近场竖向地震动对铁路桥梁地震反应的影响  

Influence of vertical component of near-fault ground motions on seismic response of RC railway bridges

作　　者：张显明[1] 朱晞[1] 

机构地区：[1]北京交通大学土木建筑工程学院,北京100044

出　　处：《华北科技学院学报》2005年第4期30-33,共4页Journal of North China Institute of Science and Technology

基　　金：国家自然科学基金资助项目(项目号50278002)

摘　　要：采用非线性三维空间梁单元来建立桥墩的有限元模型,选用了三组不同类型的地震记录作为输入,研究近场竖向地震动对我国目前常用的钢筋混凝土铁路简支梁桥桥墩地震反应的影响。研究结果表明,在最大峰值水平加速度PGA分别为0.1g和0.2g的地震输入下,桥墩结构均处于弹性工作状态,相应的竖向地震动对桥墩的地震反应影响很小(均不超过2%);而在最大峰值水平加速度PGA为0.4g的地震输入下,桥墩显示了非线性行为,竖向地震动对桥墩地震反应的影响显著增大,尤其是因PΔ效应的影响会使桥墩的墩顶位移显著增加。In this study, nonlinear 3D FEM approach was used to build the finite element model of the bridge piers and to analyze the effect of near-fauh vertical motion on response of earthquake of RC railway simply supported girder bridge piers which was commonly used presently by means of selecting three groups of different kinds of earthquake records to be excitation. The results indicated that vertical motions has few of effect on seismic response of RC piers （ 〈2% ） excited by 0.1 g and 0.2 g peak value of acceleration because the piers worked in elastic. However, vertical motions have the most significant effect on response of earthquake of RC piers excited by 0.4g peak value of acceleration, especially the P-Δeffect will remarkably increase the top displacement of piers. We concluded that large-intensity near-fauh ground motion will remarkably enlarge the seismic risk of RC piers.

关 键 词：近场 竖向地震动 地震反应 抗震设计 地震烈度 加速度峰值 

分 类 号：U442.55[建筑科学—桥梁与隧道工程]