竖向地震作用对上承式拱桥的影响

以一座跨径131 m的实际钢筋混凝土箱板拱桥为基础,建立了全桥计算模型,沿顺桥向、横桥向单向和多向输入地震反应谱,采用反应谱法计算了该桥的地震反应。通过改变反应谱输入方式和该桥的矢跨比、拱轴系数,计算了不同矢跨比、不同拱轴系数下主拱圈地震内力,比较分析了在竖向地震作用影响下,主拱圈地震内力的差别。研究结果表明,对于大跨度上承式箱板拱桥,竖向地震作用对拱圈的地震内力是有放大影响的,不考虑竖向地震作用的影响是不合理的。

Vertical Seismic Response on a Top-Bear Arch Bridge

Based on an actual reinforced concrete box arch bridge with 131 m span,the computing model of the entire bridge is established.The seismic response spectrum of the bridge is input from longitudinal,transverse and multi-direction and the seismic response of this bridge is calculated.Through changing the inputting mode of response spectrum,the span-ratio and arch-axis coefficients,the seismic internal force of main arch is calculated under different span-ratio and arch-axis coefficients.Contrastive analysis on differences of the seismic internal force of main arch under the vertical seismic response is carried out.The research result indicates that regarding the great span arch bridge,the vertical seismic response enlarges the seismic internal force of the arch,and it is not reasonable to take no consideration of the effect of vertical seismic response.