高强混凝土正截面等效矩形应力系数解析法  

Analytic method on equivalent rectangular stress coefficients of normal section of high strength concrete members

作　　者：陈旭 宋高丽 章胜平[2] CHEN Xu;SONG Gaoli;ZHANG Shengping(Department of Construction Engineering,Kunming University,Kunming 650214,China;Department of Construction Engineering,Kunming University of Science and Technology,Kunming 650504,China)

机构地区：[1]昆明学院建筑工程学院,云南昆明650214 [2]昆明理工大学建筑工程学院,云南昆明650504

出　　处：《武汉大学学报（工学版）》2023年第6期700-707,共8页Engineering Journal of Wuhan University

基　　金：国家自然科学基金项目(编号:51868034);云南省教育厅科学研究基金项目(编号:2021J0702,2021J0703)。

摘　　要：现有规范等效矩形应力图系数理论推导没有考虑小偏压受力,高估了高强混凝土小偏压柱轴向承载力,偏于不安全。按照极限状态所有可能应变分布,考虑中性轴截面内和截面外2种情况,以强度和混凝土受压边缘应变为变量,基于等效原则建立积分方程推导了应力饱满系数α和力臂系数β解析解公式。结果表明:现有规范系数α1、β1用于普通混凝土偏差小;高强混凝土系数α、β与受力有关但不是常量,高强混凝土小偏压柱应按照公式计算α、β;双线性本构作为混凝土曲线-矩形本构的补充应用于高强混凝土压弯承载力计算中,其计算精度较高,轴压极限应变乘以折减系数0.85之后还可进一步提高计算精度。Compression member with small eccentricity is not considered in the theoretical analysis of the existing specification equivalent rectanglar stress coefficient.It leads to overestimate the axial carrying force of the small eccentric column of high-strength concrete,which is not safe.According to all the possible strain distributions in the limit state,considering the neutral axis under two cases of inside and outer the crosssection,strength and strain at the concrete compressive edge were taken as variables,and a set of formulas of the stress full coefficientαand force arm coefficientβwere derived analytically based on the integration equations according to the equivalent principle.The results show that theα1 andβ1 in existing specifications are used for ordinary concrete with small deviation.Theαandβof high-strength concrete are not constant and related to forces,which should be calculated according to analytical formulas for the the small eccentric column of high-strength concrete.As a supplement to the curve-rectangular constitution of concrete,the bilinear relation is used for the calculation of compression-bending capacity of high-strength concrete,and the accuracy can be further improved after multiplying the ultimate axial compressive strain by 0.85.

关 键 词：高强混凝土 等效矩形应力 解析法 应力饱满系数 力臂系数 

分 类 号：TU375[建筑科学—结构工程] TU312