钢管混凝土拱桥拱肋抗震能力评估方法

钢管混凝土（CFST）拱桥的抗震能力取决于拱肋抗震能力,为了准确地评估CFST拱桥拱肋的抗震能力,提出基于CFST截面屈服状态的评估方法,把拱肋截面屈服状态分为5个阶段,并结合N-M曲线得出抗震能力评估区域。采用地震反应时程分析方法计算地震效应,对CFST拱桥拱肋的抗震能力进行评估,以南宁永和大桥为工程背景进行拱肋的抗震能力评估。得出以下结论：拱顶和拱脚为最危险的截面;7度地震作用下拱肋的大部分仍处于Ⅰ阶段;8度地震作用下拱肋的大部分截面已处于Ⅱ阶段,只有少数截面仍处于Ⅰ阶段;9度地震作用下拱肋的大部分截面已处于Ⅱ阶段,少数截面已处于Ⅲ阶段。基于截面屈服状态的方法是抗震能力评估的一个有效方法。

Seismic Capacity Evaluation for Ribs of CFST Arch Bridge

The seismic capacity of CFST arch bridge depends on the seismic capacity of arch ribs.In order to evaluate accurately the seismic capacity of the arch ribs,evaluation method is presented based on the yield state of the ribs cross-section.In this method,the yield state of the sections is divided into five stages and combines with N-M curves to obtain the districts in which the seismic capacity can be evaluated.The seismic effects is calculated in time-history response analysis.The seismic capacity of the ribs of Nanning Yonghe Bridge is evaluated.It is found：the top and the foot of the arch are dangerous sections,esp.the part of ribs ofⅠ state under 7 degree earthquake.Only a few sections are still inⅠ state,other sections of the arch rib are in Ⅱ yield state under 8 degree earthquake.Most sections of the arch ribs are inⅡ state and some sections are in Ⅲ state under 9 degree earthquake.This method is effective for the evaluation of seismic capacity.