竖向荷载作用下飘浮体系斜拉桥极限承载能力与失效模式分析  

ANALYSIS ON ULTIMATE LOAD-CARRYING CAPACITY AND FAILURE MODES OF LONG-SPAN CABLE-STAYED BRIDGES WITH FLOATING SYSTEMS UNDER THE ACTION OF VERTICAL LOADS

作　　者：吕文高 何政[2] LÜ Wen-gao;HE Zheng(School of Civil Engineering,Guizhou Minzu University,Guiyang,Guizhou 550025,China;School of Civil Engineering,Dalian University of Technology,Dalian,Liaoning 116024,China)

机构地区：[1]贵州民族大学建筑工程学院,贵州贵阳550025 [2]大连理工大学土木工程学院,辽宁大连116024

出　　处：《工程力学》2022年第5期145-158,共14页Engineering Mechanics

基　　金：国家自然科学基金项目(52068010);贵州省科学技术基金资助项目(黔科合基础-ZK[2021]一般291);国家重点基础研究发展计划项目(973计划)(2013CB036305);贵州民族大学自然科学类校级基金项目(GZMU[2019]YB28)。

摘　　要：提出采用塑性极限分析法研究竖向荷载作用下大跨飘浮体系斜拉桥的极限承载力和失效模式。基于塑性极限分析的相关假定并结合基本机构证明了该方法应用于斜拉桥失效分析的可行性,结合飘浮体系单塔斜拉桥推导了极限承载力计算公式并分析对应的失效模式,通过优化方法-内点法获得斜拉桥塑性极限荷载及其对应失效模式,并与OpenSEES有限元分析结果进行了对比分析。结果表明:竖向荷载作用下,主梁在拉索屈服强度较小时为整体性破坏,反之则为局部性破坏;相比拉索而言,主梁屈服强度对斜拉桥破坏的影响则正相反;拉索锈蚀在降低斜拉桥极限载荷系数的同时也改变其倒塌失效模式;相比于有限元法,塑性极限分析法简便且易操作,可用于研究竖向荷载作用下飘浮体系斜拉桥的极限承载能力与失效模式,且能够快速有效评估结构参数变化对其失效行为的影响。The plastic limit analysis method is proposed to study the ultimate load-carrying capacity and failure modes of long-span cable-stayed bridges with floating systems under the action of vertical loads. Based on the assumptions of the plastic limit analysis and on the elementary mechanisms, the feasibility of the method applied to the failure analysis of cable-stayed bridges was proved. Combined with a single-tower cable-stayed bridge with a floating system, the calculation formula of ultimate load-carrying capacity was derived and the corresponding failure modes are analyzed. The plastic collapse loads and the corresponding failure modes of the cable-stayed bridges were obtained through the interior point method which is an optimization method, and then the comparison analysis of two results respectively from the plastic limit analysis method and the OpenSEES were conducted. The results show that: the girder of cable-stayed bridges subjected to vertical loads presents the characteristic of global failure when the cable’s yield strength is relatively small, otherwise it presents the characteristics of local failure. The influence of the girder’s yield strength on the failure behavior is just the opposite of those cables. The cable corrosion not only reduces the ultimate load factor of the cable-stayed bridges,but also changes its failure modes. Compared with the FEM, the plastic limit analysis method is simple and easy to operate. It can be used to study the ultimate load-carrying capacity and failure modes of cable-stayed bridges subjected to vertical loads and can quickly and effectively evaluate the influence of changes of structural parameters on the failure behavior of bridges.

关 键 词：飘浮体系斜拉桥 极限承载力与失效模式 拉索锈蚀 塑性极限分析 线性规划 

分 类 号：U448.27[建筑科学—桥梁与隧道工程] U441.4[交通运输工程—道路与铁道工程]