高轴压比下圆钢管钢渣混凝土柱抗震性能试验研究

Experimental analysis on seismic behavior of steel slag concrete filled circular steel tubular columns under high axial compression ratio

通过2根圆钢管普通混凝土柱与5根圆钢管钢渣混凝土柱在高轴压比下的水平低周反复加载试验,研究圆钢管钢渣混凝土柱的轴压比、钢管壁厚、钢渣砂替代率和长细比对其破坏形态、滞回耗能能力、骨架曲线、延性及耗能、刚度退化的影响规律。研究结果表明:钢渣混凝土试件破坏过程和破坏形态与普通混凝土试件基本相同,主要表现为钢管底部鼓曲的压弯破坏;所有试件滞回曲线饱满,无明显“捏缩”现象;高轴压比试件存在明显承载力突降现象,合理的径厚比(钢管直径/钢管壁厚)对高轴压比试件承载力突降有明显改善作用;低轴压比试件延性系数大于4.0,高轴压比试件延性系数介于1.57~3.76之间,轴压比增大,试件延性下降;试件破坏时等效粘滞阻尼系数ξ_(eq)介于0.259~0.437之间;建议采用《钢管混凝土混合结构技术标准》(GB/T51446-2021)或《钢管混凝土结构技术规程》(DBJ/T13-51-2010)计算地震作用下钢管钢渣混凝土柱压弯承载力,但高轴压比钢管钢渣混凝土柱计算结果需乘以折减系数0.8。

The axial compression ratio,steel tube wall thickness,steel slag replacement rate and length of the cir⁃cular steel slag concrete columns were studied through the horizontal and low⁃cycle repeated loading tests of 2 circu⁃lar steel tube natural concrete columns and 5 circular steel tube steel slag concrete columns under high axial com⁃pression ratio.The effect of fineness ratio on its failure form,hysteretic energy dissipation capacity,skeleton curve,ductility and energy dissipation,and stiffness degradation.The research results show that:the failure pro⁃cess and failure mode of steel slag concrete specimen are basically the same as that of ordinary concrete specimen,which is mainly manifested in the compression bending failure of bulging at the bottom of steel pipe;The hysteretic curves of all specimens are full without obvious pinching;High axial compression ratio specimens have obvious sudden drop of bearing capacity,and reasonable diameter thickness ratio(steel pipe diameter/steel pipe wall thickness)can significantly improve the sudden drop of bearing capacity of high axial compression ratio speci⁃mens;The ductility coefficient of specimens with low axial compression ratio is greater than 4.0,and that of speci⁃mens with high axial compression ratio is between 1.57 and 3.76.With the increase of axial compression ratio,the ductility of specimens decreases;Equivalent viscous damping coefficient at failureξ_(eq)ranged from 0.259 to 0.437;It is recommended to use GB/t51446-2021 or DBJ/t13-51-2010 to calculate the flexural strength of steel slag concrete⁃filled steel tubular columns under earthquake,but the calculation results of steel slag concrete⁃filled steel tubular columns with high axial compression ratio need to be multiplied by the reduction factor of 0.8.