斜拉桥合理墩形及墩梁约束体系抗震研究

过渡墩、辅助墩墩顶设置平衡重是斜拉桥一种常见设计方式,此设计的特点是墩顶所受质量大、但重力小,由此导致过渡墩、辅助墩在地震作用下受到的地震力大、而轴压力小,进而引发过渡墩、辅助墩的动轴拉力、支座动反拉力以及支座剪力过大等抗震问题。以某斜拉桥为背景,针对其过渡墩、辅助墩墩高小的特点,以及纵向+竖向地震作用下,竖向地震作用使辅助墩墩顶支座以及墩底截面产生较大动反拉力和动轴拉力的现象,提出过渡墩以墙式墩取代门式框架墩、辅助墩墩顶支座改为双向滑动支座、过渡墩墩梁之间横向设置速度型动力锁定装置的比选方案。分析表明,此比选方案可有效解决墩中的动轴拉力、支座动反拉力以及支座剪力过大的问题。但是,由于锁定力需求较大,速度型动力锁定装置的选取需根据进一步的经济比选决定。

Research on the seismic performance of cable-stayed bridge for reasonable selection of pier type and connections between piers and main girder

Setting the balanced weights on the top of the transition piers and the auxiliary piers is a common design in cable-stayed bridge and its characteristics are the large mass and the light gravity at the top of the piers. The design can lead to the large horizontal earthquake force and the low axial pressure of the transition piers and auxiliary piers under earthquake, and can cause more further seismic problems, such as dynamic axial tension of the transition piers and the auxiliary piers, dynamic vertical tension of bearings and too large horizontal shear of bearings. Taken a cable-stayed bridge as the engineering background, according to the transition piers and auxiliary piers are short and the large dynamic reaction tension of bearings and the large dynamic axial tension at the bottom section of the auxiliary piers when the bridge is subject to the longitudinal and vertical ground motion, the renewal designs are proposed that changing the frame pier to the wall-type pier, changing the bearings at the top of the auxiliary piers to the bidirectional sliding bearings and setting lateral LUDs between the transition piers and the main girder. The seismic responses exhibit that renewal design can solve the former problems effectively. But because of the excessive demand of locking force of LUD,the selection of LUD or not should base on its economic efficiency .