圆钢管再生镍铁渣混凝土柱偏压力学性能研究

Study on the mechanical behavior of recycled aggregate concrete with ferronickel slag filled circular steel tube column under bias compression

为了研究再生粗骨料取代率和偏心距对圆钢管再生镍铁渣混凝土柱力学性能的影响,设计了13个试件进行轴心和偏心受压试验,分析试件的荷载-跨中挠度曲线、侧向挠度曲线、刚度退化和耗能。在普通钢管混凝土的研究结果基础上,回归拟合适用于钢管再生混凝土的压弯承载力预测公式。结果表明:偏压试件的挠度沿柱高呈对称分布,形状符合正弦半波曲线;加载过程中截面中性轴的位置向受压区偏移,表明受压区面积逐渐缩小,受压区高度减小;当取代率超过30%后,随着再生粗骨料取代率的增加,试件的极限承载力降低,刚度逐渐退化,试件破坏时的耗能系数表现为降低的趋势;随着偏心距的增大,试件的极限承载力降低,侧向挠度曲线的包络面积逐渐增大,刚度逐渐退化;根据拟合的压弯承载力计算公式得到的计算值与试验结果吻合较好。

To study the effects of the replacement rate of recycled coarse aggregate(RCA)and eccentricity on the mechanical properties of recycled aggregate concrete with ferronickel slag filled circular steel tube columns,13 specimens were designed for axial and eccentric compression tests,and load-mid-span deflection curve,lateral deflection curve,stiffness degradation and energy dissipation were analyzed.Based on the research results of ordinary concrete filled steel tube(CFST)column,the prediction formula for the compression-bending capacity of recycled CFST is regressed.Results show that the deflection shape of the biased specimen conforms to the sinusoidal half wave curve.The position of the neutral axis of the cross section deviates to the compression zone during loading.When the replacement rate exceeds 30%,with the increase of RCA replacement rate,the ultimate bearing capacity of the specimen decreases,the stiffness degrades more,and the energy dissipation coefficient of the specimen decreases.With the increase of eccentricity,the ultimate bearing capacity of the specimen decreases,the envelops area of the lateral deflection curve increases gradually,and the stiffness degenerates more.The values calculated by the fitting formulas are in good agreement with the experimental results.