Abstract: Based?on?an?actual?reinforced?concrete?box?arch?bridge?with?131m?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?spanratio?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.

Key words: top-bear arch bridge , vertieal seismic response , response spectrum ;

摘要： 以一座跨径131m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。

关键词: 上承式拱桥, 竖向地震反应, 反应谱