刚性悬索加劲钢桁梁桥施工阶段全桥模型试验研究

Integral model test of steel truss bridge stiffened with rigid cables in construction stage

东江大桥是国内首座双层桥面三桁刚性悬索加劲钢桁梁桥,其造型新颖独特、受力复杂,并且施工过程中存在着体系转换与内力调整。为研究这种新型结构的体系转换过程和结构整体受力性能,利用全桥模型试验模拟了实桥施工全过程。介绍了模型试验的目的、设计原则、相似关系、测点布置以及试验工况等。通过各工况下试验数据与理论数据比较,可以看出两者比较吻合,从而从试验和理论两方面证明了该桥的桥型设计及施工方法是合理的。同时发现,通过体系转换能使后安装的加劲弦较好地参与整体结构受力,以及纵向内力调整效果良好。而节点横向连接刚度较小使得横向内力调整效果与理论相差较大,因此在实桥有限元模型计算时应考虑半刚性节点的影响,同时在施工时应加强此工况的监控。

Dongjiang Bridge is the first double-deck and three-main-truss steel bridge stiffened with rigid cables in China,not only novel in type but also complicated in mechanical characteristics,and there involved system transformation and internal force adjustment during the construction process. To study the process of system transformation and mechanical characteristics of the structure,integral model test was used to simulate the entire construction process. Test objective,model design principle,similitude relationships,test cases and test point arrangement were introduced in detail. By comparison of all main construction cases,most test data are quite agreeable with the theoretical data,which verified the design concept and construction method. The test result shows that the fixed rigid cable can work effectively with the integral structure through system transformation,and the effect of longitudinal internal force adjustment is beneficial,while the lower lateral stiffness of the joint cause the lateral internal force adjustment significantly different from theory.