外套钢管夹层混凝土加固钢管混凝土短柱轴压性能试验研究  

Experimental study on CFST stub columns strengthened with outer steel tube and sandwiched concrete jackets under axial compression

作　　者：卢亦焱[1] 黄悦 颜宇鸿 李伟捷 祝涛[1] LU Yiyan;HUANG Yue;YAN Yuhong;LI Weijie;ZHU Tao(School of Civil Engineering,Wuhan University,Wuhan 430072,China;School of Civil Engineering,China University of Mining and Technology-Beijing,Beijing 100083,China)

机构地区：[1]武汉大学土木建筑工程学院,湖北武汉430072 [2]中国矿业大学(北京)力学与土木工程学院,北京100083

出　　处：《建筑结构学报》2024年第11期151-162,共12页Journal of Building Structures

基　　金：国家自然科学基金重点项目(52238006);中央高校基本科研业务费专项(2042023kf1047)。

摘　　要：钢管混凝土结构在役期间可能受到物理老化、化学腐蚀、极端灾害等因素影响,或者由于使用功能改变,亟需加固改造。为此,提出外套钢管夹层混凝土加固钢管混凝土技术,对10个组合加固柱(其中5个为圆形截面加固柱、5个为方形截面加固柱)和2个未加固钢管混凝土柱开展轴心受压试验,通过对破坏模式、荷载-位移曲线、相对荷载-应变曲线及组合抗压强度的分析,研究加固柱截面形式(方形和圆形截面)、外套钢管壁厚(2.5~5.5 mm)和夹层混凝土强度(C50~C70)对组合加固柱轴压性能的影响。试验研究结果表明:加固后由于外套钢管和夹层混凝土的存在,原钢管混凝土的局部鼓曲程度减小,轴压刚度和承载力得到大幅度提高,圆钢管混凝土和方钢管混凝土柱加固后承载力的平均提高幅度分别为151%和212%;组合加固柱的承载力随外套钢管壁厚和夹层混凝土强度的增大而增大;圆形截面加固短柱的组合抗压强度高于方形截面加固短柱,且外套钢管壁厚对圆形截面加固短柱组合抗压强度的影响比夹层混凝土强度的影响更为显著。采用极限平衡法分别给出了圆形截面和方形截面加固短柱各组成部分的受力状态及纵向应力计算方法,并提出了组合加固短柱的轴压承载力计算公式,将计算结果与试验结果对比,吻合较好,可用于该组合加固柱的承载力计算。Concrete-filled steel tube(CFST) structures may be in urgent needs of strengthening and renovation due to physical aging,chemical erosion,extreme disaster and other factors during service,or changes in their functional use.To this end,a strengthening technology using outer steel tube and sandwiched concrete jackets to strengthen concrete-filled steel tube(CFST) columns is proposed in this study.Ten strengthened columns(including five strengthened columns with inner circular and outer circular section and five strengthened columns with inner square and outer square section) and two un-strengthened CFST columns were tested under axial compression.Based on the analyses of the failure modes,load-displacement curves,relative load-strain curves,and composed compressive strength,the effects of the cross-section form(square and circular section),thickness of outer steel tube(2.5~5.5 mm),and sandwiched concrete strength(C50~C70) on the axial compressive behavior of the combined strengthened columns were investigated.The results show that the local buckling degree of the original CFST columns is reduced after strengthening owing to the presence of the outer steel tube and sandwiched concrete,and the axial stiffness and compressive capacity is greatly improved.The average increase of bearing capacity of circular concrete-filled steel tube and square concrete-filled steel tube column is 151% and 212%,respectively.The load-bearing capacity of the combined strengthened columns increases with the thickness of the outer steel tube and the strength of the sandwiched concrete.The composed compressive strength of circular-section strengthened stub columns is higher than that of square-section columns,and the influence of the outer steel tube thickness on the composed compressive strength of circular-section columns is more significant than that of sandwiched concrete strength.The limit equilibrium method was used to calculate the force state and longitudinal stress of each component of the circular-section and square-section retrof

关 键 词：外套钢管 夹层混凝土 加固 钢管混凝土 轴压试验 轴压性能 承载力 

分 类 号：TU398.9[建筑科学—结构工程] TU317.1