摘要
组合钢桁梁具有桁架结构的受力特征,同时还受节点性能和板桁组合作用的影响,受力机理复杂。传统有限元优化方法无法兼顾杆件和节点,为对组合钢桁梁设计方案进行快速、准确地优化,提出了一种基于效率系数的优化设计方法。在采用杆系有限元模型进行初步分析基础上,根据结构内力分布相似的假定,以杆件和节点承载力效率系数为优化指标对构件进行优化,再将优化方案代入有限元模型进行验证。以矩形钢管混凝土组合桁梁连续梁桥既有通用图集为依托工程,进行设计方案优化。结果表明:组合钢桁梁空间效应等因素产生的弯曲应力可达组合应力的15%~42%,弯矩产生的影响不可忽略,在计算杆件效率系数时应将弯矩和轴力同时考虑在内;效率系数可直观反映组合钢桁梁构件应力状态,快速定位优化构件,还可依据杆件截面特征将优化方案细分至板件层面;所提优化设计方法可对组合钢桁梁的节点和杆件进行统筹优化,避免反复进行有限元试算,显著提高优化计算效率。
Composite steel truss girder has the mechanical characteristics of truss structure,but also affected by the joint performance and plate truss combination.Thus,the mechanism of the girder is complicated.The traditional finite element design method cannot optimize members and joints simultaneously.In order to optimize the design scheme of composite steel truss girder quickly and accurately,an optimization calculation method was presented.The method was based on the preliminary analysis of finite element model(FEM).Considering that the force distribution of the structure was similar,the main truss members were optimized by the bearing capacity efficiency coefficient of members and joints.Then,the optimized scheme was substituted into the finite element model for verification.Based on the existing general atlas of rectangular concrete filled steel tube continuous girder bridge,the design scheme was optimized.The results show that the bending stress caused by the spatial effect of composite steel truss girder can reach 15%-42%of the combined stress,and the influence of the bending moment cannot be ignored.So,the bending moment and axial force should be taken into account when calculating the efficiency coefficient.The efficiency coefficient can directly reflect the stress state of composite steel truss members.The method can quickly locate the optimized members and subdivide the optimization scheme to the plate level according to the section characteristics of the members.The proposed optimization design method can optimize the joints and members of composite steel truss girder,avoid repeated finite element trial calculation,and improve the optimization efficiency significantly.
作者
王琨
刘永健
马印平
WANG Kun;LIU Yongjian;MA Yinping(School of Highway,Chang'an University,Xi'an 710064,Shaanxi,China;School of Civil Engineering,Chongqing University,Chongqing 400045,China)
出处
《建筑科学与工程学报》
CAS
北大核心
2023年第2期86-96,共11页
Journal of Architecture and Civil Engineering
基金
中央高校基本科研业务费专项资金项目(300102219310)。
关键词
桥梁工程
组合钢桁梁
优化设计方法
效率系数
bridge engineering
composite steel truss girder
optimization design method
efficient coefficient
