拉筋约束薄壁方钢管混凝土短柱轴压性能

Axial compression performance of thin-walled concrete-filled square steel tube short columns confined by stirrup

通过对拉筋约束薄壁方钢管混凝土短柱的轴压试验,研究了混凝土强度、拉筋体积配箍率以及拉筋与钢管壁的连接方式对试件极限承载力、刚度、延性以及横向变形系数的影响。研究结果表明:内置拉筋有助于提高试件的极限承载力及延性,提高效果随着混凝土强度的提升而降低,随着拉筋体积配箍率的增大而提升;拉筋与钢管壁焊接处理后,试件的各项力学性能并无明显改变;利用极限强度理论对极限状态下的试件进行力学分析,推导出拉筋约束方钢管混凝土轴压短柱极限承载力的计算公式,并结合其他文献中类似试件的试验数据对公式进行了验证,证明了本公式的正确性。

Through the axial compression test of the thin-walled concrete-filled square steel tube short column confined by the stirrup,the effects of the concrete strength,the volumetric stirrup ratio of the stirrup and the connection mode of the stirrup and the steel pipe wall on the ultimate bearing capacity,stiffness,ductility and transverse deformation coefficient of the specimen are studied. The research results show that the built-in reinforcement can help to improve the ultimate bearing capacity and ductility of the specimen. This improvement effect decreases with the increase of concrete strength,and increases with the increase of the volumetric stirrup ratio of the stirrup. After the stirrup is welded to the steel pipe wall,the mechanical properties of the test piece have not changed significantly. The ultimate strength theory is used to mechanically analyze the specimens in the ultimate state,and the formula for calculating the ultimate bearing capacity of the concrete-filled square steel tube short columns constrained by stirrup is deduced,and combined with the test data of similar specimens in other documents to verify the formula,which proves the correctness of the formula.