下承式拱桥吊杆的破损安全研究

Research of failure-safety of suspenders on bottom-through arch bridge

为研究吊杆破断对下承式拱桥静力响应的影响以及是否是破损安全的。以新建铁路马道口下承式拱桥为背景,采用桥梁专业软件MIDAS/CIVIL,运用准静力法对吊杆破断进行模拟。分析计算了单根吊杆破断和多根吊杆破断对桥梁结构的影响。结果表明:单根吊杆破断对下承式系杆拱桥静力响应影响较小,吊杆破断是破损安全的;当有连续的3对吊杆破断时,其相邻吊杆的安全系数严重降低,应力幅增量很大,会引起吊杆的连锁破断,对桥梁结构造成严重的损伤。

To study the effect of static response on bottom-through arch bridge in case of failure of suspenders, whether failure of suspenders is safe. The bottom-through arch bridge of new railway in Madaokou is taken as the research object and the quasi-static method is applied to simulate failure of suspenders by the professional software of bridges MIDAS/CIVIL. Failure of a single suspender and failure of multiple suspenders that have effect on bridge structure have been calculated. The results of the analysis indicate that failure of single sus- pender has small effect on static response of bottom-through arch bridge and failure of single suspender is fail- safe. When there is failure of three pairs of successive suspenders, the safety factor of adjacent suspenders se- verely declines and the stress amplitude greatly increases that can cause chain failure of suspenders, which will cause serious injury to the bridge structure.