脉冲参数对CFST拱桥地震反应的影响

为了研究近断层脉冲型地震作用下速度脉冲参数对大跨度CFST（钢管混凝土）拱桥地震反应的影响，基于有限元方法，以1座铁路CFST拱桥为工程背景，提出以脉冲参数对拱肋及桥墩地震反应非线性分析方法。研究结果表明:对于大跨度CFST拱桥，三向罕遇地震作用下，拱肋处于弹性状态，桥墩可能屈服，脉冲参数对CFST拱桥地震反应影响显著；同等PGA（峰值加速度）下，脉冲幅值越大，个数越多，脉冲成分对拱肋及墩地震反应贡献率越大，墩的损伤越严重；脉冲周期0~8 s内，中长周期（2~6 s）脉冲成分对拱肋及墩地震反应贡献率和墩的损伤影响较大，脉冲周期4 s时拱桥地震反应最大。

Influence of pulse parameters on seismic response of CFST arch bridge

In order to study the influence of velocity pulse parameters on the seismic response of long-span concrete filled steel tube (CFST) arch bridges under the action of near-fault pulse-like ground motion,based on the finite element method,a nonlinear analysis method of the seismic response of arch ribs and piers with pulse parameters was proposed based on the engineering background of a railway CFST arch bridge.The results showed that for the long-span CFST arch bridge under the action of three-way rare earthquake,the arch ribs were in the elastic state,the piers might yield,and the pulse parameters had significant influence on the seismic response of CFST arch bridge.Under the same peak ground acceleration (PGA),the larger the pulse amplitude,the greater the number of pulses,the greater the contribution rate of the pulse components to the seismic response of arch ribs and piers,and the more serious the damage to the piers.Within the pulse period of 0~8 s,the pulse components of the medium and long period (2~6 s) had greater influence on the contribution rate of the seismic response of arch ribs and piers and the damage of piers,and the seismic response of the arch bridge was the greatest when the pulse period was 4 s.