以轴压比为主要参数,对14根反复荷载作用下的钢骨-方钢管高强混凝土柱进行研究.结果表明,钢骨的加入使方钢管高强混凝土柱的位移延性系数显著提高,但轴压比仍是影响其组合柱延性的主要因素;组合柱的位移延性系数μΔ介于2.54~3.84.这表明当内填混凝土强度很高时,为满足抗震设计的要求,有必要对其轴压比的限值作出规定.通过试验轴压比与设计轴压比的换算,提出在满足组合柱有限延性基础上(μΔ≥3)轴压比的限值.
Fourteen square steel tube specimens filled with steel-reinforced high-strength concrete were tested under combined high axial load and cyclic lateral force. Axial compression ratio was the main test parameter. Test results show that the inserted steel section in square steel tubes filled with high-strength concrete can significantly improve the ductility of the composite columns, but axial compression ratio is still the most important factor that affects the ductility of the composite columns ; Displacement ductility coefficients (μΔ) of the composite columns in the test are concentrated between 2.54 and 3.84. This means that when the strength of the in-filled concrete is high, it is necessary to limit the axial load ratio to satisfy the ductility demand for seismic design of the composite columns. Finally, the limit value of the axial compression ratio is proposed on the basis of satisfying finite ductility of the composite columns (μΔ≥ 3) through the conversion formula between test axial compression ratio and design axial compression ratio.