采用超高性能混凝土和限位装置的斜拉桥易损性分析

Vulnerability Analysis of an Ultra-High Performance Concrete Cable-Stayed Bridge Equipped with Constraint Devices

摘要:

斜拉桥作为交通网络中控制性的重要节点，在强震作用下其钢筋混凝土塔柱易产生塑性破坏，从而延误灾后应急救援工作的开展。基于此提出了一种既采用新型材料又采用新型限位装置的斜拉桥结构体系，用于提升斜拉桥的抗震韧性，在仅采用形状记忆合金（SMA）拉索限位装置的普通斜拉桥基础上将塔柱中容易损伤的塑性铰区普通混凝土采用超高性能混凝土（UHPC）代替，分别建立普通斜拉桥与新型韧性斜拉桥的有限单元模型，在远场和近场地震波的作用下分别开展桥梁构件和结构体系的易损性分析。研究结果表明：同时采用UHPC和SMA拉索限位装置的斜拉桥仅需增加少许成本即可大幅提高斜拉桥结构体系的易损性，极大地拓展了UHPC材料和SMA拉索限位装置的应用场景。

关键词:超高性能混凝土;形状记忆合金（SMA）耗能限位装置;斜拉桥模型;易损性分析

Abstract:

Cable-stayed bridges， as crucial joints in transportation networks， of which the towers are vulnerable to experience plastic damage during earthquakes leading to rescue work delay. In this regard， a novel concrete material and a novel constraint device are proposed to enhance the resilience of the cable-stayed bridge system. Beside the new constraint device named SMA （shape memory alloy） cable-based restrainers which were installed in the conventional cable-stayed bridge， the new concrete material named the ultra-high property concrete （UHPC） was casted in the plastic hinges in the tower of the novel cable-stayed bridge system. Two finite element （FE） models of the conventional and innovative cable-stayed bridge systems are established， respectively. A series of far-field and near-field earthquake recorders are used to conduct the vulnerability analysis. The results show that the UHPC material and the SMA cable-based displacement restrainers can improve the resilience of the innovative cable-stayed bridge system with only a slight increase in cost， expanding the application scenarios of the UHPC and the SMA cable-based restrainer.

Key words:ultra-high performance concrete;SMA (shape memory alloy) energy consumption and displacement constraint device;cable-stayed bridge model;vulnerability analysis