地震作用下桥梁结构横向碰撞模型及参数分析

POUNDING MODEL OF BRIDGE STRUCTURES AND PARAMETER ANALYSIS UNDER TRANSVERSE EARTHQUAKES

针对桥梁结构在地震作用下梁体与横向挡块间的碰撞现象,采用非线性时程积分法,研究了横向地震作用下梁体与挡块间的碰撞效应。通过对刚体碰撞模型分析,推导出阻尼常数与恢复系数间的关系表达式,在此基础上建立了能考虑碰撞过程中能量损失的桥梁横向碰撞模型,并对碰撞刚度、初始间隙、恢复系数以及桥梁跨径等参数进行了影响分析。分析结果表明:最大撞击力随碰撞刚度和桥梁跨径的增大而增大,但随初始间隙的变化规律不明显;恢复系数对碰撞效应影响很大,忽略碰撞过程中的能量损失会高估碰撞反应。为减轻梁体与横向挡块间的碰撞效应,提出了挡块刚度的合理取值。

Based on pounding phenomenon between girders and side retainers of bridges under transverse earthquakes, nonlinear time-history integration method is employed to study the pounding effects between girders and side retainers. The relational expression between damping constant and resuming coefficient is deduced based on a rigid-body pounding model. The pounding model which can consider energy dissipation of pounding under transverse earthquakes is presented. Effects of pounding stiffness, gap distance, resuming coefficient and bridge span, etc. are analyzed. The results indicate that pounding force rises with increase in pounding stiffness and bridge span, but its change is not obvious with changes in gap distance. Neglecting energy dissipation of pounding will lead to overestimation of pounding effects. Reasonable stiffnesses of retainers for reducing pounding effects are presented.