基于修正刚接梁法的装配式T梁桥荷载横向分布计算方法研究

Research on Modified Rigidly-jointed Beam Method for Load Transverse Distribution for Prefabricated T-beam Bridges

传统刚接梁法在装配式T梁桥荷载横向分布计算中忽略纵向弯矩等因素,导致计算结果与实际情况存在一定差异。为了准确计算装配式T梁桥荷载横向分布状况,文中在刚接梁法的基础上,结合三维有限元模型分析结果,提出考虑主梁刚度修正的荷载横向分布计算方法。针对纵向弯矩等因素对主梁的竖向刚度与扭转刚度的影响,引入计算长度系数作为待修正参数,以有限元计算的荷载横向分布构造目标函数,并通过内点法对目标函数进行优化,得到修正后的刚度参数,计算出装配式T梁桥荷载横向分布影响线。结果表明,对于常规跨径的装配式T梁桥,与主梁竖向刚度相关的计算长度系数为0.5~0.6,而与主梁扭转刚度相关的长度系数则为0.18~0.22。文中提出的修正刚接梁法计算结果与三维有限元结果吻合良好,能够较好地适用于装配式T梁桥荷载横向分布计算。

In the traditional rigid-jointed beam method used for calculating the load transverse distribution of prefabricated T-beam bridges,factors such as longitudinal bending moments are overlooked,leading to discrepancies between calculated results and actual scenarios.To enhance the accuracy of calculating the load transverse distribution in prefabricated T-beam bridges,the rigid-jointed beam method is improved by integrating results from three-dimensional finite element model analysis.A load lateral distribution calculation method is proposed that considers the stiffness correction of the main girders.Considering the influence of longitudinal bending moments and similar factors on the vertical and torsional stiffness of the main girders,an effective length factor is introduced as a modifiable parameter.This factor is employed to develop an objective function grounded in the live load distribution as determined by finite element analysis.Subsequently,the interior point method is utilized to optimize this objective function,leading to updated stiffness parameters.These parameters facilitate the calculation of the influence line for load transverse distribution in prefabricated T-beam bridges.Numerical investigations suggest that for prefabricated T-beam bridges with standard spans,the effective length factor associated with the vertical stiffness ranges between 0.5 and 0.6,while the factor linked to torsional stiffness varies from 0.18 to 0.22.The modified rigid-jointed beam method proposed in this research closely aligns with the results from three-dimensional finite element analysis and proves to be effectively applicable in the computation of load transverse distribution for prefabricated T-beam bridges.