大吨位转体桥梁不平衡力矩计算方法优化研究

Optimization of Unbalanced Moment Calculation Method for Bridge with Large-Tonnage Rotated Structure

针对常用的不平衡力矩计算方法无法适应于大吨位转体桥梁而造成较大计算误差的问题,基于常用的球铰转动法和球铰应力差法,以某大吨位转体桥为背景,对2种方法的不平衡力矩计算结果进行对比,以确定适合大吨位转体桥梁不平衡力矩计算方法;建立球铰有限元模型,分析不平衡力矩对球铰应力差分布规律;采用增广拉格朗日方程对基于球铰应力差法的不平衡力矩计算公式进行优化,并以多座桥梁为例验证优化公式的适用性。结果表明:球铰应力差法与球铰转动法的不平衡力矩计算值相对误差较小;球铰两侧应力差值的大小随着与球铰中心距离的增加呈现先增大后减小的变化趋势;不平衡力矩有限元分析值大于实测值,且两者的相对误差随着不平衡力矩的增加显著增大,最大相对误差为33.4%,优化后的球铰应力差法计算得到的不平衡力矩值与实测值的相对误差在15%以内,表明优化效果良好。

The conventional unbalanced moment calculation methods are not applicable in the bridge with large-tonnage rotated structure,likely causing significant calculation errors.In this paper,the two conventional methods,including the spherical hinge rotation method and the spherical hinge stress difference method,are applied to a bridge constructed by rotation method for comparison from the working mechanism perspective,aiming to determine an unbalanced moment calculation method applicable for bridges with large-tonnage rotated structure.Finite element models of the spherical hinge were established to analyze the influence of unbalanced moment on the stress difference distribution in the spherical hinge.The unbalanced moment calculation formula based on the spherical hinge stress method is optimized by the augmented Lagrangian equation,and the optimized formula is applied to multiple bridges for verification.The results demonstrate that there is a minor relative deviation between the unbalanced bending moments calculated by the spherical hinge rotation method and the spherical hinge stress difference method,the difference of the stresses on the two sides of the spherical hinge changed from increasing to decreasing as the distance to the center of the spherical hinge increases.The calculated unbalanced moment is bigger than the measured value,and the relative error between the two becomes more significant as the unbalanced moment increases,with a maximum value of 33.4%.The relative error between the unbalanced moment calculated by the optimized spherical hinge stress difference method and the measured value is within the range of 15%,revealing a sound optimization effect.