基于极限平衡理论的徐变CFT轴压短柱的截面强度算法研究  

Research on sectional strength algorithm of creep CFT axial compression short column based on limit equilibrium theory

作　　者：赖秀英 郑娟 Lai Xiuying;Zheng Juan(College of Civil Engineerings Putian University,Putian 351100,China)

机构地区：[1]莆田学院土木工程学院,福建莆田351100

出　　处：《建筑科学》2021年第3期21-27,共7页Building Science

基　　金：福建省科技厅自然基金项目(2020J05208,2020J01910);福建省教育厅中青年教师教育科研项目(JT180474,JT180477);莆田学院引进人才科研启动项目(2018059)。

摘　　要：将持久荷载引起的钢管应力增量作为初始应力,提出徐变应力度的概念,根据极限平衡理论推导了钢管混凝土(CFT)短柱在持续轴压荷载作用之后的截面强度计算公式,并将该计算结果与试验测得的值进行比较。结果表明,本文考虑持久荷载之后的截面强度折减率与试验测得的值比较接近,并具有较小的离散度。分析了持久荷载作用之后钢管约束效应发生的时间点变化对CFT轴压短柱截面强度变化的影响机理和规律,结果表明:套箍系数和徐变应力度对持久荷载作用之后的CFT轴压短柱截面强度变化起关键作用,与未施加持久荷载的构件相比,持久荷载作用之后的CFT短柱其钢管产生约束效应的时间点更迟。在钢管混凝土拱桥实际工程常用参数范畴内,持久荷载作用之后CFT轴压短柱的截面强度变化范围不大,可以忽略其影响;对于其他结构类型,可参考本文的算法建议。Taking the incremental steel tube stress caused by lasting load as the initial stress,the concept of creep stress degree is proposed,and the formula for calculating the section strength of a concrete-filled steel tube(CFT)short column after continuous axial load is derived according to the limit equilibrium theory.The calculated results are compared with the experimentally measured values.The results show that the reduction rate of the section strength after considering the enduring load is close to the experimentally measured value and has a small dispersion.The time point change of the steel pipe restraint effect is used to analyze the mechanism and law of the change of the endurance load on the strength of the CFT axially compressed short column section.The results show that the steel content(ferrule coefficient)and creep stress degree play a key role in the strength variation of the CFT axially compressed short column section after the endurance load.Compared with the members without the enduring load,the CFT short column after the enduring load has a more restrictive effect on the steel tube.In the field of common parameters of actual engineering of concrete-filled steel tube arch bridges,the cross-sectional strength of CFT axially compressed short columns does not change much after long-term load,and its effect can be ignored;for other structural types,please refer to the algorithm suggestions in this article.

关 键 词：钢管混凝土 徐变 短柱 轴压 承载力影响 

分 类 号：U448[建筑科学—桥梁与隧道工程]