大跨度铁路连续钢桁梁桥预拱度设置研究

通过实际工程应用,对大跨度连续钢桁梁桥预拱度的设置方法进行研究。采用几何法建立上弦杆杆件调整值与下弦杆节点位移的影响矩阵,然后建立上弦杆调整值与预拱度的函数方程,通过求解多元约束条件方程组,得出合适的上弦杆调整值。几何法仅是杆件的几何关系,与受力无关,与预拼装过程一致,偏差小;并且建立影响矩阵方便,无需借助有限元计算;影响矩阵小,每跨可以单独计算,互不影响,提高收敛和计算速度;给出一种较为简单的预拱度设置方法,大大简化预拱度设置工作并经过工程验证是正确的。

Study on Camber-setting of Large Span Railway Steel Truss Bridge

The method for camber-setting of large span railway steel truss bridge is studied with reference to engineering projects. Geometry method is adopted to establish the influence matrix between the adjustment value of the top chord and the displacement of the bottom chord node and then to obtain the equation between the adjustment value of top chord and the camber. The right adjustment value of the top chord is concluded by solving multiple constraint equations. Geometry method is only involved in the geometric relationship between the members,having nothing to do with stress and consisting with the process of preassembling with little deviation. The influence matrix of the equation is easy to be created without finite element calculation. The influence matrix is small and each span can be calculated separately without mutual interference,which improves the convergence and computation speed. A relatively simple method is presented in this paper for camber-setting,which greatly simplifies camber setting and proves applicable by engineering practices.