基于无应力状态起拱法的钢桁梁桥预拱度研究

Research on pre-camber of steel truss girder bridge based on unstress state arch method

传统钢桁梁预拱度设置方法需建立优化模型,求解冗杂的约束方程,以解决杆件伸缩的统一性及附加内力等因素对钢桁梁预拱度的影响。无应力状态起拱法以相邻节间相对预拱度作为输入参数,获得各单元杆件伸缩量的数学表达式。该方法不会引起附加内力,且易获得较理想的预拱度曲线,以5根杆件组成单独节间的下承式钢桁梁桥为例进行了计算。研究结果表明:基于无应力状态起拱法钢桁梁桥预拱度,算法简单,且能满足工程对精度要求,可为类似桥型施工预拱度设置提供新的思路。

The optimization model is needed to be established using the traditional method to set steel truss pre camber,and some complex constraint equations should be solved to analyze the influence of the uniformity of member expansion and additional internal force on the pre-camber of steel truss girder.In the unstressed state arching method,the relative camber of adjacent nodes is taken as the input parameter,and the mathematical expression of the expansion and contraction of each element member is obtained.The additional internal force will be avoided using this method,and it is easy to obtain the ideal camber curve.Taking the steel truss bridge composed with five members as an example,the calculation results show that the camber algorithm of steel truss bridge based on unstressed state arching method is simple,that can meet the requirements of engineering.Which can provide a new idea setting method for similar bridge construction.