超宽简支钢箱梁动力特性及简化分析方法研究

Research on Dynamic Characteristics and Simplified Analysis Methods of the Super-wide Simply Supported steel Box Girder

随着超宽梁桥的逐渐增多,宽幅桥梁与普通的窄桥相比,在荷载横向分布、稳定分析以及横向连接等方面都有明显区别。现以一座单跨单箱多室钢箱简支梁桥为研究对象,分别建立空间梁单元模型、等效板单元模型、梁格体系模型和实体单元模型,并对四种模型进行了动力特性结果比较,探讨了超宽简支钢箱梁桥不同计算模型动力特性的差异。结果表明,梁格体系模型的竖弯频率误差最小,而所有模型的扭转频率误差都较大。对于宽度不同的梁桥,运用等效板单元模型进行参数化分析,并对桥梁的竖弯频率和扭转频率的计算,提出简化模拟公式。归纳出的结论对同类桥梁的动力特性计算具有一定的参考价值。

With the increasing of the super-wide beam bridges,there are obvious differences in the transverse load distribution,stability analysis and transverse connection between the wide bridge and the common narrow bridge.Based on a single span steel box beam bridge,the spatial beam element model,the equivalent thickness of plate model,the beam-grid system model and entity unit model were established to compare the dynamic characteristics of four models and discuss the difference of dynamic characteristics of super-wide simply supported steel box girder bridge of different calculation models.The results showed that the vertical bending frequency error of beam-grid system model was the minimum,and the torsion frequency errors of all models were large.In this paper,the equivalent plate element was used for parametric analysis of beam bridges with different widths,and the simplified simulation formulas of vertical bending frequency and torsion frequency were proposed.The conclusions were of certain reference value to the calculation of dynamic characteristics of similar bridges.