大跨度系杆拱桥合理抗震体系研究

Appropriate Earthquake Resistance Systems for Long-span Tied-arch Bridges

以某下承式系杆拱桥为工程实例,分别对系杆拱桥纵、横向采用不同支承体系下的地震响应进行了研究,在此基础上推荐了合理抗震体系,分析结果表明:对于三跨系杆拱桥,采用两个固定墩未必能够起到有效分担纵向水平地震力的作用;与常规纵向约束布置体系相比,主墩采用弹性拉索支座具有有效的减隔震效果,拉索支座自由行程及弹性索刚度为设计关键。各桥墩横桥向采用滑动支座的情况下,主墩、主梁之间采用X形板弹塑性挡块,可以在控制结构横向地震位移的同时,显著减小桥墩地震力,从而提高结构整体的横向抗震性能。

With a typical long-span tied-arch bridge as engineering background,appropriate earthquake resistance systems were clarified by systemically analyzing earthquake responses of a structure with different longitudinal and transversal earthquake resistance systems. The results indicate that setting two fixed piers may notbe able to derive horizontal seismic forces effectively. Comparing to the conventional longitudinal earthquake resistance system of a tied-arch bridge,earthquake responses can be significantly reduced by using cable-sliding friction aseismic bearings at each main pier. The key design is the bearing gap and steel wire stiffness. By usingthe X-shape Added Damping and Stiffness element（ ADAS） as the transverse retainer,pier earthquake responses can be reduced and the girder transverse displacement can be controlled. Therefore,earthquake resistances of the entire structure can be improved.