自锚式梁下斜张桥梁的结构效率研究  

Efficiency of Self-Anchoring Under-Deck Cable-Stayed Bridges

作　　者：陈孜伟 白植舟[1] 陈德伟[1] 

机构地区：[1]同济大学桥梁工程系,上海200092

出　　处：《结构工程师》2017年第4期75-82,共8页Structural Engineers

摘　　要：自锚式梁下斜张桥梁通过梁下斜张索产生向上竖向分力,达到降低恒载作用下主梁弯矩的目的。同时该类桥梁斜张系统对活载也能起到抵抗作用,能进一步降低活载作用下主梁弯矩。为进一步研究在活载作用下斜张系统对该类桥梁主梁的卸载效率,定义效率值为弯矩卸载量与无斜张系统时活载弯矩值的比值。基于力法原理,得到了单跨两端自由转动和两端带弯曲弹簧约束的该效率值的解析解。结果表明,效率值和某反映主梁与斜张系统刚度比的无量纲参数χ、梁端弯曲弹簧刚度以及荷载形式等有关。并进一步分析了撑杆高跨比、主梁长细比、两端弹簧刚度等对效率值的影响规律。研究结论可对该类桥梁的设计提供参考。Vertical force components from cables of self-anchoring under-deck cable-stayed bridges can reduce bending moment due to dead load in the deck. Meanwhile, the under-deck cable-staying system can also resist the live load and reduce bending effect under live load. To analyse the efficiency of reduction of bending moment due to live load, herein a parameter named efficiency defined as the reducing bending moment to bending moment when cable-staying system is removed. Analytical forms of efficiency were developed for single-span cases without or with flexural spring constraints at two ends of decks. The results show that the efficiency depends primarily on a dimensionless parameter that reflects the ratio of deck rigidity to the overall bridge rigidity, the rigidity of flexural spring constraints and the load type. Moreover, the influences of the strut depth to span, slenderness ratio of deck and rigidity of spring constraints on the efficiency were evaluated with some rules found. The findings yielded in this study provide references in a way for the design of self-anchoring under-deck cable stayed bridges.

关 键 词：梁下斜张桥梁 结构效率 撑杆高跨比 主梁相对刚度比 主梁长细比 

分 类 号：U441[建筑科学—桥梁与隧道工程]