钢管自应力自密实高强混凝土中长柱受压性能试验研究

为提高钢管内混凝土的密实度，减小混凝土的收缩，以保证钢管与混凝土更好地工作，满足实际工程需要，文中提出采用钢管自应力自密实高强混凝土柱，考虑初始自应力、长细比和混凝土强度等因素的影响，设计制作16个钢管自应力自密实高强混凝土中长柱试件，通过轴心受压试验，考察试件的破坏形态，实测试件的荷载-纵向变形曲线、荷载-挠度曲线和极限承载力，分析了各参数对试件轴心受压力学性能的影响。研究表明：大部分中长柱的破坏形态均为弯曲失稳破坏；初始自应力提高5MPa，钢管自应力自密实高强混凝土中长柱极限承载力提高19%，并改善了延性；长细比由5增大至12，试件的极限承载力降低16.9%；混凝土强度提高36.3%，钢管自应力自密实高强混凝土中长柱极限承载力提高16.3%。基于试验结果，参考国内相关规范，建立钢管自应力自密实高强混凝土中长柱轴心受压稳定承载力计算公式，可供工程设计参考。

Experimental research on axial compression performance of medium-and-long steel tubular columns filled with high-strength self-stressing self-compacting concrete

The steel tube filled with high-strength self-stressing self-compacting concrete is proposed to improve the compactness, reduce the shrinkage of the core concrete and enhance the working performance of steel tube and concrete in practical engineering. 16 specimens are designed and manufactured with consideration of influential factors such as initial self-stress, slenderness ratio and concrete strength. By the axial compression tests, the failure patterns of the specimens are investigated. The load-deformation curves, load-deflection curves and the ultimate load-bearing capacity are measured and the influence of different factors is analyzed. The results show that most specimens demonstrate a buckling failure pattern. When the initial self-stress increases to 5MPa, the ultimate load-bearing capacity of the specimens increases by 19% and the ductility is improved. When the slenderness ratio increases from 5 to 12, the ultimate bearing capacity is subjected to 16.9% decrease. The ultimate bearing capacity concrete strength increases by 16.3% and 36.3%, respectively. Referring to the domestic codes and experimental results, calculation equations for the axial compression bearing capacity of medium-and-long steel tubular columns filled with high-strength self-stressing self-compacting concrete are proposed, which can provide reference for engineering design.