中小跨径板式橡胶支座梁桥横向抗震设计研究

为提高中小跨径板式橡胶支座梁桥在强震作用下的横向抗震性能，在总结汶川震区该类梁桥震害特点和国内外桥梁抗震设计规范中相关抗震设计策略规定的基础上，归纳当前我国板式橡胶支座梁桥横向抗震体系存在的问题，提出适合我国中小跨径板式橡胶支座梁桥的横向抗震设计方法，即允许上、下部结构连接构件牺牲的准隔震设计方法，介绍该抗震设计方法设计思想，给出在两设防水准下结构各部件的性能目标要求。选择一座典型板式橡胶支座简支梁桥为研究对象，基于文中抗震设计方法的设计思想，提出采用新型隔震系统对计算桥例进行准隔震设计。结果表明：通过对横向限位装置力学性能参数的合理设计，通过桥梁结构在强震作用下板式橡胶支座的滑移、横向限位装置的损伤或牺牲，控制上、下部结构间传递的梁体惯性力，保护墩柱和基础等下部结构免遭严重损害，同时能有效控制墩梁相对位移，防止过大的梁体移位导致的交通阻断、甚至落梁。

Study on transverse seismic design of small and medium span bridges with elastomeric bearing pads

In order to improve the transverse seismic performance of small and medium span girder bridges with elastomeric bearing pads under strong earthquake excitations, the  existing problems associated with this kind of bridge system in China were summarized based on the damage characteristics of this kind of girder bridges in Wenchuan earthquake and the comparison of different seismic design strategies in various Chinese and foreign seismic specifications of bridges. Furthermore, a new transverse seismic design method as a quasi-isolation approach was proposed by allowing the sacrifice of connections in superstructure and substructure. The design idea in the seismic design method was introduced, and the requirements for performance objective of various structural components under two levels of seismic fortification were described. The application of the proposed seismic design method to seismic design of girder bridges with elastomeric bearing pads was evaluated using finite element simulation. The results show that in the proposed seismic design method, the sliding effect of elastomeric bearing pads and damage or sacrifice of transverse restrainers can be utilized during a strong earthquake, so that the inertia force of girder transmitted between superstructure and substructure can be controlled, the substructures of piers and foundations can be protected from severe damage, and the relative displacement between girder and pier can be effectively controlled to avoid traffic interruption or even girder unseating caused by excessive girder displacement.