活动支座摩擦作用对连续梁桥弹塑性地震反应的影响

Effect of Friction Effect at Movable Support on Elasto-plastic Seismic Response of Continuous Girder Bridge

为研究活动支座摩擦作用对连续梁桥弹塑性地震反应的影响,将活动支座摩擦作用对桥梁结构地震反应的影响分解为摩擦耗能、刚度贡献和运动相互作用3个方面,建立了同时考虑活动支座及桥墩非线性的有限元分析模型,进行了非线性时程反应分析,对支座摩擦作用对桥梁结构的墩底曲率、梁体位移、速度和加速度的影响进行了研究。研究表明,活动支座摩擦作用对桥梁结构的弹塑性地震反应并不是在任何情况下都是有利的,根据分析结果提出了需要考虑活动支座摩擦作用的情况,在非线性时程分析时需要综合考虑结构的自振特性及场地反应谱的影响。对于复杂的桥梁,尤其是固定支座墩和活动支座墩墩高和刚度差异较大的桥梁,在进行抗震分析时需考虑活动支座摩擦作用的影响。

In order to study the effect of friction at movable supports on the elasto-plastic seismic continuous girder bridges, the effect is analyzed from 3 aspects, i. e. , friction energy dissipation contribution of the movable supports and the motion-induced interaction between the girder and piers. Finite element models are established considering the friction nonlinearity of the movable the material nonlinearity of the reinforced concrete piers. analyze the effect of friction at the movable supports on A nonlinear time-history analysis is the pier bottom curvature, girder responses of and stiffness the movable supports and performed to displacement velocity and acceleration. The results indicate that the friction effect at movable supports on the elasto-plastic seismic response of bridge structure is not always favorable, thus in some cases, the friction at movable supports must be taken into account, and for the nonlinear time-history analysis, the effect of natural vibration characteristics of the bridge and the site response spectrum should also be considered. For some complicated continuous bridges, especially those with the heights and stiffnesses of the fixed pier and the movable pier being significantly different, the friction at movable supports should be considered in seismic analysis.