三跨飞燕式异型钢管混凝土拱桥地震反应及控制

Seismic Response Analysis and Control of A Three-span Irregular Flying Swallow Type of CFST Arch Bridge under Seismic Excitation

利用ANSYS有限元软件,计算并分析了某三跨飞燕式异型钢管混凝土拱桥的动力特性和一致激励与行波激励下的动力响应,并对拟安装在桥上Lock-up装置的减震效果进行了评价。研究表明,纵向和竖向联合输入下结构的动力反应明显高于纵向和竖向单独输入工况;横向地震激励时,拱肋出平面位移及内力均很大,但可以不考虑行波效应的影响;纵向和竖向地震激励下,行波输入时主拱肋面内动力响应急剧增大;Lock-up装置使得结构在纵向地震激励下由半漂浮体系转化为刚接体系,一致输入下结构内力响应减震率较低,而行波输入减震率则相对较高,其中,主拱肋轴力减震率达15%,弯矩减震率最大达35%。

Based on an irregular concrete-filled steel tube arch bridge,the 3-D spatial finite element model is built by ANSYS to complete the dynamic characteristic analysis and seismic response of the bridge under uniform excitation and non-uniform excitation.Seismic response control effectiveness of Lock-up devices is calculated then.The result shows the seismic response under the combination of longitudinal and vertical excitation input is apparently larger than the seismic response under longitudinal or vertical excitation input.Under transverse excitation,large out-plane seismic internal force and displacement are arrived,and the traveling wave effect need not considered.However,the in-plane seismic response increases rapidly under longitudinal or vertical excitation input with consideration of traveling wave effect.With Lock-up devices fixed on,the aseismic ratio of the axial force and the bending moment of the arch rib is not obvious,but can reach 15% and 35% under traveling seismic wave excitation.