基于多芯梁框架系统的悬索桥气弹模型设计方法

Design Method for Aeroelastic Models of Suspension Bridges Based on Multi-Steel Beam Frame System

摘要:

针对大跨度双层桥面钢桁架悬索桥，提出了一种新的加劲梁气弹模型设计方法，称为多芯梁框架系统。该系统包含上下两层芯梁、横向联系刚臂和竖向框架刚臂。通过将设计过程转化为优化问题，并采用有约束的模式搜索法，获得了满足设计指标的加劲梁设计参数值。敏感性分析表明，横向联系刚臂和上下两层纵向芯梁的尺寸对模态频率具有关键影响。动力特性测试结果验证了多芯梁框架系统模拟的准确性，低阶模态频率与设计目标值误差在±5%以内。这一设计方法作为全桥气弹模型设计方法的有效补充，适用于桁架形式加劲梁，实现了气动外形、刚度系统和质量系统的整体最佳模拟。

Abstract:

For long span double-deck suspension bridges with steel truss girder， a new aeroelastic model design method is proposed， referred to as the multi-steel beam frame system （MSBFS）， which comprises upper and lower steel beams， horizontal connecting rigid beams， and vertical rigid columns. By transforming the design process into an optimization problem and employing the constrained pattern search method， the design variables for the stiffening beam satisfying the design criteria are obtained. The sensitivity analysis reveals that the modal frequencies are significantly influenced by the dimensions of the horizontal connecting rigid beams， as well as the upper and lower longitudinal steel beams. The dynamic characteristic test results confirm the accuracy of the MSBFS， as the deviation in low-order modal frequencies from the design target values falls within ±5%. As a valuable complement to the full-bridge aeroelastic model design approaches， this design method is well-suited for truss girders， enabling an overall optimal simulation of aerodynamic shape， stiffness and mass system.