高强钢筋约束超高性能混凝土柱轴心受压本构模型研究  

THE AXIAL COMPRESSION STRESS-STRAIN MODEL FOR ULTRA-HIGH PERFORMANCE CONCRETE COLUMNS CONFINED BY HIGH-STRENGTH STIRRUPS

作　　者：邓宗才[1] 姚军锁 DENG Zong-cai;YAO Jun-suo(Key Laboratory of Urban Security and Disaster Engineering of Ministry of Education,Beijing University of Technology,Beijing 100124,China)

机构地区：[1]北京工业大学城市与工程安全减灾省部共建教育部重点实验室,北京100124

出　　处：《工程力学》2020年第5期120-128,共9页Engineering Mechanics

基　　金：北京市教委科技重点项目(KZ201810005008)。

摘　　要：约束超高性能混凝土(ultra high performance concrete,UHPC)轴压本构模型是进行UHPC柱结构设计和非线性分析的基础。该文对9根箍筋约束UHPC柱的应力-应变关系进行了研究,结果表明:UHPC宜采用高强箍筋约束且适配性良好,与普通箍筋相比高强箍筋可较好的提高约束UHPC强度及变形能力;高体积率、小间距、形式复杂的高强箍筋的约束效果良好;高强箍筋在约束UHPC峰值应力时不一定屈服,取屈服强度计算峰值时高强箍筋的约束应力,会高估其对峰值应力的提高程度。基于Ottosen破坏准则推导了约束UHPC峰值应力计算式,给出了峰值应变、峰值应力时高强箍筋应力取值计算式;建立了约束UHPC轴压本构模型,并与几种典型的约束本构进行了对比,表明所建立的本构与试验曲线吻合度较高。The axial compression constitutive model of confined ultra-high performance concrete(UHPC) is the basis of structural design and nonlinear analysis of UHPC columns. The axial compression test of nine UHPC columns confined by stirrups were performed in this study. The high-strength stirrups showed advantages in improving the strength and deformation performance of confined UHPC over normal stirrups, and better compatibility with UHPC than normal stirrups. The confined UHPC columns with high volume stirrup ratio, closely spaced, high-strength and complex ties configuration may lead to a smooth stress-strain curve, and significantly improves the strength and deformation performance of confined UHPC. The high-strength stirrups may not yield completely at the peak strength, indicating that using the yield strength of stirrups to calculate the confining pressure at the peak may overestimate the peak strength of confined UHPC. The formula of peak strain and high-strength stirrup stress at the peak point, and the formula of peak stress based on the Ottosen’s failure criterion were drawn for confined UHPC. A new confined UHPC constitutive model was presented. Compared with other typical models, the new model agreed with the test curve.

关 键 词：高强箍筋 超高性能混凝土 轴心受压 约束UHPC 本构模型 

分 类 号：TU375.3[建筑科学—结构工程]