大跨径组合梁斜拉桥试设计及力学性能研究

Study of Trial Design and Mechanical Performance of Long Span Composite Girder Cable-Stayed Bridges

为探索千米级组合梁斜拉桥的技术可行性,以主跨700,800,900,1 000m为目标,开展大跨度双塔组合梁斜拉桥方案试设计。从结构静力强度、静力稳定、颤振稳定等多方面论证方案的可行性,并指出设计主要控制因素。针对主跨1 000m的组合梁斜拉桥,对钢-混界面滑移影响、几何非线性效应两方面的力学性能进行研究。结果表明:设计方案是成立的,组合梁斜拉桥动、静力性能均满足要求,运营组合下近塔区混凝土桥面板应力、主梁面内失稳为设计主要控制因素。对千米级组合梁斜拉桥而言,在组合梁连接件按常规设计的情况下,钢-混界面滑移对斜拉桥受力性能的影响基本可忽略;几何非线性效应对活载工况影响较大,对收缩徐变工况影响较小。

To probe into the technical feasibility of the 1 000-m span composite girder cable- stayed bridge, the trial design of the schemes of the double-pylon composite girder cable-stayed bridges respectively with the target main spans of 700 m, 800 m, 900 m and 1 000 m was devel-oped. From the aspects of the structural static strength, static stability and flutter stability, the feasibility of the schemes of the bridges was verified and the main control factors that might be in-volved in the design were explicated. For the composite girder cable-stayed bridge with the main span of 1 000 m, the mechanical performance, including the influences of the steel and concrete in-terface slip and the effect of the geometric nonlinearity, was studied. The results suggest that the design schemes of the bridges are tenable. The dynamic and static performance of the bridges can satisfy the relevant requirements and under the operational combination load, the stresses of the concrete deck slabs in the areas nearby the pylons and the in-plane instability of the main girders are the main control factors. As regards the bridge with the main span of 1 000 m, under the regu-lar design of the connectors of the composite girder, the influences of the steel and concrete inter-face slip on the mechanical performance of the bridge can be substantially neglected, the influences of the effect of the geometric nonlinearity on the live load are great while on the shrinkage and creep are little.