刚性悬索加劲钢桁梁桥塔柱纵向稳定计算长度系数研究  

Research on the Effective Length Factor of Tower Column Longitudinal Stability in Steel Truss Bridge Stiffened with Rigid Suspension Cables

作　　者：刘世忠 刘永健[1] 李建红[1] 张俊光[1] 张国玺[1] 

机构地区：[1]长安大学桥梁与隧道陕西省重点实验室,陕西西安710064 [2]太原科技大学交通与物流学院,山西太原030024

出　　处：《中国铁道科学》2012年第6期17-23,共7页China Railway Science

基　　金：教育部新世纪优秀人才支持计划项目(NCET-06-0855);广东省交通厅科技项目(2007-15);太原科技大学校青年基金项目(20113018)

摘　　要：根据刚性悬索加劲钢桁梁桥塔柱受力特点,引入等效弹簧约束,建立简化的塔柱纵向稳定计算模型,采用中性平衡法推导出塔柱稳定特征方程。以东江大桥为例,采用有限元分析软件MIDAS/Civil,建立实桥空间与平面(单片桁)有限元模型,计算等效弹簧刚度系数值,进而得出塔柱纵向稳定计算长度系数。对比分析不同边界条件(不同弹簧刚度)对塔柱纵向稳定计算长度系数的影响。研究结果表明:在分析成桥阶段塔柱纵向稳定时可仅在塔柱弯曲平面进行,而无需考虑支点横联的影响和结构的空间效应;塔柱纵向稳定计算长度系数受塔柱的上端侧移约束刚度的影响较小,下端转动约束刚度的影响较大,上端转动约束刚度的影响最显著,且随三者的增大均减小;适当增大塔柱上端转动约束刚度最能有效地减小塔柱纵向稳定计算长度系数;此类桥梁塔柱纵向稳定计算长度系数合理取值范围为0.65～0.8。According to the mechanical characteristics of the tower column in steel truss bridge stiffened with rigid suspension cables, a simplified calculation model for the longitudinal stability of tower column was established by introducing equivalent spring restraint system. Stability characteristic equation for tow- er column was derived by using neutral equilibrium method. Dongjiang Bridge served as the research model here. With the aid of FEM software MIDAS/Civil, three-dimensional and plane （single truss structure） fi- nite element models for Dongjiang Bridge were set up to calculate the equivalent spring stiffness coefficient. Hence the effective length factor for the longitudinal stability of tower column was obtained and the influences of different boundary conditions （different spring stiffness） upon the effective length factor were compared and analyzed. The results show that the influences of lateral bracing and the structural spatial effect on tower column can be ignored when analyzing the longitudinal stability of tower column in finished stage. The change of lateral restraint stiffness at the upper end of tower column in wide range has little in- fluence on the effective length factor for the longitudinal stability of tower column. The rotating restraint stiffness at the bottom has greater influence while that at the upper end is the most significant. The effective length factor decreases with the increase of the above three restraint stiffness. The effective length factor for the longitudinal stability of tower column can be effectively reduced with the proper increase of the rotating restraint stiffness at the upper end of tower column. In addition, the rational value range for the effective length factor of tower column longitudinal stability for this kind of steel truss bridge is found to be 0.65-0.8.

关 键 词：悬索桥 钢桁梁 塔柱 刚性悬索 纵向稳定 计算长度系数 等效约束弹簧 

分 类 号：U443.38[建筑科学—桥梁与隧道工程] U448.25[交通运输工程—道路与铁道工程]