas de pretensado reales y estimadas por los códigos de diseño High performance lightweight concrete - a comparison between actual prestress losses and design code estimates

    Directory of Open Access Journals (Sweden)

    Mauricio López

    2007-04-01

    Full Text Available Dos mezclas de hormigón liviano de alto desempeño (HLAD con resistencias a compresión de 55 MPa y 69 MPa fueron desarrolladas. El peso unitario de los hormigones fue 1855 y 1890 kg/m, respectivamente. Creep, retracción y pérdidas de pretensado fueron investigadas en 36 probetas cilíndricas y en cuatro vigas pretensadas AASHTO tipo II. Las pérdidas de pretensado medidas en las vigas AASHTO tipo II fabricadas con HLAD fueron menores que las estimadas con los métodos descritos en los códigos AASHTO, PCI y ACI-209, lo que significa que los códigos de diseño dan estimaciónes conservadoras de las pérdidas de pretensado en este nuevo hormigón. Basados en los datos experimentales, las pérdidas finales de pretensado fueron estimadas como un 14.3 y 9.6% de la carga inicial aplicada para las vigas hechas con HLAD de 55 y 69 MPa, respectivamenteTwo different high performance lightweight concretes (HPLC with strengths of 55 and 69 MPa were developed. They had an air-dry unit weight of 1855 and 1890 kg/m³, respectively. Creep, shrinkage and prestress losses were investigated on 36 cylinder specimens and on four AASHTO Type II girders. Prestress losses measured on the AASHTO Type II girders made with HPLC were less than those predicted using AASHTO, PCI and ACI-209 methods which means that the design codes give conservative estimates of the actual prestress losses of this new concrete. Based on experimental data, final, total prestress losses were estimated to be 14.3 and 9.6% of the initial prestressing force for the 55-MPa and 69-MPa HPLC, respectively

  20. Comparación de las normas sísmicas más utilizadas para puentes continuos en el Perú y sus métodos de análisis

    OpenAIRE

    Acero Martínez, José Alberto

    2004-01-01

    Este trabajo esta orientado a revisar las normas sísmicas más utilizadas para puentes continuos en el Perú y sus métodos de análisis. Se revisan principalmente: la norma AASHTO STANDARD, AASHTO LRFD, CALTRANS y la Norma Sísmica para Puentes de Japón. También, se discute la propuesta de norma para puentes del Ministerio de Transportes y Comunicaciones del Perú y se revisa la NTE E.030. Por otro lado, se revisan en forma referencial, normas sísmicas de puentes de Chile, Venezuela y Canadá. T...

  1. Assessment of Index Properties and Bearing Capacities of Soils for ...

    African Journals Online (AJOL)

    Mrs Owoyemi

    on the physical properties and foundation bearing capacity of the soil in this area. This research aimed ... While many new structures are springing up daily in the .... plasticity soil. Most soil samples from both locations classify as A-2 -4 under the AASHTO classification system, rating as good subgrade materials. Bulk density ...

  2. S-HAL : safety handbook for locals.

    Science.gov (United States)

    2014-01-01

    The Safety Handbook for Locals (S-HAL) is intended to be a comprehensive : traffic safety resource for all local communities in Missouri, be it cities or : counties. The S-HAL mirrors the national Highway Safety Manual (HSM) : (AASHTO, 2010) in using...

  3. Development of a highway safety fundamental course.

    Science.gov (United States)

    2015-05-01

    Although the need for road safety education was first recognized in the 1960s, it has become an increasingly urgent issue : in recent years. To fulfill the hefty goal set up by the AASHTO Highway Safety Strategy and by state DOTS, it is critical : to...

  4. Developing a Highway Safety Fundamentals Course : Research Project Capsule

    Science.gov (United States)

    2012-10-01

    Although the need for road : safety education was fi rst : recognized in the 1960s, : recently it has become an : increasingly urgent issue. To : fulfi ll the hefty goal set up by : the AASHTO Highway : Safety Strategy (cutting : traffi c fatalities ...

  5. Guidelines for Implementing NCHRP 1-37A M-E Design Procedures in Ohio : Volume 3 -- Sensitivity Analysis

    Science.gov (United States)

    2009-11-01

    The new Mechanistic-Empirical Pavement Design Guide (NCHRP 1-37A and 1-40D) is based on fundamental engineering principles and is far more comprehensive than the current empirical AASHTO Design Guide developed for conditions more than 40 years previo...

  6. Workshop report : joint workshop on liability issues in advanced vehicle control and automated highway systems

    Science.gov (United States)

    1997-02-05

    The National Automated Highway System Consortium (NAHSC), ITS America and the American Association of State Highway & Transportation Officials (AASHTO) co-sponsored a two-day workshop in Washington, DC on February 5-6, 1997 to examine the liability i...

  7. 25 CFR 170.810 - To what standards must an IRR transportation facility be maintained?

    Science.gov (United States)

    2010-04-01

    ... WATER INDIAN RESERVATION ROADS PROGRAM BIA Road Maintenance § 170.810 To what standards must an IRR... standards; (b) AASHTO road and bridge maintenance manuals, latest edition; or (c) Other applicable Federal, State, tribal, or local government maintenance standards as may be negotiated in an ISDEAA road...

  8. Stabilization of expansive soil using bagasse ash & lime | Wubshet ...

    African Journals Online (AJOL)

    7-5 soil on the AASHTO classification was stabilized using 3% lime, 15% bagasse ash and 15% bagasse ash in combination with 3% lime by dry weight of the soil. The effect of the additives on the soil was investigated with respect to plastcity, ...

  9. Comprehensive evaluation of fracture critical bridges.

    Science.gov (United States)

    2014-02-01

    Two-girder steel bridges are classified as fracture critical bridges based on the definition given in the AASHTO LRFD Bridge Design Specifications. In a fracture critical bridge a failure of a tension member leads to collapse of the bridge. However, ...

  10. High strength reinforcing steel bars : concrete shear friction interface : final report : Part A.

    Science.gov (United States)

    2017-03-01

    High-strength steel (HSS) reinforcement, specifically ASTM A706 Grade 80 (550), is now permitted by the AASHTO LRFD Bridge Design Specifications for use in reinforced concrete bridge components in non-seismic regions. Using Grade 80 (550) steel reinf...

  11. 23 CFR 650.211 - Guidelines.

    Science.gov (United States)

    2010-04-01

    ... 23 Highways 1 2010-04-01 2010-04-01 false Guidelines. 650.211 Section 650.211 Highways FEDERAL..., STRUCTURES, AND HYDRAULICS Erosion and Sediment Control on Highway Construction Projects § 650.211 Guidelines. (a) The FHWA adopts the AASHTO Highway Drainage Guidelines, Volume III, “Erosion and Sediment Control...

  12. Some geotechnical properties of a cement-stabilized granite-gneiss ...

    African Journals Online (AJOL)

    This was with a view to determining the influence of cement on some engineering properties of the soil. ... the maximum Dry Density and the percentage cement of the samples compacted at the West African and Modified American Association of State Highways and Transportation Officials (AASHTO) levels respectively.

  13. Evaluation of repeatability of Kansas test method KT-73, "density, absorption and voids in hardened concrete," boil test.

    Science.gov (United States)

    2015-06-01

    For years, the Kansas Department of Transportation (KDOT) and concrete producers in the state have used a : Rapid Chloride Test for concrete cylinders, AASHTO T277. This test has been thought of as an appropriate quality : control test to evaluate pe...

  14. Comparison of sampling and test methods for determining asphalt content and moisture correction in asphalt concrete mixtures.

    Science.gov (United States)

    1985-03-01

    The purpose of this report is to identify the difference, if any, in AASHTO and OSHD test procedures and results. This report addresses the effect of the size of samples taken in the field and evaluates the methods of determining the moisture content...

  15. Effects of layer interface slip on the response and performance of elastic multi-layered flexible airport pavement systems

    CSIR Research Space (South Africa)

    Maina, JW

    2007-08-01

    Full Text Available in this study. The new AASHTO pavement design guide for flexible pavements is shifting from an experience (or purely empirical) based design method to a mechanistic-empirical (M-E) design method. The latter approach requires an elastic multi-layered analysis...

  16. Evaluation of repeatability of Kansas test method KT-73, "density, absorption and voids in hardened concrete," boil test : [technical summary].

    Science.gov (United States)

    2015-06-01

    For years, the Kansas Department of Transportation (KDOT) and concrete producers in : the state have used a Rapid Chloride Test for concrete cylinders, AASHTO T277. This : test has been thought of as an appropriate quality control test to evaluate pe...

  17. Design recommendations for the optimized continuity diaphragm for prestressed concrete bulb-T beams.

    Science.gov (United States)

    2008-01-01

    This research focused on prestressed concrete bulb-T (PCBT) beams made composite with a cast-in-place concrete deck and continuous over several spans through the use of continuity diaphragms. The current design procedure in AASHTO states that a conti...

  18. A STUDY OF DISPLACEMENT-LEVEL DEPENDENCY OF VERTICAL STIFFNESS OF PILE - COMPARISONS BETWEEN STATIC LOADING TEST AND MEASUREMENTS DURING TRAIN PASSING -

    Science.gov (United States)

    Nihei, Tatsuya; Nishioka, Hidetoshi; Kawamura, Chikara; Nishimura, Masahiro; Edamatsu, Masayuki; Koda, Masayuki

    In order to introduce the performance based design of pile foundation, vertical stiffness of pile is one of the important design factors. Although it had been es timated the vertical stiffness of pile had the displacement-level dependency, it had been not clarified. We compared the vertical stiffness of pile measured by two loading conditions at pile foundation of the railway viaduct. Firstly, we measured the vertical stiffness at static loading test under construction of the viaduct. Secondly, we measured the vertical stiffness at the time of train passing. So, we recognized that the extrapolation of the displacement level dependency in static loading test could evaluate the vertical stiffness of pile during train passing.

  19. Architecture and engineering in Alcoy. 90 years of the bridge of San Jorge

    Directory of Open Access Journals (Sweden)

    J. F. Picó Silvestre

    2017-04-01

    Full Text Available At the end of 1925 the construction of Saint Jorge’s bridge began in Alcoy. This was one of the first large viaduct built entirely of reinforced concrete in Spain, but it also constitutes one of the unique overwhelming examples that the language of Art Deco used in its elements. The 90th anniversary of this bridge may serve to commemorate the success of a close collaboration between engineering and architecture. This viaduct had peculiar problems and important modifications during the construction that were resolved satisfactorily in a period of history where culture was heading towards modernity. In the present case, the work of the engineer and architect, duly selected by a shrewd and effective construction company in their building abilities, resulted in a magnificent forgotten structure that should be rehabilitated in the collective memory.

  20. Rhéologie des bétons fluides à hautes performances : relations entre formulations, propriétés rhéologiques, physico-chimie et propriétés mécaniques

    OpenAIRE

    Yammine , Joumana

    2007-01-01

    The High Performance Concrete, from high to low plastic consistency, develops high long term mechanical resistances. Nevertheless, it presents the disadvantage of a very hard filling in dense steel reinforcements rebars like in the Millau's viaduct piles, which constitute a framework of barriers for the concrete casting by vibration. To guarantee a total filling in the framework, the self compacting concretes are the issue and are adopted respecting mechanical performances and durability main...

  1. Vibration monitoring of long bridges and their expansion joints and seismic devices

    OpenAIRE

    Islami Kleidi

    2015-01-01

    This paper presents a number of recently installed Structural Health Monitoring (SHM) systems: a) on a 2km double suspension bridge; b) on a long railway viaduct that has experienced cracking; and c) on a steel arch bridge in a seismically active area. Damage detection techniques have been applied based on high-frequency measurements of vibrations, pressure and strain, enabling a proper understanding of the structures’ behaviour to be gained. The diverse range of applications presented, desig...

  2. Uso de aisladores de base en puentes de concreto simplemente apoyados

    Directory of Open Access Journals (Sweden)

    Leocadio Rico Pradilla

    2012-12-01

    Full Text Available The aim of this paper is to present a comparison of the seismic behavior of simply supported concrete bridges by using three types of base isolators, namely high damping rubber bearing (HDRB, lead rubber bearing (LRB and friction pendulum system (FPS. “La Flora” viaduct is taken as case study; the geometry and the corresponding modeling of such viaduct are defined in sap2000. Additionally, the mechanical properties of three insulators are defined using a bilinear model. An analysis of histories in time was made for the model of the viaduct, considering the non-linearity in the insulators and using frontal fault earthquakes caused by the Frontal and Bucaramanga-Santa Marta fault; this is applied at a surface-level scale. The results from the model without seismic isolation are compared with the three systems of seismic isolation and the findings suggest that the different systems of seismic isolation significantly reduce both the demands of the displacements and the cutting forces in the piles of the bridge, which may induce probable earthquakes.

  3. El viaducto de Sfalassà Italia

    Directory of Open Access Journals (Sweden)

    Zorzi, S.

    1974-11-01

    Full Text Available This work is really one of the most spectacular construction on the motor road Salermo-Reggio Calabria. It consists of two lateral viaducts altogether 517 m long, with spans of prestressed concrete, and one 376 m long central metal viaduct. The viaduct bridges a valley at a maximum height of 250 m. The above mentioned central span is the most interesting one since the columns have been mounted vertically on hinges at their base which makes it possible to turn them subsequently into their final position.Esta obra es realmente una de las más espectaculares de la autopista Salermo-Reggio Calabria. Se compone de dos viaductos laterales, de 517 m de longitud total, a base de tramos de hormigón armado pretensado, y uno central, metálico, de 376 m, salvando un valle de 250 m de altura máxima. Dicho tramo central es el más interesante de todo el puente, ya que los pilares se han montado verticalmente, con rótulas en su base, que les ha permitido ser girados posteriormente a su posición definitiva.

  4. Occurrence of shale soils along the Calabar-Itu highway, Southeastern Nigeria and their implication for the subgrade construction.

    Science.gov (United States)

    Ilori, Abidemi Olujide

    2016-01-01

    This study concerned a stretch of 17 km of a 94-km highway alignment in Southeastern Nigeria that has a high incidence of pavement failure arising from subgrade failure. The subgrade of this section of the roadway is composed of Ekenkpon shale, New Netim marl, and Nkporo shale. Under the Unified Soil Classification System, the shales classify as OH (organic clay) and the marl classifies as MH (inorganic silt). Under the American Association of State and Transportation Officials (AASHTO) M 145 soil classification, all these soils classify as A-7-5 soil. Using the AASHTO M 145 group index, none of these soils was considered suitable as subgrade in its native form. Therefore, cement was investigated as a stabilizing agent. Testing demonstrated that 7, 3 and 12 % by weight were the optimum cement contents to reinforce the Ekenkpon shale, New Netim marl, and Nkporo shale, respectively.

  5. Effect of Rice Husk Ash on Cement Stabilized Laterite

    OpenAIRE

    Musa ALHASSAN; Alhaji Mohammed MUSTAPHA

    2007-01-01

    Laterite soil collected from Maikunkele area of Minna, classified as an A-7-6 on AASHTO classification, was stabilized with 2-8% cement by weight of the dry soil. Using British Standard Light (BSL) compaction energy, the effect of Rice Husk Ash (RHA) on the soil was investigated with respect to compaction characteristics, California Bearing Ratio (CBR) and Unconfined Compressive Strength (UCS) tests. Results obtained, indicate a general decrease in Maximum Dry Density (MDD) and increase in Op...

  6. Coast Guard Proceedings. Volume 68, Number 2, Summer 2011

    Science.gov (United States)

    2011-01-01

    flood damage re- duction, the economic development of depressed rural and urban areas, disaster preparedness and response, ac- tivities of the U.S...AASHTO), July 2010, p. 13. The Port of Seattle, which is celebrating its centennial anniversary this year, will host AAPA’s 100th annual convention...The dive tender assisting diver #11 testified he did not see him test the defogger/freeflow valve on his helmet, nor did he see him depress the

  7. Assessing Asphalt and Concrete Pavement Surface Texture in the Field

    OpenAIRE

    Saad I. Sarsam; Huda N. Al Shareef

    2016-01-01

    The incorporation of safety characteristics into the traditional pavement structural design or in the functional evaluation of pavement condition has not been established yet. The design has focused on the structural capacity of the roadway so that the pavement can withstand specific level of repetitive loading over the design life. On the other hand, the surface texture condition was neither included in the AASHTO design procedure nor in the present serviceability index measurements. The ...

  8. Strut elaboration in strut-and-tie model

    Directory of Open Access Journals (Sweden)

    Mohammad PANJEHPOUR

    2012-12-01

    Full Text Available The Strut-and-Tie Model (STM has been incorporated into the codes and standards because of its consistency and rationality since last decade. However, it has encountered few challenges whilst its implementation. The effective compressive strength of strut has been a complex issue among researchers since emergence of STM. This review serves as a base for future developments of STM. It addresses several ways towards enhancing our understanding of strut performance in the STM. It also throws up questions for further investigation of effective compressive strength of strut in the STM. This review is confined to the evaluation of strut effectiveness factor based on the available codes and standards particularly AASHTO LRFD and ACI 318-08. According to the example given in this paper, there is sometimes a marked difference of approximately 50% between strut effectiveness factor recommended by AASHTO LRFD and ACI 318-08. More broadly, research is needed to determine which of the complicated strut effectiveness factor recommended by AASHTO LRFD and the simple one recommended by ACI 318-08 is optimum.

  9. Determinación probabilística del tiempo de servicio de Estructuras de Pavimentos

    Directory of Open Access Journals (Sweden)

    Mario Rodríguez

    Full Text Available En Chile, como en muchos países de Suramérica, AASHTO 93 es el método oficial para el diseño de pavimentos asfálticos. El método entrega un número estimado de ejes equivalentes estándar de 80 kN que el pavimento puede soportar hasta alcanzar un cierto valor de serviciabilidad. Un factor de seguridad es luego aplicado al número estimado de ejes equivalente tomando en cuenta el nivel de confianza y la varianza estimada de los datos de entrada utilizados en el método, con lo cuál se estima la magnitud del ciclo de vida de la estructura. Normalmente, los datos utilizados en el método AASHTO 93 son asumidos como valores deterministas, sin tomar en cuenta su naturaleza aleatoria. Este trabajo presenta una evaluación probabilística del método de diseño AASHTO 93 de pavimentos bajo condiciones chilenas, el cuáll proporciona un conjunto de funciones de densidad de probabilidad, que permiten realizar la estimación probabilística del ciclo de vida del pavimento en términos del valor del número de ejes equivalente. Para alcanzar el objetivo se desarrollo un modelo de simulación a partir de una muestra de 13 grupos de carreteras ubicados a largo de Chile.

  10. Differences in Train-induced Vibration between Hard Soil and Soft Soil

    Science.gov (United States)

    Noyori, M.; Yokoyama, H.

    2017-12-01

    Vibration and noise caused by running trains sometimes raises environmental issues. Train-induced vibration is caused by moving static and dynamic axle loads. To reduce the vibration, it is important to clarify the conditions under which the train-induced vibration increases. In this study, we clarified the differences in train-induced vibration between on hard soil and on soft soil using a numerical simulation method. The numerical simulation method we used is a combination of two analysis. The one is a coupled vibration analysis model of a running train, a track and a supporting structure. In the analysis, the excitation force of the viaduct slabs generated by a running train is computed. The other analysis is a three-dimensional vibration analysis model of a supporting structure and the ground into which the excitation force computed by the former analysis is input. As a result of the numerical simulation, the ground vibration in the area not more than 25m from the center of the viaduct is larger under the soft soil condition than that under the hard soil condition in almost all frequency ranges. On the other hand, the ground vibration of 40 and 50Hz at a point 50m from the center of the viaduct under the hard soil condition is larger than that under the soft soil condition. These are consistent with the result of the two-dimensional FEM based on a ground model alone. Thus, we concluded that these results are obtained from not the effects of the running train but the vibration characteristics of the ground.

  11. State of the Art of the Development and Application of Anti-Seismic Systems in Europe and Other Countries

    Science.gov (United States)

    Martelli, Alessandro; Forni, Massimo

    2008-07-01

    There are already approximately 5,000 structures in the world, located in over 30 countries, that have been protected by seismic isolation (SI), energy dissipation (ED) and other modern seismic vibration passive control (SVPC) systems. The number of such applications is increasing everywhere more and more. It has been confirmed that, in each country, the extension of the use of the SVPC systems is conclusively influenced by earthquake experience, the availability of specific design rules and the features of those adopted. With regard to application, Japan has consolidated its worldwide leadership, with over 3,000 seismically isolated buildings, many others protected by ED systems and several isolated bridges & viaducts. Second is now the P. R. China, with 610 isolated buildings and 45 with dampers, in addition to numerous isolated bridges & viaducts. The Russian Federation is third for the number of isolated buildings, which are approximately 600. In the USA, due to the very penalizing design code in force for SI of buildings, there are at present only a few new applications of this kind (an overall number of approximately 200 was reported), although the US isolated buildings are mostly quite important, half being retrofits; on the contrary, the use of SI for bridges & viaducts and that of ED for buildings are more popular in the USA. At present (April 2008), Italy (which remains the worldwide leader as regards the application of the SVPC systems to cultural heritage and keeps a key role also as to the number and importance of bridges & viaducts protected by such systems) is at the fifth place, at least for the number of isolated buildings already open to activity: they are 51, besides others protected by other SVPC systems. There, thanks to the new national seismic code (enforced in May 2003), there has been a significant recent increase of building application and design of the SVPC systems. With regard to the use of such systems in other countries, Italy is now

  12. Investigation of Tension Forces in A Stay Cable System of A Road Bridge Using Vibration Methods

    Directory of Open Access Journals (Sweden)

    Hawryszków Paweł

    2015-01-01

    Full Text Available In the article author presents method of investigation of tension forces in stay cable systems using dynamical methods. Research was carried out during stay cable system installation on WN-24 viaduct near Poznań, that is way it was possible to compare tension forces indicated directly by devices using for tensioning of cable-stayed bridges with results achieved indirectly by means of dynamical methods. Discussion of results was presented. Advantages of dynamical methods and possible fields of application was described. This method, which has been rarely used before, may occur interesting alternative in diagnostics of bridges in comparison to traditional methods.

  13. State of the Art of the Development and Application of Anti-Seismic Systems in Europe and Other Countries

    International Nuclear Information System (INIS)

    Martelli, Alessandro; Forni, Massimo

    2008-01-01

    There are already approximately 5,000 structures in the world, located in over 30 countries, that have been protected by seismic isolation (SI), energy dissipation (ED) and other modern seismic vibration passive control (SVPC) systems. The number of such applications is increasing everywhere more and more. It has been confirmed that, in each country, the extension of the use of the SVPC systems is conclusively influenced by earthquake experience, the availability of specific design rules and the features of those adopted. With regard to application, Japan has consolidated its worldwide leadership, with over 3,000 seismically isolated buildings, many others protected by ED systems and several isolated bridges and viaducts. Second is now the P. R. China, with 610 isolated buildings and 45 with dampers, in addition to numerous isolated bridges and viaducts. The Russian Federation is third for the number of isolated buildings, which are approximately 600. In the USA, due to the very penalizing design code in force for SI of buildings, there are at present only a few new applications of this kind (an overall number of approximately 200 was reported), although the US isolated buildings are mostly quite important, half being retrofits; on the contrary, the use of SI for bridges and viaducts and that of ED for buildings are more popular in the USA. At present (April 2008), Italy (which remains the worldwide leader as regards the application of the SVPC systems to cultural heritage and keeps a key role also as to the number and importance of bridges and viaducts protected by such systems) is at the fifth place, at least for the number of isolated buildings already open to activity: they are 51, besides others protected by other SVPC systems. There, thanks to the new national seismic code (enforced in May 2003), there has been a significant recent increase of building application and design of the SVPC systems. With regard to the use of such systems in other countries, Italy

  14. Los viaductos de acceso al puente de Martigues – Francia

    Directory of Open Access Journals (Sweden)

    Perzo, R.

    1972-11-01

    Full Text Available This article describes the approaches to a large metal bridge 300 m in length. These approaches consist of two viaducts whose decks are continuous beams of prestressed concrete 260 and 315 m long; spans in both viaducts are 45 m long. The cross section is a slab with two 3 m deep ribs; there are no stiffeners, neither between the spans nor over the supports. The two structures have been constructed with spans of 45 m over a self-supporting formwork which has proven very efficient.Se describen los accesos a un gran puente metálico, de 300 m de longitud. Dichos accesos están constituidos por dos viaductos cuyos tableros son vigas continuas, de hormigón pretensado, de 260 y 315 m de longitud; las luces en ambos viaductos son de 45 m. La sección transversal es una losa con dos nervios de 3 m de canto; no existen riostras ni en los vanos ni sobre los apoyos. Las dos estructuras se han construido por tramos de 45 m sobre una cimbra autolanzable, que ha permitido muy buenos rendimientos.

  15. Paso elevado, en Manchester – Inglaterra

    Directory of Open Access Journals (Sweden)

    Hayes, J.

    1970-09-01

    Full Text Available This is an urban main traffic connection, running south of the civic centre of Manchester, and facilitates communications in the East West directions. It also links the main motor roads entering the city from the South. It involves a viaduct with two traffic directions, with a total length of 975 m, which runs over several highways and pedestrian footpaths. The article describes the structure of this viaduct and its special features, such as an improved type of prestressed concrete dowels and certain construction problems.Se trata de un paso de enlace urbano, situado al sur del centro cívico de Manchester, que descongestiona el tránsito este-oeste actuando como un distribuidor entre las carreteras principales de entrada desde el sur. Incluye un viaducto de dos calzadas, de unos 975,36 m, que pasa por encima de un conjunto de carreteras al nivel del suelo y de pasos de peatones. El artículo describe la estructura elevada con unas notas sobre los aspectos notables del proyecto, como son: las mejoras introducidas en las dovelas de hormigón pretensado y los problemas que se presentaron durante la construcción.

  16. Real-time health monitoring of civil infrastructure systems in Colombia

    Science.gov (United States)

    Thomson, Peter; Marulanda Casas, Johannio; Marulanda Arbelaez, Johannio; Caicedo, Juan

    2001-08-01

    Colombia's topography, climatic conditions, intense seismic activity and acute social problems place high demands on the nations deteriorating civil infrastructure. Resources that are available for maintenance of the road and railway networks are often misdirected and actual inspection methods are limited to a visual examination. New techniques for inspection and evaluation of safety and serviceability of civil infrastructure, especially bridges, must be developed. Two cases of civil structures with health monitoring systems in Colombia are presented in this paper. Construction of the Pereria-Dos Quebradas Viaduct was completed in 1997 with a total cost of 58 million dollars, including 1.5 million dollars in health monitoring instrumentation provided and installed by foreign companies. This health monitoring system is not yet fully operational due to the lack of training of national personnel in system operation and extremely limited technical documentation. In contrast to the Pereria-Dos Quebradas Viaduct monitoring system, the authors have proposed a relatively low cost health monitoring system via telemetry. This system has been implemented for real-time monitoring of accelerations of El Hormiguero Bridge spanning the Cauca River using the Colombian Southwest Earthquake Observatory telemetry systems. This two span metallic bridge, located along a critical road between the cities of Puerto Tejada and Cali in the Cauca Valley, was constructed approximately 50 years ago. Experiences with this system demonstrate how effective low cost systems can be used to remotely monitor the structural integrity of deteriorating structures that are continuously subject to high loading conditions.

  17. AVALIAÇÃO DOS IMPACTOS DAS OBRAS DE MOBILIDADE URBANA PARA A COPA DO MUNDO FIFA 2014 EM CUIABÁ: O Caso do Viaduto da Universidade Federal de Mato Grosso

    Directory of Open Access Journals (Sweden)

    Andrea Regina Kaneko Kobayashi

    2016-04-01

    Full Text Available The increase of vehicle fleet in recent years has been compromising the organization and flow of traffic in Brazilian cities. Factors such as government incentives to car ownership and the inefficiency of public transport have led people to opt for individual motorized transport, which has caused problems such as congestion, accidents and other traffic conflicts. In order to mitigate such problems, various infrastructure facilities were carried out, mostly prioritizing traditional urban mobility, which seeks to increase traffic speed. However, the sustainable urban mobility has as principles: speed reduction, promotion of reasonable travel times and accessibility to all users. The purpose of this article is to check the impact of urban mobility facilities regarding the 2014 World Cup preparation, which was held in the Metropolitan Region of Cuiabá /MT. The article focuses on sustainable urban mobility from the case study of the viaduct of the Federal University of Mato Grosso. The research is qualitative and exploratory and its data collection is consisted of documental research, observation of the construction, analysis of videos and images and interviews with two professional traffic planning experts. The results showed that the aspects of sustainable urban mobility were not observed in the construction of the viaduct at the Federal University of Mato Grosso, it was identified a lack of planning in the construction and in its surroundings. Other issues related to the lack of transparency regarding the use of funds for the execution and completion of the construction, and the lack of publication of structural design.

  18. Advanced testing and characterization of shear modulus and deformation characteristics of oil sand materials

    CSIR Research Space (South Africa)

    Anochie-Boateng, Joseph

    2014-09-01

    Full Text Available and Pressures,” Can. Geotech. J., Vol. 24, 1987, pp. 1–10. [5] Samieh, A.M. and Wong, R.C.K., “Deformation of Athabasca Oil Sand in Triaxial Compression Tests at Low Effective Stresses under Varying Boundary Conditions,” Can. Geotech. J., Vol.34, 1997, pp.... 985– 990. [6] Samieh, A.M. and Wong, R.C.K., “Modeling the Responses of Athabasca Oil Sand in Triaxial Compression Tests at Low Pressure,” Can. Geotech. J., Vol. 35, 1998, pp. 395–406. [7] AASHTO Standard T265, 2009, “Laboratory Determination...

  19. Una reseña de ensayos de carga no destructivos usados para la evaluación de puentes

    OpenAIRE

    Jáuregui, David

    2001-01-01

    El objetivo principal de este artículo es de proveer un breve repaso de la actividad relacionada con la evaluación experimental de los puentes en los Estados Unidos. Los dos métodos de evaluación de carga aplicados por AASHTO (La Asociación Americana de Oficiales de Carreteras Estatales y Transporte) son presentados incluyendo el esfuerzo permisible (AS) y el factor de carga (LF). Además, son discutidos los detalles básicos de los dos tipos de ensayos de carga más comunes para la evaluación d...

  20. Evaluación de estructuras de pavimento flexible usando técnicas no destructivas utilizando el deflectometro de impacto o fwd (falling weight Deflectometer)

    OpenAIRE

    Gutiérrez Bayona, Andrés Giovani

    2012-01-01

    Teniendo en cuenta que en nuestro país los recursos destinados al desarrollo y mantenimiento de infraestructura vial son limitados, es importante optimizar la inversión de los recursos en la construcción de los proyectos viales garantizando la vida útil de las estructuras de pavimento. Por tanto, a fin de determinar la capacidad estructural de algunos pavimentos de tipo flexible en la ciudad de Bogotá con base en las técnicas de la metodología AASHTO-93, se compararon los análisis y res...

  1. Diseño de un pavimento utilizando geomallas en tramo de la carretera bajada de chanduy – aguas verdes - pocito (absc. 2+900 hasta absc. 3+600)

    OpenAIRE

    Tapia Diez, Andrés Renato; Barona Fajardo, Fabricio Eduardo; Inga Morán, Luis Rolando; Santos Baquerizo, Eduardo

    2009-01-01

    This seminar graduation thesis is based on the design of a piece of the road “Bajada de Chanduy - Aguas Verdes – Pocito” using synthetic net materials that improve the structural capacity of a pavement. The mentioned piece of road starts from the abscissa 2+900 to the 3+600 and presents a low support capacity for which is necessary the use of the geosynthetic net. Primarily it is shown the AASHTO design methodology for pavements in order to compare the design thickness obtained...

  2. Analysis and design optimization of flexible pavement

    Energy Technology Data Exchange (ETDEWEB)

    Mamlouk, M.S.; Zaniewski, J.P.; He, W.

    2000-04-01

    A project-level optimization approach was developed to minimize total pavement cost within an analysis period. Using this approach, the designer is able to select the optimum initial pavement thickness, overlay thickness, and overlay timing. The model in this approach is capable of predicting both pavement performance and condition in terms of roughness, fatigue cracking, and rutting. The developed model combines the American Association of State Highway and Transportation Officials (AASHTO) design procedure and the mechanistic multilayer elastic solution. The Optimization for Pavement Analysis (OPA) computer program was developed using the prescribed approach. The OPA program incorporates the AASHTO equations, the multilayer elastic system ELSYM5 model, and the nonlinear dynamic programming optimization technique. The program is PC-based and can run in either a Windows 3.1 or a Windows 95 environment. Using the OPA program, a typical pavement section was analyzed under different traffic volumes and material properties. The optimum design strategy that produces the minimum total pavement cost in each case was determined. The initial construction cost, overlay cost, highway user cost, and total pavement cost were also calculated. The methodology developed during this research should lead to more cost-effective pavements for agencies adopting the recommended analysis methods.

  3. A User Friendly Software for Rigid Pavement Design

    Directory of Open Access Journals (Sweden)

    Aydın Kıcı

    2017-12-01

    Full Text Available Concrete pavements as concrete road slab, appear as a strong alternative for flexible superstructures especially because of their low cost for maintenance and repair and the high performance they show under heavy axle loads. The design of these concrete road slabs is quite different from the traditional concrete and reinforced concrete structures’ design. In the design for this kind of pavements, traffic conditions should be defined properly and considered an addition to the concrete and platform properties. There have been designing methods developed based on both experimental and mechanic foundations for concrete pavements. The most important ones of these methods are AASHTO (1993 and PCA (1984. In both design methods, it’s significant to know the maximum deflections and maximum strains the vehicles’ loads cause on the pavement. The calculation of this maximum deflections and maximum strains can be done via the finite element method or the closed formulas which have been developed by Westergaard. In this study, a user-friendly software has been developed based on AASHTO 1993, PCA 1984 design methods and Westergaard formulas. Thanks to this software, the user who wants to design the concrete pavement as concrete road slab can obtain the essential parameters automatically by entering the required data for the design.

  4. Design of semi-rigid type of flexible pavements

    Directory of Open Access Journals (Sweden)

    Pranshoo Solanki

    2017-03-01

    Full Text Available The primary objective of the study presented in this paper is to develop design curves for performance prediction of stabilized layers and to compare semi-rigid flexible pavement designs between the empirical AASHTO 1993 and the mechanistic-empirical pavement design methodologies. Specifically, comparisons were made for a range of different sections consisting of cementitious layers stabilized with different types and percentages of additives. It is found that the design thickness is influenced by the type of soil, additive, selection of material property and design method. Cost comparisons of sections stabilized with different percentage and type of additives showed that CKD-stabilization provides economically low cost sections as compared to lime- and CFA-stabilized sections. Knowledge gained from the parametric analysis of different sections using AASHTO 1993 and MEPDG is expected to be useful to pavement designers and others in implementation of the new MEPDG for future pavement design. Keywords: Semi-rigid, Mechanistic, Resilient modulus, Fatigue life, Reliability, Traffic

  5. Investigation of statistical relationship between dynamic modulus and thermal strength of asphalt concrete

    International Nuclear Information System (INIS)

    Qadir, A.; Gular, M.

    2011-01-01

    Dynamic modulus is a performance indicator for asphalt concrete and is used to qualify asphalt mixtures based on stress-strain characteristics under repeated loading. Moreover, the low temperature cracking of asphalt concrete mixes are measured in terms of fracture strength and fracture temperature. Dynamic modulus test was selected as one of the simple performance tests in the AASHTO 2002 guidelines to rate mixtures according to permanent deformation performance. However, AASHTO 2002 guidelines is silent in relating dynamic modulus values to low temperature cracking, probably because of weak correlations reported between these two properties. The present study investigates the relation between these two properties under the influence of aggregate type and mix gradation. Mixtures were prepared with two types of aggregate and gradations, while maintaining the binder type and air voids constant. The mixtures were later tested for dynamic modulus and fracture strength using thermal stress restrained specimen test (TSRST). Results indicate that there exists a fair correlation between the thermal fracture strength and stiffness at a selected test temperature and frequency level. These correlations are highly dependent upon the type of aggregate and mix gradation. (author)

  6. Clay stabilization by using gypsum and paddy husk ash with reference to UCT and CBR value

    Science.gov (United States)

    Roesyanto; Iskandar, R.; Hastuty, I. P.; Dianty, W. O.

    2018-02-01

    Clays that have low shear strength need to be stabilized in order to meet the technical requirements to serve as a subgrade material. One of the usual soil stabilization methods is by adding chemicals such as Portland cement, lime, and bitumen. The clay stabilization research was done by adding gypsum and paddy husk ash. The research goals were to find out the value of engineering properties of clay due to the addition of 2% gypsum and 2% - 15% paddy husk ash. The soil was classified as Clay - Low Plasticity (CL) based on USCS and was classified as A-7-6 (10) based on AASHTO classification system. The UCT value of original soil was 1.41 kg/cm2. While the CBR soaked and unsoaked values of original soil were 4.41% and 6.23% respectively. The research results showed the addition of paddy husk ash decreased the value of unconfined compressive strength as well as CBR. The stabilized soil by 2% gypsum and 0% paddy husk ash gave maximum UCT value of 1.67 kg/cm2, while the maximum value of CBR were found 6.71% for CBR soaked and 8.00% for CBR unsoaked. The addition of paddy husk ash did not alter the soil classification according to AASHTO or USCS, even degrade the engineering properties of original soil.

  7. Fatigue evaluation of socket welded piping in nuclear power plant

    International Nuclear Information System (INIS)

    Vecchio, R.S.

    1996-01-01

    Fatigue failures in piping systems occur, almost without exception, at the welded connections. In nuclear power plant systems, such failures occur predominantly at the socket welds of small diameter piping ad fillet attachment welds under high-cycle vibratory conditions. Nearly all socket weld fatigue failures are identified by leaks which, though not high in volume, generally are costly due to attendant radiological contamination. Such fatigue cracking was recently identified in the 3/4 in. diameter recirculation and relief piping socket welds from the reactor coolant system (RCS) charging pumps at a nuclear power plant. Consequently, a fatigue evaluation was performed to determine the cause of cracking and provide an acceptable repair. Socket weld fatigue life was evaluated using S-N type fatigue life curves for welded structures developed by AASHTO and the assessment of an effective cyclic stress range adjacent to each socket weld. Based on the calculated effective tress ranges and assignment of the socket weld details to the appropriate AASHTO S-N curves, the socket weld fatigue lives were calculated and found to be in excellent agreement with the accumulated cyclic life to-date

  8. Live-Load Testing Application Using a Wireless Sensor System and Finite-Element Model Analysis of an Integral Abutment Concrete Girder Bridge

    Directory of Open Access Journals (Sweden)

    Robert W. Fausett

    2014-01-01

    Full Text Available As part of an investigation on the performance of integral abutment bridges, a single-span, integral abutment, prestressed concrete girder bridge near Perry, Utah was instrumented for live-load testing. The live-load test included driving trucks at 2.24 m/s (5 mph along predetermined load paths and measuring the corresponding strain and deflection. The measured data was used to validate a finite-element model (FEM of the bridge. The model showed that the integral abutments were behaving as 94% of a fixed-fixed support. Live-load distribution factors were obtained using this validated model and compared to those calculated in accordance to recommended procedures provided in the AASHTO LRFD Bridge Design Specifications (2010. The results indicated that if the bridge was considered simply supported, the AASHTO LRFD Specification distribution factors were conservative (in comparison to the FEM results. These conservative distribution factors, along with the initial simply supported design assumption resulted in a very conservative bridge design. In addition, a parametric study was conducted by modifying various bridge properties of the validated bridge model, one at a time, in order to investigate the influence that individual changes in span length, deck thickness, edge distance, skew, and fixity had on live-load distribution. The results showed that the bridge properties with the largest influence on bridge live-load distribution were fixity, skew, and changes in edge distance.

  9. Consideraciones en el diseño de puentes de hormigón para líneas de alta velocidad ferroviaria

    Directory of Open Access Journals (Sweden)

    Cartagena Abella, Juan José

    1992-08-01

    Full Text Available Bridges and viaducts are an alternative to ground works when the tracks must pass over a road or body of water, or when a rare morphological phenomenon must be preserved, or simply to diminish the barrier effect, there by enhancing the environmental impact of the railroad. The article reviews the actions to be considered in structural calculations, with an emphasis on dynamic actions.

    Los puentes y viaductos sirven de alternativa a las obras de tierra cuando es necesario permitir transversalmente el paso de alguna vía de comunicación o un curso de agua, salvar una singularidad morfológica, o bien simplemente disminuir el efecto barrera mejorando el Impacto ambiental de una obra lineal. En el artículo se revisan las acciones a tener en cuenta en los cálculos estructurales, haciendo hincapié en las acciones dinámicas.

  10. Performance of Hydrophobisation Techniques in Case of Reinforced Concrete Structures

    Science.gov (United States)

    Błaszczyński, Tomasz; Osesek, Mateusz; Gwozdowski, Błażej; Ilski, Mirosław

    2017-10-01

    Concrete is, unchangeably, one of the most frequently applied building materials, also in the case of bridges, overpasses or viaducts. Along with the aging of such structures, the degradation of concrete, which may accelerate the corrosion of reinforcing steel and drastically decrease the load-bearing capacity of the structure, becomes an important issue. The paper analyzes the possibilities of using deep hydrophobisation in repairing reinforced concrete engineering structures. The benefits of properly securing reinforced concrete structures from the damaging effects of UV radiation, the influence of harmful gases, or progression of chlorine induced corrosion have been presented, especially in regards to bridge structures. The need to calculate the costs of carrying out investments along with the expected costs of maintaining such structures, as well as the high share of costs connected with logistics, has also been indicated in the total costs of repair works.

  11. Vibration monitoring of long bridges and their expansion joints and seismic devices

    Directory of Open Access Journals (Sweden)

    Islami Kleidi

    2015-01-01

    Full Text Available This paper presents a number of recently installed Structural Health Monitoring (SHM systems: a on a 2km double suspension bridge; b on a long railway viaduct that has experienced cracking; and c on a steel arch bridge in a seismically active area. Damage detection techniques have been applied based on high-frequency measurements of vibrations, pressure and strain, enabling a proper understanding of the structures’ behaviour to be gained. The diverse range of applications presented, designed in collaboration with structure owners and design engineers, includes damage detection on expansion joints of suspension bridges, crack analysis and correlation with accelerations of high-speed trains, and high-frequency performance monitoring of seismic devices. These case studies, based on both static and dynamic approaches, demonstrate the usefulness and ease of use of such systems, and the enormous gains in efficiency they offer.

  12. Operazioni topografiche per il collaudo di una passerella ciclo - pedonale

    Directory of Open Access Journals (Sweden)

    Giorgio Bezoari

    2013-02-01

    Full Text Available Di norma, il collaudo di ponti, viadotti, cavalcavia, strutture quasi sempre in cemento armato (spesso presollecitato oppure in acciaio (a travi reticolari od a travate piene viene fatto con la ben nota livellazione geometrica di precisione ma se si desidera una analisi dei movimenti 3D si può procedere in altri modi.Surveying for testing a cycle– pedestrian bridgeAs a rule, the testing of bridges, viaducts, overpasses, almost always reinforced concrete structures (often prestressed or steel (trussgirders or in full is done with the well-known high precision geometric leveling butif you want a 3D movements analysis this can be achieved in other ways.

  13. Intercambio direccional en roseta – Suiza

    Directory of Open Access Journals (Sweden)

    Guisan, François

    1964-11-01

    Full Text Available This crossing, at Ecublens, Switzerland, involves five viaducts. The number of roads that the Lausanne-Berne motorway had to cross presented a difficult problem, since technical, aesthetic and economic questions had to be considered, all on a complex scale. As the soil was not suitable to support heavy structures, it was decided to build five viaducts, each providing a traffic route. Some of these viaducts cross each other at three levels. The viaducts consist of box girder sections, joined together to form continuous beams. The two central piles of each section are rigid, to withstand wind forces, and the others are hinged at the top and bottom. The sections are separated by dilatation joints, fitted with a metal attachment, which provides continuity for the pavement, and allows for a relative displacement of 16 cm. Some of the supports were placed on pile foundations, to overcome the weak bearing strength of the subsoil. One of the road sections did not have any rigid central supports, and this arrangement was chosen for aesthetic reasons.El intercambio direccional en roseta, de Ecublens (Suiza, está constituido por un conjunto de cinco viaductos. La multiplicidad de vías que debía salvar la autopista Lausana-Berna planteó un problema importante, ya que era preciso tener en cuenta factores de tipo técnico, en lo que respecta a las obras de fábrica; estéticos, en cuanto a armonía con el paisaje local, y económicos. Técnicamente, y teniendo en cuenta que las condiciones del terreno eran poco apropiadas para levantar obras pesadas, la solución adoptada consiste, en esencia, en cinco viaductos que constituyen otros tantos pasos, algunos de ellos intermedios, es decir, situados entre dos vías: una superior y otra inferior. Cada uno de los pasos se ha subdividido en varios tramos de viga cajón continua. Las dos pilas centrales de cada tramo son rígidas, para poder absorber los efectos del viento; las demás están articuladas en la

  14. Numerical simulation of superelastic shape memory alloys subjected to dynamic loads

    International Nuclear Information System (INIS)

    Cismaşiu, Corneliu; Amarante dos Santos, Filipe P

    2008-01-01

    Superelasticity, a unique property of shape memory alloys (SMAs), allows the material to recover after withstanding large deformations. This recovery takes place without any residual strains, while dissipating a considerable amount of energy. This property makes SMAs particularly suitable for applications in vibration control devices. Numerical models, calibrated with experimental laboratory tests from the literature, are used to investigate the dynamic response of three vibration control devices, built up of austenitic superelastic wires. The energy dissipation and re-centering capabilities, important features of these devices, are clearly illustrated by the numerical tests. Their sensitivity to ambient temperature and strain rate is also addressed. Finally, one of these devices is tested as a seismic passive vibration control system in a simplified numerical model of a railway viaduct, subjected to different ground accelerations

  15. Comparison and calibration of numerical models from monitoring data of a reinforced concrete highway bridge

    Directory of Open Access Journals (Sweden)

    R. G. M. de Andrade

    Full Text Available The last four decades were important for the Brazilian highway system. Financial investments were made so it could expand and many structural solutions for bridges and viaducts were developed. In parallel, there was a significant raise of pathologies in these structures, due to lack of maintenance procedures. Thus, this paper main purpose is to create a short-term monitoring plan in order to check the structural behavior of a curved highway concrete bridge in current use. A bridge was chosen as a case study. A hierarchy of six numerical models is shown, so it can validate the bridge's structural behaviour. The acquired data from the monitoring was compared with the finest models so a calibration could be made.

  16. RESEARCH ON THE DEGREE OF SATURATION INVESTIGATION BY THE SAMPLING OF THE SAND FOR LIQUEFACTION

    Science.gov (United States)

    Fujii, Nao; Ohuchi, Masatoshi; Sakai, Katsuo; Nishigaki, Makoto

    The liquefaction countermeasure technical method, whereby the liquefaction strength is enhanced by making sand deposit in the state of unsaturation, is currently under study. The author et al have suggested a simple method of verifying the persistence of residual air using the undisturbed sample under ordinary temperature and sampling underground water; and have actually implemented the method in the adjacent ground with the foundation of viaduct pneumatic caisson where the leaked air during the construction was considered to have been trapped. We demonstrated the method of correcting the influence of the pressure of sampling specimen as well as of the dissolved air, and studied the precision of required degree of saturation. As the result, it has been shown that the residual air entrapped in the sand deposit is sustainable for as long time as about 28 years.

  17. Development of Flexible Link Slabs using Ductile Fiber Reinforced Concrete

    DEFF Research Database (Denmark)

    Lárusson, Lárus Helgi

    Civil engineering structures with large dimensions, such as multi-span bridges, overpasses and viaducts, are typically equipped with mechanical expansion joints. These joints allow the individual spans of the structure to undergo unrestrained deformations due to thermal expansions and load......-deformation response and crack development of representative sections of the reinforced composites, and iv) detailing, designing and testing of large scale prefabricated link slab elements. In addition, an application of ductile Engineered Cementitious Composite (ECC) in prefabricated floor panels is presented...... crack widths and crack spacing measurements are obtained, which can characterize the tensile behavior of ECC. In chapter 3 on interfacial bond, the bond slip behavior and crack development, between the reinforcement and surrounding cementitious matrix is investigated in a unique test setup with special...

  18. The effect of long-term oxidation on the rheological properties of polymer modified asphalts

    Energy Technology Data Exchange (ETDEWEB)

    Yonghong Ruan; Richard R. Davison; Charles J. Glover [Texas A & M University, College Station, TX (United States). Department of Chemical Engineering

    2003-10-01

    The effect of long-term aging on rheological properties of polymer modified asphalt binders was studied. Modifiers included diblock poly(styrene-b-butadiene) rubber, triblock poly(styrene-b-butadiene-b-styrene), and tire rubber. Asphalt aging was carried out either at 60{sup o}C in a controlled environmental room or at 100{sup o}C in a pressure aging vessel (AASHTO Provisional Standards, 1993). Both dynamic shear properties and extensional properties were investigated. Polymer modification resulted in increased asphalt complex modulus at high temperatures, decreased asphalt complex modulus at low temperatures, broadened relaxation spectra, and improved ductility. Oxidative aging decreased asphalt temperature susceptibility, damaged the polymer network in binders, further broadened the relaxation spectrum, and diminished polymer effectiveness in improving asphalt ductility. 27 refs., 8 figs., 3 tabs.

  19. Reliability and construction control

    Directory of Open Access Journals (Sweden)

    Sherif S. AbdelSalam

    2016-06-01

    Full Text Available The goal of this study was to determine the most reliable and efficient combination of design and construction methods required for vibro piles. For a wide range of static and dynamic formulas, the reliability-based resistance factors were calculated using EGYPT database, which houses load test results for 318 piles. The analysis was extended to introduce a construction control factor that determines the variation between the pile nominal capacities calculated using static versus dynamic formulae. From the major outcomes, the lowest coefficient of variation is associated with Davisson’s criterion, and the resistance factors calculated for the AASHTO method are relatively high compared with other methods. Additionally, the CPT-Nottingham and Schmertmann method provided the most economic design. Recommendations related to a pile construction control factor were also presented, and it was found that utilizing the factor can significantly reduce variations between calculated and actual capacities.

  20. Effect of Rice Husk Ash on Cement Stabilized Laterite

    Directory of Open Access Journals (Sweden)

    Musa ALHASSAN

    2007-09-01

    Full Text Available Laterite soil collected from Maikunkele area of Minna, classified as an A-7-6 on AASHTO classification, was stabilized with 2-8% cement by weight of the dry soil. Using British Standard Light (BSL compaction energy, the effect of Rice Husk Ash (RHA on the soil was investigated with respect to compaction characteristics, California Bearing Ratio (CBR and Unconfined Compressive Strength (UCS tests. Results obtained, indicate a general decrease in Maximum Dry Density (MDD and increase in Optimum Moisture Content (OMC, all with increase in RHA Content (2-8% at specified cement contents. There was also a tremendous improvement in the CBR and UCS with increase in the RHA content at specified cement contents to their peak values at between 4-6% RHA. The UCS values also improved with curing age. This indicates the potentials of using 4-6% RHA admixed with less cement contents for laterite soil stabilization.

  1. Probabilistic model of bridge vehicle loads in port area based on in-situ load testing

    Science.gov (United States)

    Deng, Ming; Wang, Lei; Zhang, Jianren; Wang, Rei; Yan, Yanhong

    2017-11-01

    Vehicle load is an important factor affecting the safety and usability of bridges. An statistical analysis is carried out in this paper to investigate the vehicle load data of Tianjin Haibin highway in Tianjin port of China, which are collected by the Weigh-in- Motion (WIM) system. Following this, the effect of the vehicle load on test bridge is calculated, and then compared with the calculation result according to HL-93(AASHTO LRFD). Results show that the overall vehicle load follows a distribution with a weighted sum of four normal distributions. The maximum vehicle load during the design reference period follows a type I extremum distribution. The vehicle load effect also follows a weighted sum of four normal distributions, and the standard value of the vehicle load is recommended as 1.8 times that of the calculated value according to HL-93.

  2. An Experimental Study on the Wind-Induced Response of Variable Message Signs

    Directory of Open Access Journals (Sweden)

    Debbie Meyer

    2017-11-01

    Full Text Available Variable message sign (VMS systems are widely used in motorways to provide traffic information to motorists. Such systems are subjected to wind-induced structural vibration that can lead to damage due to fatigue. The limited information that is available on the safe wind design of VMS motivated a large scale testing that was conducted at the wall of wind (WOW Experimental Facility at Florida International University (FIU. One of the objectives of the present study was to experimentally assess the wind-induced force coefficients on VMS of different geometries and utilize these results to provide improved design guidelines. A comprehensive range of VMS geometries was tested, and mean normal and lateral force coefficients, in addition to the twisting moment coefficient and eccentricity ratio, were determined using the measured data for each model, for wind directions of 0° and 45°. The results confirmed that the mean drag coefficient on a prismatic VMS is smaller than the value of 1.7 suggested by American Association of State Highway and Transportation Officials (AASHTO. An alternative to this value is presented in the form of a design matrix with coefficients ranging from 0.98 to 1.28, depending on the aspect and depth ratio of the VMS. Furthermore, results indicated that the corner modification on a VMS with chamfered edges demonstrated a reduction in the drag coefficient compared to sharper edges. Finally, the dynamic loading effects were considered by evaluating the gust effect factor, using the ASCE 7 formulations, for various VMS weights and geometries. The findings revealed a wide range of possible gust effect factors, both above and below the current AASHTO specification of 1.14. Future research may include different geometries of VMS and a wider range of wind directions.

  3. Critical traffic loading for the design of prestressed concrete bridge

    International Nuclear Information System (INIS)

    Hassan, M.I.U.

    2009-01-01

    A study has been carried out to determine critical traffic loadings for the design of bridge superstructures. The prestressed concrete girder bridge already constructed in Lahore is selected for the analysis as an example. Standard traffic loadings according to AASHTO (American Association of State Highway and Transportation Officials) and Pakistan Highway Standards are used for this purpose. These include (1) HL-93 Truck, (2) Lane and (3) Tandem Loadings in addition to (4) Military tank loading, (5) Class-A, (6) Class-B and (7) Class-AA loading, (8) NLC (National Logistic Cell) and (9) Volvo truck loadings. Bridge superstructure including transom beam is analyzed Using ASD and LRFD (Load and Resistance Factor Design) provisions of AASHTO specifications. For the analysis, two longer and shorter spans are selected. This includes the analysis of bridge deck; interior and exterior girder; a typical transom beam and a pier. Dead and live loading determination is carried out using both computer aided and manual calculations. Evaluation of traffic loadings is done for all the bridge components to find out the critical loading. HL-93 loading comes out to be the most critical loading and where this loading is not critical in case of bridge decks; a factor of 1.15 is introduced to make it equivalent with HL-93 -Ioading. SAP-2000 (Structural Engineering Services of Pakistan) and MS-Excel is employed for analysis of bridge superstructure subjected to this loading. Internal forces are obtained for the structural elements of the bridge for all traffic loadings mentioned. It is concluded that HL-93 loading can be used for the design of prestressed concrete girder bridge. Bridge design authorities like NHA (National Highway Authority) and different cities development authorities are using different standard traffic loadings. A number of suggestions are made from the results of the research work related to traffic loadings and method of design. These recommendations may be

  4. A study of the effectiveness of the use of gypsum and volcanic ash against the stability of clay soil in terms of UCT and CBR values

    Science.gov (United States)

    Roesyanto; Iskandar, R.; Hastuty, IP; Lubis, AIU

    2018-02-01

    Soil stabilization is an effort to improve engineering properties of soil. The conventional soil stabilization is by adding additives to the soil such as Portland cement, lime, and bitumen. The clay stabilization research was done by adding gypsum and volcanic ash. The research purposes were to find out the value of engineering properties of clay due to the addition of 2% gypsum and 2% - 15% volcanic ash. The soil was classified as Clay - Low Plasticity (CL) based on USCS and was classified as A-7-6 (10) based on AASHTO classification system. The UCT values of original soil and original soil plus 2% gypsum were 1.40 kg/cm2 and 1.66 kg/cm2 respectively. The CBR soaked and unsoaked values of original soil were 4.44% and 6.28% correspondingly. Meanwhile, CBR soaked and CBR unsoaked values of original soil plus 2% gypsum were 6.74% and 8.02% respectively. The research results showed that the additives materials of gypsum and volcanic ash improved the engineering properties of clay. The UCT result from the stabilized soil by 2% gypsum and 10% volcanic ash gave value of 2.79 kg/cm2 (increased 99.28% from original soil). For CBR test, the most effective mixture were in variation of 2% gypsum and 9% volcanic ash which gave value of 9.07% (104.27% increase from original soil) for CBR soaked and 10.29% (63.85% increase from original soil) for CBR unsoaked. The stabilized soil with 2% gypsum and 9% volcanic ash was classified as CL based on USCS and was classified as A-6 (4) based on AASHTO classification system.

  5. Prestressing Concrete with CFRP Composites for Sustainability and Corrosion-Free Applications

    Directory of Open Access Journals (Sweden)

    Belarbi A.

    2018-01-01

    Full Text Available Advancement in material science has enabled the engineers to enhance the strength and long-term behavior of concrete structures. The conventional approach is to use steel for prestressed bridge girders. Despite having good ductility and strength, beams prestressed with steel are susceptible to corrosion when subjected to environmental exposure. The corrosion of the prestressing steel reduces load carrying capacity of the prestressed member and result in catastrophic failures. In the last decades, more durable composite materials such as Aramid Fiber Reinforced Polymer (AFRP, Glass Fiber Reinforced Polymer (GFRP and Carbon Fiber Reinforced Polymer (CFRP have been implemented in concrete structures as a solution to this problem. Among these materials, CFRP stands out as a primary prestressing reinforcement, which has the potential to replace steel and provide corrosion free prestressed bridge girders. Despite its promise, prestressing CFRP has not frequently been used for bridge construction worldwide. The major contributing factor to the lack of advancement of this promising technology in the United States (U.S. is the lack of comprehensive design specifications. Apart from a limited number of guides, manuals, and commentaries, there is currently no standard or comprehensive design guideline available to bridge engineers in the U.S. for the design of concrete structures prestressed with CFRP systems. The main goal is to develop design guidelines in AASHTO-LRFD format for concrete bridge girders with prestressing CFRP materials. The guidelines are intended to address the limitation in current AASHTO-LRFD Bridge Design Specifications which is applicable for prestressed bridge girders with steel strands. To accomplish this goal, some of the critical parameters that affect the design and long-term behavior of prestressed concrete bridge girders with prestressing CFRP systems are identified and included in the research work. This paper presents

  6. Puentes de la autopista de Madrid a La Coruña

    Directory of Open Access Journals (Sweden)

    Fernández Casado, C.

    1967-11-01

    Full Text Available The fortunate circumstance that an urgent plan was approved to transform the road to La Coruña into a motor road, over a distance which was already being converted into a double lane road, led to the standardised design of the ten viaducts over the motor road, between Las Rozas and Villalba. The consequence of the above requirements, and much careful thought, are the viaducts which now emerge from constrasting landscape of plain and mountain, between Madrid and the nearby Sierra. The road ascends, following the natural topography and the positioning of the villages, and also taking advantage of parts of old Roman roads, cattle lanes, and later roads built in the times of the Austrias, the Bourbons and for the use of horse carriages. Actually, by a logical coincidence, the viaducts are sited at the cross roads of this old road pattern. The traffic and the geotechnical conditions are fairly similar for all the viaducts, and this factor was reinforced by the present tendency to standardise the design of Spanish motor roads. But in contrast to this there is the need to attend to the particular requirements of each case: a consideration that perhaps has deserved even more care than the first one. As a result of these contrasting conditions, the underpasses, three of the motor way and another of the railway, have been standardised: the same design has been used on two occasions (prestressed slabs at Pinar de Las Rozas and at Peñascales, and in addition, this design could be repeated for any other motor road or for any other two level crossing, when the lower one is a railway or secondary road. On the other hand, on the overpasses standardisation has not been possible: althought the basic pattern has been the same in all the structures, the detailed construction is different in each. The overpasses are more important projects than the underpasses, and in addition, their detailed adaptation to the site has a greater influence on the total project

  7. Viaducto sobre el rio Llobregat de la Autopista Barcelona-Tarragona, España

    Directory of Open Access Journals (Sweden)

    Fernández Casado, C.

    1973-02-01

    Full Text Available Situated in the vicinity of Barcelona, over the LIobregat River, this viaduct bears two roadways 16 meters wide and 440 meters long. It is a continuous viaduct formed of 11 sections of 40-meter spans and S double T section beams placed 3.35 meters apart. The bridge supports are also of double T formation, with a 2.5 meters wide vertical octagonal stem and changing in depth from 2 to 0.7 meters at the edge. The lower footing is supported on 9 piles each 1 meter in diameter. The 80 t beams were prefabricated in the factory and later put in place using a movable formwork. The continuity between beams was made possible by reinforcement placed in the upper slab of the deck and the lower part of the beams. A detailed study has been made on the redistribution of bending moments by creep and shrinking.Situado en las proximidades de Barcelona, y sobre el río Llobregat, está formado por dos calzadas de 16 m de ancho y 440 m de longitud. Es un viaducto continuo que consta de 11 vanos de 40 m de luz, cada uno de los cuales se compone de cinco vigas sección doble T con separación entre ellas de 3,35 metros. Las pilas sobre las que reposa tienen también forma doble T con fuste vertical octogonal de 2,5 m de ancho, cabezal superior en transición poligonal, hasta el borde, variable de 2 a 0,7 m y zapata inferior que se apoya sobre 9 pilotes de 1 m de diámetro. Tanto las vigas como el cabezal de las pilas están pretensados con cables de 150 toneladas. Las vigas de 80 t de peso fueron prefabricadas en taller y colocadas en obra por medio de una cimbra de lanzamiento. La continuidad entre vigas se realizó por medio de armadura pasiva, colocada en la losa superior del tablero y en la parte inferior de las vigas. Se ha llevado a cabo un estudio detallado de la redistribución de momentos flectores por fluencia y retracción.

  8. L'Italia unita...dalle infrastrutture

    Directory of Open Access Journals (Sweden)

    Stefania Maffeo

    2011-04-01

    Full Text Available The events that led to the proclamation of the Reign of Italy in 1861, after the heroic actions by Garibaldi and the wise politics by Cavour, opened a new stage in Italian history. This is an important moment for a country that had always lived divisions among different political parties and had always been dominated by foreign rulers. The Italian state was created in an important historical period made of technical and economical development thanks to several technological inventions, such as textile machines, the train, the electrical telegraph. These inventions needed also a development in communications. Soon after the Unity of Italy the conditions of the last ones were considerably backward. From the physical geographical viewpoint, the distance between the two extremes of the peninsula, leaving out also the two main isles, was longer than that of all the other European Countries. Besides, just in the Po Valley and along few flat coast lines the relief conditions were suitable for building roads, railways and modern highways. Currently all that is clear: there a few stretches without flyovers, bridges, tunnels and viaducts, which have greatly contributed to transform the landscape (for example the link Genoa – Savona, belonging to highway Fiori – Genova/Ventimiglia – opened in 1967, includes 158 km built along the coast with 27 galleries and 90 viaducts. Historically the “entries of Italy” were the alpine passes and the ports on the coast. The “Belpaese” has been perhaps the most famous example of what the geographer Jean Gottmann called the “crossroads regions” (carrefours with openings to the world which have given them great opportunities to connect and exchange. In the globalization age  the new entries to the world are the international airports, while the telematic networks contribute to get rid of the idea of border itself. A journey to discover the thick and wide realization of communications and

  9. Ageing in civil engineering materials and structures

    Energy Technology Data Exchange (ETDEWEB)

    Jaeger, Jean-Marc [SETEC TPI, Tour Gamma D 58, quai de la Rapee, 75583 Paris (France)

    2005-07-01

    SETEC TPI will address the 'Aging' topic of the Dijon Symposium by talking about: aging in civil engineering materials and structures, prevention of aging phenomena, in-operation monitoring of degradations related to aging and compensatory measures required to maintain a good safety level. Works as the Millau viaduct, the EdF skyscraper at La Defense - Paris, the renovation of the Grand Palais of Paris and special structures with Monaco's floating dam as well as the 'number 10' shaped gateway boat at Marseilles are illustrations for the issues discussed. The durability of civil engineering structures has become a major concern for designers. The Millau viaduct is designed for a service life of 120 years, and the Monaco dam for 100 years. Calculation rules have been evolving toward the incorporation of the concept of life cycle, for example, the Eurocodes 2 rules (reinforced concrete). The talk will expose the factors which are being taken into account to delay aging versus structure types. This part will be focused towards materials and corresponding regulations: - Reinforced concrete (coating of reinforcements, opening of cracks, choice of reinforcement types), BAEL and Eurocodes 2 rules; - Frame steel (protection, sacrificial anode), CM66 and Eurocodes 3 rules. New materials will also be mentioned: - Ultra high-performance fiber/concrete, with the example of CERACEM applied at Millau for the covering of the toll area barrier; - Titanium, which is starting to appear in the building trades, as for instance for the Beijing China Opera House shell. The second part of the talk will be devoted to a specific case namely, the 'number 10' shaped gateway bridge, a prestressed concrete structure immersed in the Port of Marseilles, which will be used to illustrate the aging phenomenon in a corrosive environment. We will focus on the types of inspection series performed by the Autonomous Port Authority of Marseilles to check the behavior of

  10. Performance of portland limestone cements: Cements designed to be more sustainable that include up to 15% limestone addition

    Science.gov (United States)

    Barrett, Timothy J.

    In 2009, ASTM and AASHTO permitted the use of up to 5% interground limestone in ordinary portland cement (OPC) as a part of a change to ASTM C150/AASHTO M85. When this work was initiated a new proposal was being discussed that would enable up to 15% interground limestone cement to be considered in ASTM C595/AASHTO M234. This work served to provide rapid feedback to the state department of transportation and concrete industry for use in discussions regarding these specifications. Since the time this work was initiated, ASTM C595/AASHTO M234 was passed (2012c) and PLCs are now able to be specified, however they are still not widely used. The proposal for increasing the volume of limestone that would be permitted to be interground in cement is designed to enable more sustainable construction, which may significantly reduce the CO2 that is embodied in the built infrastructure while also extending the life of cement quarries. Research regarding the performance of cements with interground limestone has been conducted by the cement industry since these cements became widely used in Europe over three decades ago, however this work focuses on North American Portland Limestone Cements (PLCs) which are specifically designed to achieve similar performance as the OPCs they replace.This thesis presents a two-phase study in which the potential for application of cements containing limestone was assessed. The first phase of this study utilized a fundamental approach to determine whether cement with up to 15% of interground or blended limestone can be used as a direct substitute to ordinary portland cement. The second phase of the study assessed the concern of early age shrinkage and cracking potential when using PLCs, as these cements are typically ground finer than their OPC counterparts. For the first phase of the study, three commercially produced PLCs were obtained and compared to three commercially produced OPCs made from the same clinker. An additional cement was tested

  11. Modelling of pavement materials on steel decks using the five-point bending test: Thermo mechanical evolution and fatigue damage

    International Nuclear Information System (INIS)

    Arnaud, L; Houel, A

    2010-01-01

    This paper deals with the modelling of wearing courses on steel orthotropic decks such as the Millau viaduct in France. This is of great importance when dealing with durability: due to the softness of such a support, the pavement is subjected to considerable strains that may generate top-down cracks in the layer at right angles of the orthotropic plate stiffeners and shear cracks at the interface between pavement and steel. Therefore, a five-point bending fatigue test was developed and improved since 2003 at the ENTPE laboratory, to test different asphalt concrete mixes. This study aims at modelling the mechanical behavior of the wearing course throughout the fatigue test by a finite element method (Comsol Multiphysics software). Each material - steel, sealing sheet, asphalt concrete layer - is considered and modelled. The modelling of asphalt concrete is complex since it is a heterogeneous material, a viscoelastic medium and it thermosensitive. The actual characteristics of the asphalt concrete (thermo physical parameter and viscoelastic complex modulus) are determined experimentally on cylindrical cores. Moreover, a damage law based on Miner's damage is included in the model. The modelling of the fatigue test leads to encouraging results. Finally, results from the model are compared to the experimental data obtained from the five-point bending fatigue test device. The experimental data are very consistent with the numerical simulation.

  12. Multi-Model Estimation Based Moving Object Detection for Aerial Video

    Directory of Open Access Journals (Sweden)

    Yanning Zhang

    2015-04-01

    Full Text Available With the wide development of UAV (Unmanned Aerial Vehicle technology, moving target detection for aerial video has become a popular research topic in the computer field. Most of the existing methods are under the registration-detection framework and can only deal with simple background scenes. They tend to go wrong in the complex multi background scenarios, such as viaducts, buildings and trees. In this paper, we break through the single background constraint and perceive the complex scene accurately by automatic estimation of multiple background models. First, we segment the scene into several color blocks and estimate the dense optical flow. Then, we calculate an affine transformation model for each block with large area and merge the consistent models. Finally, we calculate subordinate degree to multi-background models pixel to pixel for all small area blocks. Moving objects are segmented by means of energy optimization method solved via Graph Cuts. The extensive experimental results on public aerial videos show that, due to multi background models estimation, analyzing each pixel’s subordinate relationship to multi models by energy minimization, our method can effectively remove buildings, trees and other false alarms and detect moving objects correctly.

  13. Probabilistic Safety Analysis of High Speed and Conventional Lines Using Bayesian Networks

    Energy Technology Data Exchange (ETDEWEB)

    Grande Andrade, Z.; Castillo Ron, E.; O' Connor, A.; Nogal, M.

    2016-07-01

    A Bayesian network approach is presented for probabilistic safety analysis (PSA) of railway lines. The idea consists of identifying and reproducing all the elements that the train encounters when circulating along a railway line, such as light and speed limit signals, tunnel or viaduct entries or exits, cuttings and embankments, acoustic sounds received in the cabin, curves, switches, etc. In addition, since the human error is very relevant for safety evaluation, the automatic train protection (ATP) systems and the driver behavior and its time evolution are modelled and taken into account to determine the probabilities of human errors. The nodes of the Bayesian network, their links and the associated probability tables are automatically constructed based on the line data that need to be carefully given. The conditional probability tables are reproduced by closed formulas, which facilitate the modelling and the sensitivity analysis. A sorted list of the most dangerous elements in the line is obtained, which permits making decisions about the line safety and programming maintenance operations in order to optimize them and reduce the maintenance costs substantially. The proposed methodology is illustrated by its application to several cases that include real lines such as the Palencia-Santander and the Dublin-Belfast lines. (Author)

  14. Modeling the characteristics of wheel/rail rolling noise

    Science.gov (United States)

    Lui, Wai Keung; Li, Kai Ming; Frommer, Glenn H.

    2005-04-01

    To study the sound radiation characteristics of a passing train, four sets of noise measurements for different train operational conditions have been conducted at three different sites, including ballast tracks at grade and railway on a concrete viaduct. The time histories computed by the horizontal radiation models were compared with the measured noise profiles. The measured sound exposure levels are used to deduce the vertical directivity pattern for different railway systems. It is found that the vertical directivity of different railway systems shows a rather similar pattern. The vertical directivity of train noise is shown to increase up to about 30× before reducing to a minimum at 90×. A multipole expansion model is proposed to account for the vertical radiation directivity of the train noise. An empirical formula, which has been derived, compares well with the experimental data. The empirical model is found to be applicable to different train/rail systems at train speeds ranging up to 120 km/h in this study. [Work supported by MTR Corporation Ltd., Innovation Technology Commission of the HKSAR Government and The Hong Kong Polytechnic University.

  15. Tresfjord Bridge - a human friendly and traffic efficient structure

    Science.gov (United States)

    Dahl, Kristian B.; Anta Magerøy Tønnessen, Aja; Toverud, Lars I.

    2017-09-01

    The E136 Tresfjord Bridge opened in October 2015, and crosses the Tresfjorden on the west coast of Norway. It is a concrete bridge with a total length of 1290 m, consisting of 19 viaduct spans, 60 m each, and a FCM (free cantilever method) main span of 160 m. The E136 is one of the most important transportation routes in the county of Møre and Romsdal and starts in Ålesund, and passes along Tresfjorden to Åndalsnes. The existing road is very narrow with speed limit of 60 km/h and characterizes by many accidents involving cars and people. The traffic flow is approximately ca 2500 vehicles a day, of this is 25% heavy vehicles. Those transport fresh salmon from the breeders in the fjords along the coast. To try to decrease the transportation time is very important for the fresh salmon. The bridge reduces the distance between Ålesund and Åndalsnes by 13 km. The speed limit is now 80 km/h, and with much less risk for accidents since there are separate lanes for cars and pedestrians over the whole bridge. This means that the bridge represents a human friendly and traffic efficient structure to the benefit for the people and the region.

  16. Weighing in motion and characterization of the railroad traffic with using the B-WIM technique

    Directory of Open Access Journals (Sweden)

    J. A. DE CARVALHO NETO

    Full Text Available AbstractThe knowledge on the active moving load of a bridge is crucial for the achievement of the information on the behavior of the structure, and thus foresee maintenance, repairs and better definition of the logistics of its active vehicles. This paper presents the development of the algorithms for the application of the Bridge-Weigh In Motion (B-WIM method created by Moses for the weighing of trains during motion and also for the characterization of the rail traffic, allowing the obtainment of information like passage's train velocity and number and spacing of axles, eliminating the dynamic effect. There were implemented algorithms for the determination of the data referring to the geometry of the train and its loads, which were evaluated using a theoretical example, in which it was simulated the passage of the train over a bridge and the loads of its axles were determined with one hundred percent of precision. In addition, it was made a numerical example in finite elements of a reinforced concrete viaduct from the Carajás' Railroad, in which the developed system reached great results on the characterization and weighing of the locomotive when the constitutive equation of the Brazilian Standards was substituted by the one proposed by Collins and Mitchell.

  17. World Wide Web voted most wonderful wonder by web-wide world

    CERN Multimedia

    2007-01-01

    The results are in, and the winner is...the World Wide Web! An online survey conducted by the CNN news group ranks the World Wide Web-invented at CERN--as the most wonderful of the seven modern wonders of the world. (See Bulletin No. 49/2006.) There is currently no speculation about whether they would have had the same results had they distributed the survey by post. The World Wide Web won with a whopping 50 per cent of the votes (3,665 votes). The runner up was CERN again, with 16 per cent of voters (1130 votes) casting the ballot in favour of the CERN particle accelerator. Stepping into place behind CERN and CERN is 'None of the Above' with 8 per cent of the votes (611 votes), followed by the development of Dubai (7%), the bionic arm (7%), China's Three Gorges Damn (5%), The Channel Tunnel (4%), and France's Millau viaduct (3%). Thanks to everyone from CERN who voted. You can view the results on http://edition.cnn.com/SPECIALS/2006/modern.wonders/

  18. Camera Traps on Wildlife Crossing Structures as a Tool in Gray Wolf (Canis lupus) Management - Five-Years Monitoring of Wolf Abundance Trends in Croatia.

    Science.gov (United States)

    Šver, Lidija; Bielen, Ana; Križan, Josip; Gužvica, Goran

    2016-01-01

    The conservation of gray wolf (Canis lupus) and its coexistence with humans presents a challenge and requires continuous monitoring and management efforts. One of the non-invasive methods that produces high-quality wolf monitoring datasets is camera trapping. We present a novel monitoring approach where camera traps are positioned on wildlife crossing structures that channel the animals, thereby increasing trapping success and increasing the cost-efficiency of the method. In this way we have followed abundance trends of five wolf packs whose home ranges are intersected by a motorway which spans throughout the wolf distribution range in Croatia. During the five-year monitoring of six green bridges we have recorded 28 250 camera-events, 132 with wolves. Four viaducts were monitored for two years, recording 4914 camera-events, 185 with wolves. We have detected a negative abundance trend of the monitored Croatian wolf packs since 2011, especially severe in the northern part of the study area. Further, we have pinpointed the legal cull as probable major negative influence on the wolf pack abundance trends (linear regression, r2 > 0.75, P Croatia until there is more data proving population stability. In conclusion, quantitative methods, such as the one presented here, should be used as much as possible when assessing wolf abundance trends.

  19. Autopista Ronda-Oeste de Murcia – España

    Directory of Open Access Journals (Sweden)

    Editorial, Equipo

    1977-10-01

    Full Text Available The Ronda-West expressway in Murcia detours the traffic of route CN-301, from Madrid to Cartagena, around the center of the city, thereby facilitating the routing of vehicular traffic. This expressway consists of two access roads, four cloverleaves, three viaducts, two elevated bypasses and a large amount of masonry work. The structures are built with post-stressed beams, replaced in some stretches by prestressed slabs or also post-stressed slabs, and abutments made with formwork. The foundations have been laid over piles in situ.La autopista Ronda- Oeste de Murcia evita el paso del tráfico de la carretera CN-301, de Madrid a Cartagena, por el centro de la ciudad, con lo que facilita la ordenación de la circulación rodada. Dicha autopista consta de dos enlaces, cuatro nudos, tres viaductos, dos pasos elevados y una gran obra de fábrica. Las estructuras están realizadas a base de vigas postensadas, sustituidas en algunos tramos por losas pretensadas o también postensadas y estribos realizados con cimbra. La cimentación se ha hecho sobre pilotes in situ.

  20. Comprehensive Sustainability Evaluation of High-Speed Railway (HSR Construction Projects Based on Unascertained Measure and Analytic Hierarchy Process

    Directory of Open Access Journals (Sweden)

    Yongzhi Chang

    2018-02-01

    Full Text Available This paper aims to evaluate the sustainability of high-speed railway (HSR construction projects in a comprehensive manner. To this end, the author established an index system, involving 4 primary indices, 9 secondary indices, and 32 tertiary indices. The analytic hierarchy process (AHP and the unascertained measure were introduced to calculate the weights of these indices. Then, the index system was applied to evaluate the sustainability of the China’s Harbin-Dalian Passenger Dedicated Line (PDL. The results show that the Harbin-Dalian PDL project achieved good results in terms of process, economic benefit, impact, and sustainability, and will bring long-term benefits in the fields of tourism, economy, and transport capacity, as well as many other fields. In spite of its good overall sustainability, the project needs to further increase its economic benefits and reduce its negative environmental impact. For this purpose, it is necessary to adopt the management mode of “separation between network and transportation” and apply noise prevention measures like noise barriers, tunnels, and overhead viaducts. This research lays a solid basis for the sustainability evaluation of HSR construction projects, and simplifies the modelling process for designers of HSR.

  1. The Different Methods of Displacement Monitoring at Loading Tests of Bridges or Different Structures

    Directory of Open Access Journals (Sweden)

    Kovačič Boštjan

    2016-01-01

    Full Text Available By measuring the displacements and deformations at different structures we deal in the Faculty of Civil Engineering, transportation Engineering and Architecture in University of Maribor for about 20 years. At that time we measured over 600 structures. Most loading tests of bridges and Viaducts were made. The measurements of movements needed to be as precise and accurate as possible. To do that laboratory test of instruments were made to see which instrument gives us reliable results. Displacements can be determined by geodetic and physical methods, depends of the construction. The use of geodetic methods are still preferable. In the paper the measurements with the total station, the level and rotation level, photogrammetry and solutions on the field by physical methods with inductive transducers are presented. We need to measure displacements as quick as possible but efficiently because we can not repeat the measurements under the same conditions. Also the surveying on the bridge and in the lab with the comparison of methods is presented under the different hard terrain conditions - water beneath the construction, big height of the structure, unapproachability, large span structures.

  2. Influence of long-wavelength track irregularities on the motion of a high-speed train

    Science.gov (United States)

    Hung, C. F.; Hsu, W. L.

    2018-01-01

    Vertical track irregularities over viaducts in high-speed rail systems could be possibly caused by concrete creep if pre-stressed concrete bridges are used. For bridge spans that are almost uniformly distributed, track irregularity exhibits a near-regular wave profile that excites car bodies as a high-speed train moves over the bridge system. A long-wavelength irregularity induces low-frequency excitation that may be close to the natural frequencies of the train suspension system, thereby causing significant vibration of the car body. This paper investigates the relationship between the levels of car vibration, bridge vibration, track irregularity, and the train speed. First, this study investigates the vibration levels of a high-speed train and bridge system using 3D finite-element (FE) transient dynamic analysis, before and after adjustment of vertical track irregularities by means of installing shimming plates under rail pads. The analysis models are validated by in situ measurements and on-board measurement. Parametric studies of car body vibration and bridge vibration under three different levels of track irregularity at five train speeds and over two bridge span lengths are conducted using the FE model. Finally, a discontinuous shimming pattern is proposed to avoid vehicle suspension resonance.

  3. Using deep learning to quantify the beauty of outdoor places.

    Science.gov (United States)

    Seresinhe, Chanuki Illushka; Preis, Tobias; Moat, Helen Susannah

    2017-07-01

    Beautiful outdoor locations are protected by governments and have recently been shown to be associated with better health. But what makes an outdoor space beautiful? Does a beautiful outdoor location differ from an outdoor location that is simply natural? Here, we explore whether ratings of over 200 000 images of Great Britain from the online game Scenic-Or-Not , combined with hundreds of image features extracted using the Places Convolutional Neural Network, might help us understand what beautiful outdoor spaces are composed of. We discover that, as well as natural features such as 'Coast', 'Mountain' and 'Canal Natural', man-made structures such as 'Tower', 'Castle' and 'Viaduct' lead to places being considered more scenic. Importantly, while scenes containing 'Trees' tend to rate highly, places containing more bland natural green features such as 'Grass' and 'Athletic Fields' are considered less scenic. We also find that a neural network can be trained to automatically identify scenic places, and that this network highlights both natural and built locations. Our findings demonstrate how online data combined with neural networks can provide a deeper understanding of what environments we might find beautiful and offer quantitative insights for policymakers charged with design and protection of our built and natural environments.

  4. Theoretical and experimental study of vibration, generated by monorail trains

    Science.gov (United States)

    Rybak, Samuil A.; Makhortykh, Sergey A.; Kostarev, Stanislav A.

    2002-11-01

    Monorail transport as all other city transport vehicles is the source of high noise and vibration levels. It is less widespread than cars or underground transport but its influence in modern cities enhances. Now in Moscow the first monorail road with trains on tires is designed, therefore the problem of vibration and noise assessments and prediction of its impact on the residential region appears. To assess the levels of generated vibration a physical model of interaction in the system wagon-tire-road coating-viaduct-soil has been proposed and then numerically analyzed. The model is based on the known from publications facts of automobile transport vibration and our own practice concerning underground trains vibration generation. To verify computer simulation results and adjust model parameters the series of measurements of noise and vibration near experimental monorail road was carried out. In the report the results of calculations and measurements will be presented and some outcomes of possible acoustical ecologic situation near monorail roads will be proposed.

  5. Alternate Double Single Track Lines

    Energy Technology Data Exchange (ETDEWEB)

    Moraga Contreras, P.; Grande Andrade, Z.; Castillo Ron, E.

    2016-07-01

    The paper discusses the advantages and shortcomings of alternate double single track (ADST) lines with respect to double track lines for high speed lines. ADST lines consists of sequences of double and single track segments optimally selected in order to reduce the construction and maintenance costs of railway lines and to optimize the timetables used to satisfy a given demand. The single tracks are selected to coincide with expensive segments (tunnels and viaducts) and the double tracks are chosen to coincide with flat areas and only where they are necessary. At the same time, departure times are adjusted for trains to cross at the cheap double track segments. This alternative can be used for new lines and also for existing conventional lines where some new tracks are to be constructed to reduce travel time (increase speed). The ADST proposal is illustrated with some examples of both types (new lines and where conventional lines exist), including the Palencia-Santander, the Santiago-Valparaíso-Viña del Mar and the Dublin-Belfast lines, where very important reductions (90 %) are obtained, especially where a railway infrastructure already exist. (Author)

  6. Research of UHPC properties prepared with industrial mixer

    Science.gov (United States)

    Šerelis, E.; Vaitkevičius, V.; Kerševičius, V.

    2017-09-01

    Ultra-high performance concrete (UHPC) mixture with advanced mechanical and durability properties was created using decent Zyklos ZZ50HE mixer. Zyklos ZZ50HE rotating pan mixer is similar to mixer which has common concrete plants. In experiment UHPC was prepared with Zyklos ZZ50HE mixer and thereafter best composition was selected and prepared with industrial HPGM 1125 mixer. Experiment results revealed that UHPC with W/C=0.29 and advanced mechanical and durability properties can be prepared. In experiment tremendous amount of micro steel fibres (up to 147 kg/m3) were incorporated in UHPC. Concrete with excellent salt scaling resistance and great mechanical properties was obtained. Compressive strength was increased about 30 % from 116 MPa to 150 MPa and flexural strength was increased about 5 times from 6.7 to 36.2 MPa. Salt-scaling resistance at 40 cycles in 3 % NaCl solution varied from 0.006 kg/m2 to 0.197 kg/m2. There were a few attempts to create UHPC and UHPFRC with decent technology, however, unsuccessfully till now. In the world practice this new material is currently used in the construction of bridges and viaducts.

  7. Hybrid structure in civil engineering construction. Composite types of steel and concrete; Doboku bun`ya ni okeru fukugo kozo. Kozai to concrete no ittai keishiki

    Energy Technology Data Exchange (ETDEWEB)

    Sato, T. [JR Railway Technical Research Inst. Tokyo (Japan)

    1995-03-30

    In connection with hybrid structures in civil engineering construction, classification and application of composite types of steel and concrete are discussed. H steel embedded beam is a composite beam in which the H shape steel of the main beam is connected to rolled or welded H shape steel using cross beams. Composite structure columns are grouped into the composite column and the steel pipe concrete column. SRC piers are often adopted from the viewpoints of constraints for execution of works and vibration proof. Steel and concrete hybrid structure is a kind of structural system in which various kinds of materials such as steel, RC, or PC members are connected. The cable stayed bridge utilizes characteristics of steel and concrete effectively. For the piers of municipal expressway viaducts, there are executed cases of mixed structures which have RC, SRC columns for T shape piers and S structure for the bridges. SRC structure and composite columns are adopted often for structures of subway stations. 7 refs., 7 figs.

  8. Comparison of renewable oil, recycled oil, and commercial rejuvenating agent derived from crude oil in paving asphalt modification[Includes the CSCE forum on professional practice and career development : 1. international engineering mechanics and materials specialty conference : 1. international/3. coastal, estuarine and offshore engineering specialty conference : 2. international/8. construction specialty conference

    Energy Technology Data Exchange (ETDEWEB)

    Gordon, C.; Ho, S.; Zanzotto, L. [Calgary Univ., AB (Canada). Schulich School of Engineering

    2009-07-01

    The asphalt industry relies heavily on crude oil. In response to increasing oil prices, there have been efforts to save money on asphalt by taking harder asphalts, such as recycled asphalt pavement (RAP), and softening them with rejuvenating agents. For asphalt that is to be used in cold climates, softer asphalts are preferred because they will perform better under extreme cold conditions without cracking. This study compared the performance, economic benefits, and environmental benefits of renewable materials, recycled oil and a commercially used rejuvenating agent derived from crude oil. Different oily materials including margarine, Cyclogen L (a crude oil-derived material), a vegetable wax, and recycled cooking oil were used to modify paving asphalt. Their effectiveness at improving the superpave low-temperature performance grade was compared. The samples were all tested using the 2008 AASHTO M320 procedures. The high temperature grades were determined using the dynamic shear rheometer test, and the low-temperature grades were determined using the bending beam rheometer test. The 3 varieties of margarine that were tested were able to improve the low-temperature grade, but they caused a greater depreciation of the high-temperature performance grade than the other materials, and were much more expensive. The best candidate for an effective, economic asphalt softening agent was found to be the recycled cooking oil. It out-performed the Cyclogen L oil in terms of improving the low- temperature performance grade, and was less expensive. 12 refs., 4 tabs., 6 figs.

  9. Application of Monte Carlo filtering method in regional sensitivity analysis of AASHTOWare Pavement ME design

    Directory of Open Access Journals (Sweden)

    Zhong Wu

    2017-04-01

    Full Text Available Since AASHTO released the Mechanistic-Empirical Pavement Design Guide (MEPDG for public review in 2004, many highway research agencies have performed sensitivity analyses using the prototype MEPDG design software. The information provided by the sensitivity analysis is essential for design engineers to better understand the MEPDG design models and to identify important input parameters for pavement design. In literature, different studies have been carried out based on either local or global sensitivity analysis methods, and sensitivity indices have been proposed for ranking the importance of the input parameters. In this paper, a regional sensitivity analysis method, Monte Carlo filtering (MCF, is presented. The MCF method maintains many advantages of the global sensitivity analysis, while focusing on the regional sensitivity of the MEPDG model near the design criteria rather than the entire problem domain. It is shown that the information obtained from the MCF method is more helpful and accurate in guiding design engineers in pavement design practices. To demonstrate the proposed regional sensitivity method, a typical three-layer flexible pavement structure was analyzed at input level 3. A detailed procedure to generate Monte Carlo runs using the AASHTOWare Pavement ME Design software was provided. The results in the example show that the sensitivity ranking of the input parameters in this study reasonably matches with that in a previous study under a global sensitivity analysis. Based on the analysis results, the strengths, practical issues, and applications of the MCF method were further discussed.

  10. Effect of Palmyra Palm Leaf Ash on Cement Stabilization of Makurdi Shale

    Directory of Open Access Journals (Sweden)

    Amos Yala IORLIAM

    2012-08-01

    Full Text Available Makurdi Shale was treated with palmyra palm leaf ash (PPLA and cement to assess its suitability as a material in construction of flexible pavement. Classification, Compaction, Consistency, California bearing ratio (CBR and Unconfined compressive strength (UCS tests, were conducted on the shale specimen treated with, cement and PPLA in a combined incremental order of 2% up to 10% of cement and 2% up to 14% of PPLA of dry weight of soil sample respectively. Results of tests showed that Makurdi shale is an A-7-6, high plasticity (CH and high swell potential soil by the American Association of State Highway and Transportation Officials (AASHTO, Unified Soil Classification System (USCS and Nigerian Building and Road Research Institute (NBRRI classification systems respectively. The plasticity index (PI reduced from 30.5% for untreated Makurdi shale to 4% at 10% cement +14% PPLA contents. The maximum soaked CBR and 7 day UCS values of 92% and 1041 kN/m2 were obtained at 10% cement+14 % PPLA contents respectively. From the results, Makurdi shale treated with a combination of 10%cement+14% PPFA with a soaked CBR value of 92 %, 7 day UCS value of 1041 kN/m2 and 82 % value of resistance to loss in strength, satisfied the requirement for sub-base specification. It is therefore recommended for use as sub-base materials in flexible pavement.

  11. A MECHANISTIC-EMPIRICAL IMPACT ANALYSIS OF DIFFERENT TRUCK CONFIGURATIONS ON A JOINTED PLAIN CONCRETE PAVEMENT (JPCP

    Directory of Open Access Journals (Sweden)

    Lubinda F. Walubita

    2017-12-01

    Full Text Available Until the last decade, the 1993 American Association of State Highway and Transportation Officials (AASHTO design guide has been traditionally used for the design of flexible and rigid pavements in the USA and some parts of the world. However, because of its inability to meet the new traffic and material challenges, a Mechanistic Empirical Pavement Design Guide (MEPDG was introduced based on an NCHRP 1-37 A study conducted in 2004. This study used the MEPDG software and associated models to determine, through comparative truck damage analysis, the effects of nine different truck configurations on a 12 inch-jointed plain concrete pavement (JPCP. The study recorded truck damages at the end of each analysis period (40 years and comparatively analyzed the relative pavement damage in terms of fatigue cracking, faulting, and surface roughness. The results indicated that the most critical damage to the concrete pavement was caused by truck cases with high and uneven load distribution and relatively smaller size axles group (e.g. tandem. Other key findings included the following; (1 increase in damage when the truckloads were shifted between the same size axles, (2 decrease in truck damage when the truckloads were shifted from tandem axle to quad axles, and (3 no change in truck damage when the axle spacing was increased between wheels of a quad axle.

  12. Mechanistic and Economical Characteristics of Asphalt Rubber Mixtures

    Directory of Open Access Journals (Sweden)

    Mena I. Souliman

    2016-01-01

    Full Text Available Load associated fatigue cracking is one of the major distress types occurring in flexible pavement systems. Flexural bending beam fatigue laboratory test has been used for several decades and is considered to be an integral part of the new superpave advanced characterization procedure. One of the most significant solutions to prolong the fatigue life for an asphaltic mixture is to utilize flexible materials as rubber. A laboratory testing program was performed on a conventional and Asphalt Rubber- (AR- gap-graded mixtures to investigate the impact of added rubber on the mechanical, mechanistic, and economical attributes of asphaltic mixtures. Strain controlled fatigue tests were conducted according to American Association of State Highway and Transportation Officials (AASHTO procedures. The results from the beam fatigue tests indicated that the AR-gap-graded mixtures would have much longer fatigue life compared with the reference (conventional mixtures. In addition, a mechanistic analysis using 3D-Move software coupled with a cost analysis study based on the fatigue performance on the two mixtures was performed. Overall, analysis showed that AR modified asphalt mixtures exhibited significantly lower cost of pavement per 1000 cycles of fatigue life per mile compared to conventional HMA mixture.

  13. The analysis of overloaded trucks in indonesia based on weigh in motion data (east of sumatera national road case study

    Directory of Open Access Journals (Sweden)

    Jihanny Jongga

    2018-01-01

    Full Text Available Overloaded trucks phenomena generally common in developing countries where the traffic control is poor. In Indonesia, the percentage of overloaded trucks can reach more than 60% in the total number of trucks and may be one of the substantial factors that reduce the service life of the road pavements. This paper presents the analysis results of the weigh in motion survey data at East of Sumatera National Road (Jalintim in Indonesia and the impact of overloaded trucks on the pavement. For the analysis the simplified approach was used, the axle loads were converted into representative single-axle loads based on 4th power formula by AASHTO 1993 equation. The vehicle damage factor of vehicles is presented and will be compared with the Highways National Standard to estimate the remaining service life of pavement and IRI value prediction. The analysis showed that the vehicle damage factor that determined from weigh in motion data is extremely greater than vehicle damage factor of the national standard in Indonesia which may lead to accelerated deterioration, reducing the service life of the pavement structures and significantly influence the IRI value.

  14. Asphalt Mixture for the First Asphalt Concrete Directly Fastened Track in Korea

    Directory of Open Access Journals (Sweden)

    Seong-Hyeok Lee

    2015-01-01

    Full Text Available The research has been initiated to develop the asphalt mixtures which are suitable for the surface of asphalt concrete directly fastened track (ADFT system and evaluate the performance of the asphalt mixture. Three aggregate gradations which are upper (finer, medium, and below (coarser. The nominal maximum aggregate size of asphalt mixture was 10 mm. Asphalt mixture design was conducted at 3 percent air voids using Marshall mix design method. To make impermeable asphalt mixture surface, the laboratory permeability test was conducted for asphalt mixtures of three different aggregate gradations using asphalt mixture permeability tester. Moisture susceptibility test was conducted based on AASHTO T 283. The stripping percentage of asphalt mixtures was measured using a digital camera and analyzed based on image analysis techniques. Based on the limited research results, the finer aggregate gradation is the most suitable for asphalt mixture for ADFT system with the high TSR value and the low stripping percentage and permeable coefficient. Flow number and beam fatigue tests for finer aggregate asphalt mixture were conducted to characterize the performance of asphalt mixtures containing two modified asphalt binders: STE-10 which is styrene-butadiene-styrene (SBS polymer and ARMA which is Crum rubber modified asphalt. The performance tests indicate that the STE-10 shows the higher rutting life and fatigue life.

  15. Development of high-performance concrete having high resistance to chloride penetration

    International Nuclear Information System (INIS)

    Oh, Byung Hwan; Cha, Soo Won; Jang, Bong Seok; Jang, Seung Yup

    2002-01-01

    The resistance to chloride penetration is one of the simplest measures to determine the durability of concrete, e.g. resistance to freezing and thawing, corrosion of steel in concrete and other chemical attacks. Thus, high-performance concrete may be defined as the concrete having high resistance to chloride penetration as well as high strength. The purpose of this paper is to investigate the resistance to chloride penetration of different types of concrete and to develop high-performance concrete that has very high resistance to chloride penetration, and thus, can guarantee high durability. A large number of concrete specimens have been tested by the rapid chloride permeability test method as designated in AASHTO T 277 and ASTM C 1202. The major test variables include water-to-binder ratios, type of cement, type and amount of mineral admixtures (silica fume, fly ash and blast-furnace slag), maximum size of aggregates and air-entrainment. Test results show that concrete containing optimal amount of silica fume shows very high resistance to chloride penetration, and high-performance concrete developed in this study can be efficiently employed to enhance the durability of concrete structures in severe environments such as nuclear power plants, water-retaining structures and other offshore structures

  16. Experimental Verification of Current Shear Design Equations for HSRC Beams

    Directory of Open Access Journals (Sweden)

    Attaullah Shah

    2012-07-01

    Full Text Available Experimental research on the shear capacity of HSRC (High Strength Reinforced Concrete beams is relatively very limited as compared to the NSRC (Normal Strength Reinforced Concrete beams. Most of the Building Codes determine the shear strength of HSRC with the help of empirical equations based on experimental work of NSRC beams and hence these equations are generally regarded as un-conservative for HSRC beams particularly at low level of longitudinal reinforcement. In this paper, 42 beams have been tested in two sets, such that in 21 beams no transverse reinforcement has been used, whereas in the remaining 21 beams, minimum transverse reinforcement has been used as per ACI-318 (American Concrete Institute provisions. Two values of compressive strength 52 and 61 MPa, three values of longitudinal steel ratio and seven values of shear span to depth ratio have been have been used. The beams were tested under concentrated load at the mid span. The results are compared with the equations proposed by different international building codes like ACI, AASHTO LRFD, EC (Euro Code, Canadian Code and Japanese Code for shear strength of HSRC beams.From comparison, it has been observed that some codes are less conservative for shear design of HSRC beams and further research is required to rationalize these equations.

  17. Project in fiscal 2000 of developing international standards for supporting new industries. Standardization of method for evaluating performance of textile material for interlocking concrete block pavement; 2000 nendo shinki sangyo shiengata kokusai hyojun kaihatsu jigyo seika hokokusho. Block hosoyo sen'i zairyo no seino hyoka hoho no hyojunka

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-03-01

    Targeting at realization of international standardization of a textile material (geotextile) used for interlocking concrete block pavement, R and D has been performed on a performance evaluation method consistent with field works. This paper summarizes the achievements in fiscal 2000. A literature survey has revealed that manuals prepared by the U.S. AASHTO, and ISO related standards show the test method for single geotextile, and guidelines on durability, but the method for evaluating the durability assuming the actual using conditions has not been standardized. The result of a field test reveals definite effects of existence of geotextile on the usability of block pavement in the water permeable bitumen stabilized roadbed, wherein the effectiveness of the geotextile was verified. In the research of an indoor evaluation test method, it was identified that the test method using a roller compactor and a wheel tracking testing machine can reproduce the behavior of block pavement at site, and it is a method that can identify the durability of the geotextile to some extent. (NEDO)

  18. The stability of clay using mount Sinabung ash with unconfined compression test (uct) value

    Science.gov (United States)

    Puji Hastuty, Ika; Roesyanto; Hutauruk, Ronny; Simanjuntak, Oberlyn

    2018-03-01

    The soil has a important role as a highway’s embankment material (sub grade). Soil conditions are very different in each location because the scientifically soil is a very complex and varied material and the located on the field is very loose or very soft, so it is not suitable for construction, then the soil should be stabilized. The additive material commonly used for soil stabilization includes cement, lime, fly ash, rice husk ash, and others. This experiment is using the addition of volcanic ash. The purpose of this study was to determine the Index Properties and Compressive Strength maximum value with Unconfined Compression Test due to the addition of volcanic ash as a stabilizing agent along with optimum levels of the addition. The result showed that the original soil sample has Water Content of 14.52%; the Specific Weight of 2.64%; Liquid limit of 48.64% and Plasticity Index of 29.82%. Then, the Compressive Strength value is 1.40 kg/cm2. According to USCS classification, the soil samples categorized as the (CL) type while based on AASHTO classification, the soil samples are including as the type of A-7-6. After the soil is stabilized with a variety of volcanic ash, can be concluded that the maximum value occurs at mixture variation of 11% Volcanic Ash with Unconfined Compressive Strength value of 2.32 kg/cm2.

  19. Wireless Smart Sensor Network System Using SmartBridge Sensor Nodes for Structural Health Monitoring of Existing Concrete Bridges

    Science.gov (United States)

    Gaviña, J. R.; Uy, F. A.; Carreon, J. D.

    2017-06-01

    There are over 8000 bridges in the Philippines today according to the Department of Public Works and Highways (DPWH). Currently, visual inspection is the most common practice in monitoring the structural integrity of bridges. However, visual inspections have proven to be insufficient in determining the actual health or condition of a bridge. Structural Health Monitoring (SHM) aims to give, in real-time, a diagnosis of the actual condition of the bridge. In this study, SmartBridge Sensor Nodes were installed on an existing concrete bridge with American Association of State Highway and Transportation Officials (AASHTO) Type IV Girders to gather vibration of the elements of the bridge. Also, standards on the effective installation of SmartBridge Sensor Nodes, such as location and orientation was determined. Acceleration readings from the sensor were then uploaded to a server, wherein they are monitored against certain thresholds, from which, the health of the bridge will be derived. Final output will be a portal or webpage wherein the information, health, and acceleration readings of the bridge will be available for viewing. With levels of access set for different types of users, the main users will have access to download data and reports. Data transmission and webpage access are available online, making the SHM system wireless.

  20. Diseño de losas de hormigón con geometría optimizada Design of concrete pavement with optimized slab geometry

    Directory of Open Access Journals (Sweden)

    Juan Pablo Covarrubias V.

    2012-12-01

    condiciones de cargas mecánicas y térmicas en diferentes posiciones. El agrietamiento de las losas se determina calculando la fatiga del hormigón y los modelos utilizados por la guía de diseño AASHTO del año 2007 y mediante calibración en secciones de prueba a gran escala. La nueva metodología diseña losas de hormigón que en promedio son 7 cm más delgadas para vías de alto tráfico en relación con el diseño tradicional de pavimentos AASHTO (1993. El método de diseño también es capaz de diseñar de manera eficiente pavimentos de hormigón para vías de menor volumen de tráfico que no son cubiertos con los actuales métodos de diseño de pavimento dando una alternativa a soluciones en asfalto.A new technology has been developed to design concrete pavements, which reduces slabs' thickness and optimizes their sizes, because of trucks axles' geometry. The design is supported by a gravel base treated with concrete or asphalt. It assumes there is no adherence between the base (existing pavement and the concrete slab. The core principle of this design method consists of designing a slab size, so that no more than one wheel set stays on a given slab, thus minimizing the critical tensile stress on the surface. Test segments have been built on a large scale and they have been tested under accelerated loads, with concrete thickness of 8, 15 and 20 cm, all of them having a gravel base and non-adhered asphaltic layers. Tests demonstrated that a reduced-size slab, of low thickness, might bear a considerable amount of equivalent axles before cracking takes place. Concrete slabs on gravel bases with 20 cm thickness did not suffer from cracking, in spite of being tested under more than 50 millions of equivalent axles. Slabs of 15 cm thickness suffered from cracking when tested under an average of 12 millions equivalent axles, while slabs of 8 cm thickness endured 75,000 equivalent axles before the first cracking took place. Besides the executed tests demonstrated that fiber

  1. Bamboo as Soil Reinforcement: A Laboratory Trial

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    Alhaji Mohammed MUSTAPHA

    2008-12-01

    Full Text Available A lateritic soil classified as A-6 under AASHTO soil classification system was reinforced with 0, 1, 2 and 3 bamboo specimens at laboratory trial level to evaluate its unconfined compressive strength (UCS and modulus of rigidity. The soil specimens were molded in cylindrical form of 38mm diameter and 76mm height while the bamboo specimens were trimmed in to circular plates of 34mm diameter and 3mm thickness. The trial soil specimens are: soil specimen without bamboo specimen (0 bamboo, soil specimen with one bamboo specimen in the center (1 bamboo, soil specimen with one bamboo specimen on top and one at the bottom (2 bamboos and soil specimen with one bamboo specimen on top, center and bottom (3 bamboos. Though, the dry density of the molded soil specimen decreased from 1.638Mg/m3 at 0 bamboo to 1.470Mg/m2 at 3 bamboos, the UCS increased from 226KN/m2 at 0 bamboo to 621KN/m2 at 3 bamboos. Also, for each of the 3 percentage strains (0.5, 1.0 and 1.5% considered, the modulus of rigidity increased with bamboo specimens.

  2. A Study of the Bolt Connection System for a Concrete Barrier of a Modular Bridge

    Directory of Open Access Journals (Sweden)

    Doo-Yong Cho

    2018-04-01

    Full Text Available Modular technology has been recently studied to reduce the construction periods in the field of bridge construction. However, this method is restricted to the pier, girder, and deck, which are the main members of a bridge, and incidental facilities such as concrete barriers have been rarely studied. Thus, in this study, the connection system of a concrete barrier for modular bridges was developed, and a static loading experiment was performed to verify the structural capacity of the proposed system. The variables of the experiment were the vertical and horizontal bolt connections and the construction method. The barrier and plate were fabricated using match casting methods in which nuts were first inserted into the plates rather than anchor bolts using the conservative method. Moreover, a comparison with the conventional in situ barrier was also performed. The experiments were conducted according to the AASHTO LRFD standard. Consequently, the specimen using the vertical bolt connection had a structural capacity that was equal to 85% of that of the conventional specimen and exhibited similar crack patterns compared with the conventional specimen. In the case of the horizontal bolt connection, the separation in the connection area occurred with the application of the initial load and this specimen exhibited a poor performance because of the increase in the separation distance with the application of the maximum load.

  3. Freeze-Thaw Performance and Moisture-Induced Damage Resistance of Base Course Stabilized with Slow Setting Bitumen Emulsion-Portland Cement Additives

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    Mojtaba Shojaei Baghini

    2015-01-01

    Full Text Available Freeze-thaw (FT cycles and moisture susceptibility are important factors influencing the geotechnical characteristics of soil-aggregates. Given the lack of published information on the behavior of cement-bitumen emulsion-treated base (CBETB under environmental conditions, especially freezing and thawing, this study investigated the effects of these additives on the CBETB performance. The primary goal was to evaluate the resistance of CBETB to moisture damage by performing FT, Marshall conditioning, and AASHTO T-283 tests and to evaluate the long-term stripping susceptibility of CBETB while also predicting the liquid antistripping additives to assess the mixture’s durability and workability. Specimens were stabilized with Portland cement (0%–6%, bitumen emulsion (0%–5%, and Portland cement-bitumen emulsion mixtures and cured for 7 days, and their short- and long-term performances were studied. Evaluation results of both the Marshall stability ratio and the tensile strength ratio show that the additions of additives increase the resistance of the mixtures to moisture damage. Results of durability tests performed for determining the resistance of compacted specimens to repeated FT cycles indicate that the specimen with the 4% cement-3% bitumen emulsion mixture significantly improves water absorption, volume changes, and weight losses. This indicates the effectiveness of this additive as a road base stabilizer with excellent engineering properties for cold regions.

  4. A Brillouin smart FRP material and a strain data post processing software for structural health monitoring through laboratory testing and field application on a highway bridge

    Science.gov (United States)

    Bastianini, Filippo; Matta, Fabio; Galati, Nestore; Nanni, Antonio

    2005-05-01

    Strain and temperature sensing obtained through frequency shift evaluation of Brillouin scattered light is a technology that seems extremely promising for Structural Health Monitoring (SHM). Due to the intrinsic distributed sensing capability, Brillouin can measure the deformation of any individual segment of huge lengths of inexpensive single-mode fiber. In addition, Brillouin retains other typical advantages of Fiber Optic Sensors (FOS), such as harsh environment durability and interference rejection. Despite these advantages, the diffusion of Brillouin for SHM is constrained by different factors, such as the high equipment cost, the commercial unavailability of specific SHM oriented fiber products and even some prejudices on the required sensitivity performances. In the present work, a complete SHM pilot application was developed, installed and successfully operated during a diagnostic load test on the High Performance Steel (HPS) bridge A6358 located at the Lake of the Ozarks (Miller County, MO, USA). Four out of five girders were extensively instrumented with a "smart" Glass Fiber Reinforced Polymer (GFRP) tape having embedded fibers for strain sensing and thermal compensation. Data collected during a diagnostic load test were elaborated through a specific post-processing software, and the strain profiles retrieved were compared to traditional strain gauges and theoretical results based on the AASHTO LRFD Bridge Design Specifications for structural assessment purposes. The excellent results obtained confirm the effectiveness of Brillouin SHM systems for the monitoring of real applications.

  5. Force-based and displacement-based reliability assessment approaches for highway bridges under multiple hazard actions

    Directory of Open Access Journals (Sweden)

    Chao Huang

    2015-08-01

    Full Text Available The strength limit state of American Association of State Highway and Transportation Officials (AASHTO Load and Resistance Factor Design (LRFD Bridge Design Specifications is developed based on the failure probabilities of the combination of non-extreme loads. The proposed design limit state equation (DLSE has been fully calibrated for dead load and live load by using the reliability-based approach. On the other hand, most of DLSEs in other limit states, including the extreme events Ⅰ and Ⅱ, have not been developed and calibrated though taking certain probability-based concepts into account. This paper presents an assessment procedure of highway bridge reliabilities under the limit state of extreme event Ⅰ, i. e., the combination of dead load, live load and earthquake load. A force-based approach and a displacement-based approach are proposed and implemented on a set of nine simplified bridge models. Results show that the displacement-based approach comes up with more convergent and accurate reliabilities for selected models, which can be applied to other hazards.

  6. Analytical investigation of bidirectional ductile diaphragms in multi-span bridges

    Science.gov (United States)

    Wei, Xiaone; Bruneau, Michel

    2018-04-01

    In the AASHTO Guide Specifications for Seismic Bridge Design Provisions, ductile diaphragms are identified as Permissible Earthquake-Resisting Elements (EREs), designed to help resist seismic loads applied in the transverse direction of bridges. When adding longitudinal ductile diaphragms, a bidirectional ductile diaphragm system is created that can address seismic excitations acting along both the bridge's longitudinal and transverse axes. This paper investigates bidirectional ductile diaphragms with Buckling Restrained Braces (BRBs) in straight multi-span bridge with simply supported floating spans. The flexibility of the substructures in the transverse and longitudinal direction of the bridge is considered. Design procedures for the bidirectional ductile diaphragms are first proposed. An analytical model of the example bridge with bidirectional ductile diaphragms, designed based on the proposed methodology, is then built in SAP2000. Pushover and nonlinear time history analyses are performed on the bridge model, and corresponding results are presented. The effect of changing the longitudinal stiffness of the bidirectional ductile diaphragms in the end spans connecting to the abutment is also investigated, in order to better understand the impact on the bridge's dynamic performance.

  7. Effects of CFRP Strengthening on Dynamic and Fatigue Responses of Composite Bridge

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    Kittisak Kuntiyawichai

    2014-01-01

    Full Text Available This paper investigates the effect of CFRP strengthening on dynamic and fatigue responses of composite bridge using finite element program ABAQUS. Dynamic and fatigue responses of composite bridge due to truck load based on AASHTO standard are investigated. Two types of CFRP strengthening techniques, CFRP sheets and CFRP deck, are applied to both the damaged and undamaged bridges. For the case of damaged bridge, two through-thickness crack sizes, 3 mm and 6 mm in depth, are assumed at midspan of the steel girders. Furthermore, effects of the number of steel girders on the dynamic and fatigue responses are also considered. The results show that the maximum responses of composite bridges occur for dual lane cases. By using CFRP as a strengthening material, the maximum stress and deflection of the steel girders reduce and consequently increase the fatigue life of the girders. After introducing initial crack into the steel girders of the composite bridges, the fatigue life of the bridges is dramatically reduced. However, the overall performance of the damaged composite bridge can be improved by using CFRP, albeit with less effectiveness. Therefore, if cracks are found, steel welding must be performed before strengthening the composite bridge by CFRP.

  8. Estimation of Compaction Parameters Based on Soil Classification

    Science.gov (United States)

    Lubis, A. S.; Muis, Z. A.; Hastuty, I. P.; Siregar, I. M.

    2018-02-01

    Factors that must be considered in compaction of the soil works were the type of soil material, field control, maintenance and availability of funds. Those problems then raised the idea of how to estimate the density of the soil with a proper implementation system, fast, and economical. This study aims to estimate the compaction parameter i.e. the maximum dry unit weight (γ dmax) and optimum water content (Wopt) based on soil classification. Each of 30 samples were being tested for its properties index and compaction test. All of the data’s from the laboratory test results, were used to estimate the compaction parameter values by using linear regression and Goswami Model. From the research result, the soil types were A4, A-6, and A-7 according to AASHTO and SC, SC-SM, and CL based on USCS. By linear regression, the equation for estimation of the maximum dry unit weight (γdmax *)=1,862-0,005*FINES- 0,003*LL and estimation of the optimum water content (wopt *)=- 0,607+0,362*FINES+0,161*LL. By Goswami Model (with equation Y=mLogG+k), for estimation of the maximum dry unit weight (γdmax *) with m=-0,376 and k=2,482, for estimation of the optimum water content (wopt *) with m=21,265 and k=-32,421. For both of these equations a 95% confidence interval was obtained.

  9. Assessing Asphalt and Concrete Pavement Surface Texture in the Field

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    Saad I. Sarsam

    2016-06-01

    Full Text Available The incorporation of safety characteristics into the traditional pavement structural design or in the functional evaluation of pavement condition has not been established yet. The design has focused on the structural capacity of the roadway so that the pavement can withstand specific level of repetitive loading over the design life. On the other hand, the surface texture condition was neither included in the AASHTO design procedure nor in the present serviceability index measurements. The pavement surface course should provide adequate levels of friction and ride quality and maintain low levels of noise and roughness. Many transportation departments perform routine skid resistant testing, the type of equipment used for testing varies depending on the preference of each transportation department. It was felt that modeling of the surface texture condition using different methods of testing may assist in solving such problem. In this work, Macro texture and Micro texture of asphalt and cement concrete pavement surface have been investigated in the field using four different methods (The Sand Patch Method, Outflow Time Method, British Pendulum Tester and Photogrammetry Technique. Two different grain sizes of sand have been utilized in conducting the Sand Patch while the Micro texture was investigated using the British Pendulum tester method at wet pavement surface conditions. The test results of the four methods were correlated to the skid number. It was concluded that such modeling could provide instant data in the field for pavement condition which may help in pavement maintenance management.

  10. Application of Lean-Six Sigma Approach in a Laboratory Experimental Case Study

    Directory of Open Access Journals (Sweden)

    Hashim Raza Rizvi

    2013-12-01

    Full Text Available Laboratory experiments are a conventional activity performed at academic institutions, government and private organizations. These experimental studies provide the basis for new inventions in the field of science and engineering. Laboratory experiments are conducted on the basis of provided guidelines, already established by different standard organizations like ASTM, AASHTO etc. This article is based on a case study in which the process of an experiment is examined on the basis of Value Stream Maps (VSM and potential improvement possibilities have been identified. After determining the potential waste, appropriate Lean tools are selected to implement and observe the improvements. The process is examined after application of the Lean tools and a comparison is performed. University laboratory environment can be improved considerably by applying Lean Tools. MUDA application reduced the total work time from 90.75 hours and 10-CD to 63.75 hours and 7-CD hence saving, 27 hours and 3-CD for one experiment. This is remarkable achievement of this application. Heijunka application provided the students equal workload and they performed explicitly better than they used to. 5-S tool provided the students the opportunity to manage the laboratory in an effective and clean way. Safety of the students is a very major concern at university laboratory environment. 5-S not only upgraded the laboratory overall performance, but it significantly raised the safety standards of the laboratory. More application of the Lean Tools should be exercised explored to have more effective and efficient university laboratory experimental environment.

  11. Evaluation of techniques for the improvement of subgrade soils in flood and rainfall inundation affected areas

    International Nuclear Information System (INIS)

    Khan, A.H.

    2016-01-01

    Highways are amongst the most costly resources contributing directly to the growth of any Country's economy. Subgrade soils as component of highways deteriorate normally from numerous factors resulting into flushing or excessive settlements of embankment involving huge maintenance costs. In this research, an attempt has been made to evaluate suitable technique for stabilization of commonly available subgrade soils of Pakistan based on cost effectiveness and ease in construction. The soils identified as A-3(0) by American Association of State Highway and Transportation Officials (AASHTO) criteria has been stabilized with conventional additives i.e. cement and bitumen in this research. The optimum content of each additive for stabilization based on their relative effectiveness was used. Trials were also made to economize the cost of stabilization from both conventional additives by controlled replacing of them with waste polythene and polyester fibers. The construction methodology for stabilization using waste fibers was also proposed. Cement was observed to be the most effective stabilizer with respect to strength and durability for A-3(0) soils. Bitumen was found effective but uneconomical for A-3(0) soils. Waste polythene and polyester wastes (organic materials) have potential to economize the cost of stabilization with cement and bitumen for A-3(0) soils. However, long term degradation of these organic materials in soil stabilized mixtures needs further exploration. (author)

  12. Time-variant flexural reliability of RC beams with externally bonded CFRP under combined fatigue-corrosion actions

    International Nuclear Information System (INIS)

    Bigaud, David; Ali, Osama

    2014-01-01

    Time-variant reliability analysis of RC highway bridges strengthened with carbon fibre reinforced polymer CFRP laminates under four possible competing damage modes (concrete crushing, steel rupture after yielding, CFRP rupture and FRP plate debonding) and three degradation factors is analyzed in terms of reliability index β using FORM. The first degradation factor is chloride-attack corrosion which induces reduction in steel area and concrete cover cracking at characteristic key times (corrosion initiation, severe surface cover cracking). The second degradation factor considered is fatigue which leads to damage in concrete and steel rebar. Interaction between corrosion and fatigue crack growth in steel reinforcing bars is implemented. The third degradation phenomenon is the CFRP properties deterioration due to aging. Considering these three degradation factors, the time-dependent flexural reliability profile of a typical simple 15 m-span intermediate girder of a RC highway bridge is constructed under various traffic volumes and under different corrosion environments. The bridge design options follow AASHTO-LRFD specifications. Results of the study have shown that the reliability is very sensitive to factors governing the corrosion. Concrete damage due to fatigue slightly affects reliability profile of non-strengthened section, while service life after strengthening is strongly related to fatigue damage in concrete. - Highlights: • We propose a method to follow the time-variant reliability of strengthened RC beams. • We consider multiple competing failure modes of CFRP strengthened RC beams. • We consider combined degradation mechanisms (corrosion, fatigue, ageing of CFRP)

  13. Post-tensioning and splicing of precast/prestressed bridge beams to extend spans

    Science.gov (United States)

    Collett, Brandon S.; Saliba, Joseph E.

    2002-06-01

    This paper explores the status and techniques of post-tensioning and splicing precast concrete I-beams in bridge applications. It will look at the current practices that have been used in the United States and comment on the advantages of these techniques. Representative projects are presented to demonstrate the application and success of specific methods used. To demonstrate the benefits of using post-tensioning and splicing to extend spans, multiple analysis of simple span post-tensioned I-beams were performed varying such characteristics as beam spacing, beam sections, beam depth and concrete strength. Tables were then developed to compare the maximum span length of a prestressed I-beam versus a one segment or a spliced three segment post-tensioned I-beam. The lateral stability of the beam during fabrication, transportation and erection is also examined and discussed. These tables are intended to aid designers and owners in preliminary project studies to determine if post-tensioning can be beneficial to their situation. AASHTO Standard Specifications(2) will be used as basic guidelines and specifications. In many cases, post-tensioning was found to extend the maximum span length of a typical 72-inch precast I-beam more than 40 feet over conventional prestress.

  14. Evaluation of using crushed brick as coarse aggregate in concrete layer within rigid highway pavement

    Directory of Open Access Journals (Sweden)

    Alwash Ali

    2018-01-01

    Full Text Available Most of the present studies related to the field of highway pavement construction technique tend to make use of the local available materials as substitutes for the imported and necessary materials for some of the practical application. For this reason this research aims at looking for the prospect of used locally available aggregate such as crushed clay bricks for the aim of producing proper concrete with suitable thermal and mechanical properties. Experimental investigations have been carried out to asses the effect of partial replacement of coarse aggregate by free manually crushed Brick with percentages (10, 20, 30 and 40% of virgin coarse aggregate in concrete mix for highway rigid pavement. While the percentage (0% replacement represent reference mix. Mix proportion based on the target of compressive strength for all replacement percentage of (33 MPa at (28 days to achieve AASHTO requirement for highway concrete rigid pavement .The results of flexural strength, modulus of elasticity, density and thermal conductivity refers to better performance (less thickness of concrete layer with large spacing between contraction or expansion joints and less stresses due to warping induced concrete layer for concrete mix with 20% crushed brick as replacement of coarse aggregate.

  15. Paso superior en una ladera

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    Bender, O.

    1965-07-01

    Full Text Available The Redwood highway, through the Californian forest, runs on a viaduct, as it crosses a mountain slope of about 45° inclination. The firm ground is fairly deep, and as an additional constructional difficulty, it was necessary to respect the natural beauty of the countryside. A structure of portal frames were built, forming a number of short spans. These spans were bridged with metal girders, on which a 19 m wide deck was placed. The columns are hollow and have a transversal cross beam, to join each pair. There was difficulty in excavating the foundations for the columns, as it was necessary to dig through the soft top soil, and also prevent this soil from hurting the trunks of the forest trees. Another significant difficulty in the construction of this viaduct was the access to the working site, since there were no suitable platforms from which to operate the appropriate machinery. This made it necessary to do a lot of the work by manual operation. As one of the edges of the deck is very close to the mountain side, a supporting beam was erected on this side. It was made of concrete, on metal piles. The formwork for the deck structure was placed on the concrete stems of the supporting piles.La autopista denominada Redwood (California salva, con un paso superior, la ladera de un bosque cuya pendiente es del 1/1. El terreno firme se halla a bastante profundidad, añadiéndose, a los naturales problemas de la construcción, el imperativo de respetar la belleza agreste del paraje. La solución adoptada consiste en una estructura porticada, con varios tramos de pequeñas luces, salvados con vigas metálicas, sobre los que se coloca la losa del tablero, de 19 m de anchura total. Los soportes están constituidos por pórticos de dos montantes huecos (con bases de hormigón en masa por debajo del suelo, hasta el firme coronados por un cabezal. La perforación de pozos para el hormigonado de los montantes presentaba la dificultad de atravesar el terreno

  16. Los viaductos de la autopista Savona-Ceva (Italia

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    Braggio, Riccardo

    1965-11-01

    Full Text Available The Savone-Ceva motor road is the last section of the great European highway, known as the seventh meridian. It extends from Hamburg to Savona, crosses Switzerland, and enters Italy at Saint Bernard's. This last section has a mean height of more than 400 m, and all the characteristics of a mountain road. It involves a large number of tunnels, cuttings, and embankments, thanks to which the curves and slopes are gentle. The structures supporting the road are of many kinds, and each type has been separately allocated to contractors, although an initial project was prepared by the technical directors of the whole scheme. This initial project included the choice of the road axis and the obtention of information on the subsoil. Along the more important sections of the road special soundings were carried out, so that there was a considerably unitj/ of initial planning. The arrangement for awarding contracts involved a number of conditions and data which the bidding contractors could check over the proposed site of the motor road. One of the principal conditions required the use of supports in the form of groups of columns with a trapezoidal plan distribution. The purpose of this was to fit better the decks of the large number of viaduct decks, which have a curved outline. As there are many such viaducts, in this article the author summarizes the more significant details, and describes the most important general features.La autopista Savona-Ceva constituye el tramo final de la gran arteria europea, llamada del séptimo meridiano, que se extiende de Hamburgo a Savona pasando por Suiza y entrando en Italia a través del San Bernardo. Este tramo Ceva-Savona, de una altitud inedia que rebasa los 400 m, presenta todas las características de un trazado de montaña, con abundantes obras de fábrica, túneles y fuertes excavaciones, gracias a las cuales las curvas y pendientes son suaves y practicables. Las estructuras son muy variadas y cada uno de los lotes

  17. Experience in design and construction of the Log tunnel

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    Jovičić Vojkan

    2017-09-01

    Full Text Available A twin highway Log tunnel is a part of a new motorway connection between Maribor and Zagreb, section Draženci-Gruškovje, which is located towards the border crossing between Slovenia and Croatia. The tunnel is currently under construction, and only the excavation works have been completed during the writing of this paper. The terrain in the area of the Log tunnel is diverse, and the route of the highway in its vicinity is characterised by deep excavations, bridges or viaducts. The Log tunnel is approximately 250 m long, partly constructed as a gallery. The geological conditions are dominated by Miocene base rock, featuring layers of well-connected clastic rocks, which are covered by diluvium clays, silts, sands and gravels of different thicknesses. Due to the short length of the tunnel, the usual separation of the motorway route to the left and the right tunnel axes was not carried out. Thus, the tunnel was constructed with an intermediate pillar and was designed as a three-lane tunnel, including the stopping lane. The construction of the tunnel was carried out using the New Austrian tunnelling method (NATM, in which the central adit was excavated first and the intermediate pillar was constructed within it. The excavation of the main tubes followed and was divided into the top heading, bench and the invert, enabling the intermediate pillar to take the load off the top heading of both tubes. The secondary lining of the tunnel is currently under construction. The experience of the tunnel construction gathered so far is presented in the paper. The main emphasis is on the construction of the intermediate pillar, which had to take the significant and asymmetrical ground load.

  18. The Loma Prieta, California, Earthquake of October 17, 1989: Societal Response

    Science.gov (United States)

    Coordinated by Mileti, Dennis S.

    1993-01-01

    Professional Paper 1553 describes how people and organizations responded to the earthquake and how the earthquake impacted people and society. The investigations evaluate the tools available to the research community to measure the nature, extent, and causes of damage and losses. They describe human behavior during and immediately after the earthquake and how citizens participated in emergency response. They review the challenges confronted by police and fire departments and disruptions to transbay transportations systems. And they survey the challenges of post-earthquake recovery. Some significant findings were: * Loma Prieta provided the first test of ATC-20, the red, yellow, and green tagging of buildings. It successful application has led to widespread use in other disasters including the September 11, 2001, New York City terrorist incident. * Most people responded calmly and without panic to the earthquake and acted to get themselves to a safe location. * Actions by people to help alleviate emergency conditions were proportional to the level of need at the community level. * Some solutions caused problems of their own. The police perimeter around the Cypress Viaduct isolated businesses from their customers leading to a loss of business and the evacuation of employees from those businesses hindered the movement of supplies to the disaster scene. * Emergency transbay ferry service was established 6 days after the earthquake, but required constant revision of service contracts and schedules. * The Loma Prieta earthquake produced minimal disruption to the regional economy. The total economic disruption resulted in maximum losses to the Gross Regional Product of $725 million in 1 month and $2.9 billion in 2 months, but 80% of the loss was recovered during the first 6 months of 1990. Approximately 7,100 workers were laid off.

  19. Characterization of Desmodus rotundus (E. Geoffroy, 1810 (Chiroptera, Phyllostomidae shelters in the Municipality of São Pedro - SP

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    PJ. Mialhe

    Full Text Available Surveillance of hematophagous bats is an important public health measure for the prevention and control of rabies epidemics in domestic herbivorous animals. The aim of this study was to locate and georeference D.rotundus shelters in the Municipality of São Pedro - SP, Brazil, and verify their nature (artificial or natural, surrounding landscape and distance from main rivers. To do this, two samples were taken of populations in shelters, with an interval of six months between them, capturing all the bats existent in shelters with fewer than 20 individuals and approximately 20% of the bats present in shelters with over 20 individuals in order to quantify their gender and age distribution. The majority of D. rotundus (67% were verified to be artificial and the remainder (33% natural. Of the six artificial shelters found, five were located in abandoned houses and one in a rain water drainage channel. There were no signs of D. rotundus in other rural buildings and viaducts located in the proximities of pastures. In spite of the majority of D. rotundus shelters being artificial, the three most populated shelters were maternity colonies, two being located in grottos and only one in an artificial shelter (rain water drainage channel. The remaining shelters were occupied by only male individuals. With the exception of one shelter, all the other shelters were at a distance of less than 3 km from the main bodies of water in the study area, corroborating studies that have reported that the main rivers in the State of São Paulo are the main geographic features related to the presence of D. rotundus. It was also verified that 67% of the shelters were inhabited by only male individuals, which confirms other studies conducted in the State of São Paulo, in which over 60% of the groups of Desmodus contain only male individuals.

  20. Genetic relatedness of indigenous ethnic groups in northern Borneo to neighboring populations from Southeast Asia, as inferred from genome-wide SNP data.

    Science.gov (United States)

    Yew, Chee Wei; Hoque, Mohd Zahirul; Pugh-Kitingan, Jacqueline; Minsong, Alexander; Voo, Christopher Lok Yung; Ransangan, Julian; Lau, Sophia Tiek Ying; Wang, Xu; Saw, Woei Yuh; Ong, Rick Twee-Hee; Teo, Yik-Ying; Xu, Shuhua; Hoh, Boon-Peng; Phipps, Maude E; Kumar, S Vijay

    2018-07-01

    The region of northern Borneo is home to the current state of Sabah, Malaysia. It is located closest to the southern Philippine islands and may have served as a viaduct for ancient human migration onto or off of Borneo Island. In this study, five indigenous ethnic groups from Sabah were subjected to genome-wide SNP genotyping. These individuals represent the "North Borneo"-speaking group of the great Austronesian family. They have traditionally resided in the inland region of Sabah. The dataset was merged with public datasets, and the genetic relatedness of these groups to neighboring populations from the islands of Southeast Asia, mainland Southeast Asia and southern China was inferred. Genetic structure analysis revealed that these groups formed a genetic cluster that was independent of the clusters of neighboring populations. Additionally, these groups exhibited near-absolute proportions of a genetic component that is also common among Austronesians from Taiwan and the Philippines. They showed no genetic admixture with Austro-Melanesian populations. Furthermore, phylogenetic analysis showed that they are closely related to non-Austro-Melansian Filipinos as well as to Taiwan natives but are distantly related to populations from mainland Southeast Asia. Relatively lower heterozygosity and higher pairwise genetic differentiation index (F ST ) values than those of nearby populations indicate that these groups might have experienced genetic drift in the past, resulting in their differentiation from other Austronesians. Subsequent formal testing suggested that these populations have received no gene flow from neighboring populations. Taken together, these results imply that the indigenous ethnic groups of northern Borneo shared a common ancestor with Taiwan natives and non-Austro-Melanesian Filipinos and then isolated themselves on the inland of Sabah. This isolation presumably led to no admixture with other populations, and these individuals therefore underwent

  1. Line and Form: linear, areal, inclusive and accessible public spaces. Hoofbogen in Rotterdam

    Directory of Open Access Journals (Sweden)

    Maurizio Francesco Errigo

    2013-06-01

    Full Text Available In the contemporary city places more and more lose their character of physical stock and became space of flow; the city isn’t characterized by its immobile uniqueness, but is modified and reassembled at the rate of circulation in it comes to life. Today the city is presented as a set of discontinuous fragments, which return an image of plural spaces, places and non-places, past and present. Disappearing borders, perimeters, which marked the places, neighborhoods are uncommon spaces, undefined areas between built and unbuilt. The square is the gap in the building density; it has lost its significance as a place of socialization. The recent planning instruments (plans and programs that belong to the city of Rotterdam are geared to transform the city into a “child-friendly city" (city suitable for children, the city attracts young couples and middle-class families just for the fact that the city is distancing itself from the modernist planning based on the zoning and is encouraging the mix of urban functions; particular emphasis in this phase of planning and urban design is given by the statement of the urban Vision Rotterdam 2030. The case dealt with in the article is related to the area of ​​Bergpolder, in the north of Rotterdam, an area affected by a strong identity disposed element, a railway viaduct, and is characterized by a strong strategic value for the location and proximity with the urban center and is affected by both social and economic problem due to the insufficiency of public spaces, the use of spaces and public facilities, to the social mixité, characterized by the mixture of different ethnic groups.

  2. Experience in design and construction of the Log tunnel

    Science.gov (United States)

    Jovičić, Vojkan; Goleš, Niko; Tori, Matija; Peternel, Miha; Vajović, Stanojle; Muhić, Elvir

    2017-09-01

    A twin highway Log tunnel is a part of a new motorway connection between Maribor and Zagreb, section Draženci-Gru\\vskovje, which is located towards the border crossing between Slovenia and Croatia. The tunnel is currently under construction, and only the excavation works have been completed during the writing of this paper. The terrain in the area of the Log tunnel is diverse, and the route of the highway in its vicinity is characterised by deep excavations, bridges or viaducts. The Log tunnel is approximately 250 m long, partly constructed as a gallery. The geological conditions are dominated by Miocene base rock, featuring layers of well-connected clastic rocks, which are covered by diluvium clays, silts, sands and gravels of different thicknesses. Due to the short length of the tunnel, the usual separation of the motorway route to the left and the right tunnel axes was not carried out. Thus, the tunnel was constructed with an intermediate pillar and was designed as a three-lane tunnel, including the stopping lane. The construction of the tunnel was carried out using the New Austrian tunnelling method (NATM), in which the central adit was excavated first and the intermediate pillar was constructed within it. The excavation of the main tubes followed and was divided into the top heading, bench and the invert, enabling the intermediate pillar to take the load off the top heading of both tubes. The secondary lining of the tunnel is currently under construction. The experience of the tunnel construction gathered so far is presented in the paper. The main emphasis is on the construction of the intermediate pillar, which had to take the significant and asymmetrical ground load.

  3. Chapter A. The Loma Prieta, California, Earthquake of October 17, 1989 - Lifelines

    Science.gov (United States)

    Schiff, Anshel J.

    1998-01-01

    To the general public who had their televisions tuned to watch the World Series, the 1989 Loma Prieta earthquake was a lifelines earthquake. It was the images seen around the world of the collapsed Cypress Street viaduct, with the frantic and heroic efforts to pull survivors from the structure that was billowing smoke; the collapsed section of the San Francisco-Oakland Bay Bridge and subsequent home video of a car plunging off the open span; and the spectacular fire in the Marina District of San Francisco fed by a broken gasline. To many of the residents of the San Francisco Bay region, the relation of lifelines to the earthquake was characterized by sitting in the dark because of power outage, the inability to make telephone calls because of network congestion, and the slow and snarled traffic. Had the public been aware of the actions of the engineers and tradespeople working for the utilities and other lifeline organizations on the emergency response and restoration of lifelines, the lifeline characteristics of this earthquake would have been even more significant. Unobserved by the public were the warlike devastation in several electrical-power substations, the 13 miles of gas-distribution lines that had to be replaced in several communities, and the more than 1,200 leaks and breaks in water mains and service connections that had to be excavated and repaired. Like the 1971 San Fernando, Calif., earthquake, which was a seminal event for activity to improve the earthquake performance of lifelines, the 1989 Loma Prieta earthquake demonstrated that the tasks of preparing lifelines in 'earthquake country' were incomplete-indeed, new lessons had to be learned.

  4. Design of bridges against large tectonic deformation

    Science.gov (United States)

    Anastasopoulos, I.; Gazetas, G.; Drosos, V.; Georgarakos, T.; Kourkoulis, R.

    2008-12-01

    The engineering community has devoted much effort to understanding the response of soil-structure systems to seismic ground motions, but little attention to the effects of an outcropping fault offset. The 1999 earthquakes of Turkey and Taiwan, offering a variety of case histories of structural damage due to faulting, have (re)fueled the interest on the subject. This paper presents a methodology for design of bridges against tectonic deformation. The problem is decoupled in two analysis steps: the first (at the local level) deals with the response of a single pier and its foundation to fault rupture propagating through the soil, and the superstructure is modeled in a simplified manner; and the second (at the global level) investigates detailed models of the superstructure subjected to the support (differential) displacements of Step 1. A parametric study investigates typical models of viaduct and overpass bridges, founded on piles or caissons. Fixed-head piled foundations are shown to be rather vulnerable to faulting-induced deformation. End-bearing piles in particular are unable to survive bedrock offsets exceeding 10 cm. Floating piles perform better, and if combined with hinged pile-to-cap connections, they could survive much larger offsets. Soil resilience is beneficial in reducing pile distress. Caisson foundations are almost invariably successful. Statically-indeterminate superstructures are quite vulnerable, while statically-determinate are insensitive (allowing differential displacements and rotations without suffering any distress). For large-span cantilever-construction bridges, where a statically determinate system is hardly an option, inserting resilient seismic isolation bearings is advantageous as long as ample seating can prevent the deck from falling off the supports. An actual application of the developed method is presented for a major bridge, demonstrating the feasibility of design against tectonic deformation.

  5. El nuevo puente de Saint-Cloud París-Francia

    Directory of Open Access Journals (Sweden)

    Mathivat, J.

    1976-09-01

    Full Text Available This article describes the various problems that have been solved and the great amount of work that has been carried out to construct this bridge that connects the highway A-13 with the peripheral boulevard of the French capital making it possible to cross the Seine. The final solution has been that of a prestressed concrete bridge deck, supported by reinforced concrete piles on a foundation of plates or piles. The construction has a total length of 1,360 m out of which 1,103 are manufactured: a 574 m access viaduct and a 529 m bridge across the river. Altogether it comprises 14 sections, with spans of 46 m up to 101,75 m, one 42 m section on the left hand side and one 49 m section on the right hand side.Se describen en este artículo los diversos problemas resueltos y los múltiples trabajos realizados para construir este puente, que une la autopista A-13 con el bulevar periférico de la capital francesa, permitiendo el paso sobre el Sena. La solución adoptada, en definitiva, ha sido de tablero de hormigón pretensado, apoyado en pilas de hormigón armado sobre cimentación de placa o de pilotes, según los casos. La obra tiene una longitud total de 1.360 m, de los cuales 1.103 m son obras de fábrica: 574 m, de viaducto de acceso, y 529 m, de puente sobre el río. En total se distribuye en 14 tramos, con luces desde 46 a 101,75 m, un tramo de 42 m en la orilla izquierda y otro de 49 m en la orilla derecha.

  6. La Directísima en los Alpes, Austria

    Directory of Open Access Journals (Sweden)

    Schmidt, Wilhelm

    1979-06-01

    Full Text Available This article deals with the construction procesa of the «straight» expressway through the Tauern AIps, where several engineering works deserve special mention: — The Tauern Tunnel, 6.4 km In length. — The Katschberg Tunnel, 5.4 km In length. — The Eben-Pongan cloverleaf. — The Liesertal stretch, 75 per 100 of its length being tunnels and viaducts. The most important of this Is the Tauern Tunnel where, owing to the serious problems encountered in the brittle character of the soil, the Austrian tunnel excavation process was used, this method consisting in tensing the mountain soil in order to be able to counteract the high pressures occurring. This tunnel has a 600 m long, 11 m diameter ventilation shaft, the largest of its kind in the World.

    Se trata, en este artículo, del proceso de construcción de la Autopista de Tauern, La Directísima, en los Alpes, en la que destacan varias obras: — Túnel de Tauern, de 6,4 km de longitud. — Túnel de Katschberg, de 5,4 km de longitud. — Punto de enlace Eben-Pongau. — Tramo de Liesertal, realizado en un 75 por 100 mediante viaductos y túneles. La obra más importante es el túnel de Tauern donde, debido a los grandes problemas surgidos por la naturaleza quebradiza del terreno, hubo de emplearse un método austríaco de perforación de túneles consistente en poner en tensión la montaña para, de esta manera, contrarrestar las altas presiones que se producen. Este túnel tiene un pozo de ventilación de 600 m de longitud y 11 m de diámetro de perforación. Es el pozo vertical más grande del mundo.

  7. A composite experimental dynamic substructuring method based on partitioned algorithms and localized Lagrange multipliers

    Science.gov (United States)

    Abbiati, Giuseppe; La Salandra, Vincenzo; Bursi, Oreste S.; Caracoglia, Luca

    2018-02-01

    Successful online hybrid (numerical/physical) dynamic substructuring simulations have shown their potential in enabling realistic dynamic analysis of almost any type of non-linear structural system (e.g., an as-built/isolated viaduct, a petrochemical piping system subjected to non-stationary seismic loading, etc.). Moreover, owing to faster and more accurate testing equipment, a number of different offline experimental substructuring methods, operating both in time (e.g. the impulse-based substructuring) and frequency domains (i.e. the Lagrange multiplier frequency-based substructuring), have been employed in mechanical engineering to examine dynamic substructure coupling. Numerous studies have dealt with the above-mentioned methods and with consequent uncertainty propagation issues, either associated with experimental errors or modelling assumptions. Nonetheless, a limited number of publications have systematically cross-examined the performance of the various Experimental Dynamic Substructuring (EDS) methods and the possibility of their exploitation in a complementary way to expedite a hybrid experiment/numerical simulation. From this perspective, this paper performs a comparative uncertainty propagation analysis of three EDS algorithms for coupling physical and numerical subdomains with a dual assembly approach based on localized Lagrange multipliers. The main results and comparisons are based on a series of Monte Carlo simulations carried out on a five-DoF linear/non-linear chain-like systems that include typical aleatoric uncertainties emerging from measurement errors and excitation loads. In addition, we propose a new Composite-EDS (C-EDS) method to fuse both online and offline algorithms into a unique simulator. Capitalizing from the results of a more complex case study composed of a coupled isolated tank-piping system, we provide a feasible way to employ the C-EDS method when nonlinearities and multi-point constraints are present in the emulated system.

  8. Can Sensors Solve the Deterioration Problems of Public Infrastructure?

    Science.gov (United States)

    Miki, Chitoshi

    2014-11-01

    Various deteriorations are detected in public infrastructures, such as bridges, viaducts, piers and tunnels and caused fatal accidents in some cases. The possibility of the applications of health monitoring by using sensors is the issues of this lecture. The inspection and diagnosis are essential in the maintenance works which include appropriate rehabilitations and replacements. The introduction of monitoring system may improve accuracy and efficiency of inspection and diagnosis. This seems to be innovation of maintenance, old structures may change smart structures by the installation of nerve network and brain, specifically. Cost- benefit viewpoint is also important point, because of public infrastructures. The modes of deterioration are fatigue, corrosion, and delayed fracture in steel, and carbonization and alkali aggregate reaction in concrete. These are like adult disease in human bodies. The developments of Infrastructures in Japan were concentrated in the 1960th and 1970th. These ages are approaching 50 and deterioration due to aging has been progress gradually. The attacks of earthquakes are also a major issue. Actually, these infrastructures have been supporting economic and social activities in Japan and the deterioration of public infrastructure has become social problems. How to secure the same level of safety and security for all public infrastructures is the challenge we face now. The targets of monitoring are external disturbances such as traffic loads, earthquakes, winds, temperature, responses against external disturbances, and the changes of performances. In the monitoring of infrastructures, 3W1H(WHAT, WHERE, WHEN and HOW) are essential, that is what kind of data are necessary, where sensors place, when data are collected, and how to collect and process data. The required performances of sensors are accuracy, stability for long time. In the case of long term monitoring, the durability of systems needs more than five years, because the interval

  9. Shinkansen noise: Research and achievements in countermeasures for Shinkansen noise

    Science.gov (United States)

    Kikuchi, I.

    1988-01-01

    In 1982, the Tohoku and Joetsu Shinkansen lines were opened. The result is the present Shinkansen network that runs through Japan from north to south, leading to a remarkable improvement in railway services, together with the provision of new, efficient connections with conventional lines. Since the opening of the Tokaido Shinkansen, the high utility of the Shinkansen as a high speed, large volume, and safe mode of transport has been gaining a high reputation. On the other hand, social demands for environmental preservation increased in strength with the advent of the period of Japan's high economic growth. Such demands were posed in the form of complaints about air and water pollution and noise from transportation. The problems of noise and vibration from Shinkansen train operation were posed mainly in relation to railway viaducts in urban areas. The Japanese National Railways (JNR) has made all-out efforts in technical development for noise reduction, obtained many achievements, and put them into practical use one by one on the Shinkansen lines. In the early stage of studies, there were many virgin areas for JNR staff, such as measurement technology, estimation methods, and noise alleviation technology. With the start of full-scale testing at a general test center in 1975, various studies and the development of effective measures made a great step forward. In March 1985, the maximum speed on the Tohoku Shinkansen was increased to 240 km/h, enhancing the Shinkansen reputation and resulting in a considerable growth of traffic. As a matter of course, new measures for noise reduction were taken for this line. In view of the history and results of voluminous studies over many years on the Shinkansen noise problem, and also of the roles and surrounding conditions of the Shinkansen as a mode of transport, however, new tasks are being posed concerning such aspects as how to accomplish environmental preservation in the future.

  10. Can Sensors Solve the Deterioration Problems of Public Infrastructure?

    International Nuclear Information System (INIS)

    Miki, Chitoshi

    2014-01-01

    Various deteriorations are detected in public infrastructures, such as bridges, viaducts, piers and tunnels and caused fatal accidents in some cases. The possibility of the applications of health monitoring by using sensors is the issues of this lecture. The inspection and diagnosis are essential in the maintenance works which include appropriate rehabilitations and replacements. The introduction of monitoring system may improve accuracy and efficiency of inspection and diagnosis. This seems to be innovation of maintenance, old structures may change smart structures by the installation of nerve network and brain, specifically. Cost- benefit viewpoint is also important point, because of public infrastructures. The modes of deterioration are fatigue, corrosion, and delayed fracture in steel, and carbonization and alkali aggregate reaction in concrete. These are like adult disease in human bodies. The developments of Infrastructures in Japan were concentrated in the 1960th and 1970th. These ages are approaching 50 and deterioration due to aging has been progress gradually. The attacks of earthquakes are also a major issue. Actually, these infrastructures have been supporting economic and social activities in Japan and the deterioration of public infrastructure has become social problems. How to secure the same level of safety and security for all public infrastructures is the challenge we face now. The targets of monitoring are external disturbances such as traffic loads, earthquakes, winds, temperature, responses against external disturbances, and the changes of performances. In the monitoring of infrastructures, 3W1H(WHAT, WHERE, WHEN and HOW) are essential, that is what kind of data are necessary, where sensors place, when data are collected, and how to collect and process data. The required performances of sensors are accuracy, stability for long time. In the case of long term monitoring, the durability of systems needs more than five years, because the interval

  11. Kinetics of fatigue crack growth and crack paths in the old puddled steel after 100-years operating time

    Directory of Open Access Journals (Sweden)

    G. Lesiuk

    2015-10-01

    Full Text Available The goal of the authors’ investigations was determination of the fatigue crack growth in fragments of steel structures (of the puddled steel and its cyclic behavior. Tested steel elements coming from the turn of the 19th and 20th were gained from still operating ancient steel construction (a main hall of Railway Station, bridges etc.. This work is a part of investigations devoted to the phenomenon of microstructural degradation and its potential influence on their strength properties. The analysis of the obtained results indicated that those long operating steels subject to microstructure degradation processes consisting mainly in precipitation of carbides and nitrides inside ferrite grains, precipitation of carbides at ferrite grain boundaries and degeneration of pearlite areas [1, 2]. It is worth noticing that resistance of the puddled steel to fatigue crack propagation in the normalized state was higher. The authors proposed the new kinetic equation of fatigue crack growth rate in such a steel. Thus the relationship between the kinetics of degradation processes and the fatigue crack growth rate also have been shown. It is also confirmed by the materials research of the viaduct from 1885, which has not shown any significant changes in microstructure. The non-classical kinetic fatigue fracture diagrams (KFFD based on deformation ( or energy (W approach was also considered. In conjunction with the results of low- and high-cycle fatigue and gradual loss of ductility as a consequence (due to the microstructural degradation processes - it seems to be a promising construction of the new kinetics fatigue fracture diagrams with the energy approach.

  12. Bearing capacity evaluation of rubblized concrete pavements

    Directory of Open Access Journals (Sweden)

    González, M.

    2009-03-01

    Full Text Available The paper presents the findings of a research work performed on a real scale concrete pavement project where Rubblizing technology was used for its structural rehabilitation. Rubblizing may be defined as a fracture technique in which a concrete pavement slab is transformed in a granular base with a very high Modulus. This technique, fractures the concrete slab in angular pieces by using a concentrated dynamic load of low amplitude and high frequency. The research work was based on field study on the rehabilitation of 5 km motorway. The structural evaluations where made, before, during and after one year construction. Measurements and site evaluation where made by using DCP, Light Weight Deflectometer and FWD (on top of asphalt layer and excavating inside pits. The structural capacity of the Rubblized layer was evaluated through theoretical analysis. Because of the anisotropic properties of the Rubblized layer the results are presented using AASHTO structural layer coefficient. The structural layer coefficients recommended are between the range of 0.25 and 0.30 for concrete slabs with thickness grater than 220 mm.El trabajo presenta los resultados de un estudio a escala real de la capacidad estructural de un firme de hormigón rehabilitado utilizando la técnica de Rubblizing. La técnica de Rubblizing ha sido traducida como el pulverizado del firme de hormigón pero, es más bien un efecto combinado de trituración y fracturación de la losa de hormigón en todo su espesor para convertir esta en una base granular de alto módulo. Esta tecnica fractura la losa de hormigón en trozos angulares y entrelazados empleando una carga dinámica concentrada, de baja amplitud y alta frecuencia. La investigación se basó en el estudio de la rehabilitación de 5 km de autopista. Los estudios de la capacidad estructural fueron realizados durante, al término y un año después de la construcción. Para las mediciones y evaluaciones de terreno se utilizó, el

  13. DISEÑO DE PAVIMENTOS RÍGIDOS MEDIANTE UN DIMENSIONADO ESTRUCTURAL APOYADO EN EL MÉTODO DE ELEMENTOS FINITOS

    Directory of Open Access Journals (Sweden)

    G. Pannillo

    2016-06-01

    Full Text Available Los métodos mecanicistas representan una excelente opción a la hora de realizar diseños de elementos estructurales debido, entre otras cosas, a la precisión con la que se pueden simular las condiciones de carga, las propiedades de los materiales y las condiciones de apoyo. Dependiendo de la naturaleza de la situación que se va a estudiar, la solución de los sistemas de ecuaciones que se generan de los modelos matemáticos del fenómeno suele ser compleja, siendo por ello los métodos numéricos de importancia vital para llegar a dichas soluciones. En esta investigación se propone el uso del método de elementos finitos para auxiliar el dimensionado estructural de los pavimentos rígidos, tomando como muestra un tramo de la red vial que forma parte del Sistema de Transporte Masivo de Barquisimeto, Transbar, C.A (Transbarca. Al obtener el dimensionado de la estructura de pavimento basado en la información de tránsito, condiciones del suelo de fundación y el tipo de concreto empleado para la losa, según el proyecto original, se determinó un espesor de carpeta rígida de magnitud similar al conseguido mediante la aplicación del método AASHTO 86. Esto permite que el método planteado en esta investigación sea validado al cotejarlo con el método más utilizado en Venezuela para diseño de pavimentos. Mechanistic Methods are an excellent option when designing Structural Elements, due, among other things, to the precision simulating load conditions, the properties of the materials and support conditions. Depending on the nature of the situation to study, solving systems of equations generated from mathematical models of the phenomenon is often complex, these is why Numerical Methods are vital to get to these solutions. This research proposes the use of Finite Element Method to help in the structural dimensioning of rigid pavements, taking as example a stretch of the road network that is part of the Mass Transit System of Barquisimeto

  14. Clay content evaluation in soils through GPR signal processing

    Science.gov (United States)

    Tosti, Fabio; Patriarca, Claudio; Slob, Evert; Benedetto, Andrea; Lambot, Sébastien

    2013-10-01

    The mechanical behavior of soils is partly affected by their clay content, which arises some important issues in many fields of employment, such as civil and environmental engineering, geology, and agriculture. This work focuses on pavement engineering, although the method applies to other fields of interest. Clay content in bearing courses of road pavement frequently causes damages and defects (e.g., cracks, deformations, and ruts). Therefore, the road safety and operability decreases, directly affecting the increase of expected accidents. In this study, different ground-penetrating radar (GPR) methods and techniques were used to non-destructively investigate the clay content in sub-asphalt compacted soils. Experimental layout provided the use of typical road materials, employed for road bearing courses construction. Three types of soils classified by the American Association of State Highway and Transportation Officials (AASHTO) as A1, A2, and A3 were used and adequately compacted in electrically and hydraulically isolated test boxes. Percentages of bentonite clay were gradually added, ranging from 2% to 25% by weight. Analyses were carried out for each clay content using two different GPR instruments. A pulse radar with ground-coupled antennae at 500 MHz centre frequency and a vector network analyzer spanning the 1-3 GHz frequency range were used. Signals were processed in both time and frequency domains, and the consistency of results was validated by the Rayleigh scattering method, the full-waveform inversion, and the signal picking techniques. Promising results were obtained for the detection of clay content affecting the bearing capacity of sub-asphalt layers.

  15. Performance of Hot Mix Asphalt Mixture Incorporating Kenaf Fibre

    Science.gov (United States)

    Hainin, M. R.; Idham, M. K.; Yaro, N. S. A.; Hussein, S. O. A. E.; Warid, M. N. M.; Mohamed, A.; Naqibah, S. N.; Ramadhansyah, P. J.

    2018-04-01

    Kenaf fibre has been recognised to increase the strength of concrete, but its application in asphalt concrete is still unanswered. This research investigated the performance of Hot Mix Asphalt (HMA) incorporated with different percentages of kenaf fibre (0.1 %, 0.2% and 0.3% by weight of dry aggregate) in term of resilient modulus, rutting performance using Asphalt Pavement analyser (APA) and moisture damage using the Modified Lottman test (AASHTO-T283). The fibre was interweaved to a diameter of about 5-10 mm and length of 30 mm which is three times the nominal maximum aggregate size used in the mix. Asphaltic mixtures of asphalt concrete (AC) 10 were prepared and compacted using Marshall compactor which were subsequently tested to evaluate the resilient modulus and moisture susceptibility. Twelve cylindrical specimens (150mm diameter) from AC10, two control samples with two modified ones for each percentage of kenaf fibres compacted using Gyratory compactor were used for rutting test using APA. The laboratory results reveal that the addition of kenaf fibres slightly reduce the resilient modulus of the mixes and that asphaltic mix with 0.3% kenaf fibre can mitigate both rutting and moisture damage which makes the pavement more sustain to the loads applied even in the presence of water. 0.3% kenaf fibre content is considered to be the optimal content which had the least rut depth and the highest TSR of 81.07%. Based on grid analysis, addition of 0.3% kenaf fibre in asphaltic concrete was recommended in modifying the samples.

  16. Effect of Natural Sand Percentages on Fatigue Life of Asphalt Concrete Mixture

    Directory of Open Access Journals (Sweden)

    Nahla Yassub Ahmed

    2016-03-01

    Full Text Available The design of a flexible pavement requires the knowledge of the material properties which are characterized by stiffness and fatigue resistance. The fatigue resistance relates the number of load cycles to failure with the strain level applied to the asphalt mixture. The main objective of this research is the evaluation of the fatigue life of asphalt mixtures by using two types of fine aggregate having different percentages. In this study, two types of fine aggregate were used natural sand (desert sand and crushed sand. The crushed sand was replaced by natural sand (desert sand with different percentages (0%, 25%, 75% and 100% by the weight of the sand (passing sieve No.8 and retained on sieve No.200 and one type of binder (40/50 penetration from Al-Daurah refinery. The samples of beams were tested by four point bending beam fatigue test at the control strain mode (250, 500 and 750 microstrain while the loading frequency (5Hz and testing temperature (20oC according to (AASHTO T321. The experimental work showed that fatigue life (Nf and initial flexural stiffness increased when control strain decreased for asphalt mixtures. Acceptable fatigue life at 750 microstrain was obtained with asphalt concrete mixtures containing 100% crushed sand as well as asphalt concrete contained 25% natural sand. The asphalt concrete contained 100% and 75% of natural sand exhibited high fatigue life at low level of microstrain (250. The main conclusion of this study found that best proportion of natural sand to be added to an asphaltic concrete mixture is falling within the range (0% and 25% by weight of fraction (passing No.8 and retained on No.200 sieve .

  17. Ultimate stress increase in unbonded tendons in post-tensioned indeterminate I-beams cast with high strength normal and self compacting concrete

    Directory of Open Access Journals (Sweden)

    Yousef Askari Dolatabad

    2018-06-01

    Full Text Available The use of un-bonded tendons is prevalent in post-tensioned concrete structures. Equations for prediction of stress in un-bonded tendons of post-tensioned normal (vibrating concrete flexural members have been given in various codes. They are based on experience and don’t account all of important parameters such as concrete strength (normal and high strength and its type (vibrating and non-vibrating concrete. Since self-compacting concrete (SCC is nearly a new innovation therefore, understanding the implementation of this type of non-vibrating concrete on the ultimate unbonded tendon stress is critical. For this aim, in this paper there are presented experimental results of six continuous un-bonded post-tensioned I-beams in two groups were casted and monitored by different electrical strain gauges. In the first tested group, the beams (UPN1-12, UPN1-18, UPN1-22 were consisting of high strength normal concrete (HSNC where as in the second group (UPS1-12, UPS1-18, UPS1-22 high strength self-compacting concrete (HSSCC were tested. The variables included the type of concrete and percentage of bounded non-prestressed steel. Experimental monitored results of ultimate stress increase in unbonded tendons are compared with predicted equations of different researchers and standards. It was found that, the proposed equation is in better agreement with the test results. The results of standard error of estimate Sy/x, indicates that for two types of HSCs, the ACI 318-2011 provides better estimates than AASHTO-2010 model whereas this model provides better estimates than BS 8110-97. Keywords: Post-tensioned, Unbonded tendons, Stress increase, High strength normal and self-compacting concrete, Continuous beams

  18. Clay Stabilization Using the Ash of Mount Sinabung in Terms of the Value of California Bearing Ratio (CBR)

    Science.gov (United States)

    Hastuty, I. P.; Roesyanto, R.; Napitupulu, S. M. A.

    2018-02-01

    Most areas in Indonesia consist of clay soils with high plasticity so that to meet technical requirements the soil needs improvement, which is known as soil stabilization.There are three ways of soil stabilization process, i.e. mechanical, physical and chemical. In this study, chemical stabilization was performed, that was by adding stabilizing agents to the soil. The stabilizing agent used was the ash of Mount Sinabung. Since 2010 until now, Sinabung Mountain is still experiencing eruption that produces a lot of volcanic ash and it inconveniences the environment. So, it is expected that this research will be able to optimize the utilization of Sinabung ash. The purpose of this study was to investigate the effect of the addition of Mount Sinabung ash to CBR (California Bearing Ratio) value, to determine the effect of the curing time of one day and fourteen days mixture on the CBR value, and to find the mixed content with effective curing time to produce the largest CBR value. Based on this study, the soil type CL (Clay - Low Plasticity) was obtained, based on the classification of USCS (Unified Soil Classification System) and categorized as A-6 (6) based on the classification of AASHTO (American Association of State Highway and Transportation officials) with the most effective mixed stabilizer material which was the variation of 10% Mount Sinabung ash with fourteen days of curing time. The CBR value resulted from the mixture of 10% Sinabung ash that was cured within fourteen days was 8.95%. By the increase of the content of the Sinabung ash, the CBR value always improved to the level of 10%, Sinabung ash then decreased and became constant at the mixture of higher volcanic ash mixture but remained above the CBR value of the original soil.

  19. Moisture Sensitivity of Crumb Rubber Modified Modifier Warm Mix Asphalt Additive for Two Different Compaction Temperatures

    Science.gov (United States)

    Bilema, Munder A.; Aman, Mohamad Y.; Hassan, Norhidayah A.; Ahmad, Kabiru A.; Elghatas, Hamza M.; Radwan, Ashraf A.; Shyaa, Ahmed S.

    2018-04-01

    Crumb rubber obtained from scrap tires has been incorporated with asphalt binder to improve the performance of asphalt mixtures in the past decades. Pavements containing crumb-rubber modified (CRM) binders present one major drawback: larger amounts of greenhouse gas emissions are produced as there is rise in the energy consumption at the asphalt plant due to the higher viscosity of these type of binders compared with a conventional mixture. The objective of this paper is to calculate the optimum bitumen content for each percentage and evaluate the moisture sensitivity of crumb rubber modified asphalt at two different compacting temperatures. In this study, crumb rubber modified percentages was 0%, 5%, 10% and 15% from the binder weight, with adding 1.5% warm mix asphalt additive (Sasobit) and crush granite aggregate of 9.5mm Nominal maximum size was used after assessing its properties. Ordinary Portland Cement (OPC) used by 2% from fine aggregate. The wet method was using to mix the CRM with bitumen, the CRM conducted at 177°C for 30 min with 700rpm and Sasobit conducted at 120°C for 10 min with 1000rpm. As a result, from this study the optimum bitumen content (OBC) was increased with increased crumb rubber content. For performance test, it was conducted using the AASHTO T283 (2007): Resistance of Compacted Bituminous Mixture to Moisture-Induced Damage. The result was as expected and it was within the specification of the test, the result show that the moisture damage increased with increased the crumb rubber content but it is not exceeding the limit of specification 80% for indirect tension strength ratio (ITSR). For the temperature was with lowing the temperature the moisture damage increased.

  20. On the required complexity of vehicle dynamic models for use in simulation-based highway design.

    Science.gov (United States)

    Brown, Alexander; Brennan, Sean

    2014-06-01

    This paper presents the results of a comprehensive project whose goal is to identify roadway design practices that maximize the margin of safety between the friction supply and friction demand. This study is motivated by the concern for increased accident rates on curves with steep downgrades, geometries that contain features that interact in all three dimensions - planar curves, grade, and superelevation. This complexity makes the prediction of vehicle skidding quite difficult, particularly for simple simulation models that have historically been used for road geometry design guidance. To obtain estimates of friction margin, this study considers a range of vehicle models, including: a point-mass model used by the American Association of State Highway Transportation Officials (AASHTO) design policy, a steady-state "bicycle model" formulation that considers only per-axle forces, a transient formulation of the bicycle model commonly used in vehicle stability control systems, and finally, a full multi-body simulation (CarSim and TruckSim) regularly used in the automotive industry for high-fidelity vehicle behavior prediction. The presence of skidding--the friction demand exceeding supply--was calculated for each model considering a wide range of vehicles and road situations. The results indicate that the most complicated vehicle models are generally unnecessary for predicting skidding events. However, there are specific maneuvers, namely braking events within lane changes and curves, which consistently predict the worst-case friction margins across all models. This suggests that any vehicle model used for roadway safety analysis should include the effects of combined cornering and braking. The point-mass model typically used by highway design professionals may not be appropriate to predict vehicle behavior on high-speed curves during braking in low-friction situations. However, engineers can use the results of this study to help select the appropriate vehicle dynamic

  1. Identification of aggregates for Tennessee bituminous surface courses

    Science.gov (United States)

    Sauter, Heather Jean

    Tennessee road construction is a major venue for federal and state spending. Tax dollars each year go to the maintenance and construction of roads. One aspect of highway construction that affects the public is the safety of its state roads. There are many factors that affect the safety of a given road. One factor that was focused on in this research was the polish resistance capabilities of aggregates. Several pre-evaluation methods have been used in the laboratory to predict what will happen in a field situation. A new pre-evaluation method was invented that utilized AASHTO T 304 procedure upscaled to accommodate surface bituminous aggregates. This new method, called the Tennessee Terminal Textural Condition Method (T3CM), was approved by Tennessee Department of Transportation to be used as a pre-evaluation method on bituminous surface courses. It was proven to be operator insensitive, repeatable, and an accurate indication of particle shape and texture. Further research was needed to correlate pre-evaluation methods to the current field method, ASTM E 274-85 Locked Wheel Skid Trailer. In this research, twenty-five in-place bituminous projects and eight source evaluations were investigated. The information gathered would further validate the T3CM and find the pre-evaluation method that best predicted the field method. In addition, new sources of aggregates for bituminous surface courses were revealed. The results of this research have shown T3CM to be highly repeatable with an overall coefficient of variation of 0.26% for an eight sample repeatability test. It was the best correlated pre-evaluation method with the locked wheel skid trailer method giving an R2 value of 0.3946 and a Pearson coefficient of 0.710. Being able to predict field performance of aggregates prior to construction is a powerful tool capable of saving time, money, labor, and possibly lives.

  2. Creep and shrinkage effects on integral abutment bridges

    Science.gov (United States)

    Munuswamy, Sivakumar

    Integral abutment bridges provide bridge engineers an economical design alternative to traditional bridges with expansion joints owing to the benefits, arising from elimination of expensive joints installation and reduced maintenance cost. The superstructure for integral abutment bridges is cast integrally with abutments. Time-dependent effects of creep, shrinkage of concrete, relaxation of prestressing steel, temperature gradient, restraints provided by abutment foundation and backfill and statical indeterminacy of the structure introduce time-dependent variations in the redundant forces. An analytical model and numerical procedure to predict instantaneous linear behavior and non-linear time dependent long-term behavior of continuous composite superstructure are developed in which the redundant forces in the integral abutment bridges are derived considering the time-dependent effects. The redistributions of moments due to time-dependent effects have been considered in the analysis. The analysis includes nonlinearity due to cracking of the concrete, as well as the time-dependent deformations. American Concrete Institute (ACI) and American Association of State Highway and Transportation Officials (AASHTO) models for creep and shrinkage are considered in modeling the time dependent material behavior. The variations in the material property of the cross-section corresponding to the constituent materials are incorporated and age-adjusted effective modulus method with relaxation procedure is followed to include the creep behavior of concrete. The partial restraint provided by the abutment-pile-soil system is modeled using discrete spring stiffness as translational and rotational degrees of freedom. Numerical simulation of the behavior is carried out on continuous composite integral abutment bridges and the deformations and stresses due to time-dependent effects due to typical sustained loads are computed. The results from the analytical model are compared with the

  3. Effects of wood saw dust ash admixed with treated sisal fibre on the geotechnical properties of lateritic soil

    Directory of Open Access Journals (Sweden)

    John Engbonye SANI

    2017-12-01

    Full Text Available The preliminary investigation conducted on the lateritic soil collected at Shika, Zaria shows that it falls under A-7-6 (10 classification for AASHTO (1986 and CL according to unified soil classification system USCS (ASTM 1992. The soil was treated with both wood saw dust ash (WSDA and treated sisal fiber, in stepped concentration of 0,2,4,6, and 8% for WSDA and 0, 0.25, 0.5, 0.75 and 1% treated sisal fibre by dry weight of soil using Standard proctor. The Sisal Fibre was treated with Sodium Borohydride (NaBH4 (1% wt/vol for 60 minutes at room temperature to remove the cellulose content present in the Fibre. Statistical analysis was carried out on the obtained results using XLSTART 2017 software and analysis of variance with the Microsoft Excel Analysis Tool Pak Software Package. The liquid limit (LL of the soil was found to be 48% while the plastic limit(PL is 21.27%. The maximum dry density(MDDhowever, decreases generally from a value of 1.85 Mg/m3 to 1.68Mg/m3 at 0.25% sisal fiber content/0% WSDA. It has its least value of 1.57Mg/m3 at 1% sisal fiber and 8% WSDA. The OMC increased from 18 % of the natural soil to 23.7% at 0.75% sisal fiber / 6% WSDA content. There was a general increase in the value of UCS of the soil-sisal fibre mixture with WSDA content from 100 kN/m2 of the natural soil to 696 kN/m2 at 0.75 % sisal fibre content / 6% WSDA. The UCS value met the standard of 687-1373 kN/m2 requirements of sub base for adequate lime and cement stabilization, respectively (Ingas and Metcalf 1972.

  4. Characterization of cementitiously stabilized subgrades for mechanistic-empirical pavement design

    Science.gov (United States)

    Solanki, Pranshoo

    ettringite, responsible for sulfate-induced heaving, is also discussed. For Level 2 design of pavements, a total of four stress-based statistical models and two feed-forward-type artificial neural network (ANN) models, are evaluated for predicting resilient modulus of 28-day cured stabilized specimens. Specifically, one semi-log stress-based, three log-log stress-based, one Multi-Layer Perceptrons Network (MLPN), and one Radial Basis Function Network (RBFN) are developed. Overall, semi-log stress-based and MLPN neural network are found to show best acceptable performance for the present evaluation and validation datasets. Further, correlations are presented for stress-based models to correlate Mr with compacted specimen characteristics and soil/additive properties. Additionally, the effect of type of additive on indirect tensile and fatigue characteristics of selected stabilized P- and V-soil is evaluated. This study is based on the fact that stabilized layer is subjected to tensile stresses under wheel loading. Thus, the resilient modulus in tension (M rt), fatigue life and strength in tension (sigmat) or flexure (represented by modulus of rupture, MOR) becomes another important design parameter within the mechanistic framework. Cylindrical specimens are prepared, cured for 28 days and subjected to different stress sequences in indirect tension to study the Mrt. On the other hand, stabilized beam specimens are compacted using a Linear Kneading Compactor and subjected to repeated cycles of reloading-unloading after 28 days of curing in a four-point beam fatigue apparatus for evaluating fatigue life and flexural stiffness. It is found that all three additives improved the Mrt, sigmat and MOR values; however, degree of improvement varied with the type of additive and soil. This study encompasses the differences in the design of semi-rigid pavements developed using AASHTO 1993 and AASHTO 2002 MEPDG methodologies. Further, the design curves for fatigue performance prediction of

  5. MODELACIÓN DEL COMPORTAMIENTO REOLÓGICO DE ASFALTO CONVENCIONAL Y MODIFICADO CON POLÍMERO RECICLADO, ESTUDIADA DESDE LA RELACIÓN VISCOSIDAD-TEMPERATURA MODELAMENTO DO COMPORTAMENTO REOLÓGICO DE ASFALTO CONVENCIONAL E MODIFICADO COM POLÍMERO RECICLADO MODELING OF RHEOLOGICAL BEHAVIOR OF CONVENTIONAL AND RECYCLED POLYMER MODIFIED ASPHALT

    Directory of Open Access Journals (Sweden)

    Jaleydi Cárdenas

    2009-12-01

    Full Text Available Las propiedades reológicas del asfalto dependen de las proporciones en que están presentes sus componentes, las cuales varían de acuerdo con el origen de los crudos de petróleo. El comportamiento reológico del ligante tiene una influencia significativa en las propiedades de la mezcla asfalto-agregado (ahuellamiento, fatiga y susceptibilidad térmica. Para describir el comportamiento reológico del asfalto proveniente del Complejo Industrial de Barrancabermeja (CIB y del asfalto modificado con material reciclado (poliestireno expandido y grano de caucho de llanta reciclada con control de granulometría y sin él, se realizaron mediciones de viscosidad a diferentes temperaturas (con intervalos de 2 ºC con el viscosímetro rotacional Brookfield, y a partir de estos datos se propusieron varias expresiones matemáticas que describen el comportamiento de la viscosidad en términos de la temperatura, se evaluaron en términos del coeficiente de determinación y se hallaron las temperaturas de mezclado y compactación. Los resultados indican que el mejor ajuste en los tres casos corresponde al modelo tipo Arrhenius truncado, con correlaciones entre 0,9945 y 0,9968. Las temperaturas de mezclado y compactación calculadas a partir de este modelo comparadas con las de las normas ASTM D2493 (2001 y AASHTO (2002 resultaron significativamente disímiles para el asfalto modificado (con polímeros de granulometría controlada pero similares para el asfalto original. De otra parte, con el fin de establecer la estructura química del asfalto original y modificado así como su influencia sobre la viscosidad, se realizó la separación de cada muestra de acuerdo con la norma ASTM D4124 (2001. Los resultados indicaron que sólo ocurrió cambio estructural en el asfalto modificado con polímeros de granulometría controlada, lo que muestra la relación entre la composición química y la viscosidad de los tres ligantes estudiados.As propriedades reológicas do

  6. Evaluation of the efficiency of a repaired chloride-contaminated concrete

    Directory of Open Access Journals (Sweden)

    Andrade, C.

    1988-09-01

    Full Text Available This report describes several tests that are being carried out on a viaduct near Madrid City, whose reinforcements have been seriously damaged by corrosion. These tests consist in measuring corrosion potentials and in a time soon to come, they will include the measurement of corrosion rates by means of the apparent Polarization Resistance. A methodology of laboratory tests to evaluate the protective capacity of the repairing system used towards the reinforcements is also included. Tests results have reported that the repairing materials employed do not fit the repassivating and protective function they should satisfy. Finally, it is also recalled to attention the real need in developing suitable test specifications able to provide a characterization of these repairing materials when they are going to be employed in structures damaged by corrosion in reinforcements.

    En el presente trabajo se describen los ensayos que se están efectuando en un viaducto de las cercanías de Madrid y que tía sufrido importantes daños por corrosión de armaduras. Estos Ensayos consisten en la medida de los potenciales de corrosión y en un próximo futuro, de la velocidad de corrosión (método de la Resistencia de Polarización Aparente. También se presenta la metodología de los ensayos de laboratorio efectuados para caracterizar la capacidad protectora hacia las armaduras del sistema de reparación utilizado en el viaducto. Los resultado de estos ensayos han mostrado que los materiales de reparación no resultan idóneos para la función repasivante y protectora que deberán desempeñar. Se destaca, finalmente, la necesidad de desarrollar una normativa de ensayos adecuada que permita caracterizar a estos materiales de reparación cuando van a ser usados en obras dañadas por corrosión de armaduras.

  7. As marcas da cidade: a dinâmica da pixação em São Paulo The city's marks: the taggers dynamics in São Paulo

    Directory of Open Access Journals (Sweden)

    Alexandre Barbosa Pereira

    2010-01-01

    Full Text Available O artigo tem como foco os pixadores na cidade de São Paulo. Trata-se de jovens que percorrem as ruas da cidade deixando inscrita em muros, prédios e viadutos a sua marca. Tal prática, porém, não é vista com bons olhos pela população paulistana, que vê na pixação uma forma de degradação da paisagem urbana. Aborda também o modo particular com que estes jovens se apropriam do espaço urbano pelo estabelecimento de pontos de encontro, os seus points. Os pixadores têm uma maneira de conceber o centro e a periferia de São Paulo que dialoga com a dinâmica da metrópole. Embora se identifiquem com a periferia de onde são oriundos, eles têm o centro como importante local de atuação. A pesquisa revelou como eles estabelecem relações de troca, aliança e conflito entre si na cidade.The article has as focus the taggers in the city of São Paulo, who covers the streets of the city to leave written in walls, buildings and viaducts their marks. Such practice, however, is not seen with good eyes by the paulistana population who sees in this writing a degradation of the urban landscape. The article also approaches the particular way by which these young appropriate themselves of the urban space through the establishment of meeting points. The taggers have a way to conceive the center and the periphery of São Paulo that dialogues with the dynamics of the metropolis. Although they are identified with the periphery where they are from, they have the center as an important performance place. The research disclosed how they establish exchange relations, alliances and conflicts between them in the city.

  8. El puente de Brotonne sobre el Sena - Francia

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    Campenon, -

    1978-12-01

    Full Text Available This bridge solves the connection problem between Rouen and Le Havre. The need to preserve the maritime tradition of Rouen and to permit the heavy shipping traffic through the estuary forced a structural design which main part, 696.5 m long, consists of a 5-span triss-braced bridge. The central span, 320 m long, is the longest pre-stressed concrete span in the world. The structure also includes two access ramps. This article analyses the features and construction procedures of each element in the structure, namely: — Foundations, consisting on cylindrical piers for the main spans and piers on piles for the access ramps and viaducts. — The curved octagonal piles, creating an interesting aesthetical effect. — The deck consisting on a single monocelular girder, formed by twincore wedged, pieces, prestressed in all directions. — The tower with a constant 2.60 dimension crosswise and tapered from 4.80 to 2.84 meters lengthwise. — Tensors, prestressing, etc.

    Este puente resuelve el problema de comunicación entre Rouen y Le Havre. La necesidad de respetar la tradición marítima de Rouen y la navegación de barcos de gran tonelaje obligó a realizar una estructura cuya obra principal, de una longitud de 696,5 m, es un puente atirantado que tiene cinco tramos, de los cuales el central, de 320 m, constituye el récord del mundo de luz en hormigón pretensado. La estructura comprende, además, dos viaductos de acceso. En este artículo se hace un análisis de las características y procedimientos de construcción de cada uno de los elementos que componen la obra: — Las cimentaciones, que son columnas cilíndricas para las pilas principales, y sobre pilotes en las pilas de los viaductos de acceso. — Las pilas, de forma octogonal curvilínea, que producen un gran efecto estético. — El tablero es una viga monocelular, formada por dovelas de dos almas pretensadas en todas direcciones. — Las torres, cuya sección es

  9. Réordonner l’espace et le temps :

    Directory of Open Access Journals (Sweden)

    Nicolas Senil

    2011-07-01

    Full Text Available La multiplication des objets, des acteurs et des logiques de la patrimonialisation génère un brouillage de plus en plus important sur la force et le sens de nos rapports au passé. Dans ce contexte, cet article se propose de réfléchir aux processus d’émergence de nouveaux objets patrimoniaux et aux conséquences de ces mobilisations. Il s’appuie sur l’analyse comparée de deux objets symétriques et tous deux patrimonialisés : la grotte Chauvet et le viaduc de Millau. En montrant que chaque objet est projeté dans la dimension spatiale ou temporelle dont il se trouve a priori exclu lors de son invention, l’analyse rappelle la nécessité d’intégrer une approche patrimoniale à notre lecture des dynamiques territoriales. Elle propose alors l’idée que ces mouvements croisés représentent une reconstruction d’un espace-temps maitrisé, nécessaire pour répondre au problème renouvelé de notre société : sa durabilité.The multiplication of objects, actors and underlying rationales of heritage development, or patrimonialisation, is increasingly blurring the strength and meaning of our relationship with the past. The aim of this article is to reflect on the processes involved in the emergence of new heritage objects and on the consequences of these developments. The article is based on a comparative analysis of two symmetric objects, both of which have been the subject of heritage development processes: the Chauvet cave and the Millau viaduct in Southern France. By showing that each object is projected in the spatial or temporal dimension from which it was a priori excluded at the time of its discovery, the analysis demonstrates the necessity of integrating a heritage approach to our understanding of territorial dynamics. The analysis suggests that the interplay of territorialisation and heritage development processes represents a reconstruction of a controlled time-space, a prerequisite for addressing a recurring problem

  10. Reorganising space and time:

    Directory of Open Access Journals (Sweden)

    Nicolas Senil

    2011-07-01

    Full Text Available The multiplication of objects, actors and underlying rationales of heritage development, or patrimonialisation, is increasingly blurring the strength and meaning of our relationship with the past. The aim of this article is to reflect on the processes involved in the emergence of new heritage objects and on the consequences of these developments. The article is based on a comparative analysis of two symmetric objects, both of which have been the subject of heritage development processes: the Chauvet cave and the Millau viaduct in Southern France. By showing that each object is projected in the spatial or temporal dimension from which it was a priori excluded at the time of its discovery, the analysis demonstrates the necessity of integrating a heritage approach to our understanding of territorial dynamics. The analysis suggests that the interplay of territorialisation and heritage development processes represents a reconstruction of a controlled time-space, a prerequisite for addressing a recurring problem in our society, that of its sustainability.La multiplication des objets, des acteurs et des logiques de la patrimonialisation génère un brouillage de plus en plus important sur la force et le sens de nos rapports au passé. Dans ce contexte, cet article se propose de réfléchir aux processus d’émergence de nouveaux objets patrimoniaux et aux conséquences de ces mobilisations. Il s’appuie sur l’analyse comparée de deux objets symétriques et tous deux patrimonialisés : la grotte Chauvet et le viaduc de Millau. En montrant que chaque objet est projeté dans la dimension spatiale ou temporelle dont il se trouve a priori exclu lors de son invention, l’analyse rappelle la nécessité d’intégrer une approche patrimoniale à notre lecture des dynamiques territoriales. Elle propose alors l’idée que ces mouvements croisés représentent une reconstruction d’un espace-temps maitrisé, nécessaire pour répondre au probl

  11. Multidisciplinary Geo-scientific Hazard Analyses: Istanbul Microzonation Projects

    Science.gov (United States)

    Kara, Sema; Baş, Mahmut; Kılıç, Osman; Tarih, Ahmet; Yahya Menteşe, Emin; Duran, Kemal

    2017-04-01

    microzonation are used in land development/use plans, hazard identification in urban transformation, determination of the routes and characteristics of various types of engineering structures such as highways, tunnels, bridges, railroads, viaducts and ports. Hence, by the use of detailed geo-scientific analyses, basics of earthquake resilient urbanization is guaranteed.

  12. El túnel del Tyne – Inglaterra

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    Mott, Hay and Anderson, Ingenieros

    1970-06-01

    Full Text Available The Tyne Tunnel, which runs under the river Tyne, is the most important project of its type in Britain. It is 1,676 m long, has an inner diameter of 9.46 m, a useful width of 7.32 m and a free height of 4.88 m. It contains a two directional roadway. There are two smaller, lateral tunnels, parallel to the main one, to provide communication for pedestrians and cyclists. These served also, in a certain sense, as pilot tunnellings, to study the soil and forestall the difficulties that would develop on excavating the main opening. The tunnel was excavated by means of a compressed air system. The approach roads have a total length of 4.8 km and are 7.32 m wide, but they can be widened to 10.97 m, if needed. It was necessary to build three bridges over railway lines; one viaduct and three overpasses over roadways. The ventilation, illumination and other services of the tunnel have been very carefully planned and the project is fitted with all modern devices.El túnel del Tyne, que atraviesa el río del mismo nombre, es el más importante de su clase en Gran Bretaña. Sus dimensiones son: longitud, 1.676,4 m; diámetro interior, 9,456 m; anchura total, 7,315 m; altura libre mínima, 4,877 m. Alberga una carretera con dos sentidos de circulación. Hay dos túneles menores, paralelos al principal, destinados a ciclistas y peatones, que sirvieron, en cierto modo, de túneles piloto, permitiendo reconocer el terreno y prevenir las dificultades que aparecerían al excavar el grande. Fue excavado mediante un sistema de aire comprimido. Las carreteras de acceso suman un total de 4,8 km, con una anchura de 7,315 m, ampliable a 10,973 en caso de necesidad. Fue preciso construir tres puentes sobre ferrocarril, un viaducto y tres puentes de carretera. La ventilación, iluminación, servicios, etc., han sido muy cuidados.

  13. A case study of interior low-frequency noise from box-shaped bridge girders induced by running trains: Its mechanism, prediction and countermeasures

    Science.gov (United States)

    Zhang, Xun; Li, Xiaozhen; Hao, Hong; Wang, Dangxiong; Li, Yadong

    2016-04-01

    A side effect of high-speed railway and urban rail transit systems is the associated vibration and noise. Since the use of concrete viaducts is predominant in railway construction due to scarce land resources, low-frequency (20-200 Hz) structure-radiated noise from concrete bridges is a principal concern. Although it is the most commonly used bridge type, the mechanism of noise emission from box-shaped bridge girders when subjected to impact forces from moving trains, which sounds like beating a drum, has not been well studied. In this study, a field measurement was first made on a simply-supported box-shaped bridge to record the acceleration of the slabs and the associated sound pressures induced by running trains. These data indicated that a significant beat-wave noise occurred in the box-shaped cavity when the train speed was around 340 km/h, which arose from the interference between two sound waves of 75.0 Hz and 78.8 Hz. The noise leakage from the bridge expansion joint was serious and resulted in obvious noise pollution near the bridge once the beat-wave noise was generated in the cavity. The dominant frequency of the interior noise at 75.0 Hz was confirmed from the spectrum of the data and the modal analysis results, and originated from the peak vibration of the top slab due to resonance and the first-order vertical acoustic mode, which led to cavity resonance, amplifying the corresponding noise. The three-dimensional acoustic modes and local vibration modes of the slab were calculated by using the finite element method. A simplified vehicle-track-bridge coupling vibration model was then developed to calculate the wheel-rail interaction force in a frequency range of 20-200 Hz. Numerical simulations using the boundary element method confirmed the cavity resonance effect and the numerical results agreed well with the data. Based on the calibrated numerical model, three noise reduction measures, i.e., adding a horizontal baffle in the interior cavity, narrowing

  14. El puente de Saint-Nazaire - Saint-Brévin – Francia

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    Editorial, Equipo

    1976-05-01

    Full Text Available As a consequence of the industrial and tourist development of the region, it was necessary to construct a bridge across the Loire taking into account conditions such as the geological nature of the Loire river bed, the passing of up to 200,000 t oil tankers and other factors which were of utmost importance for the design and the subsequent construction. The work consist of two access viaducts and the central metal bridge. The viaduct, the outlines of which are curved in mutually opposite senses, are of prestressed concrete. They are made up equal spans, each of which has a length of 50.70 m between the pile axes, with in all 22 on the north side and 30 on the south side. Each span consists of: 4 prefabricated girders which are joined at the ends by tie members; between the girders there is a 0.50 cm thick fill layer, over which there is a reinforced concrete slab. The supporting piers, also of reinforced concrete, have a foundation of piles which generally speaking rest on the rocky substratum of the riverbed. The metal part rests upon two main piers, situated on either side, with same type of foundation as mentioned above. On these are located inverted V-shape pylons, with a short vertical element, to which the cables that support the centre bridge deck are anchored, formed by 96 m and 16 m long spans, welded together after having been lifted to their final level. This project —the greatest in France and the one that has the greatest clear span among the works of this kind— has required three years of work utilizing the most modern techniques and systems. More than 80,000 m2 of concrete and more than 17,000 t of different kinds of steel have been used.Como consecuencia del desarrollo industrial y turístico de la región, fue preciso construir un puente sobre el Loira, contando con condicionantes tales como la naturaleza geológica del lecho del Loira, el paso de petroleros de hasta 200.000 t, y otros factores que influyeron grandemente

  15. Deformation Monitoring of Motorway Underpasses Using Laser Scanning Data

    Science.gov (United States)

    Puente, I.; González-Jorge, H.; Riveiro, B.; Arias, P.

    2012-07-01

    The motorway Ourense - Celanova will become the next years in one of the main roads of inland Galicia (northwest region of Spain) that will connect quickly with the cities of Northern Portugal. This highway is projected as a public - private partnership between the regional government of Xunta de Galicia and the construction companies Copasa SA and Extraco SA. There are currently under construction the 19 km of this road and presents a number of structures as viaducts, overpasses and underpasses. The viaducts are part of the main road, allowing passage of the vehicles at conventional speed. Overpasses are mainly used in the connection of the highway with secondary roads. Moreover, the underpasses are better suited for the passage of wildlife animals, persons or agricultural machinery. The underpass arch-shape structures used for this project consist of two reinforced concrete voussoirs placed on two small concrete walls. For each set of voussoirs there are three joining points, two between the walls and the voussoirs and one between the both voussoirs at the top of the structure. These underpasses suffer significant mechanical stress during construction, because during the backfilling process asymmetric loads are applied to both sides. Thus, it is very important the monitoring of the structure using geodetic techniques as total stations, levels or laser scanners The underpass selected for this study is located at the kilometric point 4.9 of the highway, with a total length of 50.38 m, maximum span of 13.30 m and rise of 7.23 m. Voussoirs has a thickness of 0.35 m and a length of 2.52 m. The small lateral walls exhibit a height of 2.35 m and thickness of 0.85 m. The underpass presents a slope of approximately 4 % and the maximum height of the backfill over the top of the structure is 3.80 m. The foundation consists of a concrete slab arch-shape (curvature opposite the main arch) with a thickness of 0.7 m. The geodetic technology used for the deformation monitoring

  16. DEFORMATION MONITORING OF MOTORWAY UNDERPASSES USING LASER SCANNING DATA

    Directory of Open Access Journals (Sweden)

    I. Puente

    2012-07-01

    Full Text Available The motorway Ourense – Celanova will become the next years in one of the main roads of inland Galicia (northwest region of Spain that will connect quickly with the cities of Northern Portugal. This highway is projected as a public – private partnership between the regional government of Xunta de Galicia and the construction companies Copasa SA and Extraco SA. There are currently under construction the 19 km of this road and presents a number of structures as viaducts, overpasses and underpasses. The viaducts are part of the main road, allowing passage of the vehicles at conventional speed. Overpasses are mainly used in the connection of the highway with secondary roads. Moreover, the underpasses are better suited for the passage of wildlife animals, persons or agricultural machinery. The underpass arch-shape structures used for this project consist of two reinforced concrete voussoirs placed on two small concrete walls. For each set of voussoirs there are three joining points, two between the walls and the voussoirs and one between the both voussoirs at the top of the structure. These underpasses suffer significant mechanical stress during construction, because during the backfilling process asymmetric loads are applied to both sides. Thus, it is very important the monitoring of the structure using geodetic techniques as total stations, levels or laser scanners The underpass selected for this study is located at the kilometric point 4.9 of the highway, with a total length of 50.38 m, maximum span of 13.30 m and rise of 7.23 m. Voussoirs has a thickness of 0.35 m and a length of 2.52 m. The small lateral walls exhibit a height of 2.35 m and thickness of 0.85 m. The underpass presents a slope of approximately 4 % and the maximum height of the backfill over the top of the structure is 3.80 m. The foundation consists of a concrete slab arch-shape (curvature opposite the main arch with a thickness of 0.7 m. The geodetic technology used for the

  17. The stability of clay using volcanic ash of Mount Sinabung North Sumatera and sugarcane bagasse ash with cbr and uct value

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    Hastuty Ika Puji

    2017-01-01

    Full Text Available Soil is the fundamental material that is extremely as the place of establishment of a structure or construction, both building and road constructions. However, not all soil is well used in the constructions field, as there are several types of soil that are problematic in terms of both the soil bearing capacity and deformation. The clay with carrying capacity and low shear strength needs to stabilized in order to meet the technical requirements to be used as sub grade. The add materials that are typically used for soil stabilization are cement, lime or a mixture of two or three of the added materials. In this study, the added material use volcanic ash of Mount Sinabung at North Sumatera and sugarcane bagasse ash. The purpose of this study was to determine an index value of properties as the result of the addition of 4% volcanic ash and variations in content of bagasse ash on clay and then to determine the compressive strength for maximum testing UCT (Unconfined Compression Test and understand the value of CBR (California Bearing Capacity as the consequence of the addition of a stabilizing agent, as well as optimum level of addition of bagasse ash. The result showed that the original soil sample has the water content 12.35%, specific gravity of 2.65, liquid limit of 46.73% and plasticity index of 26.44%. The compressive strength value of 1.38 kg/cm2. Base on the USCS classification, the soil sample including the type CL while base on AASHTO classification, soil samples are include this A-7-6 type. After the soil is stabilized with a wide variety of sugarcane bagasse ash content value obtained the largest unconfined compression test in 4% addition level volcanic ash + 10% sugarcane bagasse ash is equal to 5.1kg/cm2 and the result California Bearing capacity value on the optimal mix of 4% volcanic ash + 4% sugarcane bagasse ash is equal to 13.91%.

  18. Improved Simplified Methods for Effective Seismic Analysis and Design of Isolated and Damped Bridges in Western and Eastern North America

    Science.gov (United States)

    Koval, Viacheslav

    The seismic design provisions of the CSA-S6 Canadian Highway Bridge Design Code and the AASHTO LRFD Seismic Bridge Design Specifications have been developed primarily based on historical earthquake events that have occurred along the west coast of North America. For the design of seismic isolation systems, these codes include simplified analysis and design methods. The appropriateness and range of application of these methods are investigated through extensive parametric nonlinear time history analyses in this thesis. It was found that there is a need to adjust existing design guidelines to better capture the expected nonlinear response of isolated bridges. For isolated bridges located in eastern North America, new damping coefficients are proposed. The applicability limits of the code-based simplified methods have been redefined to ensure that the modified method will lead to conservative results and that a wider range of seismically isolated bridges can be covered by this method. The possibility of further improving current simplified code methods was also examined. By transforming the quantity of allocated energy into a displacement contribution, an idealized analytical solution is proposed as a new simplified design method. This method realistically reflects the effects of ground-motion and system design parameters, including the effects of a drifted oscillation center. The proposed method is therefore more appropriate than current existing simplified methods and can be applicable to isolation systems exhibiting a wider range of properties. A multi-level-hazard performance matrix has been adopted by different seismic provisions worldwide and will be incorporated into the new edition of the Canadian CSA-S6-14 Bridge Design code. However, the combined effect and optimal use of isolation and supplemental damping devices in bridges have not been fully exploited yet to achieve enhanced performance under different levels of seismic hazard. A novel Dual-Level Seismic

  19. Safety diagnosis: are we doing a good job?

    Science.gov (United States)

    Park, Peter Y; Sahaji, Rajib

    2013-03-01

    Collision diagnosis is the second step in the six-step road safety management process described in the AASHTO Highway Safety Manual (HSM). Diagnosis is designed to identify a dominant or abnormally high proportion of particular collision configurations (e.g., rear end, right angle, etc.) at a target location. The primary diagnosis method suggested in the HSM is descriptive data analysis. This type of analysis relies on, for example, pie charts, histograms, and/or collision diagrams. Using location specific collision data (e.g., collision frequency per collision configuration for a target location), safety engineers identify (the most) frequent collision configurations. Safety countermeasures are then likely to concentrate on preventing the selected collision configurations. Although its real-world application in engineering practice is limited, an additional collision diagnosis method, known as the beta-binomial (BB) test, is also presented as the secondary diagnosis tool in the HSM. The BB test compares the proportion of a particular collision configuration observed at one location with the proportion of the same collision configuration found at other reference locations which are similar to the target location in terms of selected traffic and roadway characteristics (e.g., traffic volume, traffic control, and number of lanes). This study compared the outcomes obtained from descriptive data analysis and the BB test, and investigates two questions: (1) Do descriptive data analysis and the BB tests produce the same results (i.e., do they select the same collision configurations at the same locations)? and (2) If the tests produce different results, which result should be adopted in engineering practice? This study's analysis was based on a sample of the most recent five years (2005-2009) of collision and roadway configuration data for 143 signalized intersections in the City of Saskatoon, Saskatchewan. The study results show that the BB test's role in diagnosing

  20. Resilient modulus of black cotton soil

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    K.H. Mamatha

    2017-03-01

    Full Text Available Resilient modulus (MR values of pavement layers are the basic input parameters for the design of pavements with multiple layers in the current mechanistic empirical pavement design guidelines. As the laboratory determination of resilient modulus is costly, time consuming and cumbersome, several empirical models are developed for the prediction of resilient modulus for different regions of the world based on the database of resilient modulus values of local soils. For use of these relationships there is a need to verify the suitability of these models for local conditions. Expansive clay called black cotton soil (BC soil is found in several parts of India and is characterized by low strength and high compressibility. This soil shows swell – shrink behaviour upon wetting and drying and are problematic. The BC soil shows collapse behaviour on soaking and therefore the strength of the soil needs to be improved. Additive stabilization is found to be very effective in stabilizing black cotton soils and generally lime is used to improve the strength and durability of the black cotton soil. In this paper, the results of repeated load tests on black cotton soil samples for the determination of MR under soaked and unsoaked conditions at a relative compaction levels of 100% and 95% of both standard and modified proctor conditions are reported. The results indicate that the black cotton soil fails to meet the density requirement of the subgrade soil and shows collapse behaviour under soaked condition. To overcome this, lime is added as an additive to improve the strength of black cotton soil and repeated load tests were performed as per AASHTO T 307 - 99 for MR determination. The results have shown that the samples are stable under modified proctor condition with MR values ranging from 36 MPa to 388 MPa for a lime content of 2.5% and curing period ranging from 7 to 28 days. Also, it is observed that, the CBR based resilient modulus is not in agreement

  1. Stabilisation of Clay Soil with Lime and Melon Husk Ash for use in Farm Structures

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    I. S. Mohammed

    2014-08-01

    Full Text Available The rising cost of traditional stabilising agents and the need for economical utilisation of industrial and agricultural waste for beneficial engineering purposes has encouraged an investigation into the stabilization of clay soil with lime and melon husk ash. The chemical composition of the melon husk ash that was used in stabilising clay soil was determined. The clay soil was divided into two parts, one part was used to determine the index properties while the other part was treated at British Standard Light (BSL compaction energy with 0 %, 2 %, 4 %, 6 % and 8 % melon husk ash by dry weight of the soil and each was admixed with 2 %, 4 %, 6 % and 8 % lime. The stabilised clay soil was cured for 7, 14 and 28 days before the unconfined compressive strength were determined while the coefficients of permeability of the stabilised clay soil were also determined at 28 days of curing. The data obtained from the experiment was subjected to analysis of variance to examine the significance at 5% level. Results showed that the natural clay soil belong to A-7-6 or CH (clay of high plasticity in the American Association of State Highway Transportation Official (AASHTO and Unified Soil Classification System (1986. The chemical composition of the ash had aluminum oxide, iron oxide and silicon dioxide values of 18.5%, 2.82% and 51.24% respectively. The unconfined compressive strength and coefficient of permeability of the natural clay soil was determined to be 285 kN/m2 and 1.45 x 10-5 cm/s, respectively. Increase in melon husk ash and lime percent increases the unconfined compressive strength (UCS of the stabilised clay soil significantly (p < 0.05 and decrease the coefficient of permeability when compared with the natural clay soil. The peak values of unconfined compressive strength for 7, 14 and 28 days of curing are 1200 kN/m2, 1598 kN/m2 and 1695 kN/m2 respectively at 6% MHA and 8% lime content while the lowest value for coefficient of permeability was 0

  2. On the Need for Reliable Seismic Input Assessment for Optimized Design and Retrofit of Seismically Isolated Civil and Industrial Structures, Equipment, and Cultural Heritage

    Science.gov (United States)

    Martelli, Alessandro

    2011-01-01

    laterally is sufficient to create a structural gap compatible with the design displacement, overestimating this displacement may lead to unnecessarily renouncing of the use of such a very efficient method, especially in the case of retrofits of existing buildings. Finally, for long structures (e.g. several bridges or viaducts and even some buildings) an accurate evaluation of the possibly different ground displacements along the structure is required (this also applies to conventionally built structures). In order to overcome the limits of PSHA, this method shall be complemented by the development and application of deterministic models. In particular, the lack of displacement records requires the use of modelling, once they are calibrated against more commonly available velocity or acceleration records. The aforesaid remarks are now particularly important in the P.R. China and Italy, to ensure safe reconstruction after the Wenchuan earthquake of May 12, 2008 and the Abruzzo earthquake of April 6, 2009: in fact, wide use of SI and other anti-seismic systems has been planned in the areas struck by both events.

  3. El viaducto de San Giuliano, en Italia

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    Cestelli Guidi, Carlo

    1965-10-01

    Full Text Available This viaduct is part of the Sun Roadway, along the western coast of Italy. It is a reinforced concrete structure, with prestressed girders. It runs over a deep ravine, through which water flows intermittently into the Tiber river, a little below the bridge. As the hillside is not highly stable, the possibility of building a large arch was excluded, since the thrusts at the springers would be large. The total length to be bridged, 376 m, has been divided into three approach spans, each 32 m long, on one side, a further five spans, of similar length, on the other side, and a central 100 m long span. The remaining 20 m are taken up with the width of the piles. The project consists of two independent, twin bridges, since there is a separate structure for each of the two traffic directions. The width of each runway is 7.50 m. The planform of the bridge is S shaped, with a central straight section of 106 m length, and a maximum height of 74 m. The piles, of great height, are hollow columns, of rectangular cross section, and concreted by means of sliding formwork. The central span is the most Important feature of the project. It constitutes a portal fram .together with the two supporting piles. These slope towards the centre of the span. The intrados is arched shaped, and the extrados is the deck itself. The attachment of this central span with the springers is through hinged joints, consisting of reinforced neoprene plates. The straight sections of the bridge, of 32 m length, have been spanned with prestressed, prefabricated beams.Este viaducto, en la Autopista del Sol (Italia, es de hormigón armado con vigas pretensadas. Salva una vaguada profunda de aguas intermitentes que se unen al río Tíber en las proximidades del puente. Como las laderas de apoyo tienen poca consistencia se excluyó la solución de un arco de gran luz, dada la importancia del empuje en estos casos. Su longitud total es de 376 m, divididos en tres tramos de acceso de 33 m de

  4. The Concept of Limitation of the Vibration Generated by Rail-Vehicles at Railway Stations and Railway Crossings

    Science.gov (United States)

    Adamczyk, Jan; Targosz, Jan

    2011-03-01

    One of the possibilities of limitation of effects of dynamic influence of the rail-vehicles is the application of the complex objects of vibroinsulation when the mass of the vibroinsulating element is significant, and that is the case of the transporting machines and devices, when the geometric dimensions of the elements of vibroinsulation system are similar to the slab, where the process of modelling of the vibroinsulation mechanism as a discrete system, creates extreme hazards. The article presents the concept of limitation of effects of dynamic influence of the rail-vehicles and tram-vehicles, mainly in the railway tracks located at the railway stations, tram-stops and other engineering structures. The digital model was developed for simulation regarding the propagation of the vibration to the environment. The results of simulation were the basis for development of the vibroinsulation system for the rail-tracks located at the engineering structures such as railway stations, viaducts. The second part of the article presents the approach for controlling of the tension as a function of load of the railway crossing, which was modelled as discrete-continous model. The continuous systems consist of two elements, that is of the support made of elastomer and of the tension members with controlled tension depending on the crossing load. Together with development and more popular application of tension member systems in engineering structures, among others in vibroinsulation systems, it is important to include into calculations and experiments the dynamic loads of the tension member with the mass attached to it. In case of complex objects of vibroinsulation when the mass of the vibroinsulator is significant, and that is the case of the transporting machines and devices, when the geometric dimensions of the elements of vibroinsulation system are similar to the slab, where the process of modelling of the vibroinsulation mechanism as a discrete system, creates extreme

  5. Vulnerabilidad sísmica y capacidad de carga de un puente atirantado basados en confiabilidad estructural Seismic vulnerability and loading capacity of a wire strained bridge based on structural reliability

    Directory of Open Access Journals (Sweden)

    Edgar Muñoz

    2010-08-01

    Full Text Available Se presenta en este documento los análisis de vulnerabilidad sísmica y de capacidad de carga del Viaducto Cesar Gaviria Trujillo, empleando las técnicas de confiabilidad estructural basada en las labores de instrumentación. En él se incluye labores tales como: ensayos geofísicos, ensayos de las propiedades mecánicas de materiales, vibraciones ambiéntales, medición de los efectos de la cargas vehiculares, instrumentación inalámbrica, pruebas de carga, medición de tensiones de tirantes, etc. También se explican los modelos estructurales en elementos finitos desarrollados para el puente y su proceso de calibración basado en la prueba de carga y las propiedades dinámicas determinadas experim en taimen te. Además la forma como se realizó la reconstrucción de las historias de esfuerzos de todos los elementos estructurales durante su construcción, de acuerdo con la bitácora de obra. Para los análisis de confiabilidad se hizo un estudio de amenaza sísmica y respuesta dinámica del sitio del puente, donde se obtuvieron nueve espectros de respuesta con diferentes periodos de retorno. Al estudiar las curvas de probabilidad de resistencia y solicitaciones sísmicas de los pilones, se encontró que tienen unos índices de confiabilidad adecuados dentro de las recomendaciones de las normas internacionales. Además que uno de los elementos de la superestructura que se instrumentó para evaluar su capacidad para los efectos de tráfico, tiene un índice de confiabilidad por fuera de los rangos sugeridos por las normas internacionales. Finalmente algunos tirantes tienen niveles de tensiones mayores a las admisibles especificadas durante su diseño y a las recomendadas internacionalmente para este tipo de puentes.This document presents the analysis of seismic vulnerability and load capacity for Cesar Gaviria Trujilo Viaduct, by means of structural reliability techniques based on instrumentation works. Such study includes: geophysical trial

  6. SISTEMA DE PESAGEM EM MOVIMENTO – WIM: INSTALAÇÃO E CALIBRAÇÃO EM PISTA EXPERIMENTAL PARA MONITORAMENTO E CLASSIFICAÇÃO DO ESPECTRO DE CARGAS RODANTES DA BR-290/RS - FREEWAY

    Directory of Open Access Journals (Sweden)

    Lelio Brito

    2014-08-01

    Full Text Available O tráfego de veículos representa um dos importantes papéis no dimensionamento de pavimentos bem como no desempenho da sua vida útil. Métodos empíricos, como o atualmente vigente no Brasil, especificado pelo IPR-719 do DNIT consideram o tráfego de projeto a partir de um “eixo padrão rodoviário”, no qual as configurações e magnitudes de cargas de eixo são convertidas em um número equivalente de solicitações de carga padrão – hoje um eixo simples de rodas duplas (ESRD com 80kN, através de fatores de equivalência de carga. Métodos de dimensionamento mais atuais, como AASHTO 2002, caracterizam o trafego através de espectros de carga por eixo; para isto é necessário que sejam determinados os vários tipos de carregamentos e suas magnitudes para caracterização do tráfego rodante. O uso de sistema de pesagem em movimento, conhecidos como “Weigh-in-motion”, são equipamentos que permitem a determinação do peso dos eixos rodantes em vias em serviço a velocidade operacional da via; estes equipamentos associados a classificadores de tráfego, permitem a completa classificação do espectro de cargas nas rodovias. Este estudo investigou a sensibilidade de um sistema de pesagem em movimento através de sua implantação em uma pista experimental através do Simulador de Tráfego DAER/UFRGS na Universidade Federal do Rio Grande do Sul para avaliar a acurácia deste sistema e suas limitações com vistas à implantação posterior em uma via em serviço na BR-290/RS. Com os resultados obtidos foi possível estabelecer um protocolo de instalação e coleta de dados para futura instalação em campo e verificar a sensibilidade dos sistemas em condições características do estado. Os resultados mostraram uma variação de até 57% nas leituras de carga para variação uma variação de 17°C na temperatura do pavimento e também sensibilidade da carga em função do posicionamento do rodado na seção transversal do

  7. Geotechnical and geochemical assessments of shales in Anambra basin, SE-Nigeria as compacted clay liner in landfill system

    International Nuclear Information System (INIS)

    Tijani, Moshood N.; Adesina, Rasheed B.; Wagner, Jean-Frank

    2012-01-01

    Document available in extended abstract form only. A major constraint to the development of properly engineered landfills is the high cost of synthetic liners and its scarcity in the local markets in developing country like Nigeria, which calls for alternative local materials for landfill liner. Consequently, crushed shale / clay shale deposits appear inexpensive and can be utilized to effectively retard the spread of leachate from landfills. Hence, this study focus on the assessment of geotechnical, geochemical and sorption characteristics of shale units from Anambra Basin, SE-Nigeria for suitability or otherwise as compacted clay liner (CCL) in landfills. Twelve samples consisting of three each from four different formations namely: Enugu, Nkporo, Imo and Ameki formations were collected and subjected to basic geotechnical tests such as grain size analysis, Atterberg's limits, compaction and coefficient of permeability following standard testing methods (BS 1377). In addition, mineralogical X-ray Diffraction (XRD) and geochemical ICP-MS / ICP-ES analyses were employed for geochemical characterization. CEC and batch sorption tests with respect to Pb, Ni, Cd, Cu and Zn as contaminant in leachates were also employed for sorption characterization. The results of the geotechnical tests conducted on the shale samples revealed that the crushed shale samples have liquid limit range of 55-79%, percentage fines of 80-93%, percentage clay of 23- 36% and activity of 0.8-2.1, all of which satisfy the basic requirements of clay liners according to the specifications of Daniel, 1993. Samples from Enugu, Nkporo and Imo shale have plasticity index range of 40- 54% which is above the recommended limit of 35% and thus likely to exhibit excessive shrinkage and settlement. However, the laboratory compaction shows maximum dry density of 16.8-18.4 kN/m 3 and 17.3- 19.1 kN/m 3 respectively for Standard Proctor and Modified AASHTO energy levels which suggests no significant change the

  8. Coeficiente de fricción por curvatura no intencional en concreto postensado

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    Diego Ernesto Dueñas Puentes

    2007-09-01

    Full Text Available En el presente artículo se establece un coeficiente de fricción por curvatura no intencional (K para puentes de placa y vigas y puentes por voladizos sucesivos a partir de los registros de tensionamiento de algunos puentes postensados construidos en Colombia, el cual es inferior al empleado habitualmente en el diseño de puentes pos-tensados en el país y establecido por el Código Colombiano de Diseño Sísmico de Puentes (CCDSP publicado por el Instituto Nacional de Vías en 1995. Este estudio parte del hecho de que en algunas importantes obras se obtienen alargamientos de torones mayores a los estimados teóricamente, puentes de los cuales se dispone de registros de tensionamiento y de los que se deducen valores de coeficientes más cercanos a los indicados por las últimas ediciones de la Standard Specifications for Highway Bridges, publicada por American Association of State Highway and Transportation Officials “AASHTO”. En Colombia, el CCDSP, considera un coeficiente de fricción por curvatura no intencional (K para cables, con valores entre 0.0050 y 0.00066 m-1, dependiendo del material del que esté fabricado el ducto (acero galvanizado, sin galvanizar, metal brillante, valor superior al encontrado en este trabajo. En este artículo, en primer lugar, se realiza una breve descripción del efecto de fricción a lo largo de los cables, presentando los diferentes valores de coeficientes de fricción indicados en el CCDSP y en “AASHTO.”, en el diseño de puentes preesforzados. Se hace una corta descripción de cada uno de los puentes de los cuales se tienen registros de tensionamiento con el fin de identificar otras variables que intervienen en el proceso de ten-sionamiento como materiales, equipos y mano de obra, y posteriormente, a partir de la validación y tabulación de datos registrados en obra (registros en los cuales se controla la fuerza aplicada y el alargamiento de los torones, se efectuó la evaluación del coeficiente

  9. Viaducto sobre el río Fiumarella, Italia

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    Morandi, Riccardo

    1964-04-01

    Full Text Available The viaduct over the Fiumarella river, which links Catanzaro and the Two Seas lines of communication, has recently been opened to the public. The central arch has a theoretical span of 231 m and a maximum rise of 62 m. It bridges a river, and is made of reinforced concrete. The cross section is a hollow rectangle. The arch supports a palisade of inclined, slender columns, upon which rests the deck. This is sufficiently wide to accommodate a pavement, 10.5 m wide, and two sidewalks, each 1.5 m wide. This project is remarkable because of the slender, logical design of each of its structural components, and also because the columns have a slope of 15° 30' with respect to the vertical. This inclination causes the columns to transmit to the outer surface of the arch loading components which tend to improve the stability of the bridge. Near the springers, the arch branches out into two legs, which at the base are distanced 22 m apart. This arrangement gives a better distribution of the loads on the foundations. The central span consists of two independent arches, the box section of which is 7.5x6.6 m at the springers, and 5.25x2 m at the crown. The neutral axis of the arch, whose total length is 274 m, corresponds to a fifth degree curve, such that at many points it is coincident with the funicular of forces due its own weight. Only at certain points is there some discontinuity, due to the concentrated loads and the corrections which have been applied to allow for the elastoplastic deformation of the material.El viaducto sobre el río Fiumarella, que constituye la unión entre Catanzaro y la vía de comunicación de Los dos Mares (Italia, ha entrado recientemente en servicio. El tramo central, de 231 m de luz teórica y 62 m de flecha, salva, el río con un arco de hormigón armado, de sección transversal hueca, formando una estructura tipo cajón. Este arco, junto con una serie de soportes inclinados, esbeltos, soportan el tablero de anchura

  10. Classificação tecnológica de solos e resíduos industriais, com e sem tratamento térmico, para fins rodoviários Technological classification of soils and industrial residues with and without thermal treatment for forest road pavement

    Directory of Open Access Journals (Sweden)

    Carlos Cardoso Machado

    2003-10-01

    Full Text Available Estudou-se o comportamento mecânico das misturas solo-alcatrão, solo-cal-alcatrão e solo-cimento-alcatrão, com base nos ensaios de limites de liquidez e plasticidade, CBR, compressão simples e permeabilidade, visando a aplicabilidade destas em rodovias. Trabalhou-se com três amostras de solos (ETA, NV e VS, representativos das ocorrências da microrregião de Viçosa-MG. Foram empregados alcatrão, nos quantitativos de 0,25, 0,5, 1, 2, 4 e 6%, cal hidratada e cimento Portland, em conjunto com o alcatrão, na dosagem de 2%, considerando-se a energia do ensaio de compactação AASHTO Normal. A adição de alcatrão reduziu significativamente os valores de LL dos solos, mas com pouca variação nos valores de IP. Conclui-se que o alcatrão contribuiu para melhorar as características mecânicas e hidráulicas dos solos, para alguns tratamentos, não atingindo, entretanto, os padrões de resistência mecânica exigida pelo DNER para camadas de sub-base de pavimentos flexíveis. Quanto às misturas solo-cal-alcatrão e solo-cimento-alcatrão, constatou-se melhoria substancial nos parâmetros de resistência mecânica em relação aos solos, principalmente devido à ação cimentante da cal e do cimento, e que para alguns tratamentos esta ação foi potencializada pelo alcatrão, incidindo em resistência mecânica superior à das misturas solo-cal e solo-cimento. O alcatrão, em alguns tratamentos, ocasionou decréscimos na permeabilidade das misturas, com relação ao solo, de até dez vezes. O alcatrão mostrou ser um estabilizante de interesse para fins rodoviários apenas para determinadas condições, envolvendo tipo de solo e tipo e teor de alcatrão, o que indica que estudos nesta direção devem apresentar uma característica regional.The behavior of the mechanical mixtures soil-wood tar, soil-lime-wood tar and soil-cement-wood tar, based on the Atterberg limits California Bearing Ratio (CBR, Unconfined Compression Strength (UCS and