【作者】 闫金鑫；

【导师】 倪永军； 李江；

【作者基本信息】 北京交通大学 ， 桥梁与隧道工程， 2012， 硕士

【摘要】 桥梁是交通生命线系统中的重要组成部分。我国过去对桥梁抗震不够重视和设防目标偏低,导致许多已建桥梁抗震能力不足,因此开展桥梁的抗震性能研究工作十分必要。本文结合我国桥梁结构的特点及国内外有关研究,采用增量动力分析方法(IDA)对简支梁桥桥墩进行性能评估,并分析研究了墩高、墩顶质量及配筋率对其性能点的影响。另外本文还选取了125条地震记录对墩高一致的钢筋混凝土连续梁桥和墩高不一致的钢筋混凝土连续梁桥进行非线性动力时程分析,然后建立桥墩、支座及全桥的易损性曲线,对此两类桥的易损性进行全面系统的研究。综合起来,本文主要做了以下几部分的工作：(1)在查阅大量国内外文献的基础上,对IDA分析方法及易损性分析的发展和研究现状进行了系统的回顾和全面的总结。(2)参照国内外有关研究,采用IDA分析对简支梁桥桥墩进行性能评估的方法,并分析墩高、墩顶质量、配筋率对性能点的影响。结果表明墩高的变化对结构性能点的影响较大；墩顶质量的变化对结构性能影响不大；配筋率的改变对性能点OP、IO、LS影响较小,而对性能点CP影响较大。(3)为进行连续梁桥易损性研究,选取PGA为地震动强度指标,结合国内外关于损伤状态和损伤指标的研究,最终确定了以位移延性比作为墩柱的损伤指标,位移作为支座的损伤指标。(4)以某墩高一致的3跨钢筋混凝土连续梁桥为算例,选取125条地震记录,进行非线性动力时程分析,然后建立桥墩、支座及桥梁系统的易损性曲线,并对所得易损性曲线进行对比分析。得出结论：桥墩在不同PGA下的失效概率相同；滑动支座与固定支座的失效概率差别较大；桥梁作为一个整体,比任何一个构件在地震作用下更容易受到损坏。(5)鉴于实际工程中墩高不一致的桥梁居多,本文进一步研究墩高不一致的钢筋混凝土连续梁桥,用同样的地震记录对桥梁进行非线性动力时程分析,然后建立桥墩、支座及桥梁系统的易损性曲线,对所得易损性曲线进行比较。结果表明：在轻微破坏状态下,1#、2#桥墩的失效概率几乎一致；而在中等破坏、严重破坏和倒塌破坏状态下两者的失效不同,其中2#桥墩(矮墩)的失效概率略大。2#桥墩(矮墩)处的板式橡胶支座较1#桥墩处的板式橡胶支座易破坏。(6)对比墩高不一致和墩高一致的钢筋混凝土连续梁桥桥梁系统的易损性曲线：在轻微破坏、中等破坏和严重破坏状态下,两类桥的易损性曲线差异性较小,而倒塌破坏阶段,两条易损性曲线的差别明显。墩高不一致的桥梁比墩高一致的桥梁有更高的失效概率。更多还原

【Abstract】 The bridge is an important part of transportation systems. Due to the neglect of bridge earthquake-resistance and low design criteria in the past, the seismic capacity of many constructed bridges are weak, therefore it is necessary to carry out the research on seismic performance of bridge. According to bridge characteristics in China, this thesis proposed a method to analyze the seismic performance of the simply supported beam bridge piers with Incremental dynamic analysis method(IDA) and then do the research on the influence of the pier height, weight above the pier and reinforcement ratio. Then,125seismic records are used to analysis the continuous-beam bridge with the same piers height and the different piers height in nonlinear dynamic time-history analysis. The fragility curves are established to analysis piers, bearing and the bridge system. Above all, the main processes are as follows:(1) Based on the comprehensive reading and understanding of related study home and abroad, this thesis conducted a systematic review and comprehensive summary of the IDA analysis methods and the development of fragility analysis.(2) In this thesis, the seismic performance of the simply supported beam bridge piers is researched with IDA analysis method, and analyse the effect of the pier height, the weight on the top of pier and reinforcement ratio on the performance point. The results show that: pier height changes the pier seismic performance most, while the weight on the top of pier almost has no influence on it. The reinforcement ratio influences the performance point OP, IO, LS slightly and CP huge.(3) To analysis the fragility of the continuous girder bridge, PGA is selected as the ground motion intensity measure, while the displacement-ductility ratio, displacement are selected as the damage measures of the pier and the bearing refer to the related researches.(4) Taking a continuous girder bridge with the same pier height as example, the fragility curves of piers, bearings and the bridge are established after a serious of nonlinear dynamic-history analysis. Then the research on the curve rules and their differences is done. The research shows that the failure probability of different piers is indifferent. After suffering from a slightly earthquake, the laminated rubber bearing is easily slightly and moderately damaged than PTFE rubber bearing; but the PTFE rubber bearing is easily damaged at seriously damaged and collapsed. Bridge, as a whole, is easily damaged than any of the components.(5) Most of the bridges have different piers height actually, So it is necessary to do the research on the these bridge. The same seismic records can to do time-history analysis to establish the fragility curves, the comparison shows that the failure probability of the1#and2#piers are almost the same when they are slightly damaged, while it is different under moderately damaged, seriously damaged and collapsed, the lower pier is easily damaged. The laminated rubber bearing on the lower pier is easily damaged.(6) Compare the fragility curves of the two kinds of bridges, it can be saw that the fragility curves are almost the same while the whole bridge is slightly damaged, moderately damaged and seriously damaged, the asymmetrical bridge is higher that the symmetrical one, the curves are apparently different while the whole bridge is s collapsed.更多还原