整体式断面双车道索道桥上部结构研究

Study of Superstructure of Two-Lane Suspension Bridge with Integral Cross Section

为寻求整体式断面双车道索道桥上部结构的可行布置形式,采用考虑索梁组合结构几何非线性的空间有限元法,对几种桥面系构造方案的结构特性进行研究。研究结果表明:对于双车道索道桥,活载单车道偏载是比活载双车道同时偏载更为不利的荷载工况;在活载作用下,整个桥面系在横桥向不再保持线性变位;简单地采用横向线性扩展车道宽度的措施来构造双车道索道桥上部结构方案,将很难满足结构横倾稳定性要求;主索在横桥向的不同分布是影响索道桥结构抗扭能力的最主要因素;在桥面中央布置适量的主索对优化横梁内力分布状况是有益的。

To find a rational superstructure configuration for two-lane suspension bridges with integral cross section,the spatial finite element method taking into consideration of non-linearity of cable-beam composite structure was employed and the structural features of different bridge deck system schemes were studied.The results of the study demonstrate that for a two-lane suspension bridge,the load case of single-lane unbalanced live loads is much more unfavorable than that of two-lane unbalanced live load.Under the action of live loads,the overall bridge deck system no longer exhibits linear variation in the transverse bridge direction.To form the superstructure of the two-lane suspension bridge simply via linear expansion of traffic lanes in the transverse direction is hard to meet the demands of the transverse overturning stability of the structure.How to arrange the main cables in the transverse direction is the key concerning the torsional capacity of a suspension bridge.Installing aproper amount of main cables in the central part of the bridge deck is good to optimize the internal force distribution in the floor beams.