重庆长江大桥复线桥主跨钢—砼接头内力组合分析

An Analysis of the Combined Internal Forces of the Steel-Concrete Joints of the Main Span of the Chongqing Yangzhe River Bridge of the Double-tracking Railways

重庆长江大桥复线桥主跨中间108 m采用钢箱梁结构,两端为混凝土梁,钢梁和混凝土梁采用钢—砼节段组合结构,在连续刚构桥中首次实现330 m的跨径。着重介绍了钢—砼接头内力组合的过程,分析研究认为:在新老规范交替过程中,荷载组合过程中采用新规范未必偏于保守;对规范中未明确规定的体外预应力力学效应,可按永久荷载进行组合。研究成果对同类结构的设计和研究有一定的参考价值。

The 108m mid-span of the Chongqing Double-tracking Railway Yangtze River Bridge is made up of steel box girders, at both ends of which concrete beams are adopted. The steel box girder and the concrete beams are joined with steel-concrete joints, which help realise the spanning distance of 330m in a continuous rigid structure bridge. The combining process of the internal forces of the joints is dealt with in the paper. Our analysis and study show that in the transitional period from the old norm to the new norm, the application of the new norm to the loads-combining process is not necessarily conservative; as far as the pre-stressing effects outside the body are concerned, which are not clearly prescribed in the new norm, they may be regarded as permanent loads and combined. The results of our study may serve as a useful ref- erence for the study and design of structures of the same type.