摩擦摆支座不同步受力对地震响应的影响

摘要:

采用摩擦摆支座桥梁的常规抗震分析中一般按所有摩擦摆支座同步受力考虑,但实际上由于活动支座顶面平面滑板具有较大的纵向自由程,摩擦摆支座受力不同步。本文以MIDAS CIVIL通用有限元软件为例,提出准确模拟摩擦摆支座顶部平面滑动与底部圆弧滑动的方法,并以城市高架桥中45+70+45连续钢砼组合梁为研究对象,在E2地震作用下,分析了不同步受力时的地震响应机理,并从减隔震位移、梁端位移、端缝闭合量等多个角度,分析支座同步受力与不同步受力的差异,得出采用非同步受力更符合实际,而同步受力模拟方法,位移响应偏小的结论。

Abstract:

In the conventional seismic analysis of bridges with friction pendulum bearings, the synchronous forces of all the friction pendulum bearings are generally considered, but in fact, the forces of the friction pendulum bearings are not synchronous because of the large longitudinal free path of the sliding plate on the top surface of the movable support. Taking Midas Civil general finite element software as an example, this paper puts forward a method to accurately simulate the top plane sliding and bottom arc sliding of friction pendulum bearing, and takes 45+70+45 continuous steel concrete composite beam in urban viaduct as the research object. Under the E2 earthquake action, the seismic response mechanism under asynchronous stress is analyzed. The differences between synchronous and asynchronous forces are analyzed from the perspectives of seismic isolation displacement, beam end displacement and end joint closure, etc. It is concluded that the asynchronous force is more practical, while the synchronous force simulation method has a small displacement response.