内置约束芯柱的方钢管混凝土组合柱轴压承载力分析  

Axial compression capacity of square steel-concrete-FRP-concrete composite columns

作　　者：陶毅[1,2] 叶思君 陈建飞 TAO Yi;YE Sijun;CHEN Jianfei(School of Civil Engineering,Xi’an University of Architecture and Technology,Xi’an710055,China;State Key Laboratory of Green Building in Western China,XAUAT,Xi’an 710055,China;Department of Ocean Science and Engineering,Southern University of Science and Technology,Shenzhen 518055,China)

机构地区：[1]西安建筑科技大学土木工程学院,陕西西安710055 [2]西安建筑科技大学省部共建西部绿色建筑国家重点实验室,陕西西安710055 [3]南方科技大学海洋科学与工程系,广东深圳518055

出　　处：《建筑结构学报》2022年第3期148-158,共11页Journal of Building Structures

基　　金：国家重点研发计划(2017YFC0703004);国家自然科学基金项目(51978567);陕西省自然科学基础研究计划项目(2018JM5074)。

摘　　要：内置FRP约束混凝土芯柱的方钢管混凝土(steel-concrete-FRP-concrete,SCFC)组合柱可以改善方钢管对混凝土的约束不均匀的问题,核心混凝土的约束需求可以通过内层FRP管、夹层混凝土、外层钢管叠加满足。为了建立该组合柱的轴压承载力计算式并分析主要参数对其承载力的影响,以FRP约束混凝土芯柱的直径和FRP管铺层数为主要设计参数,完成了4个SCFC组合柱轴压性能试验,通过分析组合柱的破坏过程对其轴压性能进行研究。考虑芯柱对方钢管不均匀约束的减缓作用,提出了方钢管有效约束系数模型。在此基础上,针对组合柱各部分,采用双剪统一强度理论,提出了相应的承载力计算方法(模型1)。对钢管还采用了von Mises屈服准则计算其承载力,并将各部分承载力叠加提出了SCFC组合柱的承载力计算模型(模型2)。通过与试验结果对比表明,钢管采用双剪统一强度理论的计算结果略优于von Mises屈服准则的计算结果。进一步分析了混凝土侧压系数对承载力的影响,表明核心混凝土侧压系数对承载力的影响大于夹层混凝土侧压系数,即组合柱轴压承载力主要取决于核心混凝土及其相应约束,并建议模型2侧压系数值均取为1.5。模型参数分析表明,增大FRP管厚度对SCFC组合柱轴压承载力的提升更有效。Steel-concrete-FRP-concrete(SCFC)composite column can improve the nonuniform confinement from the square steel tube because of the appearance of the FRP-confined concrete core.The confinement demands of the concrete core can be satisfied from the confinement provided from inner FRP,sandwich concrete and outer steel tubes.In order to establish the axial bearing capacity model of the composite column and analyze the influence of the main parameters,an axial compression test on four SCFC composite columns was carried out with varying diameters of the FRP confined concrete core and FRP thickness.The failure process of the columns was analyzed in order to study the axial compression performance of composite column.An effective confinement model was proposed for square steel tube to consider the improvements on the nonuniform confinement of the square steel tube due to the application of FRP-confined concrete core.The bearing capacity of each component of SCFC column was calculated using the twin shear unified strength theory(model 1).In addition,the von Mises yield criterion was also adopted to calculate the bearing capacity of steel tube for comparison(model 2).The axial bearing capacity model for SCFC column was eventually proposed by superimposing the bearing capacity of each component.It is found that the predictions from the twin shear unified strength theory is more accurate than those from the von Mises yield theory model.It is also found that the influence of lateral pressure coefficient of concrete core on bearing capacity is more significant than that of sandwich concrete.It means that the axial bearing capacity of SCFC column is dominated by the concrete core and its confinements.The value of lateral pressure coefficients for model 2 is finally recommended to be 1.5.It is concluded that increasing FRP thickness is efficient to promote the bearing capacity of SCFC column.

关 键 词：SCFC组合柱 轴压试验 有效约束系数 双剪强度理论 von Mises屈服准则 轴压承载力 

分 类 号：TU398.902[建筑科学—结构工程] TU317.1