Based on the OpenSees platform,a model of a concrete-filled steel tubular(CFST)arch bridge is analyzed,and then it is compared with the results of the Midas Civil model.Through the incremental dynamic analysis (IDA)under strong earthquake records,the transverse nonlinear seismic performance of the arch rib of the CFST arch bridge is discussed.The bending moment time history curves of the arch foot and the displacement time history curves of the vault are com-pared with those of two different arch rib models (elastic beam element and fiber beam element). The yield mechanisms of the key sections of the arch rib are analyzed,and their IDA curves and vault displacement are drawn.The results show that under strong ground motions,the arch foot and vault do not necessarily yield first,but the section-changing position or limped-mass connection of arch rib,which must be carefully considered in the design.With the increase in ground motion,the arch rib gradually yields,beginning with the bracings,and then the arch foot and vault,and then the whole arch rib.The arch rib has a good nonlinear performance and seismic capacity.%基于 OpenSees平台建立钢管混凝土拱桥动力分析模型,并与 Midas Civil 模型结果进行比对.通过一条强震记录下的IDA分析,得到钢管混凝土拱桥拱肋横桥向非线性地震性能,比较拱肋采用弹性梁单元和纤维梁单元两种模型的拱脚弯矩时程曲线和拱顶位移时程曲线,分析拱肋关键截面屈服机理,绘制它们的曲率IDA曲线和拱顶位移 IDA曲线.研究结果表明:横桥向在强震作用下拱脚和拱顶不一定先屈服,而是在拱肋截面突变或有集中质量连接处,在设计时需重点考虑;随着地震动增大,先是与横撑连接处拱肋首先屈服,然后是拱脚和拱顶位置,最后向整个拱肋扩展,拱肋非线性性能良好,仍有一定的抗震储备能力.
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