曲线波形腹板钢箱-混凝土组合梁扭转振动频率分析

Analysis of Torsional Vibration Frequency of Steel Box-Concrete Composite Beams with Curved Wavy Webs

为科学合理地分析曲线波形腹板钢箱-混凝土组合梁的扭转振动特性,首先,综合考虑弯扭耦合效应和波形钢腹板的剪切变形效应,基于Galerkin法和Hamilton原理建立了该桥型的扭转振动频率控制微分方程和自然边界条件.随后,根据自然边界条件,求解了剪切变形效应和弯扭耦合效应共同作用下曲线波形腹板钢箱-混凝土组合梁扭转振动频率的解析公式,将计算结果与ANSYS三维有限元进行了对比,结果表明,曲线波形腹板钢箱-混凝土组合梁扭转振动频率的解析公式与ANSYS有限元分析结果吻合良好.在此基础上,当R无穷大时,利用实测值和模型结果,进一步验证了解析解的正确性和通用性.并分析得出了波形钢腹板剪切变形效应对扭转振动的影响较大.最后,对影响扭转振动频率的相关参数进行了分析,结果表明:合理设置横隔板数量和厚度能有效改善抗扭刚度;曲率半径从50 m分别增加到100 m和300 m时,1阶扭转振动频率分别减小了5.86%和8.22%,当曲率半径较小时,对扭转振动频率的影响较大.研究结论可为此类曲线组合梁桥扭转振动频率的分析提供参考价值.

In order to scientifically and reasonably analyze the torsional vibration characteristics of steel box-concrete composite beams with curved corrugated webs.First,the coupling effect of bending and torsion and the shear deformation effect of corrugated steel webs is investigated comprehensively,and the bridge type is established based on the Galerkin method and the Hamilton principle.The differential equation and natural boundary conditions are controlled by the torsional vibration frequency.Subsequently,according to the natural boundary conditions,the analytical formula for the torsional vibration frequency of the curved steel box-concrete composite beam under the combined action of the shear deformation effect and the bending-torsion coupling effect was solved,and the calculation results were compared with the ANSYS three-dimensional finite element.The results shows that the analytical formula for the torsional vibration frequency of the steel box-concrete composite beam with curved wavy webs is consistent with the result of ANSYS finite element analysis.On this basis,when R infinity is infinite,the correctness and generality of the analytical solution are further verified by using measured values and model results.It is also analyzed that the shear deformation effect of the corrugated steel web has a greater influence on the torsional vibration.Finally,the relevant parametric analysis are carried out,and the results show that reasonable number and thickness setting of the diaphragm could effectively improve the torsional stiffness;When the radius of curvature increases from 50 m to 100 m and 300 m,the first-order torsional vibration frequencies are respectively reduced by 5.86% and 8.22% respectively.In addition,the torsional vibration frequency is obviously affected when the radius of curvature is smaller.The research results can provide a reference for the torsional vibration frequency analysis of such kind of curved composite beam bridges.