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进行了16根带约束拉杆和11根不带约束拉杆T形钢管混凝土短柱试件的偏压试验研究,分析了不同荷载角、偏心率、约束拉杆间距下该类型柱的偏压性能。试验结果表明:约束拉杆的设置减小钢板的屈曲半波长、延迟钢管局部屈曲的发生、提高核心混凝土的约束作用,有助于提高该类型柱的承载力和延性;临近或达到极限荷载时近力侧拉杆及钢板对核心混凝土的约束作用明显,且约束作用从近力侧向远力侧减小;偏心受压下该类型柱的截面应变符合平截面假定。采用带约束拉杆T形钢管混凝土短柱的核心混凝土等效单轴本构关系,利用纤维模型法程序对该类型柱进行参数研究。分析结果表明:钢材屈服强度、含钢率越大,N/Nu-M/Mu相关曲线向内收拢;混凝土强度和拉杆约束系数越大,N/Nu-M/Mu相关曲线向外凸出。
Sixteen specimens with constrained tie bars and eleven T-shaped concrete-filled CFST columns were tested. The bias characteristics of the columns under different loading angles, eccentricity and restraining tie bar spacing were analyzed. The experimental results show that the restraining rod can reduce the buckling half wavelength of the steel plate, delay the local buckling of the steel pipe and improve the restraint effect of the core concrete, which can help to improve the bearing capacity and ductility of this type of column. When approaching or reaching the limit load The restraining action of the tension rod and the steel plate on the core concrete is obvious, and the restraint effect decreases from the near force side to the far force side. The cross-sectional strain of this type of column under eccentric compression complies with the assumption of flat section. The equivalent uniaxial constitutive relation of core concrete with T-shaped concrete-filled steel tube short columns with restraining rod is adopted. The parameters of this type of column are studied by fiber model method. The results show that the N / Nu-M / Mu correlation curves converge inward as the yield strength and steel content of the steel increase. The larger the concrete strength and tie bar constraint coefficient, the more the N / Nu-M / Mu correlation curve protrudes outward.