双柱墩新型减震梁桥的失效机制与减震控制

Failure mechanism and damping control of a new type damping beam bridge with double-column pier

研究双柱墩新型减震梁桥的失效机制与减震控制,控制双柱墩梁桥在地震下的破坏。采用pushover方法得到双柱墩抗震结构的塑性铰位置以及失效顺序。为提高墩柱薄弱节点抗震能力,提出3种减震结构:BRB减震结构、新型减震结构Ⅰ(墩-系梁连接点外侧替换为金属耗能铰)、新型组合减震结构Ⅱ(同时使用金属耗能铰和BRB支撑)。考察远场类谐和地震动下抗震结构与3种减震结构的非线性地震响应,揭示各个结构的失效机制。结果表明:新型组合减震结构Ⅱ的总体抗震性能最优,可实现耗能集中于BRB支撑与金属耗能铰,将墩-系梁破坏节点外移,增强墩柱的抗侧向力刚度,较大程度减小桥梁横向地震响应。

The failure mechanism and damping control of the new type of Double-pillar Bridge were studied to control the damage of the double-column pier bridge under earthquake action.The plastic hinge position and failure sequence of the double-column pier seismic structure by Pushover method were obtained.In order to improve the seismic capacity of weak nodes of the pier and column,there kinds of seismic absorption structures were proposed,which were BRB damping structure,new damping structure I(the outer side of the pier-tie beam connection point is replaced with metal energy dissipation hinge),and a new combined damping structure II(using metal energy dissipating hinges and BRB support at the same time).The nonlinear seismic response of the double-column pier seismic structure and three types of damping structures under far-field harmonic-like ground motions was investigated to reveal failure mechanisms of structures.The results show that the overall seismic performance of the new combined damping structure II is optimal,which can realize the energy consumption concentrated on BRB support and metal energy consumption hinge,shift the pier-beam damage node,enhance the lateral resistance stiffness of the pier column,greatly reduce the lateral seismic response to the bridge.