纵向限位连续梁桥分散减震效果参数分析

Parameters analysis of the vibration distributing effect of longitudial displacement limited continuous beam bridges

连续梁桥的地震作用大多由固定支座墩承担,为均衡地震作用在各墩间的分配、降低固定墩的地震反应,可在活动墩上设置限位挡块作为分散减震措施,使活动墩共同承担地震作用。利用有约束的刚体碰撞模型分析了梁部结构与限位装置碰撞时阻尼比参数的取值方法。考虑活动支座的摩擦非线性、限位装置的接触及材料非线性和钢筋混凝土桥墩的材料非线性,建立了设置限位装置的连续梁桥考虑接触碰撞的全桥动力分析模型,并分为限位装置弹性和弹塑性两个模型。采用非线性时程分析方法,对限位装置的初始间隙和刚度对连续梁桥分散减震效果的影响进行了参数分析,结果表明,可通过有限元分析合理调整限位装置设计参数,使限位装置对连续梁桥的分散减震效果最佳。

For continuous beam bridges,most of the earthquake loading was borne by the fixed pier.In order to deduce the sesmic response of the fixed pier and to make the movable support pier bear some earthquake loading and to distribute the earthquake loading to all the piers,the restrainers can be used as the vibration dissipation devices and are installed at the movable piers.The damping ratio for the contact and pounding between the beam and the restrainers was determined by the analysis of the pounding model of constrained rigid body.The longitudinal pounding model for continuous beam bridges with restrainers was established.The friction nonlinearity of the movable support and the contact and material nonlinearity of the restrainers and the material nonlinearity of the reinforced concrete pier were all involved in the finite element model.According to the nonlinear characteristic of the restrainers,two different models were established.The effect of the design parameters,such as initial gap and stiffness of the restrainers,on the vibration dissipation of the continuous beam bridges was analyzed by the nonlinear time-history method.The results indicate that the design parameters of the restrainers can be adjusted according to the nonlinear analysis to take the best vibration dissipation effects.