钢桁腹式混凝土组合箱梁的扭转效应分析

结合钢桁腹式混凝土组合箱梁的结构特点,基于薄壁箱梁扭转理论,推导出组合箱梁闭口断面的混凝土顶底板和换算钢腹板的扭转翘曲应力表达式,进而推导出组合箱梁约束扭转控制微分方程;利用初参数法求解微分方程,并分析出翘曲双力矩以及扭转翘曲正应力随梁跨的变化规律.通过有限元模拟分析,将有限元值和理论值进行比较,结果吻合良好.研究表明,翘曲双力矩在集中扭矩作用处达到最大值,并且衰减速度很快,使得该处箱梁截面的翘曲应力达到最大值,箱梁的翘曲双力矩在远离集中扭矩作用处几乎为零,翘曲正应力也几乎为零;有限元数值与理论数值的差值百分比在10％以内,说明本文建立的理论计算方法合理可行.

Analysis on torsion effect of concrete composite box girder with steel truss webs

Combined with the structural characteristics of a steel truss web concrete composite box girder,based on the torsion theory of thin-walled box girders,the expressions of the torsional warping stress of the concrete top and bottom plates of the closed section of the composite box girder and the converted steel webs are derived,and then the restrained torsion control differential equation of the composite box girder is derived;the initial parameter method is used to solve the differential equation,and the variation law of warping double moment and normal stress with span is analyzed.Through the finite element simulation analysis,the finite element value is compared with the theoretical value,and the results are in good agreement.The results show that the warping double moment reaches the maximum value at the action of concentrated torque,and the decay speed is very fast,which makes the warping stress of the box girder section reach the maximum value.The warping double moment of the box girder is almost zero at the position far away from the action of concentrated torque,and the warping normal stress is almost zero.The relative error between the finite element value and the theoretical value is less than 10%,which shows that the theoretical calculation method established in this paper is reasonable and feasible.