【摘要】 汶川大地震中桥梁结构横向抗震挡块遭到严重破坏,其中部分是由于梁体与其发生碰撞所致。针对桥梁结构横向抗震挡块与梁体在强震作用下的碰撞现象,建立了考虑上部结构与挡块间偏心距、支座非线性和墩柱弹塑性的横桥向单墩碰撞模型。采用非线性地震反应时程分析方法,详细研究了偏心距、碰撞刚度、初始间隙、桥墩线刚度、上部结构与盖梁质量比、上下部结构周期比以及墩柱弹塑性等参数对桥梁结构横向地震反应的影响。结果表明:考虑偏心的碰撞进一步增强了系统的非线性,低高度梁(e<70 cm)不考虑偏心碰撞分析可能导致不保守的结果,需引起重视。更多还原

【Abstract】 During Wenchuan earthquake,some lateral shear keys of bridges suffered severe damage partially caused by poundings between shear keys and girders.Based on pounding phenomena between shear keys and girders under strong ground motions,a pounding model of a single column considering eccentric distances between shear keys and girders,nonlinear behaviors of bearings and elasto-plastic behaviors of piers was established.With the time history analysis method for nonlinear seismic responses of structues,the effects of many parameters,such as,eccentric distance,pounding stiffness,initial gap between shear key and girder,linear stiffness of pier,mass ratio of uppertructure and bent cap,period ratio of upperstructure and lowerstructure,and elasto-plastic behaviors of piers on the lateral seismic responses of a bridge were analyzed.The results indicated that the poundings considering eccentric distances between shear keys and girders can enhance the non-linearity of the system,ignoring eccentric poundings in an analysis for a lower height girder(e<70cm) can cause nonconservative results,they should be paid to more attention.更多还原