【摘要】 为精确计算地震过程中桥梁的瞬态波响应,研究了多次重撞击现象对桥梁地震响应和安全性能的影响。针对剧烈竖向地震作用下梁可能偏离支座的双跨单墩连续梁桥,采用Ber-noulli-Euler梁模型描述上部结构和St.VENANT杆理论模拟桥墩结构。将竖向地震动以正弦激励形式的人工地震激励代替,应用瞬态波传播理论研究地震过程中上部结构和桥墩之间的多次重撞击现象。提出了计算桥梁多次重撞击瞬态动力学响应的瞬态波效应法。该方法避免了求解耦合重撞击力的强非线性方程,能够较精确地计算多次重撞击过程和分离过程中的瞬态波响应,准确描述结构中的撞击波传播现象。研究结果表明:重撞击力数值巨大;随着桥墩弹性模量的增大,最大重撞击力逐渐增大,而最大墩顶位移逐渐减小;竖向地震动引起的多次重撞击对桥梁的地震响应有较大影响,应当在连续梁桥的抗震设计中予以考虑。更多还原

【Abstract】 To precisely calculate the transient wave response of bridges under earthquakes,the effect of multiple-pounding on the seismic response and the security performance for bridges is researched.The single-pier and two-span continuous girder bridges under severe vertical earthquakes may be apart from the supports,the Bernoulli-Euler beam model is employed to describe the superstructure and the St.VENANT rod theory is used to simulate the pier structure.The transient wave propagation theory is used to study the multiple-pounding between the superstructure and the pier by means of the artificial earthquake in the form of sinusoidal excitation instead of vertical earthquakes.The transient wave effect approach is proposed to calculate the multiple-pounding transient dynamic responses of bridges.It can avoid solving the strongly nonlinear equation coupled of pounding force and can calculate the transient wave responses of multiple-pounding and separation process accurately.The phenomenon of the pounding-induced transient wave propagation in the structure can be found clearly.The results show that the multiple-pounding force is huge.With the increase of the elastic modulus of piers,the maximum multiple-pounding force is increased and the maximum movement on the top of piers is decreased.The multiple-poundings caused by vertical earthquakes have a significant impact on the seismic response of bridges,which should be considered in the seismic design for continuous girder bridges.更多还原