WorldWideScience

Sample records for twelve-span viaduct aashto

  1. Implementation of the AASHTO pavement design procedures into MULTI-PAVE.

    OpenAIRE

    Bekele, Abiy

    2011-01-01

    This thesis implements the empirical pavement design procedures for flexible as well as rigid pavement by American Association of State Highways and Transportation Officials (AASHTO) into two MATLAB modules of MULTI-PAVE. MULTI-PAVE was developed as a teaching tool that performs pavement thickness design for multiple design procedures using a common input file and a common output format. The AASHTO components were developed in accordance with the 1993 AASHTO Pavement Design Guide, and verifie...

  2. Dynamic test on the Millau viaduct

    OpenAIRE

    Gautier, Y.; MORETTI, O; C. Cremona

    2005-01-01

    In November 2004, the Public Works Regional Laboratory of Lyon has operated dynamic tests on the Millau viaduct. The purpose of these was to identify the modal characteristics as reference values for future monitoring and to compare them to the theoretical values. It was in particular the opportunity to assess the real structural damping. Measurements were carried out in partnership with three companies or institutes : ADVITAM, SITES and CSTB. Excitation was performed by a tended cable fixed ...

  3. 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. PMID:25397962

  4. 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.

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

    Directory of Open Access Journals (Sweden)

    Mesut Tiğdemir

    Full Text Available 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.

  6. Seismic analysis and strengthening of viaduct Ravbarkomanda – Transverse direction

    OpenAIRE

    Vidrih, Zlatko

    2006-01-01

    The knowledge about seismic response of bridges was poor at the time of construction of viaduct Ravbarkomanda. That lead to underestimated earthquake forces and therefore to unsuitable construction details, such as lap splices, situated in the regions of plastic hinges, use of plain reinforcement, insufficient transverse reinforcement and, as in the case of viaduct Ravbarkomanda, transverse reinforcement constructed on the inner side of the longitudinal bars. The main aim of the study was to ...

  7. Seismic performance of viaducts with probabilistic method

    Institute of Scientific and Technical Information of China (English)

    ZHU Xi; WANG Jianmin

    2007-01-01

    Due to the uncertainty of both ground motions and structural capacity,it is necessary to consider the seismic performance of viaduct structures using the probabilistic method.The risk is quantified by a procedure on the basis of a numerical determination of the fragility curves.A group of ground motions,Large Magnitude-Short Distance Bin (LMSR-N),selected specially due to its response spectra,is accorded well with the corresponding spectra of the Chinese code for seismic design.The characteristic values of the curvature ductility factors for the serviceability and the damage control limit states are obtained,and two equations for estimating the characteristic values of the curvature ductility factors are developed through regression analysis.Then,the serviceability and damage control limit states were proposed.Three damage states were constituted according the results of the experiment by Pacific Earthquake Engineering Research (PEER) Center.The analytical fragility curves were obtained specifically,using both Capacity Spectrum Method (CSM) (non-linear static) analysis and Ineremental Dynamic Method (IDM) (non-linear dynamic) analysis,respectively,in this paper.The structural fragility curves developed by CSM method can help make the structural analysis simple and quick,avoiding the implementation of the dynamic response history analysis (RHA).Although the dynamic RHA requires a lot of complicated analysis for the structure,the results from RHA are reliable and accurate.Fragility curves are powerful tools for use in performance-based seismic bridge design.

  8. Site investigations on cavernous limestone for the Remouchamps Viaduct, Belgium

    OpenAIRE

    Waltham, Antony; Vandenven, Georges; Ek, Camille

    1986-01-01

    POOR GROUND CONDITIONS on cavernous limestone created severe difficulties at the sites of four piers of the Remouchamps Viaduct. The discovery, during excavations for foundations, of large open cavities prompted a major re-appraisal of site investigation procedure, and also some redesign of the viaduct structure. La situation défavorable des fondations de quatre des piliers du viaduc autoroutier de Remouchamps posa des problèmes de construction. La présence de cavités karstiques largement ...

  9. 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 th

  10. 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.

  11. 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.

  12. Diseño definitivo comparativo del puente de 60.0 m. de luz sobre el rio Toachi en base a las normas AASHTO estándar y LRFD. : Tomo I

    OpenAIRE

    Prieto Salazar, Juan Carlos; Tipán Aceveso, René Oswaldo

    2012-01-01

    Generalidades. Análisis de estudios preliminares. Diseño estructural (código AASHTO estándar). Aplicación de las normas AASHTO LRFD al diseño estructural de puentes. Diseño estructural (código AASHTO estándar).Presupuesto y programación de obra. Comparación técnico económica. Impacto ambiental. Conclusiones y recomendaciones. Bibliografía

  13. Natural frequencies of a flat viaduct road part simply supported on two ends

    Indian Academy of Sciences (India)

    İsmail Yüksek; Ahmet Çelık; Kayhan Gülez

    2006-02-01

    Viaduct roads have wide application in big cities with high traffic loads, in order to decrease traffic density and to connect subways to highways. Viaduct roads are constructed using steel structures instead of concrete ones in areas of earthquake risks. 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 are supported by six fixed elements of rectangular cross-sectional elements are considered. Natural frequencies are obtained using the Rayleigh–Ritz technique, finite elements analysis, experimentally and neural networks (NN).

  14. Estudio de los criterios de diseño geométrico de las intersecciones a nivel según la AASHTO

    OpenAIRE

    Ochoa Pineda, Emilio José

    2009-01-01

    En Colombia, el diseño y la construcción de una intersección a nivel debe realizarse según las normas del Instituto Nacional de Vías (INVIAS), en el cual se indica información muy conceptual para el diseño y se presentan pocos datos específicos para que el diseñador tenga elementos suficientes de trabajo. En Estados Unidos de Norteamérica, la reglamentación para el diseño de carreteras es suministrada por la American Association of State Highway and Transportation Officials (AASHTO) en el tex...

  15. A theoretical investigation on influences of slab tracks on vertical dynamic responses of railway viaducts

    Science.gov (United States)

    Shi, Li; Cai, Yuanqiang; Wang, Peng; Sun, Honglei

    2016-07-01

    A railway viaduct model consisting of infinite spans of elastically-supported girders carrying a slab track of infinite length is established to investigate the influence of the slabs on the vertical dynamic response of the viaduct, when a moving harmonic point load or a moving sprung wheel is applied. The infinite rail, the discontinuous slabs and girders of identical span lengths are idealized as Euler-Bernoulli beams. The rail fasteners, the cushion layer beneath the slab and the elastic bearings at the girder supports are represented by discretely distributed springs of hysteretic damping. Due to the repetitive nature of the girders, the model can be divided into periodic three-beam units by the span length of the girder, and then solved analytically in the frequency domain using the property of periodic structure. Besides the first natural frequency of the girder with elastic bearings, it is found that the resonance frequency of the slab on the cushion layer has a significant influence on the dynamic response of the track and the girder. Parametric excitations due to the moving wheel periodically passing the discontinuous slabs contribute significantly to the wheel/rail interactions.

  16. Thailand Ranks Second in the World for Number of Road Accidents under Thailand’s Codes of Geometrical Design and Traffic Engineering Concept When Compared with AASHTO

    Directory of Open Access Journals (Sweden)

    Cheewapattananuwong Weeradej

    2016-01-01

    Full Text Available Traffic problems in Bangkok have an influence on road users during peak hours. Especially, the traffic bottleneck on curves under the saturation flow situation must be remedied in order to increase the roadway capacity and speed. However, the appropriate speed for heavy vehicles is taken into consideration during off peak after the increasing lanes. This leads to the Rollover of heavy truck and rear-end collisions which are the main causes of vehicles accidents on curves. In addition, road accidents on curves account for the majority of all accidents in Thailand. According to the road accidents data collected in Thailand, 44 road deaths per 100,000 people, the country ranks second in the world for road accidents. When Thailand’s Code of Geometrical Design is compared with AASHTO (The American Association of State Highway and Transportation Officials, the super elevation length of Thailand’s Code is more than AASHTO. As a result, drivers are not made aware of the appropriate speed and the stooping sight distances (SSD on curves. Therefore, the Design of Traffic Signage under the Perception and Reaction Times (PRT for Thai Drivers will be taken into account.

  17. Análisis estructural comparativo basado en los códigos AASHTO standar y LRFD, caso de estudio puente metálico sobre el Río Pachijal, ubicado en la Provincia de Pichincha.

    OpenAIRE

    Maya Aguirre, Luis Alberto

    2015-01-01

    En el presente trabajo, se expone un análisis estructural comparativo basado en las especificaciones técnicas de los códigos AASHTO STANDARD y AASHTO LRFD (Diseño por Factores de Carga y Resistencia) para el caso de un puente vehicular metálico, para lo cual, se aplicaron las normas vigentes y los conocimientos adquiridos durante el curso de la maestría. En este documento, se hace referencia al tipo de cargas vehiculares que se deben emplear de acuerdo a las disposiciones dadas en cada norma ...

  18. Faixas adicionais para aclives de rodovias de pistas simples brasileiras: uma adaptação dos critérios da AASHTO

    Directory of Open Access Journals (Sweden)

    Ricardo Almeida de Melo

    2009-12-01

    Full Text Available

    Caminhões carregados quando trafegam em aclives reduzem a velocidade de operação e provocam a formação de pelotões, aumentando o custo operacional e o tempo de viagem dos veículos mais rápidos, além de diminuir a segurança de trânsito. Esses problemas são solucionados quando construídas faixas adicionais, que são obras de melhoria de baixo custo de construção e menor impacto ambiental quando comparado à duplicação de rodovias. Com o intuito de propor diretrizes para implantação de faixas adicionais em aclives de rodovias de pista simples brasileiras, este trabalho visou adaptar, às condições de tráfego e veículos nacionais, os critérios estabelecidos no Livro Verde da AASHTO. Os aspectos adaptados às condições brasileiras foram: (i curvas de desempenho de caminhões; (ii redução máxima admissível de velocidade dos caminhões em rampas; e (iii fluxos mínimos de veículos e porcentagens de caminhões que justificam economicamente a construção da faixa adicional.

  19. Optimization of Post-Tensioned Box Girder Bridges with Special Reference to Use of High-Strength Concrete Using AASHTO LRFD Method

    Directory of Open Access Journals (Sweden)

    Byungik Chang

    2012-01-01

    Full Text Available With the Federal Highway Administration-mandated implementation of the LRFD specifications, many state departments of transportation (DOTs have already started implementing LRFD specifications as developed by the AASHTO. Many aspects of the LRFD specifications are being investigated by DOTs and researchers in order for seamless implementation for design and analysis purposes. This paper presents the investigation on several design aspects of post-tensioned box girder bridges designed by LRFD Specifications using conventional or High-Strength Concrete (HSC. A computer spreadsheet application was specifically developed for this investigation. It is capable of analysis, design, and cost evaluation of the superstructure for a cast-in-place post-tensioned box girder bridge. Optimal design of a post-tensioned box girder is achievable by correct selection of design variables. Cost evaluation of superstructures with different geometrical and material configurations has led to the development of optimum design charts for these types of superstructures. Variables used to develop these charts include, among others, span length, section depth, web spacing, tendon profile, and concrete strength. It was observed that HSC enables the achievement of significantly longer span lengths and/or longer web spacing that is not achievable when using normal strength concrete.

  20. Prediction and mitigation analysis of ground vibration caused by running high-speed trains on rigid-frame viaducts

    Science.gov (United States)

    Sun, Liangming; Xie, Weiping; He, Xingwen; Hayashikawa, Toshiro

    2016-03-01

    In this study a 3D numerical analysis approach is developed to predict the ground vibration around rigid-frame viaducts induced by running high-speed trains. The train-bridge-ground interaction system is divided into two subsystems: the train-bridge interaction and the soil-structure interaction. First, the analytical program to simulate bridge vibration with consideration of train-bridge interaction is developed to obtain the vibration reaction forces at the pier bottoms. The highspeed train is described by a multi-DOFs vibration system and the rigid-frame viaduct is modeled with 3D beam elements. Second, applying these vibration reaction forces as input external excitations, the ground vibration is simulated by using a general-purpose program that includes soil-structure interaction effects. The validity of the analytical procedure is confirmed by comparing analytical and experimental results. The characteristics of high-speed train-induced vibrations, including the location of predominant vibration, are clarified. Based on this information a proposed vibration countermeasure using steel strut and new barrier is found effective in reducing train-induced vibrations and it satisfies environmental vibration requirements. The vibration screening efficiency is evaluated by reduction VAL based on 1/3 octave band spectral analysis.

  1. Performance-Based Seismic Design of Bitlis River Viaduct Based on Damage Control Using Seismic Isolation and Energy Dissipation Devices

    Science.gov (United States)

    Dicleli, Murat; Salem Milani, Ali

    2017-06-01

    This paper presents a sample application of seismic isolation techniques in performance-based design of a major viaduct. The Bitlis River viaduct is located in a seismically active region. The targeted performance goal required no damage at 475-year return period earthquake and repairable damage at 2475-year return period earthquake. The bridge is designed with a seismic isolation system composed of spherical bearings and MRSD (Multidirectional Re-centering steel Damper) hysteretic dampers. The MRSD is a recently-developed hysteretic damper with a controllable post-elastic stiffness. To keep the dampers from being activated during the thermal displacements, the attachment of the dampers to the deck are made through elongated holes oriented in the longitudinal direction of the bridge. The gaps are sized based on the amount of expected maximum thermal displacement in each pier. The gap length is thus different for different piers. This means that the number of the dampers to be engaged during an earthquake will depend on the intensity of the displacements. The distinct feature in this design is how it achieves double purpose: (i)preventing the dampers from engagement during service life as a result of thermal displacements and (ii) sequential engagement of the dampers depending on the level of seismically-induced displacements. The paper presents the basic design features of this seismically isolated bridge designed based on performance-based principles, a brief description of the newly-developed damper and a summary of analyses results.

  2. Design and construction of precast PC-slab for the `Tokai Obu viaduct`; Tokai Obu kokakyo ni okeru precast PC yukaban no sekkei to seko

    Energy Technology Data Exchange (ETDEWEB)

    Mizuguchi, K.; Murayama, A. [Japan Highway Public Corporation, Tokyo (Japan); Kitayama, K.; Yamashita, S. [P.S. Corp., Tokyo (Japan)

    1998-03-31

    This paper describes the construction of Toukai Obu viaduct completed in 1997. This viaduct is specified by use of PC slabs, length of 974.5m and design speed of 100km/h, and was constructed aiming at cost reduction and new rational structure. Precast PC (PCa) slabs prestressed in a direction of slab span were produced under severe quality control in a factory. The PCa slabs stocked in a factory were transported by trailer and specific frame to the construction site, and laid on steel bridge girders by crane. An RC loop joint method for PCa slabs was newly adopted as one of the lap splice methods of reinforcing bars which is superior in cost and maintenance to conventional slab connecting methods in a longitudinal direction of bridges with PC steel material. Because of less domestic applications, a cyclic loading fatigue test at fixed points was carried out using a small model to obtain fatigue proof stress and fracture morphology. A moving loading test was also carried out at an actual loading level using full-scale slab specimens to obtain fatigue proof stress and long-span slab behavior. 7 refs., 24 figs., 8 tabs.

  3. 南通通宁大道快速化改造工程高架桥总体设计%A Viaduct General Design of Nantong Tongning Ave. Rapidness Reconstruction Project

    Institute of Scientific and Technical Information of China (English)

    郭俊伟

    2013-01-01

      Nantong Tongning Ave. rapidness reconstruction project is adopting a combined reconstruction plan of viaduct expressway and ground expressway. The standard width of viaduct is 18.5 m. The upper structure of the whole viaduct is adopting inclined web continuous box girder with circular arc and the substructure is adopting vase pier. The whole line of this project is setting up a pair of ramps, 3 foot bridges and 3 ground bridges, and otherwise, a special aseismic design of viaduct has been made about this project.%  南通市通宁大道快速化改造工程,采用高架快速路+地面快速路相结合的改造方案。高架桥标准宽度为18.5 m。高架全线上部结构采用带圆弧的斜腹板连续箱梁,下部结构为花瓶墩。工程全线设1对匝道、3座天桥、3座地面桥;还进行了高架桥抗震专项设计。

  4. 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.

  5. 特殊环境下上跨铁路高架桥关键技术应用研究%The application of Key Technologies to Over-crossing Railway Viaduct in Special Environment

    Institute of Scientific and Technical Information of China (English)

    赵文聘

    2015-01-01

    With reference to the design of Jia-Min viaduct ( Chun-Shen section) , this paper addresses the key technologies employed in Jia-Min viaduct ( Chun-Shen section ) , including the selection of bridge-type, the span layout, “Expansion engineering of Beizhugang river-way underpass the existing Hu-Chun railway, building island in Beizhugang river”,“Steel bent cap girder on both side of Hu-hang passenger dedicated line”,“Presupposed design of key bridge construction technology”,”Transformation of the existing low height T beam bridge jacket box into frame bridge” and “Close range foundation pit enclosure of pier and pile cap on Hu-hang passenger dedicated lines”.%结合嘉闵高架路(春申铁路段)工程设计实例,详细介绍嘉闵高架路(春申铁路段)工程的桥型选择、孔跨布置以及采用的实施“北竹港河道下穿既有沪春铁路扩孔工程+北竹港河中筑岛”方案、“沪杭客运专线两侧桥墩钢盖梁方案”、“桥梁关键施工工艺预设计”、“既有百年低高度T梁桥套箱改造成框架桥方案”及“沪杭客运专线特大桥桥墩承台近距离框架桥基坑围护方案”等关键技术。

  6. THE DESIGN AND CONSTRUCTION OF A SEALED SOUND BARRIER FOR URBAN VIADUCT%城市高架道路全封闭声屏障的设计与施工

    Institute of Scientific and Technical Information of China (English)

    王庭佛; 冯苗锋; 徐剑

    2012-01-01

    为控制高架道路交通噪声的影响,南京市应天大街纬七路西延高架道路上安装了一条总长度764m的全封闭声屏障。该长度的全封闭声屏障在城市高架道路上实施在国内尚属首例。简要介绍该声屏障的工程概况,重点阐述了该声屏障的声学、建筑、结构的设计和施工情况,以供类似工程参考。%This article generally introduces the design and construction of a sealed sound barrier for the viaduct in Nanjing, whose length is 764 m. It also explains the acoustics design, architectural design, the structure design, construction and the main technical problems during the installation.

  7. Programa de Comparaciones Interlaboratoriales que organiza el AASHTO - NIST (AASHTO Materials Reference Laboratory - AMRL para Laboratorios de Ensayos de Asfaltos

    Directory of Open Access Journals (Sweden)

    Jorge Grgich

    2011-04-01

    Full Text Available Un laboratorio debe llevar a cabo periódicamente controles de calidad internos y externos con la finalidad de verificar que sus resultados tienen una precisión y exactitud aceptable y mejorar en conjunto el funcionamiento del mismo. Dentro de los controles externos tenemos:Ensayos de Aptitud Interlaboratorio - " Proficiency Testing". La participación en estos ensayos permite al laboratorio comparar sus resultados frente a los de otros laboratorios que participan en dichos programas. Se expondrá con algunos ejemplos la evaluación de los resultados obtenidos como una manera de comprobar la calidad de los ensayos, y se señalan las medidas que se adoptan de ser necesario. El caso se refiere al Laboratorio de Asfaltos del LATU (Departamento Construcciones, acreditado por UKAS que participa en dicho programa. Mostraremos como se realiza la calificación de los resultados reportados por un laboratorio y presentaremos algunos de los resultados obtenidos a la fecha para los programas en los cuales participamos: AMRL Emulsified Asphalt Proficiency Sample Program AMRL Viscosity Graded Asphalt Cement Proficiency Sample Program AMRL Bituminous Asphalt Proficiency Sample Program

  8. Noise Attenuation Effect of Green Vegetation on Beijing Viaduct Rail Traffic System%北京高架轨道交通沿线绿地噪声衰减效果研究

    Institute of Scientific and Technical Information of China (English)

    王淑芬; 任杰

    2012-01-01

    轨道交通系统沿线绿地可以有效地降低高架轨道交通噪声.选取北京地铁13号线沿线15块绿地进行高架轨道交通噪声测试实验.采用相关性分析方法对绿地噪声净衰减值与6个影响因子进行分析,提出绿地植物配置建议和噪声衰减预测数学模型.实验结果表明:绿地植物群落噪声衰减效果明显,声源高度、绿地宽度、测试点与噪声源的水平距离、植物配置指数、郁闭度和契合度各影响因素与绿地噪声净衰减值的P值分别为0.632、0.538、0.126、0.048、0.024和0.143,植物配置指数和郁闭度呈显著相关性,在降噪绿地设计时应着重考虑绿地的这2个因子.%Green vegetation along the viaduct rail traffic system (VRTS) plays a vital role in the reduction of noise produced by VRTS. An observational trial to obtain practical data is a convinced method. The noise testing experiments were conducted in 15 patches of greenery along Beijing Subway Line 13. Based on the data analysis on correlation between excessive noise attenuation and six factors, suggestions on green plant configuration and the mathematical model to forecast the attenuation effect are worked out. The results showed that green plant community has obvious effect to reduce noise. The SPSS software analysis shows that P value of the correlation coefficient of the height of sound source, the width of greenbelt, the horizontal distance of test point and noise source, plant configuration index, canopy density and fitness are 0.632, 0.538, 0.126, 0.048, 0.024 and 0.143 respectively. Plant disposition index and canopy density showed a significant correlation. Thus, the design of noise reduction greenbelt should consider them.

  9. Vibration Reduction Characteristics of Steel Spring Floating Slab Track in Metro Viaduct%高架钢弹簧浮置板轨道减振特性分析

    Institute of Scientific and Technical Information of China (English)

    韦红亮; 练松良; 周宇

    2012-01-01

    The vibration reduction characteristics of steel spring floating slab track in metro viaduct were analyzed by the finite element method and field test in time domain and frequency domain respectively. The results show that the stiffness and distance span of the damper have a large influence on the top 10 order natural frequency distribution of floating slab, the variation of stiffness and distance span of damper control the vibration reduction effects of floating slab by changing the stiffness per unit length, the vibration level of roof, flange, web and the bottom plate of elevated girder decreased with 11-22 dB, 12-20 dB, 20-30 dB and 12- 21 dB respectively in the range of 25 - 100 Hz when slab is lifted, the vibration levels reduction increases as damper stiffness decreases and as the distance span increases, the stiffness and distance of steel spring almost have no effect on the displacement of elevated girder. The floating slab track has a certain reduction affection on wheel rail noise in the range of 63-2 000 Hz.%分别采用有限元和现场试验方法从时频域角度对高架钢弹簧浮置板轨道结构的减振特性进行了分析.研究结果表明,减振器刚度和间距的改变对浮置板前10阶振动频率分布影响较大,减振器刚度和间距的变化是通过改变浮置板单位长度刚度来达到控制减振效果的目的,浮置板顶升后高架箱梁结构顶板、翼缘、腹板和底板的振动水平在25~100 Hz范围内分别减小11~22 dB,12~20 dB,20~30 dB和12~21dB,减振效果随减振器刚度的增大而减小,随减振器间距的增大而增大,箱梁结构的位移受减振器刚度和间距变化的影响较小;浮置板轨道在63~2 000 Hz范围对轮轨噪声具有一定的降噪效果.

  10. 78 FR 52819 - Environmental Impact Statement: Interstate 81 Viaduct Project (Onondaga County, New York)

    Science.gov (United States)

    2013-08-26

    ... greater Syracuse; and providing transportation solutions that enhance the livability, sustainability, and... held in Syracuse, New York in November 2013; a series of public/stakeholder meetings; a public hearing... Domestic Assistance Program Number 20.205, Highway Planning and Construction. The regulations implementing...

  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. Reorganising space and time: A comparative analysis of the heritage development of the Chauvet cave and the Millau viaduct

    OpenAIRE

    Senil, Nicolas; Sénil, Nicolas

    2011-01-01

    International audience; 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 dev...

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

    Institute of Scientific and Technical Information of China (English)

    冯世敏

    2014-01-01

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

  14. 77 FR 153 - Passenger Train Emergency Systems II

    Science.gov (United States)

    2012-01-03

    ... Association of State Highway and Transportation Officials (AASHTO); American Chemistry Council; American... accessible and identifiable quick-release mechanisms for the exterior doors, removable windows or kick...

  15. 23 CFR 500.106 - PMS.

    Science.gov (United States)

    2010-04-01

    ... process that provides information for use in implementing cost-effective pavement reconstruction, rehabilitation, and preventative maintenance programs and that results in pavements designed to accommodate... the “AASHTO Guidelines for Pavement Management Systems.” 1 1 AASHTO Guidelines for Pavement...

  16. 25 CFR Appendix B to Subpart D - Design Standards for the IRR Program

    Science.gov (United States)

    2010-04-01

    ... Transportation Landscape and Environmental Design. 3. AASHTO Roadside Design Guide, latest edition. 4. AASHTO... 25 Indians 1 2010-04-01 2010-04-01 false Design Standards for the IRR Program B Appendix B to... ROADS PROGRAM Planning, Design, and Construction of Indian Reservation Roads Program Facilities Pt. 170...

  17. 76 FR 34286 - ITS Joint Program Office; Webinar on Connected Vehicle Infrastructure Deployment Analysis Report...

    Science.gov (United States)

    2011-06-13

    ... agencies, and one metropolitan planning organization. Automotive representatives from the Vehicle... in the ITS program in conjunction with their respective stakeholder organizations. The AASHTO Working... weather, and public transportation. Persons planning to attend the webinar should send their full...

  18. Trends in Engineering and Design

    OpenAIRE

    Hamersly, Alan; Cripe, Mary

    2013-01-01

    Trail design and engineering are complex tasks that change as rules and technology change. The discussion in this session will cover design criteria such as drainage, wayfinding signage, road crossings and surface materials. AASHTO standards for trails will also be discussed and analyzed. Good engineering and design can make trails easier to maintain for the future and safer for your users.

  19. 23 CFR 625.4 - Standards, policies, and standard specifications.

    Science.gov (United States)

    2010-04-01

    ...) Accommodation of Utilities, refer to 23 CFR part 645, subpart B. (8) Pavement Design, refer to 23 CFR part 626... TRAFFIC OPERATIONS DESIGN STANDARDS FOR HIGHWAYS § 625.4 Standards, policies, and standard specifications.... (a) Roadway and appurtenances. (1) A Policy on Geometric Design of Highways and Streets, AASHTO...

  20. 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...

  1. 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...

  2. 78 FR 46117 - National Tunnel Inspection Standards

    Science.gov (United States)

    2013-07-30

    ... September of 2009, and is another activity that FHWA conducted in partnership with AASHTO and NCHRP to... on this measure was a little over 24 months (2.05 years). \\11\\ The definition of a highway tunnel..., including tribally and federally owned tunnels. 650.505 Definitions At-grade Roadway. A definition for at...

  3. 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 acquisitio

  4. The North Atlantic Engineers: A History of the North Atlantic Division and its Predecessors in the U.S. Army Corps of Engineers 1775 - 1975

    Science.gov (United States)

    1980-01-01

    military engineers. One of its graduates, Gustave Eiffel , built bridges and viaducts throughout the French Empire and became world famous when he...Division Eastport, ME District , Corps of Engineers Eaton, Col. Charles Ecole Poly technique Edgewood Arsenal , MD Egypt Eiffel , Gustave Eiffel

  5. Electrical pulses protect concrete

    NARCIS (Netherlands)

    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

  6. 76 FR 67020 - Notice of Availability of the Final Environmental Impact Statement: Los Angeles County, CA

    Science.gov (United States)

    2011-10-28

    ... Angeles County, CA AGENCY: Federal Highway Administration (FHWA), DOT. ACTION: Notice of Availability of... Street Viaduct Seismic Improvement Project in Los Angeles County, California. DATES: The comment period... locations: City of Los Angeles Bureau of Engineering, Bridge Improvement Program, 1149 South Broadway,...

  7. Traffic load model based on weigh in motion measurements

    NARCIS (Netherlands)

    Steenbergen, R.D.J.M.; Morales Napoles, O.

    2012-01-01

    The assessment of the structural safety of existing bridges and viaducts becomes increasingly important in many countries. Within the actions applied to the bridges, the traffic load is, in general, the most significant variable action to be considered when the ultimate limit states are under

  8. Calibration of partial factors in the safety assessment of existing concrete slab bridges for shear failure

    NARCIS (Netherlands)

    Steenbergen, R.D.J.M.; De Boer, A.; Van der Veen, C.

    2012-01-01

    The assessment of the structural safety of existing bridges and viaducts becomes increasingly important in many countries due to the age of the structures and an increase in traffic loads. Many structures need to be reassessed in order to find out whether the safety requirements are met. Most existi

  9. 美国的ITS标准化状况

    Institute of Scientific and Technical Information of China (English)

    杨琪; 柏青

    2003-01-01

    @@ 美国的相关标准化组织主要有:AASHTO(美国国家公路和交通管理者协会)、ANSI(美国标准委员会)、ASTM(美国测试和材料协会)、IEEE(电子电气工程师协会)、ITE(交通工程师协会)、SAE(汽车工程师协会)等.

  10. Simplified Pavement Design for LPAs: Introduction to PaveXpress

    OpenAIRE

    2015-01-01

    Simplified Pavement Design for LPA's; An introduction to and use of PaveXpress, a simplified, free, web-based pavement design scoping tool for roadway and parking lot pavements. The system was developed by Pavia Systems in partnership with the National Asphalt Pavement Association. PaveXpress creates technical sound pavement structural designs for flexible and rigid pavements based on widely accepted industry standards from the Association of State Highway Officials (AASHTO). The simplified p...

  11. Field Testing and Load Rating of a Short-Span Thermoplastic Bridge System, Bridge T-8519

    Science.gov (United States)

    2010-11-01

    defined as elastoplastic , meaning it had primarily elastic behavior com- bined with time-dependent fluid properties as well. Allowable stress and...degradation or damage must be considered in future load ratings. ERDC/GSL TR-10-48 38 References AASHTO. 2003. Manual for the condition evaluation... damage or deterioration. Often, bridges are rated poorly because of inaccurate representations of the structural geometry or because the material and/or

  12. Shear Reinforcement Requirements for High-Strength Concrete Bridge Girders

    OpenAIRE

    Ramirez, J. A.; Aguilar, Gerardo

    2005-01-01

    A research program was conducted on the shear strength of high-strength concrete members. The objective was to evaluate the shear behavior and strength of concrete bridge members with compressive strengths in the range of 10 000 to 15 000 psi. The goal was to determine if the current minimum amount of shear reinforcement together with maximum spacing limits in the 2004 AASHTO LRFD Specifications, and the upper limit on the nominal shear strength were applicable to concrete compressive strengt...

  13. Redundancy Evaluation of Fracture Critical Bridges

    OpenAIRE

    Bapat, Amey Vivek

    2014-01-01

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

  14. Simplified Pavement Design for LPAs: Introduction to PaveXpress

    OpenAIRE

    Bonte, Dudley

    2015-01-01

    Simplified Pavement Design for LPA's; An introduction to and use of PaveXpress, a simplified, free, web-based pavement design scoping tool for roadway and parking lot pavements. The system was developed by Pavia Systems in partnership with the National Asphalt Pavement Association. PaveXpress creates technical sound pavement structural designs for flexible and rigid pavements based on widely accepted industry standards from the Association of State Highway Officials (AASHTO). The simplified p...

  15. 基于Creator的城市高架三维模型的构建%Construction of Urban Elevated Road 3D Model Basde on Creator

    Institute of Scientific and Technical Information of China (English)

    王瑞青

    2012-01-01

    目前高架三维模型得到了越来越广泛的应用。基于Multigen Creator(以下简称Creator)构建高架三维模型高效、快捷,所构建的高架三维模型具有良好的真实感。本文简单介绍了利用Creator软件建立三维模型的优点,主要结合郑州市大石桥立交桥三维模型的构建,详细介绍了基于Creator城市高架三维模型的构建的准备工作及其流程。为了更好地说明如何构建,插入了一些附图,并列出了一些构建时的注意事项。%3D Modeling Viaduct of the City was more and more popularity at present.3D Modeling Viaduct of the City Based on Multigen Creator was efficient and rapid,it has good realistic.This article gives a simple introduction of advantages of 3D Modeling Viaduct of the City Based on Creator.The process of 3D Modeling Viaduct was introduced in detail points of attention were presented,combined with model of 3D viaduct of zhengzhou city large stone bridge.In order to explain how to construct,some accompanying diagrams were inserted,points for attention were listed out.

  16. Application of Numerical Simulation and Vibration Measurements for Seismic Damage Assessment of Railway Structures

    Science.gov (United States)

    Uehan, Fumiaki; Meguro, Kimiro

    In this study, the authors discuss methods to assess the future/actual damage to RC structures by using numerical simulations and vibration measurements. First, the applicability of the Applied Element Method (AEM) is examined as an assessment tool for the seismic performance of RC structures with/without retrofit. Cyclic loading tests and seismic response of RC structures are simulated. Next, a method to improve the accuracy of vibration diagnoses of earthquake damaged RC structures is discussed by using damage assessment criteria calculated with the AEM. The AEM could simulate the damage behavior of RC columns, jacketed RC columns and an actual railway viaduct. The change of natural frequencies due to damage to RC columns and an actual railway viaduct with steel jacket were also correctly estimated. Seismic performance check of structures and development of assessment criteria for damage inspection can be effectively done by the AEM.

  17. The use of ALS, botanical, and soil data to monitor the environmental hazards and regeneration capacity of areas devastated by highway construction.

    Science.gov (United States)

    Kopeć, Dominik; Woziwoda, Beata; Forysiak, Jacek; Sławik, Łukasz; Ptak, Agnieszka; Charążka, Edyta

    2016-07-01

    The impact of viaduct construction on the vegetation of a river valley was studied in Central Poland (Natura 2000 site PLH100006). The research aimed at assessing the suitability of ALS (airborne laser scanning), soil, and botanical data for monitoring the environmental effects of right-of-way reclamation 1 year after the road construction. Based on the data mentioned above, the following problems were identified: changes in topography and hydrological conditions of the valley as a result of improper land levelling, the use of inadequate soil for reclamation, no spontaneous regeneration of natural vegetation along the entire right-of-way, as well as the abundant occurrence of invasive species. The results of analysis were used to define strategies for mitigation of adverse impacts of the viaduct construction.

  18. Viaductos Requejo - la Canda - España

    Directory of Open Access Journals (Sweden)

    Llombart, José Antonio

    1976-06-01

    Full Text Available The main masonry works of the stretch Requejo- La Canda of the Access Roads to Galicia are four viaducts that span over deep valleys. The four viaducts have 37 spans each of 32.2 m length. The bridge decks are formed by prefabricated beams, in V section, joined by means of an upper slab made on the site, which in its turn establishes continuity with the adjoining bridge decks. After every third or fourth span expansion joints have been placed. The maximum height of the viaducts is 70 m. The construction of the viaducts has been carried out in quite a short time in spite of the fact that most of it has been undertaken during the winter months, with frequent snow falls and low temperatures, as the site is located in the mountains at a height that varies between 900 m and 1,300 m.Las principales obras de fábrica del tramo Requejo-La Canda de los accesos a Galicia son cuatro viaductos que franquean profundos valles. Existe un total de 37 vanos de 32,20 m de luz, a lo largo de los cuatro viaductos. Los tableros han sido resueltos mediante vigas prefabricadas, de sección en V, unidas por una losa superior construida in situ, que, a su vez, establece la continuidad entre tableros adyacentes. Se han dispuesto juntas de dilatación cada tres o cuatro vanos. La altura máxima de los viaductos es de 70 m. La construcción de los viaductos se ha realizado con gran rapidez, a pesar de haberse desarrollado gran parte de la misma en invierno, con frecuentes nevadas y bajas temperaturas reinantes, por encontrarse la obra en una zona montañosa entre las cotas + 900 y + 1.300 m.

  19. Parking Spoorzone Delft: Addressing expected parking challenges 2015-2017

    OpenAIRE

    Piccot, C.; Groenendijk, L.; Rot, M.; Van der Meijs, P.; Rakers, T.; Negenborn, R.R.; Annema, J.A.; Van Pel, A; Vleugel, J.

    2014-01-01

    This project is carried out on request of the BVOW, the interest group of the neighbourhoods Olofsbuurt and Westerkwartier in Delft, in order to propose solutions for the parking issue of Spoorzone Delft expected between 2015 and 2017. They are worried that parking disturbances will emerge in their neighbourhoods when the parking places of Spoorzone Delft will be removed. Indeed, in 2015 the parking places that are currently situated below the viaduct will disappear due to the removal of the ...

  20. Estudio de mejora y automatización de un simulador de procesos de deformación plástica para la determinación del coeficiente de fricción de aceros

    OpenAIRE

    ROMERO CARRASCO, AITOR

    2015-01-01

    [EN] The department of Mechanical Engineering and Materials has a test bench in the Viaduct building of the Campus of Alcoy, aimed at testing on high hardness steels. These steels are a new step in the safety of vehicles and aircraft, among other applications. The simulator has a limitations that the student must correct with the design and construction of new pieces and elements. Also, he will have to complete its automation system. With the Simulator, it will be possible t...

  1. THE DEGREE OF SILTING AND THE IMPACT ON ALLUVIAL DEPOSITS IN THE RIVER BEDS OF BISTRIŢA RIVER BASIN

    OpenAIRE

    COJOC MARIA GEANINA; ROMANESCU GH.; TIRNOVAN ALINA

    2014-01-01

    Since 1960 the Bistriţa River basin came under the profound influence of anthropic incidence. This river basin represents a pattern of use for hydropower potential: reservoirs (9); channels (61 km); water dams; transfers of flows; protection structures works for banks and slopes; relocation of human settlements (13 villages); gravel pits; galleries; viaducts; communication paths, etc. Bistriţa River development has led to significant changes in the structure of the hydrological regime, throug...

  2. The five-point bending test applied on wearing courses laid on orthotropic steel decks

    OpenAIRE

    Houel, Adrien; Arnaud, Laurent

    2009-01-01

    This paper deals with the evolving behaviour of wearing courses on steel orthotropic decks, such as the French Millau viaduct bituminous mix or an ultra high performance concrete (UHPC) pavement. This is of great importance when dealing with durability. A five-point bending fatigue test was developed since 2003 at the ENTPE laboratory. It enables to test various bituminous concrete mixes. Recent works on UHPC pavements on steel orthotropic decks are considered to improve service life of such ...

  3. 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.

  4. Performance of pile foundation for the civil infrastructure of high speed rail in severe ground subsidence area

    Science.gov (United States)

    Yang, H. W.

    2015-11-01

    In this study, the performance of pile foundation is assessed for the 30 km long viaduct bridge structure seating in the ground subsidence area in the central part of Taiwan. The focus of this paper is placed on the settlement behaviour of a continuous 3-span R. C. viaduct bridge supported on piles adjacent to highway embankment. Monitoring data accumulated over the last 12 years indicate that the observed pace of the settlement of the viaduct structure in other sections matches that of the ground. However, the bridge piers adjacent to the embankment have been suffering an additional approximately 1 cm settlement every year since the completion of the embankment construction. It was believed that the piers may suffer from enormous negative skin friction owing to the surcharge from the embankment and groundwater depression. This paper first summarizes the settlement analysis results to quantify the settlement of pile due to regional ground subsidence and the combined effects from ground water fluctuation and embankment surcharge loading. Accordingly, a loading path on P'-q stress space is formulated to illustrate the loading variation subject to the combined loading effects that can explain why the combined effect becoming significant on settlement control for civil infrastructure in ground subsidence area.

  5. Alternatives to conventional gravel wearing courses on low volume rural roads: Phase 1

    CSIR Research Space (South Africa)

    Paige-Green, P

    2003-01-01

    Full Text Available : • Wages can be negotiated, i.e. that one is not governed by the industry minimum wages. For Limpopo Province the industry minimum is currently about R50/day (~USD7.0). Based on research of acceptable wage rates in the province, a wage of R30/daily task... gravel layers should be compacted to refusal for the plant available and not a specified density. It is necessary, however, that a minimum density is achieved in all cases, preferably 98 per cent of the modified AASHTO maximum dry density. It is thus...

  6. 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.

  7. Refinement of Strut-and-Tie Model for Reinforced Concrete Deep Beams.

    Directory of Open Access Journals (Sweden)

    Mohammad Panjehpour

    Full Text Available Deep beams are commonly used in tall buildings, offshore structures, and foundations. According to many codes and standards, strut-and-tie model (STM is recommended as a rational approach for deep beam analyses. This research focuses on the STM recommended by ACI 318-11 and AASHTO LRFD and uses experimental results to modify the strut effectiveness factor in STM for reinforced concrete (RC deep beams. This study aims to refine STM through the strut effectiveness factor and increase result accuracy. Six RC deep beams with different shear span to effective-depth ratios (a/d of 0.75, 1.00, 1.25, 1.50, 1.75, and 2.00 were experimentally tested under a four-point bending set-up. The ultimate shear strength of deep beams obtained from non-linear finite element modeling and STM recommended by ACI 318-11 as well as AASHTO LRFD (2012 were compared with the experimental results. An empirical equation was proposed to modify the principal tensile strain value in the bottle-shaped strut of deep beams. The equation of the strut effectiveness factor from AASHTTO LRFD was then modified through the aforementioned empirical equation. An investigation on the failure mode and crack propagation in RC deep beams subjected to load was also conducted.

  8. The model of local mode analysis for structural acoustics of box structures

    Science.gov (United States)

    Ngai, King-Wah

    Structure-borne noise is a new noise pollution problem emerging from railway concrete box structures in Hong Kong. Its low frequency noise with intermittent effect can cause considerable nuisance to neighborhoods. The tonal noise peaks in this low frequency range should be one of the important factors in structure-borne noise analysis. In the acoustic field, the deterministic analysis of all the resonant modes of vibration is generally considered as not practical. Many acoustic experts use the statistical energy analysis as the main tool for the noise investigation whereas the application of the experimental modal analysis in the structural acoustic problem is comparatively rare. In the past, most studies mainly focused on the structure-borne noise measurement and analysis. The detail study of the cause of structure-borne noise is lack, especially for the rectangular concrete box structure. In this dissertation, an experimental and analytical approach is adopted to study a typical concrete box model. This thesis aims at confirming the importance of modal analysis in the structure-borne noise study and then at identifying the local vibration modes along the cross-section of box structure. These local modes are responsible for the structure-borne noise radiation. The findings of this study suggest that the web of viaduct cross-section is not as rigid as assumed in the conventional viaduct design and the web face is likely to be more flexible in the vertical displacement of the concrete viaduct. Two types of local vibration modes along the cross-section are identified: the centre mode and the web mode. At the top panel of the viaduct, the centre mode has movement in the middle but not at the edges. The web mode has movement at the edges with the middle fixed. The combined centre and web mode has been found to be important in the structural acoustics of the concrete box structure. In the actual concrete viaduct, the coincidence frequency is especially low (often around

  9. Parametric correlations between experimental results and the base isolation, in situ, structural ones

    Directory of Open Access Journals (Sweden)

    Polidor Bratu

    2014-03-01

    Full Text Available The paper addresses the topic of the inconsistency between experimental, laboratory results for antiseismic devices and the dynamic stiffness, internal damping and dissipation parameters through additional devices. The necessary corrections of the stiffness and dissipation (damping parameters will be presented when the antiseismic devices are equipped to satisfy the adequate functions in a complex structural system (buildings, viaducts, bridges under the conditions of seismic motions characteristic to the Romanian territory. In this context, the kinematic excitation method, compared to the dynamic evaluation method of the vibration dissipation capacity, produced by a seismic shock is shown.

  10. 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

  11. 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.

  12. El viaducto de Boudry

    Directory of Open Access Journals (Sweden)

    Sarrasin, Alexandre

    1963-04-01

    Full Text Available To improve the road traffic between Iverdon and Neuchâtel (Switzerland the layout of the motorway has been modified along the river Areuse Valley: a beautiful valley which is highly attractive to tourists. The village of Boudry is situated in this zone, and the old road used to run through the town. To avoid this, a viaduct and approaches have been constructed. This not only improves the earlier layout, but also greatly facilitates the main road traffic, which no longer interferes with the local vehicles. The viaduct is 500 ms long, and is one of the most important public works recently constructed in Switzerland. The soil did not have a great bearing capacity, and due to the topography, part of the structure, over a distance of 50 ms, rests on a sloping hillside. The viaduct includes various types of spans. Some of them are suitable to accommodate parking spaces underneath, others consist of reinforced concrete beams, and others are made of prestressed concrete members. The main span, 41 ms in length, runs over the river Areuse. In planform the viaduct has a polygonal shape, with rectilinear spans.Con objeto de mejorar la circulación por carretera entre Yverdon y Neuchâtel (Suiza se ha estudiado la modificación del trazado en el trozo correspondiente al valle del río Areuse, pintoresco y con características propias para el turismo. En este valle se encuentra, el poblado de Boudry, cuyo casco urbano era atravesado por la carretera cantonal. Para evitar esta circunstancia se proyectó, después de un detenido estudio, un viaducto y accesos al mismo, que no sólo mejora el trazado primitivo, sino que canaliza el tráfico sin interferir la circulación urbana local. El viaducto, que tiene una longitud total de 500 m, es una de las más importantes obras públicas construidas últimamente en Suiza. El terreno de apoyo no tenía gran capacidad de sustentación, y, dadas las condiciones locales, uno de los tramos se apoya a media ladera, en una

  13. Modelling of pavement materials on steel decks using the fivepoint bending test: thermo mechanical evolution and fatigue damage

    OpenAIRE

    Arnaud, Laurent; Houel, Adrien

    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 improv...

  14. Bridge Influence Line Estimation for Bridge Weigh-in-Motion System

    OpenAIRE

    Ieng, Sio Song

    2015-01-01

    This paper presents an algorithm that estimates the influence line (IL) of a bridge using data collected when trucks pass over the sensors installed in the bridge. The algorithm is tested with data collected from the Millau Viaduct in France using a bridge weigh-in-motion (B-WIM) device. The algorithm uses the maximum likelihood estimation (MLE) and is compared with an old algorithm. The algorithm is more robust because it takes into account many signals for the estimation of the IL.

  15. Prospective ecological risk assessment of sediment resuspension in an estuary.

    Science.gov (United States)

    Rial, Diego; Beiras, Ricardo

    2012-08-01

    This study assesses potential ecological risk of resuspended sediment in the water column during the construction of a viaduct in the estuary of the Ulla river (Galicia, NW Iberian Peninsula), a shellfish production area. Chemical analyses and toxicity bioassays with elutriates were performed with sediments from the area where the three pillars of the viaduct will be located (CT1, CT2 and CT3) and a reference sediment (A2). Acute toxicity of the elutriate was evaluated in five species of three trophic levels (Isochrysis galbana, Paracentrotus lividus, Mytilus galloprovincialis, Venerupis pullastra and Siriella armata). The sediments of the pillars showed moderate levels of contamination by trace elements (Cu, Cr). Clam and sea urchin embryo-larval toxicity tests showed slightly higher sensitivity than mussel embryo tests, and toxicity was not detected for phytoplankton and mysid bioassays. The predicted no-effect environmental concentration (PNEC) was calculated from the arithmetic mean of the lowest calculated EC(50)s for each sampling site. The predicted environmental concentration (PEC) was estimated from a simple dilution model and the PEC/PNEC ratio was calculated according to different scenarios of resuspension. Negligible ecological risk in the water column is expected during construction of the pillars.

  16. The Loma Prieta, California, Earthquake of October 17, 1989: Performance of the Built Environment

    Science.gov (United States)

    Coordinated by Holzer, Thomas L.

    1998-01-01

    Professional Paper 1552 focuses on the response of buildings, lifelines, highway systems, and earth structures to the earthquake. Losses to these systems totaled approximated $5.9 billion. The earthquake displaced many residents from their homes and severely disrupted transportation systems. Some significant findings were: * Approximately 16,000 housing units were uninhabitable after the earthquake including 13,000 in the San Francisco Bay region. Another 30,000-35,000 units were moderately damaged in the earthquake. Renters and low-income residents were particularly hard hit. * Failure of highway systems was the single largest cause of loss of life during the earthquake. Forty-two of the 63 earthquake fatalities died when the Cypress Viaduct in Oakland collapsed. The cost to repair and replace highways damaged by the earthquake was $2 billion, about half of which was to replace the Cypress Viaduct. * Major bridge failures were the result of antiquated designs and inadequate anticipation of seismic loading. * Twenty one kilometers (13 mi) of gas-distribution lines had to be replaced in several communities and more than 1,200 leaks and breaks in water mains and service connections had to be excavated and repaired. At least 5 electrical substations were badly damaged, overwhelming the designed redundancy of the electrical system. * Instruments in 28 buildings recorded their response to earthquake shaking that provided opportunities to understand how different types of buildings responded, the importance of site amplification, and how buildings interact with their foundation when shaken (soil structure interaction).

  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. Los viaductos de acceso al puente de Martigues – Francia

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    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.

  19. 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.

  20. 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.

  1. El porvenir de los puentes con vigas prefabricadas

    Directory of Open Access Journals (Sweden)

    Perzo, R.

    1972-11-01

    Full Text Available The article discusses a structure, 375 m long, composed of two approach viaducts 63 and 45 m long, respectively, and the main bridge, 268 m long. The spans of the viaducts are 21 and 22,50 m long, and the seven spans of the bridge have spans varying between 34 and 42 m. The deck consists of prefabricated beams bound by the upper slab and without intermediate stiffeners. The author describes the process of construction, including the prefabrication of the beams. Taking this work as an example, he analyses the evolution of bridges of prefabricated beams and draws his conclusions on the future of this type of bridge.Se trata de una estructura, de 375 m de longitud, compuesta por dos viaductos de seceso, de 63 y 45 m de longitud, respectivamente, y el puente principal, de 268 m. Las luces de los viaductos son de 21 y 22,50 m, y los 7 vanos del puente tienen luces variables entre 34 y 42 m. El tablero está constituido por vigas prefabricadas, unidas por la losa superior y sin riostras intermedias. El autor describe el proceso constructivo, incluyendo la prefabricación de las vigas. Tomando esta obra como ejemplo, analiza la evolución de los puentes de vigas prefabricadas y saca conclusiones sobre el porvenir de este tipo de puentes.

  2. Análisis de la seguridad en el cálculo de espesores de refuerzo para pavimentos flexibles

    OpenAIRE

    Zaldívar Serrano, Ernesto

    2012-01-01

    En el trabajo se analiza el uso del concepto de seguridad en el diseño de refuerzos de pavimentos flexibles; la opción más utilizada en los países latinoamericanos es el concepto de confianza del diseño, en especial el utilizado en el método AASHTO de las guías de 1986 y 1993. En el método se utiliza el nivel de confianza expresado en porcentaje y la desviación estándar general asociada a los datos del proyecto. En estas guías se hacen recomendaciones sobre el uso de estos elementos y que al ...

  3. Chloride permeability of concrete under static and repeated compressive loading

    Energy Technology Data Exchange (ETDEWEB)

    Saito, Mitsuru; Ishimori, Hiroshi [Kanazawa Inst. of Technology, Ishikawa (Japan)

    1995-05-01

    The chloride permeability of normal weight concrete subjected to static and repeated compressive loading was evaluated by using the AASHTO T277 test method. The results of concrete under static loading showed that the application of loads up to 90% of the ultimate strength had little effect on the chloride permeability. It was found from the results of concrete under repeated loading that load repetitions at the maximum stress levels of 60% or more caused the chloride permeability to increase significantly. The test results also indicated that the chloride permeability of concrete subjected to static and repeated loading increased at an increasing rate with its residual strain. The relation between the chloride permeability obtained and the cracking behavior of concrete previously reported was discussed.

  4. Structural Design of Pavement Overlays Based on Functional Parameters

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    This paper reports a practical pavement overlay design methodbased on PCI (Pavement Condition Index). Current pavement investigation method (JTJ 073-96) is compared to the ASTM D 5340, which is the standard test method for airport pavement condition evaluation initially developed for US Air Force. The deficiency in the calculation of PCI based on field data in JTJ 073 is discussed. The proposed design method is compared to AASHTO overlay design method with good agreement. The paper concludes with an example illustrating how the existing pavement structural capacity is related to pavement distress survey results. The presented design method can be used in the design for overlay rehabilitation of pavements of highways, urban streets and airports.

  5. 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.

  6. Effect of Rice Husk Ash on Cement Stabilized Laterite

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    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.

  7. 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.

  8. 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

  9. Los viaductos de Chillón Suiza

    Directory of Open Access Journals (Sweden)

    Hofer, Roland

    1970-02-01

    Full Text Available The articles describes in detail the problems involved in the construction of this important motor road in the Alto Leman region, which is characterised by its difficult topography and density of population. Details are also given about the design of the viaduct, which runs along the mountain slope and overcomes many difficult geographical features, whilst satisfying strict aesthetic, technical and low cost conditions.El artículo explica detalladamente los problemas que ha originado la construcción de esta importante autopista a la región del Alto Leman, caracterizada por su accidentada topografía y gran densidad demográfica. Igualmente se describe la solución adoptada de viaducto con trazado a media ladera, venciendo diversas e interesantes dificultades y cumplimentando todas las exigencias estéticas, técnicas y económicas impuestas.

  10. 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.

  11. 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.

  12. 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.

  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. Puente de Almodóvar sobre el río Guadalquivir, cerca de Córdoba

    Directory of Open Access Journals (Sweden)

    Fernández Casado, Carlos

    1967-02-01

    Full Text Available The Almodóvar Bridge is the first of several structural works forming part of the new Cordoba-Sevilla motorway. The construction procedure adopted—cantilever method by means of precast sections—is very interesting and will be used also for other similar bridges. The bridge structure, with its two approach viaducts, consists of a Gerber beam of prestressed concrete resting on two piers, including a central span of 70 m and two side cantilevers of 35 m. The suspended span, 30 m long, and the two approach viaducts are constituted by precast prestressed beams. The central cantilever arms of the Gerber beam are constructed by means of precast sections which are subsequently connected together by prestressing bars. The article describes the design principles, the bridge structure as well as the methods of construction.Es la primera de una serie de obras destinadas a la construcción de la autopista Córdoba-Sevilla. El método de voladizos sucesivos de hormigón pretensado que se ha adoptado para su construcción, es de gran interés y permitirá su empleo en obras posteriores. La estructura del puente, que está constituida por una viga Gerber apoyada en dos pilas intermedias, comprende un tramo central de 70 m de luz y dos vanos laterales de 35 m de luz cada uno de ellos. El tramo central está formado por una viga prefabricada de hormigón pretensado, de 30 m de luz, simplemente apoyada en dos voladizos de 20 m. Los tramos en voladizo se ejecutaron mediante elementos sucesivos prefabricados, solidarizados mediante los cables del pretensado. Completan la obra los dos viaductos de acceso, con tableros construidos con vigas pretensadas prefabricadas. Este artículo describe el proyecto y ejecución de la obra.

  15. Identification of a new sucrose transporter in rye-grass (LpSUT2): effect of defoliation and putative fructose sensing.

    Science.gov (United States)

    Berthier, Alexandre; Meuriot, Frédéric; Dédaldéchamp, Fabienne; Lemoine, Rémi; Prud'homme, Marie-Pascale; Noiraud-Romy, Nathalie

    2014-11-01

    Rye-grass fast regrowth after defoliation results from an efficient mobilization of C reserves which are transported as sucrose towards regrowing leaves, and which can be supported by one or several sucrose transporters (SUTs) like LpSUT1. Therefore, our objectives were to isolate, identify, characterize and immunolocalize such sucrose transporters. A protein (LpSUT2) showing a twelve spanning trans-membrane domain, extended N terminal and internal cytoplasmic loop, and kinetic properties consistent with well-known sucrose transporters, was isolated and successfully characterized. Along with LpSUT1, it was mainly localized in mesophyll cells of leaf sheaths and elongating leaf bases. These transporters were also found in parenchyma bundle sheath (PBS) cells but they were not detected in the sieve element/companion cell complex of the phloem. Unlike LpSUT1 transcript levels which increased as a response to defoliation in source and sink tissues, LpSUT2 transcript levels were unaffected by defoliation and weakly expressed. Interestingly, sucrose transport by LpSUT2 was inhibited by fructose. LpSUT1 and LpSUT2 appeared to have different functions. LpSUT1 is proposed to play a key role in C storage and mobilization by allowing sucrose transport between PBS and mesophyll cells, depending on the plant C status. LpSUT2 could be involved in sucrose/fructose sensing at sub-cellular level. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  16. Fluxos mínimos de veículos para implantação de faixas adicionais em aclives de rodovias de pista simples

    Directory of Open Access Journals (Sweden)

    Ricardo Almeida de Melo

    2009-10-01

    Full Text Available

    Este trabalho trata de uma adaptação do critério de fluxos mínimos de veículos, proposto pela AASHTO, para avaliar a necessidade de implantação de faixas adicionais em aclives de rodovias brasileiras. Os fluxos mínimos de veículos foram obtidos por análise econômica com uso de relação benefício/custo. Os benefícios considerados foram a redução dos custos operacionais dos veículos e dos tempos de viagens, quando implantada a faixa adicional. Os benefícios foram calculados do ganho de velocidade média, redução do tempo de viagem e da porcentagem de veículos em espera nos pelotões; essas informações foram extraídas de mais de 20.000 simulações efetuadas com o simulador

     

    TRARR. O custo do investimento foi composto por duas parcelas: custo de construção e custo de manutenção da faixa adicional. Os fluxos mínimos obtidos foram aqueles em que a relação benefício/custo era igual à unidade. O critério mencionado complementa uma proposta de adaptação das diretrizes da AASHTO, para análise da necessidade de faixas adicionais de subida em rodovias de pista simples brasileiras que, se adotadas, irão possibilitar a melhoria do nível de serviço e da segurança do trânsito.

  17. Evaluación de la resistencia a abolladura por cortante de vigas armadas híbridas de acero según la norma venezolana COVENIN 1618:1998

    Directory of Open Access Journals (Sweden)

    Chacón, R.

    2015-06-01

    Full Text Available In this paper, an in-depth analysis of the structural response of hybrid steel plate girders subjected to shear forces is presented. The analysis is focused on the Venezuelan Code for Steel Structures COVENIN 1618:1998. The study is based upon a review of experimental tests as well as upon a numerical study carried out by the authors. Both experimental and numerical results are compared with the results provided by the aforementioned Code. Likewise, other relevant Codes such as EN1993-1-5 and AISC-AASHTO are employed for the sake of comparison. The results obtained show that the values given by COVENIN 1618:1998 concerning the shear resistance of hybrid steel plate girders are particularly conservative. A design proposal that may enhance the current COVENIN formulation in this particular topic is presented accordingly.En este estudio se presenta un análisis de la resistencia a abolladura por cortante de vigas armadas híbridas según la norma venezolana COVENIN 1618:1998. El estudio se basa en una recopilación bibliográfica de ensayos experimentales encontrados así como en una base de datos numérica creada por los autores. Se comparan los valores obtenidos tanto experimental, como numéricamente con los derivados de la formulación teórica recogida en dicha normativa. Asimismo, dentro de la comparación, se incluyen los resultados derivados de la aplicación del Eurocódigo 3(EN1993-1-5 y las normativas americanas AISC-AASHTO. Los resultados que arrojan dichas comparaciones muestran el carácter conservador de COVENIN 1618:1998 en la valoración de dicha resistencia. En base a los resultados obtenidos, se proponen expresiones de diseño que permiten incluir el diseño híbrido de vigas armadas obteniendo del mismo su máximo beneficio estructural.

  18. Shear and shear friction of ultra-high performance concrete bridge girders

    Science.gov (United States)

    Crane, Charles Kennan

    Ultra-High Performance Concrete (UHPC) is a new class of concrete characterized by no coarse aggregate, steel fiber reinforcement, low w/c, low permeability, compressive strength exceeding 29,000 psi (200 MPa), tensile strength ranging from 1,200 to 2,500 psi (8 to 17 MPa), and very high toughness. These properties make prestressed precast UHPC bridge girders a very attractive replacement material for steel bridge girders, particularly when site demands require a comparable beam depth to steel and a 100+ year life span is desired. In order to efficiently utilize UHPC in bridge construction, it is necessary to create new design recommendations for its use. The interface between precast UHPC girder and cast-in-place concrete decks must be characterized in order to safely use composite design methods with this new material. Due to the lack of reinforcing bars, all shear forces in UHPC girders have to be carried by the concrete and steel fibers. Current U.S. codes do not consider fiber reinforcement in calculating shear capacity. Fiber contribution must be accurately accounted for in shear equations in order to use UHPC. Casting of UHPC may cause fibers to orient in the direction of casting. If fibers are preferentially oriented, physical properties of the concrete may also become anisotropic, which must be considered in design. The current research provides new understanding of shear and shear friction phenomena in UHPC including: (1) Current AASHTO codes provide a non-conservative estimate of interface shear performance of smooth UHPC interfaces with and without interface steel. (2) Fluted interfaces can be created by impressing formliners into the surface of plastic UHPC. AASHTO and ACI codes for roughened interfaces are conservative for design of fluted UHPC interfaces.(3) A new equation for the calculation of shear capacity of UHPC girders is presented which takes into account the contribution of steel fiber reinforcement. (4) Fibers are shown to preferentially

  19. 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.

  20. Development of the applicability of simplified Henry's method for skewed multicell box-girder bridges under traffic loading conditions

    Institute of Scientific and Technical Information of China (English)

    Iman MOHSENI; A.R.Khalim RASHID

    2012-01-01

    Concrete precast multicell box-girder (MCB) bridges combine aesthetics with torsional stiffness perfectly.Previous analytical studies indicate that currently available specifications are unable to consider the effect of the twisting moment (torsional moment) on bridge actions.In straight bridges the effect of torsion is negligible and the transverse reinforced design is governed by other requirements.However,in the case of skewed bridges the effect of the twisting moment should be considered.Therefore,an in-depth study was performed on 90 concrete MCB bridges with skew angles ranging from 0° to 60°.For each girder the bridge actions were determined under the American Association of State Highway and Transportation Officials (AASHTO) live load conditions.The analytical results show that torsional stiffness and live load positions greatly affected the bridges' responses.In addition,based on a statistical analysis of the obtained results,several skew correction factors are proposed to improve the precision of the simplified Henry's method,which is widely used by bridge engineers to predict bridge actions.The relationship between the bending moment and secondary moments was also investigated and it was concluded that all secondary actions increase with an increase in skewness.

  1. Evaluation of Resilient Modulus of Subgrade and Base Materials in Indiana and Its Implementation in MEPDG

    Directory of Open Access Journals (Sweden)

    Richard Ji

    2014-01-01

    Full Text Available In order to implement MEPDG hierarchical inputs for unbound and subgrade soil, a database containing subgrade MR, index properties, standard proctor, and laboratory MR for 140 undisturbed roadbed soil samples from six different districts in Indiana was created. The MR data were categorized in accordance with the AASHTO soil classifications and divided into several groups. Based on each group, this study develops statistical analysis and evaluation datasets to validate these models. Stress-based regression models were evaluated using a statistical tool (analysis of variance (ANOVA and Z-test, and pertinent material constants (k1, k2 and k3 were determined for different soil types. The reasonably good correlations of material constants along with MR with routine soil properties were established. Furthermore, FWD tests were conducted on several Indiana highways in different seasons, and laboratory resilient modulus tests were performed on the subgrade soils that were collected from the falling weight deflectometer (FWD test sites. A comparison was made of the resilient moduli obtained from the laboratory resilient modulus tests with those from the FWD tests. Correlations between the laboratory resilient modulus and the FWD modulus were developed and are discussed in this paper.

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

    Science.gov (United States)

    Liang, Zach; Lee, George C.

    2013-06-01

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

  3. Research on Design of Reconstruction Structure of Trunk Highway Asphalt Pavement in Central South China%中南地区干线公路沥青路面改建结构设计研究

    Institute of Scientific and Technical Information of China (English)

    张明

    2014-01-01

    According to the weather conditions, traffic conditions and other factors of central south China, the present situation for the sections of asphalt pavement maintenance and transformation, proposed flexible base pavement pro-gram and semi-rigid asphalt pavement structure program, on the design methods of asphalt pavement in china, AASHTO and software of BISAR, calculation and analysis of the program of overlay structure.%根据中南湖区当地气候条件及交通状况等因素,针对该路段沥青路面维修改造的现状,提出了柔性基层沥青路面结构方案和半刚性基层沥青路面结构方案,采用我国沥青路面设计方法、AASHTO设计方法和BISAR软件对路面加铺结构方案进行计算和分析。

  4. New U.S. pavement design guide will have major impact in Canada

    Energy Technology Data Exchange (ETDEWEB)

    Hein, D.

    2002-03-31

    The potential impacts and benefits that are likely to accrue to Canada with the upcoming release of the 2002 Pavement Design Guide of the American Association of State Highway and Transportation Officials (ASSHTO) are reviewed. The impact will be felt through AASHTO's 2002 mechanistic-empirical design method, a multi-level hierarchical approach based on design data requirements reflecting roadway classification and current roadway use configurations. A significant departure from the previous system is the emphasis on vehicle axle load distribution rather than equivalent single axle loads to evaluate pavement loading over service life. Specific benefits include: (1) consideration of inherent variations in materials, traffic and environmental factors in construction processes facilitating agency managers to be better able to weigh life cycle costs and cash flow in their decision making processes; (2) enhanced cost-responsibility studies through the improved ability to evaluate consequences of new pavement loading conditions; (3) ability of designers to use available and evolving materials ; (4) improved evaluation of premature pavement failures through better diagnostic techniques; and (5) better assessment of the effects of aging and that of the freeze-thaw cycle through better environmental data and analysis.

  5. ASSHTO模型中碰撞几何概率的修正及在长江上的应用

    Institute of Scientific and Technical Information of China (English)

    周立; 万大斌; 王辉; 杨洋

    2015-01-01

    AASHTO(美国道路工程师协会)规范模型为目前应用最广泛的船桥碰撞概率计算模型之一,该模型将船桥碰撞几何概率作为正态分布考虑,正态分布的标准差等于设计代表船只的船长,期望为0.通过统计长江上船舶过桥时的船位分布情况得知,受航行规则影响,船舶通过单孔双向通航的桥梁时船位沿桥轴线方向成“双峰”分布,该双峰分布可近似的看成由两个正太分布混合而成,据此对AASHTO模型中碰撞几何概率参数进行了修正,修正后的模型与长江干线实际情况更加适应.

  6. 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.

  7. A Comparative Study on Properties of Malaysian Porous Asphalt Mixes with Different Bitumen Contents

    Directory of Open Access Journals (Sweden)

    Mohamad Yusri Aman

    2015-04-01

    Full Text Available Inadequate bitumen content in porous pavement construction may result in incomplete coating of aggregates which a thin bitumen film can oxidize rapidly resulting in premature failure of the pavement. This and presents the effects of porous asphalt prepared with 4.0% and up to 6.0% binder content with 0.5% increments binder. Bitumen penetration grade 60/70 and crushed granite were used in preparing the porous asphalt specimen. The porous asphalt mixes were compacted by applying 50 blows on each face using a Marshall Impact compactor. The specimens were tested for air voids, indirect tensile strength and water permeability and abrasion loss. The moisture sensitivity was assessed according to the AASHTO T283 procedures. The result shows that the increasing of bitumen content has decreased the, bulk density air voids, coefficient of permeability and abrasion loss values However, the Indirect Tensile Strength (ITS has significantly increased and this is a good indication to resistance against moisture sensitivity. It can be concluded that the increasing of bitumen content in porous asphalt has increased the thickness of binder coating around the aggregates. This results reduction in air voids and water permeability, on the other hands it increases resistance to disintegration and ITS value which give better resistance to moisture sensitivity of porous specimens.

  8. Development of a real-time bridge structural monitoring and warning system: a case study in Thailand

    Science.gov (United States)

    Khemapech, I.; Sansrimahachai, W.; Toachoodee, M.

    2017-04-01

    Regarded as one of the physical aspects under societal and civil development and evolution, engineering structure is required to support growth of the nation. It also impacts life quality and safety of the civilian. Despite of its own weight (dead load) and live load, structural members are also significantly affected by disaster and environment. Proper inspection and detection are thus crucial both during regular and unsafe events. An Enhanced Structural Health Monitoring System Using Stream Processing and Artificial Neural Network Techniques (SPANNeT) has been developed and is described in this paper. SPANNeT applies wireless sensor network, real-time data stream processing and artificial neural network based upon the measured bending strains. Major contributions include an effective, accurate and energy-aware data communication and damage detection of the engineering structure. Strain thresholds have been defined according to computer simulation results and the AASHTO (American Association of State Highway and Transportation Officials) LRFD (Load and Resistance Factor Design) Bridge Design specifications for launching several warning levels. SPANNeT has been tested and evaluated by means of computer-based simulation and on-site levels. According to the measurements, the observed maximum values are 25 to 30 microstrains during normal operation. The given protocol provided at least 90% of data communication reliability. SPANNeT is capable of real-time data report, monitoring and warning efficiently conforming to the predefined thresholds which can be adjusted regarding user's requirements and structural engineering characteristics.

  9. 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.

  10. Influencia de la carga de viento en puentes. Caso de estudio tablero del Puente del Abra del Yumurí.

    Directory of Open Access Journals (Sweden)

    Carlo Fidel Taboada

    2014-01-01

    Full Text Available El proyecto de construcción de una Refinería de hidrocarburo en la periferia de la ciudad de Matanzas trae como consecuencia la redistribución del flujo vehicular ocasionado por su construcción y su posterior puesta en marcha a través de una solución vial que incluye la construcción de un puente en el Abra del Yurumí. Dado que el puente se encuentra situado a gran altura y en una zona próxima a la desembocadura del río, influyen sobre él cargas de viento considerables. Para dar solución a esta problemática se debe escoger un método eficaz y racional, al mismo tiempo. Para ello se analizan la NC 285 2003 “Carga de viento. Método de cálculo” (Norma vigente para el cálculo del viento en estructuras en Cuba y la AASHTO (American Association of State highway and Transportation Officials LRFD Bridge 2007, procedente de EEUU y con la cual se calculan muchos puentes en la actualidad en varios países a fin de aplicarlas al puente en cuestión y así, posteriormente, seleccionar el proceder óptimo entre estas dos propuestas.

  11. Seismic displacement of gravity retaining walls

    Directory of Open Access Journals (Sweden)

    Kamal Mohamed Hafez Ismail Ibrahim

    2015-08-01

    Full Text Available Seismic displacement of gravity walls had been studied using conventional static methods for controlled displacement design. In this study plain strain numerical analysis is performed using Plaxis dynamic program where prescribed displacement is applied at the bottom boundary of the soil to simulate the applied seismic load. Constrained absorbent side boundaries are introduced to prevent any wave reflection. The studied soil is chosen dense granular sand and modeled as elasto-plastic material according to Mohr–Column criteria while the gravity wall is assumed elastic. By comparing the resulted seismic wall displacements calculated by numerical analysis for six historical ground motions with that calculated by the pseudo-static method, it is found that numerical seismic displacements are either equal to or greater than corresponding pseudo-static values. Permissible seismic wall displacement calculated by AASHTO can be used for empirical estimation of seismic displacement. It is also found that seismic wall displacement is directly proportional with the positive angle of inclination of the back surface of the wall, soil flexibility and with the earthquake maximum ground acceleration. Seismic wall sliding is dominant and rotation is negligible for rigid walls when the ratio between the wall height and the foundation width is less than 1.4, while for greater ratios the wall becomes more flexible and rotation (rocking increases till the ratio reaches 1.8 where overturning is susceptible to take place. Cumulative seismic wall rotation increases with dynamic time and tends to be constant at the end of earthquake.

  12. Shrinkage behavior of self-compacting concrete

    Institute of Scientific and Technical Information of China (English)

    Farhad ASLANI; Shami NEJADI

    2012-01-01

    In the structures where long-term behavior should be monitored and controlled,creep and shrinkage effects have to be included precisely in the analysis and design procedures.Shrinkage varies with the constituent and mixture proportions,and depends on the curing conditions and the work environment as well.Self-compacting concrete (SCC) contains combinations of various components,such as aggregate,cement,superplasticizer,water-reducing agent and other ingredients which affect the properties of the SCC including shrinkage.Hence,the realistic prediction shrinkage strains of SCC are an important requirement of the design process for this type of concrete structures.This study reviews the accuracy of the conventional concrete (CC) shrinkage prediction models proposed by the international codes of practice,including CEB-FIP (1990),ACI 209R (1997),Eurocode 2 (2001),JSCE (2002),AASHTO (2004; 2007) and AS 3600 (2009).Also,SCC shrinkage prediction models proposed by Poppe and De Schutter (2005),Larson (2007),Cordoba (2007) and Khayat and Long (2010) are reviewed.Further,a new shrinkage prediction model based on the comprehensive analysis on both of the available models,i.e.,the CC and the SCC is proposed.The predicted shrinkage strains are compared with the actual measured shrinkage strains in 165 mixtures of SCC and 21 mixtures of CC.

  13. Standards guidelines for human comfort tested on timber footbridges

    Directory of Open Access Journals (Sweden)

    Pedro Gutemberg de Alcântara Segundinho

    2011-06-01

    Full Text Available Activities such as walking, running and jumping can produce undesirable dynamic excitations, which are a phenomenon that occurs due to pedestrian-induced dynamic forces whenever a footbridge features a natural frequency within stepping frequency ranges. Dynamic evaluations of timber footbridges are necessary to verify the level of human comfort and the suitability of the bridges when subjected to human traffic. The objective of this paper is to present a bibliography review on the standards guidelines contained in international codes BS 5400, SIA 160, OHBDC, CEB, EUROCODE 5, AASHTO, BRO and ISO 10137 as well as in studies by various researchers, in order to verify the serviceability limit state for vibrations. In Brazil, codes ABNT NBR 7190 and ABNT NBR 7188 set the sizing criteria for timber footbridges considering the ultimate and serviceability limit states, with the latter ignoring human comfort with regard to vibrations. Thus, the information contained in this study can contribute to the refinement of Brazilian code ABNT NBR 7190, as it takes into account human comfort in pedestrian-induced vibrations on footbridges.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Science.gov (United States)

    Liang, Zach; Lee, George C.

    2013-06-01

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

  16. Towards multiple hazard resilient bridges: a methodology for modeling frequent and infrequent time-varying loads Part II, Examples for live and earthquake load effects

    Science.gov (United States)

    Liang, Zach; Lee, George C.

    2012-09-01

    The current AASHTO load and resistance factor design (LRFD) guidelines are formulated based on bridge reliability, which interprets traditional design safety factors into more rigorously deduced factors based on the theory of probability. This is a major advancement in bridge design specifications. However, LRFD is only calibrated for dead and live loads. In cases when extreme loads are significant, they need to be individually assessed. Combining regular loads with extreme loads has been a major challenge, mainly because the extreme loads are time variable and cannot be directly combined with time invariant loads to formulate the probability of structural failure. To overcome these difficulties, this paper suggests a methodology of comprehensive reliability, by introducing the concept of partial failure probability to separate the loads so that each individual load combination under a certain condition can be approximated as time invariant. Based on these conditions, the extreme loads (also referred to as multiple hazard or MH loads) can be broken down into single effects. In this paper, a further breakdown of these conditional occurrence probabilities into pure conditions is discussed by using a live truck and earthquake loads on a bridge as an example.

  17. Towards multiple hazard resilient bridges: a methodology for modeling frequent and infrequent time-varying loads Part I, Comprehensive reliability and partial failure probabilities

    Science.gov (United States)

    Liang, Zach; Lee, George C.

    2012-09-01

    The current AASHTO load and resistance factor design (LRFD) guidelines are formulated based on bridge reliability, which interprets traditional design safety factors into more rigorously deduced factors based on the theory of probability. This is a major advancement in bridge design specifications. However, LRFD is only calibrated for dead and live loads. In cases when extreme loads are significant, they need to be individually assessed. Combining regular loads with extreme loads has been a major challenge, mainly because the extreme loads are time variables and cannot be directly combined with time invariant loads to formulate the probability of structural failure. To overcome these difficulties, this paper suggests a methodology of comprehensive reliability, by introducing the concept of partial failure probability to separate the loads so that each individual load combination under a certain condition can be approximated as time invariant. Based on these conditions, the extreme loads (also referred to as multiple hazard or MH loads) can be broken down into single effects. In Part II of this paper, a further breakdown of these conditional occurrence probabilities into pure conditions is discussed by using a live truck and earthquake loads on a bridge as an example. There are three major steps in establishing load factors from MH load distributions: (1) formulate the failure probabilities; (2) normalize various load distributions; and (3) establish design limit state equations. This paper describes the formulation of the failure probabilities of single and combined loads.

  18. 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.

  19. Hybrid reliability model for fatigue reliability analysis of steel bridges

    Institute of Scientific and Technical Information of China (English)

    曹珊珊; 雷俊卿

    2016-01-01

    A kind of hybrid reliability model is presented to solve the fatigue reliability problems of steel bridges. The cumulative damage model is one kind of the models used in fatigue reliability analysis. The parameter characteristics of the model can be described as probabilistic and interval. The two-stage hybrid reliability model is given with a theoretical foundation and a solving algorithm to solve the hybrid reliability problems. The theoretical foundation is established by the consistency relationships of interval reliability model and probability reliability model with normally distributed variables in theory. The solving process is combined with the definition of interval reliability index and the probabilistic algorithm. With the consideration of the parameter characteristics of theS−N curve, the cumulative damage model with hybrid variables is given based on the standards from different countries. Lastly, a case of steel structure in the Neville Island Bridge is analyzed to verify the applicability of the hybrid reliability model in fatigue reliability analysis based on the AASHTO.

  20. Performance of Laterite-Cement Blocks as Walling Units in Relation to Sandcrete Blocks

    Directory of Open Access Journals (Sweden)

    James Isiwu AGUWA

    2010-12-01

    Full Text Available A study of the performance of laterite-cement blocks as walling materials in relation to those of sandcrete was conducted, for the purpose of establishing a cheaper building material in Minna, Niger state, Nigeria and surrounding towns, in the present ever increasing cost of building material. An A-2-6 laterite according to the AASHTO classification system was stabilized with 0-10% cement content by weight of the soil at a constant interval of 2% to produce 20 blocks of size 100mm × 100mm × 100mm for each mix. One hundred laterite-cement blocks were produced, cured under laboratory conditions and subjected to compressive strength test at 7, 14, 21, and 28-days of age, in five applications for each cement mix ratio. The average compressive strength was determined from five blocks crushed in each mix at every age of curing and the same procedure was repeated using sandcrete blocks. At a common cement content of 6%, the compressive strengths, densities, water absorption and the cost per square metre of wall for both types of blocks were determined. The study recommends the use of laterite-cement blocks as walling materials in Minna and environs because it has better engineering properties and more economical with a saving of 30% per square metre of wall when compared with the use of sandcrete blocks.

  1. Experimental evaluation and field implementation of FRP bridge deck modules

    Directory of Open Access Journals (Sweden)

    Woraphot Prachasaree

    2008-07-01

    Full Text Available Construction of highway bridge decks using fiber reinforced polymer (FRP composite deck and superstructuremodules in lieu of concrete decks has proven to be feasible. However, FRP’s are not widely accepted yet despite theirbenefits such as non-corrosiveness, higher strength to weight ratio, and better fatigue resistance than conventional materials.Lack of wider usage of FRP material is mainly attributed to the absence of: 1 standardized test procedures, 2 designspecifications, and 3 construction procedures. The higher initial cost is also inhibiting bridge engineers in selecting FRPmodules as highway bridge super structural systems.Implementation of FRP composites technology for highway bridge decks leads to higher safety and lower life cyclecosts. Significant ongoing research and development of FRP deck modules as illustrated herein, has proven to enhancedeck module properties in developing FRP modules with enhanced structural performance.Prodeck 4 is one such multicellular deck that was recently developed, and extensively evaluated for static and fatigueloads, and its response results are presented herein. From rigorous testing, it was concluded that Prodeck 4 could resistAASHTO HS 25 loading with maximum stringer spacing of 48 inches. This led to construction of two bridges (one in Ohioand other in West Virginia using Prodeck 4 as decking.

  2. 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.

  3. An investigation of the seismic behavior of a deck-type reinforced concrete arch bridge

    Science.gov (United States)

    Farahani, Emadoddin Majdabadi; Maalek, Shahrokh

    2017-07-01

    This paper attempts to explore potential benefits of form in a deck-type reinforced concrete (RC) arch bridge in connection with its overall seismic behavior and performance. Through a detailed three-dimensional finite element modeling and analysis of an actual existing deck-type RC arch bridge, some useful quantitative information have been derived that may serve for a better understanding of the seismic behavior of such arch bridges. A series of the nonlinear dynamic analyses has been carried out under the action of seven different time histories of ground motion scaled to the AASHTO 2012 response spectrum. The concept of demand to capacity ratios has been employed to provide an initial estimation of the seismic performance of the bridge members. As a consequence of the structural form, a particular type of irregularity is introduced due to variable heights of columns transferring the deck loads to the main arch. Hence, a particular attention has been paid to the internal force/moment distributions within the short, medium, and long columns as well as along the main arch. A study of the effects of the vertical component of ground motion has demonstrated the need for the inclusion of these effects in the analysis of such bridges.

  4. 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.

  5. 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.

  6. Simulating the Effects of Surface Roughness on Reinforced Concrete T Beam Bridge under Single and Multiple Vehicles

    Directory of Open Access Journals (Sweden)

    Rahul Kalyankar

    2016-01-01

    Full Text Available This research focuses on the application of the spatial system of finite element modeling for the vehicle-bridge interaction on reinforced concrete US Girder Bridge in order to obtain the effect of surface roughness. Single vehicle and multiple vehicles on reinforced concrete T beam bridge were studied with variable surface roughness profiles. The effects of six different surface roughness profiles (very good, good, measured, average, poor, and very poor were investigated for vehicle-bridge interaction. The values of the Dynamic Amplification Factor (DAF were obtained for single and multiple vehicles on T Beam Bridge for different surface roughness profiles, along with the distances between the axles of heavy vehicle. It was observed that when the bridge has very good, good, measured, and average surface roughness, the DAF values for the single vehicle over the bridge were observed to be within acceptable limits specified by AASHTO. However, for the bridge with multiple vehicles only very good and measured surface roughness profiles showed a DAF and vehicle axle distances within the acceptable limits. From the current studies, it was observed that the spatial system showed reliable responses for predicting the behavior of the bridge under variable road surface roughness conditions and was reliable in vehicle axle detection, and therefore, it has a potential to be use for realistic simulations.

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

    Directory of Open Access Journals (Sweden)

    Jiho Moon

    2016-01-01

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

  8. Evaluation of seismic design spectrum based on UHS implementing fourth-generation seismic hazard maps of Canada

    Science.gov (United States)

    Ahmed, Ali; Hasan, Rafiq; Pekau, Oscar A.

    2016-12-01

    Two recent developments have come into the forefront with reference to updating the seismic design provisions for codes: (1) publication of new seismic hazard maps for Canada by the Geological Survey of Canada, and (2) emergence of the concept of new spectral format outdating the conventional standardized spectral format. The fourth -generation seismic hazard maps are based on enriched seismic data, enhanced knowledge of regional seismicity and improved seismic hazard modeling techniques. Therefore, the new maps are more accurate and need to incorporate into the Canadian Highway Bridge Design Code (CHBDC) for its next edition similar to its building counterpart National Building Code of Canada (NBCC). In fact, the code writers expressed similar intentions with comments in the commentary of CHBCD 2006. During the process of updating codes, NBCC, and AASHTO Guide Specifications for LRFD Seismic Bridge Design, American Association of State Highway and Transportation Officials, Washington (2009) lowered the probability level from 10 to 2% and 10 to 5%, respectively. This study has brought five sets of hazard maps corresponding to 2%, 5% and 10% probability of exceedance in 50 years developed by the GSC under investigation. To have a sound statistical inference, 389 Canadian cities are selected. This study shows the implications of the changes of new hazard maps on the design process (i.e., extent of magnification or reduction of the design forces).

  9. Introduction and comprehensive Evaluation of the Bougainvillea in Guangzhou%观赏簕杜鹃在广州地区的引种及综合评价

    Institute of Scientific and Technical Information of China (English)

    张继方; 代色平; 傅小霞; 谭梓轩; 王伟; 刘悦明

    2016-01-01

    自紫花簕杜鹃在广州天桥绿化中成功应用以来,为丰富簕杜鹃在天桥应用的花色种类,近年来广州市林业和园林科学院在国内外先后引种了120多个较具观赏特色的簕杜鹃种类品种,同时建立簕杜鹃种质资源圃对其进行栽培观察,并通过进一步分类鉴定,确定了其中96个簕杜鹃种类品种的拉丁名。利用AHP层次分析法,构建簕杜鹃种质资源综合评价模型,对各种类品种生态适应性、观赏特性以及开发应用潜力进行了综合评价。评价结果表明,其中有19个种类品种的综合值较高,适合在天桥绿化上大规模推广应用。%Since Bougainvillea spectabilis was successful applied to Viaduct Greening in Guangzhou, 120 varieties of Bougainvillea have been introduced in Guangzhou in order to enrich the colours of Bougainvillea. And germplasm nursery of Bougainvillea were built for observing. According to the classification and identification of the ornamental characteristics, 96 kinds of Bougainv ille aˊs correct Latin name have been identified. Using the Analytic Hierarchy Process (AHP) to evaluate their ecological adaptability, ornamental charactees and the development potential, and constructe the evaluation model on germplasm resources of Bougainv ille a. The results showed that there are 19 varieties of Bougainv ille a suited for popularizing on Viaduct Greening generally in Guangzhou.

  10. 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.

  11. 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

  12. Distribution Characteristics of T raffic Congestion Duration Time for Urban Expressway%城市快速路交通拥堵持续时间分布特性研究

    Institute of Scientific and Technical Information of China (English)

    张轮; 施奕骋; 杨文臣; 杨涛

    2014-01-01

    依托上海市南北高架西侧的交通流数据,引入生存分析方法,建立基于风险的交通拥堵持续时间模型。其根据大量交通拥堵样本的时间属性,采用Kaplan-M eyer非参数回归模型定量估计拥堵持续时间,并按星期数、高峰时段、数据年限、样本位置和天气划分五类影响因素,从生存函数和危险函数两个方面,分析拥堵持续时间的时空分布特性。结果表明上海市南北高架西侧的交通拥堵持续时间70%能在1小时内消散,在不同类别的影响因素下分布特性存在明显差异。%Based on the historical traffic data of the west-side North-South Viaduct in Shanghai ,this paper introduces survival analysis into the analysis of traffic congestion mechnism ,and a hazard-based traffic congestion duration time model is presentd .This model analyzes the time attributes of many traffic congestion samples ,and employs nonparametric regression-based Kaplan-Meyer model to esti-mate traffic congestion duration time .Then ,the key influence factors of traffic congestion are divided into five types including weekdays ,peak time ,data year ,location and weather ,and the spatial-tem-poral distribution characteristics of traffic congestion duration time is analyzed .Analsis results has shown that the 70% of traffic congestion durations on road segments of west-side North-South Via-duct are no longer than an hour ,and there exists significant difference of distribution characteristics under different influence factors .

  13. Design and practice of regional health informatization by constructing a"collaborative service chain"%区域医疗信息化“协同服务链”建设模式的设计与实践

    Institute of Scientific and Technical Information of China (English)

    蒋璐; 赵强; 王竞; 董瑞国

    2014-01-01

    The paper first analyzes the development of regional health informatization and the existing construction mode .Modern Education Technology Center of Xuzhou Medical College , using its advantages , unique and innovative ideas , planned , implemented and completed the construction of "Viaduct-Association-New Specialty".It built a service chain collaborative construction mode that can meet the requirements of local regional health informatization as well as a network viaduct and information integration platform for regional health informatization , established a management organization and carried out personnel training .Practice proves that these can help improve the quality of health care and promote cooperation and collaboration between medical institutions and medical personnel and the construction of regional health informatization .%在分析区域医疗信息化发展与现有建设模式基础上,徐州医学院现代教育技术中心经历了约6年时间的探索与努力,利用自身优势,以独特的构想、创新的理念,策划、实施并完成了“高架桥-协会-新专业”的建设,构建了符合当地区域医疗信息化要求的“基础设施-信息资源-人才发展”服务链式的协同建设模式及为区域医疗信息化搭建网络高架桥和信息整合平台,建立组织管理机构,进行人才培养。实践证明,该模式有利于提高医疗质量、促进各医疗机构、医护人员的协同合作及区域医疗信息化的建设。

  14. 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

  15. 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.

  16. Performance evaluation of corrosion-affected reinforced concrete bridge girders using Markov chains with fuzzy states

    Indian Academy of Sciences (India)

    M B ANOOP; K BALAJI RAO

    2016-08-01

    A methodology for performance evaluation of reinforced concrete bridge girders in corrosive environments is proposed. The methodology uses the concept of performability and considers both serviceability- and ultimate-limit states. The serviceability limit states are defined based on the degree of cracking (characterized by crack width) in the girder due to chloride induced corrosion of reinforcement, and the ultimate limit states are defined based on the flexural load carrying capacity of the girder (characterized in terms of rating factor using the load and resistance factor rating method). The condition of the bridge girder is specified by the assignment of a condition state from a set of predefined condition states. Generally, the classification of condition states is linguistic, while the condition states are considered to be mutually exclusive and collectivelyexhaustive. In the present study, the condition states of the bridge girder are also represented by fuzzy sets to consider the ambiguities arising due to the linguistic classification of condition states. A non-homogeneous Markov chain (MC) model is used for modeling the condition state evolution of the bridge girder with time. The usefulness of the proposed methodology is demonstrated through a case study of a severely distressed beam of the Rocky Point Viaduct. The results obtained using the proposed approach are compared with those obtained using conventional MC model. It is noted that the use of MC with fuzzy states leads to conservative decision making for the problem considered in the case study.

  17. 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.

  18. Analysis on construction monitoring of large cantilever pre-stressed concrete cap beam%大悬臂预应力混凝土盖梁的施工监测分析

    Institute of Scientific and Technical Information of China (English)

    郭锐

    2015-01-01

    Taking the large cantilever pre-stressed concrete cap beam construction of a viaduct as an example,from the structure modeling,pre-stressed steel beam system,stress monitoring and other aspects,introduced the construction monitoring technology of bridge structure engineer-ing,through the stress and displacement monitoring analysis of construction process,pointed out that the theory calculated value of large cantile-ver cap beam model in line with construction measured value.%以某高架桥大悬臂预应力混凝土盖梁施工为例,从结构建模、预应力钢束体系、应力监测等方面,介绍了桥梁结构工程的施工监测技术,通过对施工过程中应力和位移的监测分析,指出大悬臂盖梁模型的理论计算值与施工实测值比较吻合。

  19. Measuring thermal expansion using X-band persistent scatterer interferometry

    Science.gov (United States)

    Crosetto, Michele; Monserrat, Oriol; Cuevas-González, María; Devanthéry, Núria; Luzi, Guido; Crippa, Bruno

    2015-02-01

    This paper is focused on the estimation of the thermal expansion of buildings and infrastructures using X-band Persistent Scatterer Interferometry (PSI) observations. For this purpose an extended PSI model is used, which allows separating the thermal expansion from the total observed deformation thus generating a new PSI product: the map of the thermal expansion parameter, named thermal map. The core of the paper is devoted to the exploitation of the information contained in the thermal maps: three examples are discussed in detail, which concern a viaduct, a set of industrial buildings and two skyscrapers. The thermal maps can be used to derive the thermal expansion coefficient of the observed objects and information on their static structure. In addition, the paper illustrates the distortions in the PSI deformation products that occur if the thermal expansion is not explicitly modelled. Finally, an inter-comparison exercise is described, where the thermal expansion coefficients estimated by PSI are compared with those derived by a Ku-band ground-based SAR campaign.

  20. A review of bridge scour monitoring techniques

    Institute of Scientific and Technical Information of China (English)

    L.J. Prendergast; K. Gavin

    2014-01-01

    The high profile failure of the Malahide Viaduct in Dublin, Ireland, which is a part of the EU TEN-T network of critical transport links, was caused by foundation scour. Scour is a common soil-structure interaction problem. In light of current changes in climate, increasing frequency of flooding, coupled with the increasing magnitude of these flood events, will lead to a higher risk of bridge failure. Moni-toring scour is of paramount importance to ensure the continued safe operation of the aging bridge asset network. Most monitoring regimes are based on expensive underwater instrumentation that can often be subjected to damage during times of flooding, when scour risk is at its highest. This paper presents a critical review of existing scour monitoring equipments and methodologies with a particular focus on those using the dynamic response of the structure to indicate the existence and severity of the scour phenomenon affecting the structure. A sensitivity study on a recently developed monitoring method is also undertaken.

  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. Accumulation of polycyclic aromatic hydrocarbons (PAHs) on the spider webs in the vicinity of road traffic emissions.

    Science.gov (United States)

    Rybak, Justyna; Olejniczak, Teresa

    2014-02-01

    Studies focused on the possible use of spider webs as environmental pollution indicators. This was a first time ever attempt to use webs as indicators of polycyclic aromatic hydrocarbons (PAHs) pollution. The aim of the study was (a) to evaluate whether webs are able to accumulate PM-associated road traffic emissions and be analyzed for organic toxics such as PAHs, (b) to assess if the distance from emission sources could have an influence on the accumulation level of pollutants, and (c) to determine types of pollution sources responsible for a structure of monitoring data set. Webs of four species from the family Agelenidae were sampled for PAHs presence. Data from vehicle traffic sites (i.e., road tunnel, arterial surface road, underground parking) and from railway traffic sites (i.e., two railway viaducts) in the city of Wroclaw (Southwest of Poland) showed a significantly higher mean concentrations of PAHs than the reference site 1 (municipal water supply works). We also found a significant differences at sites differed by the distance from emission sources. The result of PCA analysis suggested three important sources of pollution. We conclude that spider webs despite of some limitations proved useful indicators of road traffic emissions; they could be even more reliable compared to use of bioindicators whose activity is often limited by a lack of water and sun.

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

    Science.gov (United States)

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

    2014-11-01

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

  4. Vibration Analysis of Air Condition Unit on Subway

    Directory of Open Access Journals (Sweden)

    Yan Liu

    2013-06-01

    Full Text Available Subway system has many merits including large passenger carrying ability, high speed, strong controllability and reliability of driving. Nevertheless, subways also have brought many disadvantages for human. In many subway systems, noisy environments are clearly observed and passengers are exposed to higher noise levels than permissible limit. This study presents a study of noise and vibration of subway air condition system, so as to grasp the vibration distribution laws of the air condition system. By the tested of noise and vibration, the researcher find the sound distribution rule of air condition is very important Based on the consequence of the testing, the acceleration of air condition has little to do with the subway speed and more to do with the vibration of fan; When the train driving on the viaduct bridge, the acceleration of air condition is biggish in 125 Hz and In 50-1000 Hz the vibration of air condition is obviously. When the train running underground line, as a result of the resonance of body, air condition’s vibration is biggish in 630 Hz and the vibration is obviously in 125-1250 Hz. With the increase of the speed, the influence of the ground’s second radiation on body vibration is enhanced. The superfine gross wool which is used to air condition can achieve good results for noise reduction. This research has higher reference for the vibration and noise reduction of the subway air condition system.

  5. Spatial Configuration of Energy Consumption and Carbon Emissions of Shanghai, and Our Policy Suggestions

    Directory of Open Access Journals (Sweden)

    Kexi Pan

    2017-01-01

    Full Text Available This research constructs a 1 km × 1 km Shanghai energy consumption and carbon emission spatial grid through a bottom-up approach. First, we locate all energy consumption locations in Shanghai via GIS. Second, we calculate energy consumption and associated CO2 emissions by energy type, by usage type, and by facilities. Finally, we use a spatial grid to represent the energy consumption and CO2 emissions. The grid shows CO2 emissions in Shanghai are highly spatially correlated with energy types and volumes of consumption. This research also finds out that high energy consumption and carbon emission locations in Shanghai display significant spatial aggregation. In 7209 spatial energy consumption cells, the top 10 grids of emissions account for 52.8% of total CO2 emissions in Shanghai; the top 20 grids account for 64.5% and the top 50 grids account for 76.5%. The most critical point emission sources are coal-fired power plants and iron and steel plants. The most important line emission sources are the Yan’an Road and Inner Ring viaducts. The area emission sources that account for the most future-projected growth are commercial and residential natural gas. After this spatial analysis, this paper makes policy suggestions and solutions to conserve energy consumption and mitigate carbon emissions in Shanghai.

  6. Recording ground motions where people live

    Science.gov (United States)

    Cranswick, E.; Gardner, B.; Hammond, S.; Banfill, R.

    The 1989 Loma Prieta, Calif., earthquake caused spectacular damage to structures up to 100 km away in the San Francisco Bay sedimentary basin, including the Cypress Street viaduct overpass, the Bay Bridge, and buildings in the San Francisco Marina district. Although the few mainshock ground motions recorded in the northern San Francisco Bay area were “significantly larger … than would be expected from the pre-existing data set,” none were recorded at the sites of these damaged structures [Hanks and Krawinkler, 1991].Loma Prieta aftershocks produced order-of-magnitude variations of ground motions related to sedimentary basin response over distances of 1-2 km and less [Cranswick et al., 1990]. In densely populated neighborhoods, these distances can encompass the residences of thousands of people, but it is very unlikely that these neighborhoods are monitored by even one seismograph. In the last decade, the complexity of computer models used to simulate high-frequency ground motions has increased by several orders of magnitude [e.g., Frankel and Vidale, 1992], but the number of seismograph stations—hence, the spatial density of the sampling of ground motion data—has remained relatively unchanged. Seismologists must therefore infer the nature of the ground motions in the great unknown regions between observation points.

  7. Viaducto sobre el río Flon, Suiza

    Directory of Open Access Journals (Sweden)

    Sarrasin, A.

    1966-11-01

    Full Text Available This viaduct is part of the motor road from Lausanne to Saint Moritz, and consists of two independent structures, 56 cm apart one from the other, each of which is 434.30 m long, and 12.90 m wide. They consist of a main arch, 120 m in span, and 11 straight sections, with a maximum span of 29 m. The deck rests on three longitudinal girders, whose depth is 2.18 m. The material is reinforced concrete, and the structure is divided into five parts, with intervening dilation joints. The concreting of the arches has been done in successive stages, using a single formwork.Este viaducto, que forma parte de las obras de fábrica de la autopista Lausanne-Saint—Maurice, se compone de dos viaductos independientes, separados 56 cm, cada uno de los cuales tiene una longitud total de 434,30 m y una anchura de 12,90 m. Los once tramos rectos que complementan al tramo principal en arco—de 120 m de luz—tienen una luz máxima de 29 m, estando el tablero soportado por tres vigas longitudinales de 2,18 m de canto. La obra es de hormigón armado y está subdividida en cinco trozos, con cuatro juntas; el hormigonado de los arcos se ha realizado sucesivamente con una sola cimbra.

  8. 三维激光扫描仪精度测试及应用%Accuracy testing and application of 3D laser scanner

    Institute of Scientific and Technical Information of China (English)

    张铁军; 沈家海; 申文永

    2015-01-01

    The basic principle of 3D laser scanner, and the test methods of its positional accuracy in pile surveying were introduced in this paper. According to engineering requirements, we arranged control points, chose columns under the viaduct in land as observation target, measured the center coordinates respectively using 3D laser scanner and total station, analyzed the measuring accuracy of 3D laser scanner based on total station measuring results, and explored its application in engineering surveying.%介绍了三维激光扫描仪的基本原理及其应用于桩基测量精度分析的测试方法。按照工程需求,布置控制点,选择陆地高架桥下的圆柱作为观测目标,分别用三维激光扫描仪和全站仪测量出圆心坐标,以全站仪测量成果为基准,分析三维激光扫描仪的测量精度,探索其在工程测量中的应用。

  9. 轨道交通工程建设风险管理的研究%Construction Of Rail Transit Project Risk Management Research

    Institute of Scientific and Technical Information of China (English)

    赵鹏; 雷斌

    2012-01-01

    由于轨道交通工程所处地层工程地质、水文地质条件及工程环境复杂,不可预见因素较多,前期工作量大,工作难度大等特点,使工程施工风险性增加.通过对矿山法、盾构法、明挖法、高架桥修建轨道交通工程建设应注意问题进行分析总结,从而得出规避风险的对策,提出强化工程建设管理应采取的举措.%Due to the formation of rail traffic engineering engineering geology, hydrogeology and engineering environment is complex, unpredictable factors, the workload, working difficulty is great wait for a characteristic, make engineering construction risk increase. Based on the mining method, shield method, the open-cut method, the viaduct rail transit construction engineering construction should pay attention to the problem were analyzed, thus to avoid risk, put forward to strengthen the project construction and management measures.

  10. Puente sobre el río Severn – Inglaterra

    Directory of Open Access Journals (Sweden)

    Editorial, Equipo

    1970-09-01

    Full Text Available The bridge described in this article has solved the increasing traffic problem in the South West of Wales. The total project involves the suspension bridge itself, a second bridge over the river Wye, and a 10 span metal viaduct, which joins both bridges, and runs over the Beachley peninsula. The suspension bridge is outstanding because of its main towers and the compact construction of the main deck, as well as for the oblique positioning of the secondary cables.El puente que se describe en el artículo ha venido a resolver el problema del tráfico creciente en el SO. del País de Gales. La obra completa comprende: el puente colgante propiamente dicho, otro puente sobre el río Wye y un viaducto metálico, de 10 tramos, que une a ambos, sobre la península de Beachley. Se trata de una solución muy interesante, por sus torres de suspensión, por la construcción compacta de su tablero y por la disposición oblicua de los cables, entre otros detalles.

  11. 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.

  12. A review of bridge scour monitoring techniques

    Directory of Open Access Journals (Sweden)

    L.J. Prendergast

    2014-04-01

    Full Text Available The high profile failure of the Malahide Viaduct in Dublin, Ireland, which is a part of the EU TEN-T network of critical transport links, was caused by foundation scour. Scour is a common soil-structure interaction problem. In light of current changes in climate, increasing frequency of flooding, coupled with the increasing magnitude of these flood events, will lead to a higher risk of bridge failure. Monitoring scour is of paramount importance to ensure the continued safe operation of the aging bridge asset network. Most monitoring regimes are based on expensive underwater instrumentation that can often be subjected to damage during times of flooding, when scour risk is at its highest. This paper presents a critical review of existing scour monitoring equipments and methodologies with a particular focus on those using the dynamic response of the structure to indicate the existence and severity of the scour phenomenon affecting the structure. A sensitivity study on a recently developed monitoring method is also undertaken.

  13. 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/

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

    Science.gov (United States)

    Arnaud, L.; Houel, A.

    2010-06-01

    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.

  15. 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

  16. Establish and Manage Jurisdiction-wide Traffic Monitoring Systems: North American Experiences%管辖范围内的交通监控系统的建立和管理:北美经验

    Institute of Scientific and Technical Information of China (English)

    钟鸣; 刘国新

    2007-01-01

    With the rapid motorization process in China, an increasingly complicated highway transportation system has been developed. Reliable national and provincial traffic monitoring systems are becoming necessary. A review of experiences from developed countries in North America can be helpful for highway administrations and agencies to design and implement effective and efficient traffic monitoring systems. Highway agencies in North America have over time developed "standard" traffic monitoring systems based on guidelines from the Federal Highway Administration (FHWA), the American Association of State Highway and Transportation Officials (AASHTO), and the American Society for Testing and Materials (ASTM). Common practices are adopted based on analyses of system accuracy, reliability, and cost-effectiveness. The common practices can produce equivalent and comparable traffic summary statistics, which are able to support sensible decision-makings at all aspects of highway transportation. The experiences of highway agencies, current practices, and related guidelines in North America are therefore presented first. Principles for guiding development and operation of traffic data programs are then summarized and reviewed. Existing problems and active research for traffic monitoring practices and standards are also identified and discussed. It is believed that the reviewed experiences, guidelines and principles will be helpful for China to establish effective and common-practice based "standard" traffic monitoring systems.%随着中国机动化进程的加快,高速公路运输系统日益复杂化,建立可靠的国家和地方交通监控系统已成为必需.回顾北美发达国家的经验对于高速公路的管理和设计部门设计及实施有效的交通监控系统是有益的.在联邦高速公路管理局(FHWA),美国州公路和运输官员协会(AASHTO)以及美国材料与试验协会(ASTM)的指导方针下,北美高速公路部门开发了一套"标准的"

  17. Study on combination of internal forces on bridges subjected to earthquake and heavy trucks based on Ferry Borges theory%基于Ferry Borges理论的地震与重卡车作用下桥梁内力的组合问题

    Institute of Scientific and Technical Information of China (English)

    孙得璋; 孙柏涛; George C. Lee

    2011-01-01

    The current AASHTO LRFD Bridge Design Specifications are mainly calibrated against gravity load and live load. However, they do not cover extreme load effects in a consistent probability-based fashion. Many seismic design specifications including LRFD mainly focus on seismic load, even not consider any other loads. And the time and method for identifying the factors of truck load in LRFD guide specification are not detailed. In this paper, earthquake load and truck load are time variable processes with their load characteristics. Based on some extreme loads data from USGS, it is very necessary to combine earthquake load and heavy truck load in seismic bridge de sign. Some methods for loads combination are compared and the Ferry Borges-Castanheta model is proposed, which considers loads lasting duration and happening probability and well describes how the random process converts to random variable and how it combines with other random variables. Finally, a simple example of bridge in Seattle is given for heavy truck load and earthquake load combination.%目前的AASHTO LRFD桥梁规范主要考虑重力荷载和卡车等活荷载的组合情况,而没有在概率基础上考虑地震等极端荷载的组合问题.包括LRFD在内的很多桥梁抗震规范都是主要考虑地震的作用,甚至设计时不考虑其他荷载的作用,LRFD设计指导手册中在考虑地震等极端荷载时,也只是提到在特殊情况和桥梁比较长的情况下再考虑卡车的作用,而且,也比较模糊.文中在考虑地震荷载与卡车荷载时将其视为2种随机过程函数,并分析其各自的荷载特点.结合最近一些年USGS收集的极端荷载数据,文中认为桥梁设计(考虑地震和重卡车设计)时应该综合考虑地震和重卡车的影响,对它们进行荷载组合.接着,文中简单回顾了几种荷载组合方法,对比之后,认为Ferry Borges(也称Ferry Borges-Castanheta模型)模型考虑了荷载的持时因素与荷载发生概

  18. 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

  19. Effect of high temperature curing on the compressive strength of concrete incorporating large volumes of fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Rivera-Villarreal, R. [Universidad Autonoma de Nuevo Leon, Monterrey (Mexico)

    2001-07-01

    The effect of using different types of heat treatment on the compressive strength of concrete with and without large volumes of fly ash was studied. Curing of concrete is important to obtain a good quality concrete, but it is important to keep concrete from drying until the originally water-filled space in fresh cement paste has been filled to the desired extent by the products of hydration. In hot weather, high temperature promotes faster drying of concrete so a given degree of hydration is reached more rapidly than at lower temperatures. The provision of moist curing is advantageous because of a gradual gain in strength and because of reduced plastic shrinkage and drying shrinkage-cracking. The portland cement content in all the mixtures used in this study was 200 kg per cubic metre and the amount of fly ash varied from 0 to 33, 43, 50 and 56 per cent by mass of the total binder. A superplasticizer was used to obtain 200-220 mm slump. The compressive strength was tested at 3, 7, 14, 28, 56 days and at 6 months. Results showed that, using ASTM standard curing, the compressive strength of portland cement concrete made at 35 degrees C was reduced by about 12 per cent at 28 days compared to that of the concrete made at 23 degrees C. The AASHTO curing strength was found to be a bit higher than with the ASTM curing. The concrete made at 35 degrees C showed no loss of strength when continuous moist-curing was applied. The fly ash concrete mixtures that were cast at 35 degrees C were cured by covering them with membrane curing compounds and placed under ambient conditions. It was crucial to allow enough curing water to promote the pozzolanic reaction. The membrane curing did not allow the ingress of water to the concrete mass. 6 refs., 4 tabs., 13 figs.

  20. Caracterización de los cuencos de deflexión en estructuras de pavimentos flexibles

    Directory of Open Access Journals (Sweden)

    Carlos Hernando Higuera Sandoval

    2010-12-01

    Full Text Available El propósito del  artículo es mostrar  la  caracterización de  los  cuencos de deflexión  en una  estructura de pavimento flexible y modelar el comportamiento del cuenco de deflexión ante la variación de los módulos de elasticidad y los espesores de las diferentes capas  que  integran  un modelo  estructural  de  pavimentos. El análisis de la deflexión se hace  teniendoen  cuenta  una  estructura  de  pavimento  flexible  de referencia,  constituida  por  una  capa  de  rodadura asfáltica, una capa de base granular y una capa de subbase granular, apoyado todo el paquete estructural  sobre  la  subrasante. Para  la modelación  de  los cuencos de deflexión se utilizó el programa BISAR 3.0 de la SHELL, y para el cálculo de los parámetros que caracterizan el cuenco de deflexión se utilizó lametodología de la AASHTO. Finalmente, se presentan  las  conclusiones  del  comportamiento  de  los cuencos de deflexión en pavimentos  flexibles. El artículo es producto del proyecto de investigación titulado Caracterización de los cuencos de deflexión

  1. CJJ 169-2012《城镇道路路面设计规范》沥青路面设计方法浅析%Analysis of Design Methods for Asphalt Pavement in CJJ 169-2012“Code for Design of Urban Road Pavement”

    Institute of Scientific and Technical Information of China (English)

    李洪; 谭练武

    2015-01-01

    This paper introduces design methods for urban road asphalt pavement from two aspects :one is brief introduction of design methods for asphalt pavement in CJJ 169 -2012 “Code for Design of Urban Road Pavement” according to design flow of asphalt pavement , the other is emphatic comment on major improvements , differences and some problems still existing in CJJ 169-2012 relative to design methods for asphalt pavement in design guidance documents including CJJ 37-90“Code for Design of Urban Roads”, JTG D50 -2006 “Code for Design of Highway Asphalt Pavement”, design methods in American Association of State Highway and Transportation Officials ( AASHTO) and SHELL design method, etc., and proposes opinions and recommendations for these improvements , differences and existing problems .%从2方面对城镇道路沥青路面设计方法进行介绍:一是按照沥青路面设计流程简要介绍CJJ 169—2012《城镇道路路面设计规范》的沥青路面设计方法;二是重点评述CJJ 169—2012相对于CJJ 37—90《城市道路设计规范》、JTG D50—2006《公路沥青路面设计规范》、美国各州公路和运输官员协会( AASHTO)设计法以及SHELL设计法等设计指导文件中沥青路面设计方法进行的主要改进、区别以及依然存在的一些问题,并对这些改进、区别以及存在的问题提出看法和建议。

  2. Section 3: Optimization of a 550/690-MPa high-performance bridge steel

    Energy Technology Data Exchange (ETDEWEB)

    Magee, A.B.; Gross, J.H.; Stout, R.D. [and others

    1997-04-01

    This project to develop a high-performance bridge steel was intended to avoid susceptibility of the steel to weld heat-affected-zone cracking and therefore minimize the requirement for preheat, and to increase its fracture toughness at service temperatures. Previous studies by the Lehigh University Center for Advanced Technology for Large Structural Systems have suggested that a Cu-Ni steels with the following composition was an excellent candidate for such a bridge steel: C/0.070; Mn/1.50; P/0.009; S/0.005; Si/0.25; Cu/1.00; Ni/0.75; Cr/0.50; Mo/0.50; V/0.06; Cb/0.010. To confirm that observation, 227-kg heats of the candidate steel were melted and processed to 25- and 50-mm-thick plate by various thermomechanical practices, and the weldability and mechanical properties determined. To evaluate the feasibility of reduced alloy content, two 227-kg heats of a lower hardenability steel were melted with C reduced to 0.06, Mn to 1.25, and Mo to 0.25 and similarly processed and tested. The results indicate that the steels were not susceptible to hydrogen-induced weld-heat-affected-zone cracking when welded without preheat. Jominy end-quench tests of the higher-hardenability steel indicate that a minimum yield-strength of 690 MPa should be readily attainable in thicknesses through 50 mm and marginally at 100 mm. The toughness of the steel readily met AASHTO specifications for Zone 3 in all conditions and thicknesses, and may be sufficiently tough so that the critical crack size will minimize fatigue-crack-extension problems.

  3. The Effects of Eggshell Ash on Strength Properties of Cement-stabilized Lateritic

    Directory of Open Access Journals (Sweden)

    Okonkwo U. N

    2012-04-01

    Full Text Available Eggshell ash obtained by incinerating Fowls’ eggshells to ash has been established to be a good accelerator for cement-bound materials and this would be useful for road construction work at the peak of rainy seasons for reducing setting time of stabilized road pavements. However this should be achieved not at the expense of other vital properties of the stabilized matrix. This is part of the effort in adding value to agricultural materials which probably cause disposal problems. Thus this study aimed at determining the effect of eggshell ash on the strength properties of cement-stabilized lateritic soil. The lateritic soil was classified to be A-6(2 in AASHTO rating system and reddish-brown clayey sand (SC in the Unified Classification System. Constant cement contents of 6% and 8% were added to the lateritic soil with variations in eggshell ash content of 0% to 10% at 2% intervals. All proportions of cement and eggshell ash contents were measured in percentages by weight of the dry soil. The Compaction test, California Bearing Ratio test, Unconfined Compressive Strength test and Durability test were carried out on the soil-cement eggshell ash mixtures. The increase in eggshell ash content increased the Optimum Moisture Content but reduced the Maximum Dry Density of the soil-cement eggshell ash mixtures. Also the increase in eggshell ash content considerably increased the strength properties of the soil-cement eggshell ash mixtures up to 35% in the average but fell short of the strength requirements except the durability requirement was satisfied.

  4. PRODUCTION OF CONSTRUCTION AGGREGATES FROM FLUE GAS DESULFURIZATION SLUDGE

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-12-01

    Through a cooperative agreement with DOE, the Research and Development Department of CONSOL Inc. (CONSOL R and D) is teaming with SynAggs, Inc. and Duquesne Light to design, construct, and operate a 500 lb/h continuous pilot plant to produce road construction aggregate from a mixture of wet flue gas desulfurization (FGD) sludge, fly ash, and other components. The proposed project is divided into six tasks: (1) Project Management; (2) Mix Design Evaluation; (3) Process Design; (4) Construction; (5) Start-Up and Operation; and (6) Reporting. In this quarter, Tasks 1 and 2 were completed. A project management plan (Task 1) was issued to DOE on October 22, 1998 . The mix design evaluation (Task 2) with Duquesne Light Elrama Station FGD sludge and Allegheny Power Hatfields Ferry Station fly ash was completed. Eight semi-continuous bench-scale tests were conducted to examine the effects of mix formulation on aggregate properties. A suitable mix formulation was identified to produce aggregates that meet specifications of the American Association of State High Transport Officials (AASHTO) as Class A aggregate for use in highway construction. The mix formulation was used in designing the flow sheet of the pilot plant. The process design (Task 3) is approximately 80% completed. Equipment was evaluated to comply with design requirements. The design for the curing vessel was completed by an outside engineering firm. All major equipment items for the pilot plant, except the curing vessel, were ordered. Pilot plant construction (Task 4) was begun in October. The Hazardous Substance Plan was issued to DOE. The Allegheny County (PA) Heat Department determined that an air emission permit is not required for operation of the pilot plant.

  5. 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.

  6. Effects of Waste Glass (WG on the Strength Characteristics of Cement Stabilized Expansive Soil

    Directory of Open Access Journals (Sweden)

    I.A.Ikara

    2015-11-01

    Full Text Available The study investigates the suitability of using waste glass (WG as admixture to cement stabilized black cotton soil (BCS for roads, fills and embankment. The soil was classified as A-7-5 and CH according to the American Association of State Highway and Transport Officials (AASHTO and the Unified Soil Classification System (USCS Classifications. Chemical analysis revealed that WG is rich in main oxides such as Silicon Oxide (69.2, Aluminium Oxide (2.29, Iron Oxide (1.57, Calcium Oxide (15.1 and Sodium Oxide (8.75. The soil was stabilized with 0, 2, 4, 6 and 8% cement and 0, 5 10, 15 and 20% WG by weight of the dry soil. Laboratory tests were carried out using the Standard Proctor (SP compactive efforts, California Bearing Ratio (CBR, Unconfined Compressive Strength (UCS, and compaction characteristics tests to evaluate the effectiveness of WG on Ordinary Portland cement (OPC stabilized BCS. The results obtained showed a decrease in the plasticity index (PI, liquid limit (LL, plastic limit (PL and increase Maximum Dry Density (MDD with increase in WG content in all cement proportions used and as compared to the values obtained for the natural soil. The peak 7 days UCS values of 1152kN/m2 was obtained at 8% OPC and 20% WG. Similarly, highest CBR value of 53.8% was obtained at an optimum blend of 8% OPC/20%WG. The results indicate that there is a potential in the use of WG as admixture to strengthen Black cotton soils.

  7. 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

  8. 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

  9. Paso superior en una ladera

    Directory of Open Access Journals (Sweden)

    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

  10. 运行列车辐射噪声源定位与声级定量分析研究%Running train noise source locating and quantitive prediction of sound pressure level

    Institute of Scientific and Technical Information of China (English)

    张海滨; 蒋伟康; 闫肖杰

    2015-01-01

    高架轨道交通的运行噪声影响沿线居民的正常工作和休息,建立一套适用于高架轨道交通噪声辐射的模型,有助于在建造轨道交通线之前合理的预估由于轨道交通造成的噪声辐射影响及传播特性,从而帮助改进设计方案。建立列车辐射噪声模型的首要任务是获得列车的噪声辐射特性。为达成此目的,采用波束形成方法重建列车外侧面的波束输出能量分布图,并利用参考传声器将波束输出能量修正为声压级,获得定量的声压级分布结果。运动声源波束形成方法结合能量修正方法,可以定量的获得列车辐射噪声声压级分布结果,得到比传统波束形成方法精确的结果。该方法用于重建某高架线轨道交通列车的噪声声级分布,结果与实际声场接近。试验分析表明方法可以用于高架轨道噪声辐射模型的定量分析。%The noise radiated by running trains on viaducts seriously influences people living or working along rail-lines.Optimizing the rail-line layout based on a train noise model alleviates the bad influence in advance.The characteristics of running train noise are obtained ahead for building the train noise model.Here,beam-forming combined with sound pressure level modification was presented for quantitively determining the distribution of sound pressure level on a train profile.The reference microphones were set in the reconstructing plane to modify the sound pressure level with the presented method.Subsequently,the characteristics of a running train noise were obtained quantitively.The method was applied to reconstruct the sound field induced by a running train on viaducts.The results agreed well with those of the real sound field.The method was verified with tests to be suitable for analyzing the train noise quantitively.

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

    Directory of Open Access Journals (Sweden)

    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

  12. Road Traffic Noise Level Assessment at an Institutional Area

    Directory of Open Access Journals (Sweden)

    Dev Swaroop

    2014-09-01

    Full Text Available Unplanned and rapid urbanization, industrialization, increasing number of vehicles, poor traffic management, poor road condition etc. are the major causes of higher noise levels in most of the Indian cities. Prolonged exposure to higher noise levels can lead to irreversible Noise Induced Hearing Loss (NIHL. Noise-induced hearing loss is contributing one-third to the total persons suffering from hearing loss in every country in the world. The present study aims at measuring the noise levels in the university campus to analyze the current situation and suggesting noise control measures to be adopted in University campus and along MMA Jauhar Marg. The numbers of vehicles were counted during November 17-21, 2012 and noise levels were measured at various pre decided locations. The traffic load in horizon years 2013, 2017, 2022, 2027 and 2032 on the MMA Jauhar Marg Road is predicted on the basis of observed traffic data and expected annual growth rate as 8.0% for pre Metro and 3.5% for post Metro. The noise levels were measured using Larson Davis Model 831 Class 1 Sound Level Meter on both sides of road at foot paths along MMA Jauhar Marg and at various receptor locations inside the different buildings in the university campus. Model RLS-90 is used for prediction of noise levels. The prediction of metro noise is carried out using statistical calculations. The combined noise levels were compared with standard criteria for silent zone and found on higher side. Installation of environment noise barrier is suggested as one of the noise control measure to be adopted along MMA Jauhar Marg and along metro viaduct to save students and staff from exposure of higher noise levels.

  13. 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.

  14. SIMULATION STUDY OF AERODYNAMIC FORCE FOR HIGH-SPEED MAGNETICALLY-LEVITATED TRAINS

    Institute of Scientific and Technical Information of China (English)

    LI Renxian; LIU Yingqing; ZHAI Wanming

    2006-01-01

    Based on Reynolds average Navier-Storkes equations of viscous incompressible fluid and k-ε two equations turbulent model, the aerodynamic forces of high-speed magnetically-levitated(maglev) trains in transverse and longitudinal wind are investigated by finite volume method. Near 80 calculation cases for 2D transverse wind fields and 20 cases for 3D longitudinal wind fields are and lyzed. The aerodynamic side force, yawing, drag, lift and pitching moment for different types of maglev trains and a wheel/rail train are compared under the different wind speeds. The types of maglev train models for 2D transverse wind analysis included electromagnetic suspension (EMS) type train,electrodynamic suspension (EDS) type train, EMS type train with shelter wind wall in one side or two sides of guideway and the walls, which are in different height or/and different distances from train body. The situation of maglev train running on viaduct is also analyzed. For 3D longitudinal wind field analysis, the model with different sizes of air clearances beneath maglev train is examined for the different speeds. Calculation result shows that: ① Different transverse effects are shown in different types of maglev trains. ② The shelter wind wall can fairly decrease the transverse effect on the maglev train. ③ When the shelter wall height is 2 m, there is minimum side force on the train.When the shelter wall height is 2.5 m, there is minimum yawing moment on the train. ④ When the distance between inside surfaces of the walls and center of guideway is 4.0 m, there is minimum transverse influence on the train. ⑤ The size of air clearance beneath train body has a small influence on aerodynamic drag of the train, but has a fairly large effect on aerodynamic lift and pitching moment of the train. ⑥ The calculating lift and pitching moment for maglev train models are minus values.

  15. 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.

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

    Science.gov (United States)

    Mialhe, P J

    2013-08-01

    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.

  17. 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.

  18. 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.

  19. 波纹钢腹板梁疲劳性能的试验研究%Experimental study on fatigue performance of the beam with corrugated steel webs

    Institute of Scientific and Technical Information of China (English)

    谭莲飞; 王清远; 王志宇; 吴彦增

    2012-01-01

    结合国内已建波纹钢腹板PC组合梁桥(平铁大桥)的波形尺寸,设计了4根Q345c高强钢的波纹钢腹板试验梁.试验首先对第一根梁(GA)进行四点弯曲静力试验,分析了其在竖向荷载作用下的受力特征和破坏形态;另外3根梁分别采用R=0.1,荷载下限分别为9,11,13 kN的不同条件下的疲劳试验.结果表明,由于波纹腹板的“折扇”效应,在弯矩作用下不完全满足平截面假定条件,弯矩主要由上下翼缘承受;二级焊缝条件下,试验梁波纹处焊缝能满足美国AASHTO规范B类焊接的疲劳强度,焊缝搭接位置以及构造处是该类型梁的疲劳薄弱位置之一.%Combined with the built box-girder bridge with corrugated webs named Ping Tie Bridge, designed 4 beams with corrugated webs of Q345c high-strength steel. The first beam ( CA) test for four-point bending static test, it tells the static characteristics and failure mode in the vertical load force. The other three beams were under fatigue test in different loading conditions, with R =0. 1 and the load lower limits were 9,11 ,13 kN respectively. The results show that there is a "folding" effect in the corrugated web,thus the beam does not fully meet the plane section assumption under the action of the moment which mainly endured by the upper and lower flange. Under second level welding condition, the weld of corrugated web and flange may meet fatigue strength of Class B specifications according to United States AASHTO. The overlap of welding or constructions on the beam may be the fatigue weak positions.

  20. NCHRP有关震区快速桥梁施工技术的研究

    Institute of Scientific and Technical Information of China (English)

    瓦泽姆·德克巴

    2015-01-01

    美国联邦公路局和许多州的交通厅一直在积极推行快速桥梁施工技术ABC,以便将施工对公共交通的影响最小化,并加强施工区域的安全。许多ABC技术已经成功地应用在那些地震较少的地区。联邦公路局在2009年出版的《桥梁预制构件和系统》一书中罗列了不少ABC技术的应用实例。然而,ABC技术的应用在地震较频繁区域却有所限制,因为对于各预制构件的连接要求更高。如果在震区应用ABC技术,可靠的连接设计是保证结构安全的必要条件。许多有关预制构件连接的技术创新和特殊设计为ABC技术在地震地区的广泛应用提供了保障,但是,至今为止,这些设计还没有经受现实生活中地震荷载的检验。另外,美国各州公路工作者协会(ASSHTO)的桥梁抗震设计指南禁止或限制在桥梁墩柱的塑性区使用结构连接。本文主要阐述了已完成的、正在进行的和将来立项的相关ABC技术桥梁抗震的研究。这些研究由国家公路研究部门直接管理,由美国各州公路工作者协会(AASHTO)资助,以帮助桥梁业主、制造商和承包商更好地在地震地区修建预制拼装类桥梁。

  1. Performance testing of asphalt concrete containing crumb rubber modifier and warm mix additives

    Science.gov (United States)

    Ikpugha, Omo John

    American Association of State Highway and Transportation Official's Mechanistic-Empirical Pavement Design Guide (AASHTO MEPDG) software was used to predict long term low temperature performance of the mixtures in various areas of Ontario. Sasobit, Rediset LQ and Rediset WMX gave good 15 years prediction with stone mastic asphalt mixtures but the performance of dense graded mixtures was less satisfactory.

  2. Anylisis of Effects of Gradation and Compaction Number on Mixture Performance%级配和压实次数对沥青混合料性能的影响分析

    Institute of Scientific and Technical Information of China (English)

    何昌轩

    2011-01-01

    This study investigates the effects of different aggregate gradations and compaction number on road performance of asphalt mixtures. The dynamic stability, low temperature bending failures strain, soaking marshall stability) AASHTO T283, split strengthen and freeze-thaw split strengthen are used to evaluate the road performance. Three gradations (Supl3, Sup20 coarse and Sup20 fine) and two compaction (100.125) number were selected. Means comparison using Tukey test is used to analyze. Increasing compaction number would bring on higher dynamic stability, low temperature bending failures strain, split strengthen and freeze-thaw split strengthen. Compared with fine gradation, coarse gradation gives higher dynamic stability, low temperature bending failures strain, split strengthens and freeze-thaw split strengthen under the same compaction number. There are no significant differences between water stability with coarse and fine gradation or different compaction number. Coarse gradation is top-priority compared with increasing compaction number.%以混合料的高温动稳定度、低温小梁弯曲应变、浸水马歇尔残留稳定度、劈裂强度、冻融劈裂强度以及AASH-TO T283劈裂强度比为评价指标,探讨集料级配和旋转压实次数对沥青混合料路用性能的影响.研究选取Sup13、Sup20粗、Sup20细3种级配和100次、125次的压实次数,用Tukey-Kramer方法对级配和设计旋转压实次数等水平的试验结果进行均值比较.结果表明:增加设计压实次数可以显著提高沥青混合料的高温动稳定度、低温弯曲破坏应变、劈裂强度和浸水劈裂强度,对混合料的水稳定性提高不显著.在相同设计压实次数下,粗级配相比细级配具有更显著的高温稳定性、低温抗裂性、劈裂强度和浸水劈裂强度,水稳定性相当.在混合料设计时,应优先考虑粗级配进行混合料设计.

  3. MARKET ASSESSMENT AND TECHNICAL FEASIBILITY STUDY OF PRESSURIZED FLUIDIZED BED COMBUSTION ASH USE

    Energy Technology Data Exchange (ETDEWEB)

    A.E. Bland; T.H. Brown

    1997-04-01

    Western Research Institute, in conjunction with the Electric Power Research Institute, Foster Wheeler International, Inc. and the US Department of Energy, has undertaken a research and demonstration program designed to examine the market potential and the technical feasibility of ash use options for PFBC ashes. Ashes from the Foster Wheeler Energia Oy pilot-scale circulating PFBC tests in Karhula, Finland, combusting (1) low-sulfur subbituminous and (2) high-sulfur bituminous coal, and ash from the AEP's high-sulfur bituminous coal-fired bubbling PFBC in Brilliant, Ohio, were evaluated in laboratory and pilot-scale ash use testing at WR1. The technical feasibility study examined the use of PFBC ash in construction-related applications, including its use as a cementing material in concrete and use in cement manufacturing, fill and embankment materials, soil stabilization agent, and use in synthetic aggregate production. Testing was also conducted to determine the technical feasibility of PFBC ash as a soil amendment for acidic and sodic problem soils and spoils encountered in agricultural and reclamation applications. The results of the technical feasibility testing indicated the following conclusions. PFBC ash does not meet the chemical requirements as a pozzolan for cement replacement. However, it does appear that potential may exist for its use in cement production as a pozzolan and/or as a set retardant. PFBC ash shows relatively high strength development, low expansion, and low permeability properties that make its use in fills and embankments promising. Testing has also indicated that PFBC ash, when mixed with low amounts of lime, develops high strengths, suitable for soil stabilization applications and synthetic aggregate production. Synthetic aggregate produced from PFBC ash is capable of meeting ASTM/AASHTO specifications for many construction applications. The residual calcium carbonate and calcium sulfate in the PFE3C ash has been shown to be of

  4. 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

  5. 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.

  6. Viaducto de ferrocarril, en Gerona

    Directory of Open Access Journals (Sweden)

    Fernández Casado, C.

    1975-02-01

    Full Text Available This article describes the construction of the 5 km long viaduct, with 20 m corbels, intended to facilitate the expansion towards the north-eastern part of the city, the stretch of which was interrupted upto now by the railway line Barcelona-Port Bou. In view of the special conditions of the work and the need to maintain the traffic during the entire construction time the system of two self supporting arch centerings was chosen. Transversally the dintel is of trapezoidal cross-section with overhangs and lightened internally with circular holes. Longitudinally a solution of a continuous beam was adopted. Thus whether joints nor anchorages were required. The foundation rests directly on footings. The construction has been carried out in prestressed concrete and can be divided into three basic parts: entry on the Barcelona side; passenger station; passenger station-río Ter.Se describe la construcción de un viaducto de unos 5 km de vía elevada, con vanos de 20 m de luz media, destinado a facilitar la expansión hacia el NE. de la ciudad, cortada hasta ahora por la línea del ferrocarril Barcelona-Port Bou. Dadas las condiciones particulares de la obra y el imperativo de mantener el tráfico en todo momento, se eligió el sistema de dos cimbras autoportantes. Transversalmente el dintel se resuelve a base de sección trapecial con voladizos, aligerado interiormente con alvéolos circulares. Longitudinalmente se adoptó la solución de viga continua, por las ventajas que representa en cuanto a supresión de juntas y de anclajes. Cimentación sobre zapatas directas. La construcción se ha realizado con hormigón pretensado y puede dividirse en tres partes fundamentales: Acceso lado Barcelona; Estación de viajeros; Estación de viajeros-río Ter.

  7. APPLICATION OF SYNCHRONOUS JACK-UP SYSTEM IN CORRECTION AND BEARING-REPLACEMENT OF CURVED BEAM%液压同步顶升系统在弯梁纠偏及支座更换中的应用

    Institute of Scientific and Technical Information of China (English)

    戴岩; 周天华

    2015-01-01

    The curved beam bridge is widely used in modern city viaduct.Because the complexity of its space stress mechanism, diseases are often found in curved beam bridge which could harm structural safety and serviceability.For this reason, such sort of bridge should be repaired.In this paper, some repair schemes were compared via finite element analysis based on a real bridge project.It is decided that synchronous jack-up system should be used for this project.This system has many advantages, especially when it is used in curved beam bridge.It was discussed the feasibility of using the system for repairing curved bridge project, based on the analysis of synchronous jack-up system’ s construction process, construction system, correction and bearing-replacement operation process.Through the analysis of monitoring data, the usability of this system was demonstrated in this kind of engineering project.In the end, some recommendations were put forward for popularizing.%弯梁桥在城市高架建设中被广泛应用,但由于其空间受力复杂,导致桥梁出现病害,影响其安全性与适用性,需对既有病害进行修复。选定某一工程实例,通过有限元分析对弯梁的维修方案进行比选,明确采用液压同步顶升系统进行维修施工,并进一步归纳该系统的优势。在详细分析液压同步顶升系统的施工流程、施工系统、纠偏与支座更换操作流程的基础上,通过分析监控数据,论证了此系统应用于弯梁纠偏及支座更换的可行性。

  8. 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.

  9. El túnel del Tyne – Inglaterra

    Directory of Open Access Journals (Sweden)

    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.

  10. Puentes Santa María y Pantano, en la Autopista del Sol (Italia

    Directory of Open Access Journals (Sweden)

    Frizzi, Dorian

    1966-03-01

    Full Text Available Of all the constructional features along the 750 km of the Milan-Napoles motor road, only the two above mentioned bridges will be described. Both have have a large radius curvature in the horizontal plane, two independent pavements, and in both cases the deck is supported by a palisade of cylindrical columns, some of them very tall and of considerable diameter. The main spans are 40 m long, and the piles can reach a height of up to 40 m above their base. The foundations of these have necessitated the adoption of pneumatic caissons. The longest beams of the Santa Maria bridge are prestressed, concreted in the workshop and placed with the aid of auxiliary girders and travelling cranes, which lift them to their final emplacement. At the Fosso Pantano viaduct the girders were concreted at one end of the deck, and were then transported to their final position with the help of a provisional tubular framework. The beams rest either on led or neoprene plates, in order to provide suitable flexible joints.Entre todas las obras de fábrica, construidas a lo largo de los 750 km de esta autopista Milán-Nápoles, se describen aquí sólo los dos puentes enunciados. Ambos tienen su eje en curva circular de gran radio, dos calzadas independientes y soportes formando palizadas de montantes de fuste cilíndrico, algunas de gran diámetro y altura. Los tramos de mayor importancia son de 40 m de luz, y sus soportes ganan la mayor cota a unos 40 m de la base. Para los cimientos de estos últimos ha sido necesario el empleo de cajones neumáticos. Las vigas de mayor longitud en el puente de Santa María son de hormigón pretensado, hormigonadas en taller y lanzadas con vigas auxiliares, provistas de un puente-grúa para llevarlas a su posición definitiva. En el viaducto de Fosso Pantano, las vigas se hormigonaron en una extremidad del tablero y se riparon después hasta llevarlas a su posición definitiva, para lo cual se preparó previamente un entramado tubular

  11. 城市道路特大断面双层隧道设计关键技术研究%Research on key technologies for extra-large section double-decked tunnel design on urban road

    Institute of Scientific and Technical Information of China (English)

    吴涛; 万利; 李振江

    2016-01-01

    双层隧道为解决城市地面交通堵塞问题提供了新思路,但相关的设计、施工方面的探讨较少。以济南市顺河高架南延工程可行性研究为工程依托,在充分调研国内外双层隧道研究现状的基础上,采用Midas/GTS有限元软件建立模型,对双层隧道的结构设计参数进行校核;同时,对双层隧道空间的实现、通风方式进行研究,并提出通过设置港湾式加宽段解决紧急情况下的人员逃生问题。研究结果表明:设计方案理论上是合理可行的,可为解决类似条件下交通拥堵问题提供借鉴。%As a new structure,the double-decked tunnel provides a new method to solve the traffic jam in the cit-y,but there is little investigation on its design and construction.The article was based on the feasibility research of the South Extension Project of the ShunHe Viaduct Bridge.The current research status of the double-decked tunnel at home and abroad was fully surveyed,and the finite element analysis software Midas/GTS was used to evaluate the tunnel support parameters for their rationality of the design.Meanwhile,this article also put forward how to car-ry out the idea of the double-decked tunnel in room and ventilation mode,as well as a design plan was provided to solve some emergency of personnel escape in the fire by setting up widened section bay.The results show the de-sign,which provides reference to other similar engineering projects in the future,is reasonable and feasible.

  12. Study on the Flow Rules of Highway Rainwater Runoff Pollutants%高速公路路面雨水径流污染物出流规律研究

    Institute of Scientific and Technical Information of China (English)

    徐明; 李贺; 傅大放

    2012-01-01

    Based on the monitoring data of rainwater runoff at Lukou viaduct of Nanjing airport highway, as well as the research achievements both at home and abroad, the flow rules of highway rainwater runoff pollutants were discussed, the event mean concentration ( EMC) and influential factors of the highway runoff were studied. The results showed that the flow rules of COD and SS were similar, when the precipitation a-mount and intensity were large, the concentrations of COD and SS were high, then gradually decreased and finally became stable, the primary runoff effect was significant; but when the precipitation amount and intensity became small, the concentrations of COD and SS experienced small fluctuations without significant primary effect. The rainwater runoff of road surface was seriously polluted, the EMCs of each pollutants were 238, 196, 3. 86, 11. 93 and 0. 89 mg/L for SS, COD, NH3-N and TP. The pollutants were influenced by the factors in this order; number of previous sunny days > precipitation intensity > rainfall amount and rainfall duration.%基于南京机场高速公路禄口高架桥降雨径流监测资料,结合国内外的研究成果,探讨了高速公路路面降雨径流污染物的出流规律,路面径流事件平均浓度及其影响因素.研究表明,COD与SS的出流规律基本类似,当降雨量和降雨强度较大时初期浓度较高,随后逐渐减小,最终趋于稳定,径流初期效应显著;当降雨量和降雨历时较小时,COD与SS浓度波动较小,初期效应不明显.路面降雨径流污染严重,各污染物EMC平均值分别为:SS 238 mg/L、COD 196 mg/L、NH3-N 3.86 mg/L、TN 11.93 mg/L、TPO.89 mg/L.降雨特性对各污染物影响权重为:前期晴天数>降雨强度>降雨量、降雨历时.

  13. 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

  14. 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

  15. 城市道路交通拥堵的分析及对策研究--以济南市为例%Analysis of Urban Road Traffic Congestion and Countermeasure Study:Take Ji'nan as an Example

    Institute of Scientific and Technical Information of China (English)

    赵华

    2016-01-01

    随着经济的发展,人们的生活质量也在不断提高,衣食住行都有了很大的转变,尤其是近几年来,私家车数量不断增多,这在方便人们出行的同时也增加了城市道路的负荷。济南作为省会城市,拥堵现象更是严重,虽然也采用了许多措施如拓宽道路、继续修建高架桥等等,但由于私家车增长速度过快,此类方法效果并不显著。本文从济南市交通状况的实际情况出发,通过提高道路运营车辆的满载率来实现车辆的合理利用,从而达到缓解交通拥堵的目的,并为其他城市治理交通拥堵的问题提供依据。%With the development of economy, people's living quality has been improved, causing great changes in basic necessities of life, especially the increasing number of private cars, which has increased the load of urban roads as well as making travel convenient. Ji'nan as the capital city, the traffic congestion is very serious. Although many measures have been taken such as widened pavement, and building more viaducts, but the effect is not significant due to the excessive growth of number of private cars. Based on the actual traffic situation of Ji’nan, this article studies to realize reasonable use of cars by improving the loading rate of operating cars on the road so as to ease traffic congestion and provide reference for other cities to deal with traffic congestion.

  16. Grey Target Optimization of Waterproof Adhesive Material for Concrete Bridge Deck Pavement Based on Mechanical Analysis%基于力学分析的桥面铺装防水粘结层材料灰靶优选

    Institute of Scientific and Technical Information of China (English)

    于新; 李英涛; 刘云

    2012-01-01

    为了优选与混凝土箱梁桥防水粘结层实际受力状态相匹配的材料,以沪杭高速公路拓宽改建工程高架桥为例,采用有限元法建立了全桥模型,在分析刹车、超载、随机动荷载等因素对防水粘结层力学响应的基础上,利用灰靶理论优选室内实测典型防水粘结层的相关技术参数.研究结果表明:刹车超载使防水粘结层产生的剪应力大于由桥面不平度引起的防水粘结层剪应力,最大可达0.397 MPa;橡胶沥青和SBS改性沥青防水粘结层综合性能较优,可作为混凝土桥防水粘结层材料.%In order to select the optimal waterproof adhesive material that meets the stress needs of concrete box girder bridge deck pavement, taking the viaduct in widening project of the Shanghai-Hangzhou Expressway as an example, a composite structure model of the whole bridge was established using the finite element method, and the influence of braking, overloading, random dynamic loading on the mechanical response of the waterproof adhesive layer was analyzed. The technique parameters of some typical materials for waterproof adhesive layer were tested in lab, and then analyzed by the grey target theory. The result shows that braking plus overloading has a larger effect on the shear stress of adhesive layer than the random dynamic loading caused by bridge deck roughness, and may produce a maximum shear stress of 0. 397 MPa. The rubber asphalt and SBS modified asphalt both have good performance, and can be used as the material of waterproof adhesive layer.

  17. El puente de Brotonne sobre el Sena - Francia

    Directory of Open Access Journals (Sweden)

    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

  18. Modelo de Evaluación Probabilística de la Seguridad Estructural de Puentes de Hormigón Model for Probabilistic Assessment of Structural Safety of Concrete Bridges

    Directory of Open Access Journals (Sweden)

    António A Henriques

    2006-01-01

    Full Text Available En este trabajo se describen las características principales de la metodología desarrollada para la evaluación probabilística de la seguridad y funcionalidad de puentes de hormigón teniendo en cuenta las relaciones constitutivas no lineales de los materiales, los efectos diferidos y las incertidumbres asociadas a los parámetros del proyecto de este tipo de estructuras. El modelo estructural está basado en las técnicas de los elementos finitos usando una formulación elasto-viscoplástica para la estimación precisa de la respuesta y de la capacidad resistente de estructuras de hormigón. Se presenta la aplicación de esta metodología a un viaducto de hormigón pretensado para evaluar el código computacional y para ilustrar su campo de aplicación. Los resultados obtenidos de los análisis fueron usados para identificar los parámetros más importantes para cada estado límite y las zonas críticas que deben ser cuidadosamente controladas para conseguir un mantenimiento racional.This study describes the main features of the methodology developed for the probabilistic assessment of safety and serviceability of concrete bridges, taking into account the non-linear constitutive relationships of the materials, time dependent effects, and uncertainty associated with the design parameters of these types of structure. The structural model is based on finite element techniques using an elasto-viscoplastic formulation for precise estimation of the response and ultimate strength of concrete structures. Application of this methodology to a prestressed concrete viaduct is presented to evaluate the computational code and to illustrate its scope of applicability. The results obtained from the analyses were used to identify the most important parameters for each limiting state studied, and the critical zones that should be carefully controlled to obtain rational maintenance.

  19. 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.

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

    Directory of Open Access Journals (Sweden)

    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

  1. 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

  2. Comparative Analysis of the Effect on Shrinkage and Creep of Concrete Due to Loading Age & Humidity%加载龄期及湿度对混凝土收缩徐变影响比较分析

    Institute of Scientific and Technical Information of China (English)

    郑江; 童锋发

    2014-01-01

    Taking one parameter variation between different loading time and different environmental relative humidity which are coming from reinforced and pre-stressed cement concrete design of high-way bridge (JTJ 023-85 )and (JTG D62-2004),pre-stressed and reinforced cement concrete design of railway bridge published in 1999 and 2005,AASHTO 1994 into consideration,shrinkage strain and creep coefficient of cement concrete according to different design specification are analyzed and com-pared.Some conclusions can be gained as follows:shrinkage strain of cement concrete is mainly asso-ciated with the relative humidity of environment;creep coefficient of cement concrete changes greatly according to different designing specification,creep coefficient of cement concrete which is only related to loading time and not relevant to relative humidity has a little change in railway specification;but creep coefficient is sensitive to humidity which is influenced by loading time and humidity in highway specification.So,humidity factor should be paid more attention for cement concrete maintenance dur-ing process of design and construction.The shrinkage strain and creep coefficient of cement concrete is comparatively reasonable in highway specification because more parameters are considered and there is a need of some appropriate adjustment in railway specification.%对《公路钢筋混凝土及预应力混凝土桥涵设计规范》(JTJ 023-85)和(JTGD62-2004)《铁路桥涵钢筋混凝土及预应力混凝土桥涵设计规范》99年版和2005年版、ASSHTO-1994规范中在相同条件下,通过不同的加载龄期、不同的环境相对湿度等其中一个参数变化时对各规范收缩应变、徐变系数进行分析和比较。主要结论为:混凝土收缩应变主要与环境的相对湿度有关;混凝土的徐变系数,各规范相差较大,铁路规范中徐变系数仅与加载龄期有关,与混凝土的所处相对湿度无关,且其徐

  3. GPR-based evaluation of strength properties of unbound pavement material from electrical characteristics

    Science.gov (United States)

    Benedetto, Andrea; D'Amico, Fabrizio; Tosti, Fabio

    2013-04-01

    the use of road material, typically employed for subgrade and subbase courses. Different types of soil ranging from group A1 to A4 by AASHTO soil classification system, are analyzed. As regards the laboratory experiments, material is gradually compacted in electrically and hydraulically isolated test boxes. A large metal sheet supports the experimental boxes, so that the transmitted GPR signal is totally reflected. GPR inspections are carried out for any compaction step up to the maximum density value available. Moreover, in-situ tests are carried out on targeted types of soil, with grain size distribution and texture comparable to those analyzed in laboratory environment. The results of this study confirm a promising correlation between the electric permittivities and the strength and deformation properties of the surveyed soils. Laboratory analyses show that the relationship between the relative permittivity and the bulk density is positive: the higher the density of the compacted soil sample, the higher the electric permittivity of the medium. Analogously, in-situ validation presents a good comparison between measured and predicted data. Percentage errors less than 20% demonstrate that a reliable prediction of Young Modulus using this GPR-based approach can be achieved.

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

    Institute of Scientific and Technical Information of China (English)

    耿波; 徐龙

    2012-01-01

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

  5. Using a Ground Based radar interferometer during emergency: the case of A3 motorway (Salerno Reggio-Calabria) treated by landslide

    Science.gov (United States)

    Del Ventisette, Chiara; Intrieri, Emanuele; Luzi, Guido; Casagli, Nicola

    2010-05-01

    An application of Ground Based radar interferometry (GB-InSAR) technique to monitor a landslide threatening infrastructures in emergency conditions is presented. During December 2008 and January 2009 intense rainfalls occurred in Italy, especially in the southern regions. These rain events occurred in the last days of January, worsened the already critical hydrogeological conditions of some areas and triggered many landslides. One of these landslides, named Santa Trada landslide, is located close to a periodical stream called Fiumara di Santa Trada, near Villa San Giovanni municipality (Reggio Calabria, Calabria Region). The volume involved is about 100 000 m3. This estimate represents the case of a collapse of the landslide which destabilize a larger part of the slope, involving other areas delimited by some fractures observed upstream. Nevertheless the landslide does not directly threaten the roadway, its complete collapse would hit the pillars of a motorway viaduct. Through GB-InSAR data it has been possible to obtain an overview of the area affected by movement and to quantify the displacements magnitude. The main benefit of the system was not only limited to the capability of fully characterizing the landslide in spatial terms, it also permitted emergency operators to follow, during the whole campaign, the evolution of the mass movement and to study its cinematic behaviour. This aspect is fundamental to evaluate the volume of the material involved and to assess the temporal evolution of the risk scenario. The GB-InSAR installed at Santa Trada points up toward the landslide from a distance of 250 m. The apparatus produces a synthesized radar image of the observed area every 6 minutes, night and day, with a pixel resolution of about 0.75 m in range and 1.2 m on average in cross range, performing a millimeter accuracy on the final displacement maps. The interferometric analysis of sequences of consecutive images allows the operator to derive the entire line of

  6. 高速铁路牵引供电接触网用带间隙避雷器的研制%Development of Metal Oxide Surge Arrester With Series Gap for Traction Power Supply System Catenary of High-speed Electrified Railway

    Institute of Scientific and Technical Information of China (English)

    边凯; 陈维江; 沈海滨; 李成榕; 王立天; 赵海军; 王彦利; 尹彬; 李庆余

    2013-01-01

    中国高速铁路线路高架桥路段比例大,且相对集中在雷电活动较强烈地区,牵引供电接触网雷击故障多,须采取措施加以解决.在接触网绝缘子旁并联安装带间隙避雷器是一种有效的防雷措施.根据接触网布局结构和运行可靠性要求高的特点,提出了一种与绝缘子一体化安装的避雷器分体结构型式,特别设计抱箍增强安装稳定性,提出了一种避雷器本体压力释了U型放结构可有效释放短路能量,研究选择了本体关键参数和串联间隙距离,确定了短路试验和振动试验方法和条件,对样品进行了雷电冲击放电伏秒特性试验、短路试验和振动试验,从而验证该技术性能的可靠性.最后,研制了适合接触网正馈线、接触线和加强线绝缘子使用的3种形式避雷器,并获国家发明专利授权,已在京沪高速铁路上试运行,状态良好.%In China, viaduct sections are widely adopted in high-speed electrified railway lines and most of the lines go through strong lightning activity areas. This leads to high lightning stroke failure rate of traction power supply catenary. To install metal oxide surge arrester with series gap(GMOA) parallel with insulators is an ideal lightning protection measure to solve the problem. In the paper, a kind of arrester and insulator integral mounting structure type was put forward, U-shaped clamp was specially designed to enhance the stability of the installation, an arrester body pressure release structure was presented to release the short-circuit energy effectively, the primary parameters of MOA body and the distance of series gap were selected, the test methods and conditions of short-circuit test and vibration test were provided, and the samples proved reliable by the results of lightning impulse test .short-circuit current test and vibration test. Three kinds of GMOA products with positive feeder/contact wire/strengthened contact wire insulators were

  7. Analysis on the Debris Flow Characteristics and Effectiveness of Prevention Proj ects in Huangyang Gully in Longchi Town of Duj iangyan City%都江堰市龙池镇黄央沟泥石流特征与防治工程效果分析

    Institute of Scientific and Technical Information of China (English)

    曾庆铭; 薛强; 徐继伟

    2014-01-01

    Huangyang gully is located in Longchi town of Dujiangyan city,a severe disaster area of Wenchuan earthquake in Sichuan province.The earthquake induced large scale collapses and landslides which provided plenty of loose solid material for debris flow.The debris flow activity was very active after earthquake.Under the effect of heavy rainfall,debris flow occurred in the Huangyang gully both on August 13 and August 18 of 2010 as well as on July 9 of 2013,which has caused serious economic losses.Based on the field investigation of debris flow disaster,this paper presented a detailed analysis of the formation conditions and development characteristics of the debris flow,and discussed the effectiveness of debris flow prevention projects.For the problems of prevention proj ects and the characteristics of debris flow,following measures has been put forward by the authors:building drainage ditches in the downstream and accumulation region of debris flow to make the debris flow into Longxi river smoothly;and taking engineering and biological measures to stabilize landslides accumulation body and unstable slopes;besides,the road in the exit position of debris flow should adopt viaduct across the debris flow fan.The study results could provide a reference for the prevention and control of debris flow disaster in strong earthquake area.%黄央沟位于“5.12”汶川地震的极重灾区四川省都江堰市龙池镇,地震使沟内山体发生大规模的滑坡和崩塌,其为泥石流的形成提供了丰富的松散固体物质。地震后黄央沟泥石流十分活跃,2010年8月13日、8月18日和2013年7月9日均暴发了泥石流,造成了严重的经济损失。笔者通过对黄央沟泥石流灾害现场进行实地调查,详细分析了黄央沟泥石流的形成条件和发育特征,并对已有防治工程效果进行了分析和探讨。针对防治工程存在的问题和黄央沟泥石流的特点,建议在沟道下游和堆积区修建排导沟,使泥石流

  8. El viaducto de San Giuliano, en Italia

    Directory of Open Access Journals (Sweden)

    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

  9. 薄壁波纹钢管混凝土柱滞回性能试验研究%Experimental study on the hysteretic behaviors of thin-walled corrugated concrete-filled steel tube column

    Institute of Scientific and Technical Information of China (English)

    高剑平; 吴永根; 霍静思

    2012-01-01

    exceed three. The law and degree of strength degradation and stiffness degradation are almost the same. In general, the seismic performance of thin-walled corrugated steel concrete column is almost the same or even better than that of circle and square thin-walled steel concrete column. The research results could give a reference to analysis and design of urban elevated viaducts.

  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

  11. 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