钢桁腹-混凝土组合箱梁畸变效应研究

为研究梯形截面的钢桁腹-混凝土组合箱梁的畸变效应，在薄壁箱梁理论的基础上，考虑钢桁腹杆的力学特性，应用改进的板元分析法建立畸变控制微分方程，并给出畸变解析解。通过ANSYS建立实体模型验证所推公式的正确性。结合数值算例，对比分析在均布畸变荷载作用下相同截面参数的钢桁腹-混凝土组合箱梁和传统混凝土箱梁的畸变翘曲正应力，并分析梁宽和钢腹杆俯角对组合箱梁畸变内力的影响。结果表明，相同截面参数下，由于组合箱梁钢桁腹杆的纵向刚度很小，其畸变翘曲正应力为混凝土箱梁的1.71倍；梁宽对畸变内力影响较大，当梁宽增加至4.5 m时，畸变双力矩和畸变矩分别增大至3.68倍和1.36倍，且前者在纵向上双峰的分布趋势逐渐平缓；腹杆俯角对畸变双力矩影响较大，当腹杆俯角增加至27°时，畸变双力矩减小了约14.3%,但其对畸变矩影响很小。

Distortion effect of concrete composite box girder with steel truss webs

In order to study the distortion effect of a composite concrete box girder with a steel truss web,on the basis of the thin-walled box girder theory,considering the mechanical properties of the steel truss web,the improved plate element analytic method is used to establish the differential equation for distortion.The distortion analytical solution are given.A solid model through ANSYS to verify the correctness of the derived formula is established.Combined with numerical examples,the distortion stresses of a composite box girder and a traditional concrete box girder with the same cross-sectional parameters under a uniformly distributed distortion load are compared and analyzed.The influence of the beam width and the depression angle of the steel web on the distortion internal force of the composite box girder is analysed.The results show that under the same section parameters,due to the small longitudinal stiffness of the steel truss web member of the composite box girder,of which distortion warping normal stress is 1.71 times of that of the concrete box girder;the beam width has a great influence on the distortion internal force,and when the beam width increases to 4.5 m,the distortion double moment and the distortion moment increase to 3.68 times and 1.36 times respectively,and the distribution trend of the former two peaks in the longitudinal direction is gradually flat;When the depression angle of the steel web increases to 27°,the distortion double moment is reduced by about 14.3%,but it has little effect on the distortion moment.