大跨度连续刚架拱桥的地震响应研究

广州新光大桥是世界上第一座三跨连续钢桁拱与钢筋混凝土V型刚构结合的钢-混凝土组合体系桥梁,主桥跨度为(177 428 177)m.以广州新光大桥为例,研究地震动空间变化对大跨度连续刚架-拱组合体系桥梁地震响应的影响.地震空间效应变化考虑了桥梁支点间横桥向和顺桥向多点激励和行波效应,研究结果表明:在不同的地震激励下桥梁的地震响应特征截然不同,地震动的空间变化对主拱肋、V型刚架的影响很大,而对边拱肋的影响相对较小;且随着剪切波速增加,主拱顶相对拱脚的纵桥向位移逐渐减小,而边拱拱顶的纵桥向位移基本不受剪切波速的影响.

Seismic response of long span continuous rigid-frame arch bridge

This paper investigates the spatial variability effects of ground motion on the seismic response of long-span continuous rigid-frame arch bridge.The analyses are performed on the Xinguang bridge in Guangzhou,which is the worldwide first 3-span continuous rigid-frame and steel-truss arch bridge with reinforced concrete V-shaped rigid frame.Its spans of the main bridge are as long as(177 428 177)m.The spatial variability of ground motions between pivots of the bridge is taken into account with multi-support excitation and traveling wave effect by exciting the bridge in both transverse and longitudinal directions of the bridge.New study shows the characteristics of seismic response of the critical bridge members are varied with different seismic excitations.The spatially varying ground motion has a considerable influence on the seismic responses of the ribs of the main arch and V-shaped rigid frame,whereas the influence on the side arch ribs is insignificantly predominant.As the shear wave velocity increases the peak longitudinal displacement of the crown of the main arch relative to the arch springing decreases,while,the effect of shear wave velocity on the longitudinal displacement of the ribs of the side arch can be neglected.