方钢管螺旋筋复合约束混凝土轴压短柱破坏机理试验研究  

Experimental study on failure mechanism of square steel tube and spiral reinforcement multiple confined concrete stub columns under axial compression

作　　者：经承贵 陈宗平[1,2] 周山崴 徐金俊[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：《建筑结构学报》2018年第3期93-102,共10页Journal of Building Structures

基　　金：国家自然科学基金项目(51578163);广西高等学校高水平创新团队及卓越学者计划资助项目(桂教人[2017]38号)

摘　　要：为研究方钢管螺旋筋复合约束混凝土轴压短柱破坏机理,完成了12个试件的轴心受压试验。观察了试件外观破坏情况、核心混凝土破坏形态及螺旋筋失效模式,并分析了受力过程中螺旋筋、纵筋、方钢管的应力发展和内力分配情况。试验结果表明：方钢管、螺旋筋、纵筋及核心混凝土四者能协同工作,各种材料强度均能充分发挥;螺旋筋在弹性受力阶段发挥的作用较小,不能延缓方钢管发生局部鼓曲,而主要在弹塑性及流塑阶段发挥约束作用,能显著提高轴压短柱的承载力和变形能力;方钢管和螺旋筋对核心混凝土形成双重约束机制,当方钢管发生鼓曲后螺旋筋能有效补充对核心混凝土的约束作用,进而改善了方钢管对核心混凝土约束不均匀的特性。In order to reveal the failure mechanism of square steel tube and spiral reinforcement multiple confined concrete stub columns under axial compression, twelve specimens subjected to axial compressive load were tested. The failure modes of outer steel tube, inner concrete and spiral reinforcement were observed. The inner forces and stress state of spiral reinforcement, longitudinal reinforcement and outer steel tube were also studied during the experimental research. The test results indicate that the square steel tube, spiral reinforcement, longitudinal reinforcement and inner concrete can work well with each other, and the strength of the materials can be well mobilized. The spiral reinforcement in the elastic stage plays a limited role in delaying the onset of square steel tube local buckling. However, it can provide significantly confinement to the inner concrete in the inelastic and flow-plastic stage and therefore improve the bearing capacity and deformation ability. The square steel tube and spiral reinforcement form a multiple confined mechanism to the inner concrete. In other words, the spiral reinforcement can effectively offer extra confinement in addition to that provided by the square steel tube after the occurrence of local buckling, and can address the issue of uneven confinement provided by square steel tube.

关 键 词：方钢管混凝土短柱 螺旋筋 约束混凝土 轴心受压试验 破坏机理 

分 类 号：TU398.903[建筑科学—结构工程]