京沪高速铁路沧德特大桥地震反应分析

Analysis of Seismic Response of Cangde Bridge on Beijing-Shanghai High Speed Railway

沧德特大桥为京沪高速铁路上的一座(80+128+80)m连续梁桥,为评估该桥的抗震性能,建立全桥有限元动力分析模型,进行动力特性分析、弹性及弹塑性时程反应分析,并根据2009年版《铁路工程抗震设计规范》三水准抗震设防要求进行抗震性能验算。分析结果表明:该桥纵向、横向1阶自振周期均小于1.0s,与地震动的主要周期存在共振成分,地震反应较大;多遇地震作用下,桥墩及桩基础的强度满足规范要求;设计地震作用下,支座抗剪能力满足规范要求;罕遇地震作用下,桥墩纵、横向抗剪能力及塑性铰区的变形能力均满足规范要求。该桥满足了"小震不坏,大震不倒"的抗震设防目标。

The Cangde Bridge is a （80＋128＋80）m continuous beam bridge on the Beijing Shanghai High Speed Railway. In order to appraise the seismic performance of the bridge, the fi nite element dynamic analytical model of the overall bridge was set up to carry out the dynamic property analysis, elasticity and elastoplastic time history analysis, and the seismic performance was checked in accordance with the requirements of threelevel seismic prevention suggested in the Code for Seismic Design of Railway Engineering （2009 Edition）. The results of the analysis indica ted that in both the longitudinal and transverse directions, the 1st order natural vibration period was less than 1.0 s, which had resonant proportion with the main seismic vibration periods and the seismic response is greater. Under the action of lowlevel earthquakes, strength of the piers and the pile foundations could meet the code requirements. Under the action of design earthquakes, the shear bearing capacity of the bearings were able to meet the code requirements; and in case of the highlevel earthquakes, the shear bearing capacity of piers in both the longitudinal and transverse directions and the deformability in the plastic hinge region were able to meet the code require ments. The bridge meets the seismic defense principle of ＂no damages occurring under lowlevel earthquakes and being not able to collapse under highlevel earthquakes＂.