【摘要】 为研究结构-地基相互作用对上承式大跨度钢管混凝土拱桥地震反应的影响,以黏弹性人工边界模拟半无限介质的辐射阻尼及远场地球介质的弹性恢复性能.用大型计算软件ANSYS为计算平台,以跨径为430 m的上承式钢管混凝土拱桥为工程背景,分析了多种地基情况对上部结构地震反应的影响.结果表明,考虑结构-地基相互作用后与拱脚固结情况相比拱桥固有频率、地震应力值降低,地震位移反应有所增加;该桥各关键截面的地震应力变化不大,钢管应力下降最大不超过1%,混凝土应力下降最大不超过3.5%;基岩材料变化对结构地震反应的影响大于混凝土桥基材料的变化对结构地震反应的影响;在地震响应下,最危险截面下弦杆是拱脚截面,上弦杆是离拱脚3/8跨径处截面,桥面系是跨中截面.更多还原

【Abstract】 A viscoelastic artificial boundary was constructed to simulate radiation damping in a semi-infinite medium and the elasticity recovery capacity of the medium at the far field.The seismic response of a deck-type concrete-filled steel tube(CFST)arch bridge having a 430 m span was analyzed using the program ANSYS.Several forms of foundation were incorporated into the model.The results show that the natural frequency and the seismic response stress both decrease and seismic displacements become larger when considering the structure-foundation interaction.The seismic stresses in key cross sections change little,the stresses in the steel tube decrease less than 1% and the stresses in the concrete decrease 3.5%.The influence of rock to bridge’s seismic response is greater than that of the concrete foundation itself.The dangerous cross-section of the lower chord is at the skewback,that of the top chord is at the point 3/8 distant from the skewback and that of the deck is at the span center.更多还原