拉筋复合箍约束混凝土短柱轴心受压试验研究  

Experimental study on axial compressive behavior of short concrete columns confined with hoops and crossties

作　　者：钱稼茹[1] 纪晓东[1] 乐毓敏[1] 

机构地区：[1]清华大学,北京100084

出　　处：《土木工程学报》2012年第11期61-68,共8页China Civil Engineering Journal

基　　金：十一五国家科技支撑计划(2009BAJ28B01)

摘　　要：拉筋复合箍是常用的箍筋形式,其拉筋应钩住纵筋还是应钩住箍筋,国内外的试验研究很少。为研究拉筋复合箍及其两种拉筋钩结方式对混凝土的约束效果,完成15个复合箍约束混凝土短柱试件的轴心受压试验,其中6个试件的拉筋钩住纵筋,6个试件的拉筋钩住箍筋,3个为井字复合箍对比试件。试验结果表明,试件的破坏形态都是纵筋压屈、混凝土压碎,但井字复合箍和拉筋钩住纵筋试件的外箍外凸,拉筋钩住箍筋试件的外箍被拉筋剪断;两种拉筋复合箍和井字复合箍约束混凝土的峰值应力与非约束混凝土轴心抗压强度试验值的比值、约束混凝土的峰值应变和延性分别基本相同。建议拉筋钩住纵筋,不必钩住箍筋。通过比较常用的约束混凝土本构模型与实测约束混凝土应力-应变曲线,推荐Legeron模型作为箍筋约束混凝土的单轴受压应力-应变模型。Supplementary crossties with peripheral hoops are commonly used configuration of transverse reinforcements for RC columns. However, experimental studies on crossties details （i. e. , whether crossties should engage longitudinal bars or engage peripheral hoops） are very limited. To investigate the confinement effects of two types of crossties, a total of fifteen short RC column specimens were axially loaded in compression. Six specimens had the crossties engaging longitudinal bars, six specimens had the crossties engaging peripheral hoops, and the other three specimens had combined hoops. All specimens failed in similar manners, featured by buckling of longitudinal bars and crushing of concrete. For the specimens with combined hoops and those with crossties engaging longitudinal bars, the peripheral hoops were observed to bend outward, whereas for the specimens with the crossties engaging peripheral hoops, the hoops fractured due to the concentrated shear forces exerted by crossties. Peak stress, peak strain and ductility of the confined concrete were nearly identical for various sets of specimens. It is suggested that the crossties should peripheral hoops but longitudinal bars. Three existing analytical models for stirrup confined concrete are compared with the stress-strain relationship curves measured by the test, and the Legeron model is recommended as the theoretical model.

关 键 词：拉筋复合箍 约束混凝土 轴心受压试验 应力.应变关系 

分 类 号：TU375.3[建筑科学—结构工程]