整体桥面钢桁梁桥桥面荷载传递途径的研究

Study on the Load Transfer Routine in Truss Bridges with Integral Decks

在多横梁整体桥面结构中,桥面荷载有两条传递途径:一是通过纵梁、纵肋和钢桥面板纵向传递到节点横梁,再传到下弦节点;二是通过节间内横梁及钢桥面板横向传递到下弦杆,再传到下弦节点。前者引起节点处横梁的竖向弯曲,后者引起下弦杆的竖向弯曲。本文采用有限元法对该类型桥面结构中桥面荷载的传递情况进行分析计算和试验研究。研究结果表明:影响传力比(路径传递的荷载与一个节间总荷载的比)的主要因素有下弦杆与桥面系(纵梁、纵肋和钢桥面板)的竖向刚度比α和节间横梁与节点横梁的竖向刚度比β;路径2的传力比R2随着α的增加而增加,当α小于8.3时,R2的增加速度较快,当α大于25后,R2变化很小;R2随着β的增加而增加,但增加速度略有减慢;不同节间内通过两条路径传递的荷载比例变化不大,理论值与试验值吻合良好。

There are two routes of load transfer in the integral deck with multi-transversal beams. Part of the load transferred to bottom chord joints is through longitudinal beams, longitudinal ribbed stiffeners, deck and transversal beams at chord joints; and the other is through transversal beams in the panel, deck and bottom chord elements. The former causes transversal beams at chord joints to bend and the latter makes bottom chord elements bend. In this paper, the struαure calculation and the experimental research were carried out to investigate the load transfer in the type of floor system. The results indicate that the main influence faαors of the load transfer ratio, which is namely the ratio of the load distributed by a route to the total load in a panel, are the ratio a of the vertical stiffness of bottom chord elements to that of the floor system （including the longitudinal beams, longitudinal ribbed stiffeners and deck） and the ratio β of the vertical stiffness of a transversal beam in the panel to that of a transversal beam at the chord joint; load transfer ratio R2 of the second route increases gradually with the increment of α R2 increases quickly when a is less than 8.3 and varies small when a is greater than 25; R2 also becomes greater and the increasing speed reduces slightly with the increment of β the load transfer ratios in different panels change small and the experimental results achieve good agreement with the theoretical results.