高速铁路跨度40 m双线混凝土简支箱梁的约束扭转效应分析

为分析高速铁路跨度40 m双线混凝土简支箱梁桥约束扭转效应，采用薄壁箱梁约束扭转的理论解析法，建立列车活载作用下的约束扭转微分方程，结合ANSYS软件的精细数值模拟结果，对比研究了箱梁在约束扭转下的扭转角、翘曲双力矩、约束扭矩等力学参数的变化规律,研究了腹板倾角、高宽比和悬臂板宽度等计算参数对约束扭转应力的影响规律。结果表明：扭转角在跨中处达到最大，翘曲双力矩在1/4跨、1/2跨处峰值基本一致，约束扭矩在跨中处达到最大值。板壳有限元解与解析解的计算结果存在一定差异，且翘曲正应力在腹板和底板相交处最大相差为66.6%，有限元解更为精确。简支梁跨中截面悬臂端的翘曲效应最明显，翘曲比例系数可达9.16%。翘曲应力总体随高宽比、腹板倾角的增大而减小。

Analysis of Constrained Torsional Effect of High-speed Railway Span 40m Double-line Concrete Simple Box Girder

In order to analyze the constrained torsion effect of high-speed railway span 40m double-line concrete simple box girder bridges, the theoretical analytical method of confined torsion of thin-walled box girders are used to establish the constrained torsional differential equation under train live load, Combining with the fine numerical simulation results of ANSYS software, the paper makes a comparative study of the variation of mechanical parameters, such as torsion angle, warping double moment and restraining torque of box girder under restrained torsion. In addition, the effects of calculation parameters are explored, such as aspect ratio, cantilever width and web inclination on constrained torsional stress. The results show that the torsion angle reaches the maximum at the mid-span, the peak of the warping double moment is basically the same at the 1/4 span and the 1/2 span, and the restraining torque reaches the maximum at the mid-span. There are some differences between the calculation results of finite element solutions and analytical solutions of plate and shell elements, and the maximum difference of the warping normal stress at the intersection of the web and the bottom plate is 66.6%, and the finite element solution is more accurate. The warping effect of the cantilever end of the mid-section of the simply supported beam is the most obvious, and the warpage proportional coefficient can reach 9.16%. With the increase of the aspect ratio and the inclination of the web, the overall warping stress decreases.