基于分灾模式的梁端构造优化设计研究

Research on Optimal Edsign of Beam and Structure Based on Damage-reduction Mode

板式支座具有构造简单、安装方便的优点,普遍应用于我国中小跨径的梁桥中。强震作用下,支座易产生滑移或失效情况,落梁风险较大。为防止震害落梁的发生,通常在梁端加设防落梁措施,但会显著增大下部结构内力。文中基于分灾模式的抗震设计理念,采用midas Civil有限元计算软件,通过建立板式支座配合连梁装置、HDR隔震支座2种工况桥梁模型,对比强震作用下结构内力响应、经济性、适用性差异。研究表明,HDR隔震支座与梁搁置长度的分灾模式设计受墩高影响,对于短周期矮墩桥梁在不显著增大下部结构内力的情况下,可以很好地控制梁端位移,降低落梁风险,且经济效益较好,随着墩高增加改善效应降低。

Plate bearing has the advantages of simple structure and convenient installation.It is widely used in small and medium span girder bridges in China.Under the action of strong earthquake,the bearing is easy to slip or fail,and the risk of falling beam is high.In order to prevent the occurrence of falling beam earthquake damage,anti-falling beam measures are usually added at the end of the beam,but the internal force of the substructure will be significantly increased.Based on the seismic design concept of damage-reduction mode,midas Civil finite element calculation software is used to compare the internal force response,economy,and applicability of the structure under strong earthquake by establishing two working condition bridge models of plate bearing with coupling beam device and HDR isolation bearing.The research shows that the design of the damage-reduction mode of the HDR isolation bearing and the beam shelving length is affected by the pier height.For the short-period low-pier bridge,the displacement of the beam end can be well controlled without significantly increasing the internal force of the substructure,the risk of falling beams can be reduced,and better economic benefits are achieved.The improvement effect decreases with the increase of pier height.