双薄壁高墩系梁设置方式对连续刚构桥地震响应的研究

Effect of Link Beam between Slender Double-wall Piers on the Seismic Responses of Continuous Rigid Frame Bridges

为研究横系梁的设置方式对双薄壁高墩连续刚构桥地震响应的影响,基于OpenSEES建立了全桥三维非线性纤维模型,采用时程分析法,对比研究了4种横系梁工况。结果表明:横系梁对桥梁动力特性影响很大,有无横系梁的桥梁第一阶周期相差1倍以上;横系梁越强,墩身剪力的增幅越大,高墩纵向曲率和弯矩在横系梁附近的突变越显著;横系梁较强时,墩身纵向位移分布接近线性,最大位移在墩顶,增大了桥台支座的变形需求。从兼顾桥梁地震内力和变形两个方面而言,横系梁的设置均不宜过强。

In order to examine the effect of link beams on the seismic responses of a continuous rigid frame bridge with slender double-wall piers, a three dimensional nonlinear fiber model was established on the basis of the OpenSEES software. Time history analytical method was applied to comparatively investigate the following four cases, i.e. bridge models. The results show that the link beams play an important role in affecting the dynamic characteristics of the bridge. The fundamental period of the bridge with stronger link beams can be 2 times larger than that of the bridge without stronger unit beams. With stronger link beams, the increase of shear forces become more significant, and the longitudinal curvature and moment responses vary more drastically in the vicinity of the link beams. With stronger link beams, the displacement response along the pier remains in a linear shape with the maximum value at the top, which increases the de- formation requirements for the bearings at the abutments. From both aspects of seismic internal force and displacement responses, it is more appropriate to design weak link beams.