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1.
汶川大地震公路桥梁震害初步调查 总被引：17，自引：4，他引：13
2008年5月12日我国四川省汶川县发生8级大地震,造成大量公路桥梁破坏。本文详细介绍了百花大桥、小鱼洞大桥、庙子坪大桥、龙尾大桥等9座典型公路桥梁的震害情况及原因。这个地区的桥梁主要为桥面连续简支梁桥,支座多为直接搁置的板式橡胶支座,地震中稳定性较差,主梁与桥墩连接较为薄弱,更多地发生横、纵向移位,乃至最终落梁。这种薄弱连接一定程度上降低了桥墩的地震荷载,总体上看桥墩震害较轻,但从破坏的桥墩、拱肋、盖梁来看,直接剪切或形成弯曲塑性铰后的剪切破坏较为多见。提出了公路桥梁抗震设计若干建议,涉及桥台抗震稳定性及强度校核、曲线梁桥和高墩桥梁设计、支座及防落梁措施设计、桥墩及构件延性设计、场地液化等多个方面。强调了抗震构造措施能够维持公路桥梁大震后应急通行功能的"最强设计原则"。 相似文献
2.
《地震工程与工程振动》2017,(2)
桥梁作为生命线工程的重要组成部分,一旦在地震中发生破坏,会造成巨大的经济损失和社会损失。地面上相邻的桥跨结构由于其动力特性存在差异及地震动输入的空间变化特性,地震发生时会引起相邻桥跨间的非同向振动,当桥跨间预留的间隙不能满足彼此的相对位移时就会发生相互碰撞,间隙过大时很容易引起落梁。针对相邻桥跨间的碰撞和落梁问题,对历次大地震中与碰撞和落梁相关的震害进行了回顾,介绍了纵桥向各种防碰撞与防落梁措施的研究现状,主要包括限位器、阻尼限位装置、模数式伸缩缝、减震装置以及组合限位装置五个方面。同时通过对研究现状的分析对以上各种防碰撞与防落梁措施的优点和缺点分别进行总结,进而对有待进一步研究的问题进行了展望。 相似文献
3.
2021年5月22日青海玛多发生了Ms7.4级地震,从地震中桥梁震害情况看:此次地震的特点是断层北侧震害轻,南侧震害重。位于断层南侧的野马滩大桥是简支梁桥,发生大量落梁,是此次地震中受损最为严重的大桥之一;而位于北侧的大野马岭大桥是连续梁桥,仅发生了部分挡块开裂。其中原因值得深入研究。本文通过有限元分析软件Midas/Civil建立大野马岭大桥（上行线）模型,进行地震反应分析,讨论分析了大野马岭大桥在此次地震中的震害机理。发现南北向的地震动是造成该桥横向挡块破坏的主要原因,东西向地震动因受到桥台和纵向挡块的约束并没有出现严重损伤。若将该桥由连续梁桥变成简支梁桥,地震反应会有所变化,但总体趋势特点变化并不大。另外,本文通过现有资料选定5组地震动作为输入,进行地震反应分析,比较分析不同地震动对该桥的影响,并验证地震动模拟效果。 相似文献
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地震序列下落梁震害的防灾设计分析 总被引：1，自引：0，他引：1
地震的发生具有丛集的特征,主震发生之后通常伴随余震,主震震级越高其余震震级亦越高,对结构的破坏越大.桥梁结构作为重要交通枢纽工程,其在整个地震序列发生时应能确保通行.为得到桥梁结构在地震系列作用下的响应,选用集集地震序列对桥梁进行地震响应分析,结果显示结构在主震作用下发生落座,余震时有发生落梁的可能,对结构设置连梁装置,验证其在地震序列中的防落梁效果.结果显示连梁装置可有效减小桥梁上、下部结构相对位移,同时可提高结构整体性,使各桥墩平均分配地震力,并能在地震序列中有效防止落梁震害的发生. 相似文献
5.
地震作用下隔震简支梁桥碰撞反应的振动台试验 总被引：2，自引：0，他引：2
由地震引发的碰撞是影响桥梁地震反应以及造成桥梁破坏的重要因素。本文对地震作用下隔震简支梁桥的碰撞反应进行了振动台试验。设计制作1个两跨简支的隔震梁桥模型,试验研究了梁间隙、邻梁质量比、隔震支座类型等参数对桥梁碰撞反应的影响。试验结果表明邻梁间隙、邻梁质量比、隔震支座类型等参数对桥梁的碰撞反应有着显著的影响。邻梁间隙越大,碰撞次数越少;邻梁质量比越大,撞击力越大。铅芯橡胶支座比板式橡胶支座耗能能力更强,可以有效降低邻梁之间的撞击力甚至避免碰撞发生。从而为桥梁防碰撞设计提供了可靠的试验依据。 相似文献
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为深入研究液化场地梁的约束对桥台震害模式的影响,首先在对唐山地震中胜利桥震害调查的基础上,采用有限元软件UWLC对该桥震害进行数值模拟分析,并将数值模拟结果与实际震害结果进行对比验证。研究结果表明:数值模拟结果与实际震害结果基本一致,说明采用UWLC软件进行震害数值模拟分析是可行的。然后对有、无桩基条件下梁的约束力和液化层厚度对桥台震害模式的影响分别进行数值模拟分析。研究结果表明:在地震作用下,桥梁发生落梁破坏后会导致桥台的滑移破坏更为严重。与无桩基的重力式桥台不同,桩基桥台的震害模式均表现为前倾式破坏,这主要是因为桩基础限制了桥台底部的水平移动。梁的约束力对桩基桥台震后残余位移的影响程度要明显小于无桩基桥台。对于重力式桥台,液化砂层对地震波的中高频段有一定滤波作用,反映出液化层的减震作用;而对于桩基桥台,由于桩-土-台身的相互作用,液化砂层的减震效果不明显。 相似文献
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应用一款自主设计的油阻尼器进行了力学性能及简支梁桥减振试验研究。通过用FCS-250k N电液伺服控制作动器对油阻尼器进行加载试验,得出油阻尼器阻尼系数等参数。试验结果表明,本试验所用油阻尼器具有十分理想的速度相关特性,F-V图形在一定工作速度范围内呈线性关系,且具有良好的滞回性能。经过与典型实际桥梁的质量、刚度、频率以及初始阻尼比的组合计算,典型公路、铁路简支梁桥安装本油阻尼器后,在线弹性阶段可实现结构总体阻尼比在5%—20%之间可调;在强地震作用下,可实现梁体滑移限位,避免落梁,确保强地震后桥梁的可通行性。因此,油阻尼器在我国中小型简支梁桥抗震方向具有很大的发展前景。 相似文献
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《地震工程与工程振动》2015,(5)
强震作用下,简支梁桥固定支座容易发生破坏导致相邻梁体和梁台间产生较大的相对位移,引发邻梁碰撞,造成梁体的损坏甚至落梁。本文以我国西部某典型4×30 m公路简支梁桥为工程背景,分析了4种不同地震动激励下的碰撞效应,并在梁体间和梁台间引入限位索,进行了防碰撞研究。结果表明:在峰值加速度为0.30 g的地震动激励下,固定支座均出现了剪坏现象,梁体和梁台间最大相近位移超过了邻梁间距,均发生了碰撞;限位索可以有效地避免梁体间碰撞现象的发生,但在实际选用限位索数量时,既要考虑防碰撞效果,又要防止限位索拉断现象。 相似文献
9.
汶川大地震曲线梁桥震害及破坏机理分析 总被引：4，自引：0，他引：4
以汶川大地震中严重破坏的回澜立交桥为例,基于数值模拟手段并结合现场震害调查,分析了回澜立交桥的地震破坏机理。数值分析表明,地震时设有支座的最矮的1号桥墩支座发生滑移破坏,以致刚度较大（次矮）的2号刚构桥墩承受很大的地震惯性力,2号墩首先发生弯曲屈服,此后随延性发展因抗剪能力不足最终发生剪切破坏直至倒塌损毁,呈现典型的弯剪破坏特征。现场震害调查发现,回澜立交桥震害集中于抗弯刚度较大的刚构墩上,而其余桥墩震害相对较轻,主要表现为混凝土保护层的脱落、混凝土开裂以及墩顶支座的滑移破坏等。数值分析结果与震害调查呈现出较好的一致性。 相似文献
10.
2022年3月16日日本福岛县发生了M7.4级地震，不仅造成了大量铁路基础设施破坏，而且导致了一辆行驶中的新干线列车脱轨。本文介绍了东北新干线在此次地震中的震害特点和应急功能恢复情况，总结了此次地震震害的典型特征及启示。通过与2021年福岛地震和2011年东日本大地震的震害情况进行比较，从强震特点、列车脱轨、土木结构损伤和电气设施损伤等几方面对该铁路系统在此次地震中的震害特点进行了分析，从抗震韧性角度讨论了此次地震应急恢复时间，总结了日本铁路设施抗震的经验和对我国铁路设施抗震的启示。分析表明：随着地震强度的增大，可能伴有轨道变形、墩柱开裂和横系梁开裂等震害现象，甚至出现列车脱轨。从震害现象的比较中，可以看出东日本大地震以来的维修加固措施是具有一定成效，但列车防脱轨系统的有效性还需进一步检验，设计还需进一步完善。 相似文献
11.
1 Introduction Structural retro?t techniques (Roberts, 2005), such as restrainers, concrete shear keys, steel jackets, CFRPshells, base isolators, or dampers have been widely studied and implemented in actual structures based on the experiences learned from past earthquakes. In the Chi-Chi earthquake (EERI, 2001), the damage to simply-supported PCI girder bridges provided a different view from which to examine the function of a rubber bearing system for simply- supported bridges (NCREE,… 相似文献
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This paper presents an experimental study to investigate the performance of shape memory alloy(SMA) restrainers for mitigating the pounding and unseating of highway bridges when subjected to seismic excitations.Mechanical property tests of the SMA wire used in the restrainers are conducted first to understand the pseudo-elastic characteristics of the material.Then,a series of shaking table tests are carried out on a highway bridge model.The structural responses of the highway bridge model equipped with SMA restrainers,installed in the form of deck-deck and deck-pile connections,are analyzed and compared with the uncontrolled structures.The test results of this study indicate that the SMA restrainers are not only effective in preventing unseating but also in suppressing the seismic-induced pounding of the highway bridge model used in this study. 相似文献
13.
Many highway bridges were severely damaged or completely collapsed during the 2008 Wenchuan earthquake.A field investigation was carried out in the strongly affected areas and over 320 bridges were examined. Damage to some representative highway bridges is briefly described and a preliminary analysis of the probable causes of the damage is presented in this paper. The most common damage included shear-flexural failure of the pier columns, expansion joint failure, shear key failure, and girder sliding in the transversal or longitudinal directions due to weak connections between girder and bearings. Lessons learned from this earthquake are described and recommendations related to the design of curved and skewed bridges, design of bearings and devices to prevent girder collapse, and ductility of bridge piers are presented.Suggestions for future seismic design and retrofitting techniques for bridges in moderate to severe earthquake areas are also proposed. 相似文献
14.
Evgueni T. Filipov Jessica R. Revell Larry A. Fahnestock James M. LaFave Jerome F. Hajjar Douglas A. Foutch Joshua S. Steelman 《地震工程与结构动力学》2013,42(9):1375-1394
Modern highway bridges in Illinois are often installed with economical elastomeric bearings that allow for thermal movement of the superstructure, and steel fixed bearings and transverse retainers that prevent excessive movement from service‐level loadings. In the event of an earthquake, the bearing system has the potential to provide a quasi‐isolated response where failure of sacrificial elements and sliding of the bearings can cause a period elongation and reduce or cap the force demands on the substructure. A computational model that has been calibrated for the expected nonlinear behaviors is used to carry out a parametric study to evaluate quasi‐isolated bridge behavior. The study investigates different superstructure types, substructure types, substructure heights, foundation types, and elastomeric bearing types. Overall, only a few bridge variants were noted to unseat for design‐level seismic input in the New Madrid Seismic Zone, indicating that most structures in Illinois would not experience severe damage during their typical design life. However, Type II bearing systems, which consist of an elastomeric bearing and a flat PTFE slider, would in some cases result in critical damage from unseating at moderate and high seismic input. The sequence of damage for many bridge cases indicates yielding of piers at low‐level seismic input. This is caused by the high strength of the fixed bearing element, which justifies further calibration of the quasi‐isolation design approach. Finally, the type of ground motion, pier height, and bearing type were noted to have significant influence on the global bridge response. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
15.
通过对分别采用板式支座和铅芯支座的2座3跨连续梁桥模型进行振动台试验,对比分析了这2类桥梁的动力特性、破坏过程及2种支座对连续梁桥地震反应的影响。研究结果表明：地震波特性对桥梁结构的地震反应有较大影响,在对桥梁结构进行抗震设计时,需选择合理的地震动输入;在地震强度较小时,板式支座的滑动能够起到一定的隔震效果,铅芯支座的隔震性能能得到较好的发挥;在地震强度较大时,铅芯支座的隔震性能不能得到很好的发挥,采用铅芯支座的桥梁地震反应不一定小于普通桥梁;通过合理的设计,2类桥梁都完全可以实现大震不倒的设防目标。 相似文献
16.
Cheung Pakchiu 《地震工程与工程振动(英文版)》2012,11(2):173-183
During past strong earthquakes, highway bridges have sustained severe damage or even collapse due to excessive displacements and/or very large lateral forces. For commonly used isolation bearings with a pure friction sliding surface, seismic forces may be reduced but displacements are often unconstrained. In this paper, an alternative seismic bearing system, called the cable-sliding friction bearing system, is developed by integrating seismic isolation devices with displacement restrainers consisting of cables attached to the upper and lower plates of the bearing. Restoring forces are provided to limit the displacements of the sliding component. Design parameters including the length and stiffness of the cables, friction coefficient, strength of the shear bolt in a fixed-type bearing, and movements under earthquake excitations are discussed. Laboratory testing of a prototype bearing subjected to vertical loads and quasi-static cyclic lateral loads, and corresponding numerical finite element simulation analysis, were carried out. It is shown that the numerical simulation shows good agreement with the experimental force-displacement hysteretic response, indicating the viability of the new bearing system. In addition, practical application of this bearing system to a multi-span bridge in China and its design advantages are discussed. 相似文献
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18.
Damage investigation of small to medium-span highway bridges in Wenchuan earthquake revealed that typical damage of these bridges included: sliding between laminated-rubber bearings and bridge girders, concrete shear keys failure, excessive girder displacements and even span collapse. However, the bearing sliding could actually act as a seismic isolation for piers, and hence, damage to piers for these bridges was minor during the earthquake. Based on this concept, an innovative solation system for highway bridges with laminated-rubber bearings is developed. The system is comprised of typical laminated-rubber bearings and steel dampers. Bearing sliding is allowed during an earthquake to limit the seismic forces transmitting to piers, and steel dampers are applied to restrict the bearing displacements through hysteretic energy dissipation. As a major part of this research, a quarter-scale, two-span bridge model was constructed and tested on the shake tables to evaluate the performance of this isolation system. The bridge model was subjected to a Northridge and an artificial ground motion in transverse direction. Moreover, numerical analyses were conducted to investigate the seismic performance of the bridge model. Besides the test bridge model, a benchmark model with the superstructure fixed to the substructure in transverse direction was also included in the numerical analyses. Both the experimental and the numerical results showed high effectiveness of this proposed isolation system in the bridge model. The system was found to effectively control the pier-girder relative displacements, and simultaneously, protect the piers from severe damage. Numerical analyses also validated that the existing finite element methods are adequate to estimate the seismic response of bridges with this isolation system. 相似文献
19.
Damage investigation of girder bridges under the Wenchuan earthquake and corresponding seismic design recommendations 总被引：9，自引：3，他引：6
An investigation of girder bridges on National Highway 213 and the Doujiangyan-Wenchuan expressway after the Wenchuan earthquake showed that typical types of damage included： span collapses due to unseating at expansion joints; shear key failure; and damage of the expansion joint due to the slide-induced large relative displacement between the bottom of the girder and the top of the laminated-rubber bearing. This slide, however, can actually act as a form of isolation for the substructure, and as a result, the piers and foundation of most of the bridges on state route 213 suffered minor damage. The exception was the Baihua Bridge, which suffered severe damage. Corresponding seismic design recommendations are presented based on this investigation. 相似文献