钢箱格子梁桥的荷载横向分配与格子刚度的量化关系

Quantitative Relationship between Load Transverse Distribution and Grid Stiffness of Steel Box Grid-beam Bridges

摘要:

为建立钢箱格子梁桥设置横梁的理论依据，提出一种由目标荷载横向分配系数来确定横梁设置的方法。首先推导抗弯扭格子刚度的无量纲表达式，然后通过计算绘制出荷载横向分配系数与抗弯扭格子刚度的关系曲线，再计算多根横梁的格子刚度换算系数，最后选定目标荷载横向分配系数反算所需横梁根数和横梁抗弯刚度。以交通部颁布的标准箱形钢混组合梁桥为例，运用这个方法优化了横梁的数量和梁高。研究结果表明：荷载横向分配系数与格子刚度之间具有一一对应关系；箱形主梁有利于荷载横向分配，协同工作能力比工字形主梁更好；简支箱形钢混组合格子梁桥设置3~5根横梁即可，跨径越小需要的横梁越多。

Abstract:

In order to establish the theoretical basis for setting up the crossbeam of steel box grid-beam bridge, a method to determine the crossbeam setting by the transverse distribution coefficient of target load is proposed. Firstly, the dimensionless expression of flexural and torsional grid stiffness is derived. Then, the relationship curves between load transverse distribution coefficient and bending torsional grid stiffness are drawn by the calculation. And the grid stiffness conversion coefficient for multiple crossbeams are calculated. Finally, the required number of crossbeams and bending stiffness of crossbeams are back calculated by the selected target load transverse distribution coefficient. The proposed method is used to optimize the number and height of crossbeams by the example of the standard box steel-concrete composite beam bridges issued by the Ministry of Communications. The research result shows that there is a one-to-one correspondence between the load transverse distribution coefficient and the grid stiffness. The box girder is beneficial for load transverse distribution and the collaborative working ability is better than I-shaped girder. 3~5 crossbeams are only set up for the simple-supported box steel-concrete composite grid-beam bridge. The smaller the span, the more crossbeams are required.