箍筋对方形配筋钢管再生混凝土受力性能的影响机理

Influencing Mechanism of Lateral Hoops on Reinforced Recycled Aggregate Concrete-Filled Square Steel Tube

为探究再生骨料100%取代率时方形配筋钢管再生混凝土(R-RACFST)箍筋的影响机理,以箍筋形式和间距为变量,进行了轴压试验,分析了破坏模式、荷载位移、荷载应变、延性和断裂韧性。结果表明:所有试件均呈现多折腰鼓破坏,与钢管混凝土(CFST)试件相比,钢管再生混凝土(RACFST)试件的承载力、延性和断裂韧性分别降低7.77%、35.31%和15.30%;与RACFST试件相比,R-RACFST试件的承载力、延性和断裂韧性最大可分别提高25.63%、123.76%和56.35%。箍筋形式和间距对峰值荷载前的受力性能无显著影响。与平行式箍筋相比,螺旋式箍筋展现了更优越的延性和断裂韧性。随着箍筋间距的减小,试件的延性、断裂韧性更为优越。本文推荐的计算公式可以较安全地预估试件承载力。

To investigate the influencing mechanism of lateral hoops on reinforced recycled aggregate concrete-filled square cross-section steel tube(R-RACFST)with 100%recycled coarse aggregate replacement-rate,the axial compression tests were performed,by using pattern and spacing of lateral hoops as variables.The failure mode,load displacement curve,load strain curve,ductility and fracture toughness were analyzed.Results demonstrated that the failure mode characters with Multi-fold waist drum destruction.Compared with concrete filled steel tube(CFST)specimens,the bearing capacity,ductility and fracture toughness of recycled aggregate concrete-filled steel tube(RACFST)specimens are lower by 7.77%,35.31%and 15.30%respectively.Compared with RACFST specimens,the bearing capacity,ductility and fracture toughness of R-RACFST specimens are higher by 25.63%,123.36%and 56.35%respectively.Hoop pattern and spacing have no significant impact on the mechanical performance before peak load.Spiral hoops exhibit superior ductility and fracture toughness compared with flat hoops.Ductility and fracture toughness are increased with the decrease of the spacing.It is recommended to adopt small spacing to improve the ductility and fracture toughness,and prevent brittle damage.The calculation formula recommended in this paper can estimate the bearing capacity more safely.