行波效应对长跨连续刚构桥地震响应的影响

Influence of Traveling Wave Effect on the Seismic Response of Long-Span Continuous Rigid Frame Bridge

为了研究行波效应对于桥梁地震响应的影响,以一座实际工程高桩大跨度连续刚构桥(70+7×105+70)m为例,通过Midas/civil软件建立有限元模型,运用相对运动法对其进行地震动时程分析。考虑了2种地震波和3种视波速的不同组合,对比分析了行波效应对桥梁地震响应的弯矩和剪力。计算分析表明,对于不同的地震波输入,其对弯矩和剪力的影响有较大的差别。行波效应对于桥梁不同位置地震响应内力值影响的程度和变化趋势不同,但总体是随着视波速的增大,行波效应对内力的影响程度减小,墩底弯矩在视波速为500 m/s时减小-17.11%;800 m/s时减小-11.22%;1 000 m/s时减小-8.83%。且这种变化的规律在桥梁顺桥向空间上有一定的规律性。

In order to study the influence of traveling wave effect on the seismic response of bridges, the relative movement method was adopted to analyze the acceleration history of a practical high pile continuous rigid frame bridge with spans of（70＋7×105＋70）m by using Midas/civil to establish a finite element model. In this paper, the bending moment and shearing force of the traveling wave effect on the seismic response of the bridge were compared under different combinations between two types of seismic waves and three types of apparent wave velocity. The calculation and analysis show that the input of different seismic waves has great difference in its influence on the bending moment and shearing force; the influence of the traveling wave effect on the internal force of the seismic response of the bridge is different in extent and tendency. But with the increase of the apparent velocity, the influence of the traveling wave effect on the internal force is reduced and the bending moment is reduced by 17.11% when the apparent wave velocity is 500 m/s, reduced by 11.22% when the apparent wave velocity is 800 m/s, and reduced by 8.83% when the apparent wave velocity is 1 000 m/s. Besides, this change has certain regularity in the longitudinal bridge.