空间异形桥塔的稳定极限承载力计算方法  

Calculation Method for Stable Ultimate Bearing Capacity of Irregular Space-shaped Bridge Pylon

作　　者：王欢 康玲 牟廷敏 陈明 WANG Huan;KANG Ling;MU Ting-min;CHEN Ming(Sichuan Highway Planning,Survey,Design and Research Institute Ltd.,Chengdu,Sichuan 610041,China)

机构地区：[1]四川省公路规划勘察设计研究院有限公司,四川成都610041

出　　处：《公路交通科技》2024年第4期110-119,共10页Journal of Highway and Transportation Research and Development

基　　金：四川省交通运输科技项目(2022-ZL-07,2022-ZL-08);广西科技计划项目(桂科AB22036007-7);成都交投集团横向科研项目([2022]94号)。

摘　　要：空间异形桥塔几何构形复杂,存在非规则截面和非理想边界特征,利用现有方法难以获得其稳定极限承载力,无法准确感知结构安全性,保守设计思维引发材料浪费。而这类桥塔形式发展快、规模大,朝着结构高耸化、材料高强化、构件薄壁化的趋势发展,稳定问题突出,需重点关注其稳定极限承载力。本研究剖析了桥塔稳定问题的实质,从非线性稳定安全系数入手,系统考虑构件长细比、双重非线性、初始缺陷的影响,寻求稳定安全系数与稳定折减系数的内在映射关系,提出了空间异形桥塔稳定极限承载力计算方法。采用矩形和圆形钢筋混凝土、纯钢箱、钢箱混凝土等典型理想压杆算例,将稳定承载力结果与规范值比对,验证了所提计算方法的可行性和准确性。最后,以一座典型的空间异形桥塔斜拉桥为工程依托,构建了精细化非线性有限元模拟策略,获得其稳定极限承载力。结果表明:该工程的弹性稳定安全系数为18.56,非线性稳定安全系数为4.125,稳定折减系数为0.899,考虑双重非线性和初始缺陷后,非线性稳定安全系数仅为弹性稳定安全系数的0.22,稳定极限承载力大幅降低。对于长细比较大的异形压杆索塔结构,设计上应充分考虑非线性对结构稳定承载力的影响。The geometric configuration of irregular space-shaped bridge pylon(IS-SBP)is complex,which has the characteristics of irregular cross sections and non-ideal boundaries.It is difficult to obtain the stable ultimate bearing capacity(SUBC)by using the existing methods,and the safety of structure cannot be accurately perceived so that the material cost increases.Whereas the development of this kind of bridge pylon is rapid and with large numbers,the stability issues are prominent with the trend of towering structures,high strengthening materials and thin-walled components,and there is an urgent need to carry out study on the SUBC.The essence of the stability problem of bridge pylons is analyzed.By focusing on nonlinear stability safety factors and systematically considering the effects of component slenderness ratio,material nonlinearity,geometry nonlinearity and initial defects,the internal mapping relationship between stability safety factors and stability reduction factors is established,and the analysis method for the SUBC of IS-SBP is proposed.Then,the feasibility and accuracy of the proposed method are verified by comparing the SUBC results with the value from specifications by using the examples of typical ideal compression pylons,e.g.rectangular and circular reinforced concrete compression pylons,pure-steel box compression pylons,and concrete-filled steel box pylons.Finally,based on a typical IS-SBP cable-stayed bridge,a refined nonlinear finite element simulation strategy is constructed to obtain its SUBC.The result shows that the elastic stability safety factor of the structure is 18.56,the nonlinear stability safety factor is 4.125,and the stability reduction factor is 0.899.The SUBC is greatly reduced after considering the dual nonlinearity and initial defects,and the nonlinear stability safety factor is only 0.22 times of the elastic stability safety factor.For irregular space-shaped strut-pylon structure,the influence of nonlinearity on the SUBC of structure should be considered in design.

关 键 词：桥梁工程 稳定极限承载能力 数值模拟 空间异形桥塔 非线性稳定 

分 类 号：U442.5[建筑科学—桥梁与隧道工程]