大跨度预应力混凝土连续刚构桥动力特性及P-Δ效应分析

摘要

以某已建成的连续刚构桥为研究对象,采用Midas/civil 2010有限元程序,建立连续刚构桥有限元模型,分析了连续刚构桥采用钢筋混凝土双薄壁实心墩、双薄壁空心墩和单柱式空心墩三种截面形式的动力特性和分别在纵向地震和横桥向地震作用下结构的PΔ效应。研究结果表明：三种不同截面类型的桥梁自振频率依次增大,不同的桥墩截面形式使桥梁结构的振型序列发生变化;在三种桥墩截面形式下,考虑P-Δ效应后,对纵向地震响应的影响显著而对横向地震响应的影响较小,但P-Δ效应并不影响桥梁结构的时程曲线趋势。%With a completed continuous rigid-frame bridge as the object of our research,the finite element program Midas/civil 2010 is used to help establish a finite element calculating model for the continuous rigid-frame bridge.The dynamic characteristics and P-Δ effects of the continuous rigid frame bridge respectively with the double thin-walled solid pillars,the double thin-walled hollow pillars and the single-column hollow pillar respectively under the action of the longitudinal earthquake and the bridge-crossing earthquake are analyzed in the paper.The research results show that the self-vibration frequencies of the three kinds of bridges increase in turn.The mode shape sequence changes with the different cross-section types of the pier.With all the three different cross-section types taken into consideration,the influence of the P-Δ effects on the longitudinal seismic response is obvious while the influence of the P-Δ effects on the lateral seismic response is comparatively small.However,the P-Δ effects have no impact on the trend of the time-history curve.