方钢管螺旋筋复合约束混凝土柱轴压机理及承载力计算  

Mechanism and load-bearing capacity of square steel tubular and spiral stirrup composite confined-concrete stub columns under axial compression

作　　者：陈宗平[1,2] 经承贵 徐金俊[1] 周春恒[1] 

机构地区：[1]广西大学土木建筑工程学院,广西南宁530004 [2]广西大学工程防灾与结构安全教育部重点实验室,广西南宁530004

出　　处：《土木工程学报》2017年第5期47-56,共10页China Civil Engineering Journal

基　　金：国家自然科学基金(51268004;51578163)

摘　　要：为研究方钢管螺旋筋复合约束混凝土柱的轴压受力性能,完成了25个方钢管螺旋筋复合约束混凝土柱试件和4个普通方钢管混凝土柱试件的轴心受压试验。从试件的表观破损全过程、核心混凝土的碎裂形态、螺旋筋的失效模式、荷载位移曲线、各钢材组分的应变发展规律等多个角度对方钢管螺旋筋复合约束混凝土柱的轴压机理展开分析,并与普通方钢管混凝土柱进行了对比。研究结果表明:螺旋筋有效改善了方钢管对核心混凝土约束不均匀的特点;螺旋筋、纵筋及方钢管之间具有良好的变形协调性,在本研究的配筋率范围内(0.44%~2.90%),螺旋筋的屈服强度均能充分发挥;方钢管螺旋筋复合约束混凝土柱比普通方钢管混凝土柱具有更好的轴压承载能力和变形能力,且随着螺旋筋间距的减小、直径和径宽比的增大,其表现出更优良的轴压性能;基于复合约束模型推导的承载力公式,其物理意义明确、形式简单,且计算值与试验值吻合较好,可供工程设计参考。To investigate the axial compressive behavior of square steel tubular and spiral stirrup composite confined- concrete （STSCC） stub columns, a total of 29 specimens were tested under axial loads. The compressive mechanical of STSCC were analyzed based on the apparent evolution process, the failure modes of core concrete and spiral stirrup, the load-displacement and load-strain curves. The experimental results show that the spiral stirrups can effectively improve the uneven characteristics of confinement provided by the square steel tube. The deformation compatibility among spiral stirrup, longitudinal reinforcement and square steel tube is very good, and the yield strength of spiral stirrup can be fully developed within the scope of reinforcement ratio. The axial compressive bearing capacity and deformation performances of STSCC columns are better than those of normal square CFST columns. The compression performance increases with the spacing of the spiral stirrups, while decreases with the diameter and the ratio diameter to width. A axial compressive capacity formula with clear physical meaning and simple form is proposed based on the composite confinement model. The test results agree well with the theoretical ones, which validates the effectiveness of the proposed formula and can provide reference for engineering application .

关 键 词：方钢管混凝土 螺旋筋 约束混凝土 轴心受压 承载力计算 

分 类 号：TU375.3[建筑科学—结构工程]