钢管再生混凝土轴压长柱试验研究及力学性能分析

设计5个圆钢管再生混凝土长柱和5个方钢管再生混凝土长柱，对其进行轴压静力单调加载试验，考虑截面形式、再生粗骨料取代率、长细比3个变化参数，观察试件受力的全过程和破坏形态，得到试件屈服应变、峰值变形、承载力等重要特征点数据，绘制出荷载-变形、荷载-应变、轴压刚度-变形等关系曲线，并分析变化参数对试件承载力的影响规律，采用相关规程计算2种截面形式的钢管再生混凝土轴压长柱的承载力以及在正常使用极限状态下的刚度。试验研究和计算结果表明：钢管再生混凝土轴压长柱受力过程均经历了弹性阶段、屈服阶段和破坏阶段，破坏形态主要有材料强度破坏和弹塑性失稳破坏；再生粗骨料取代率对钢管再生混凝土轴压长柱的承载力影响不大；长细比对圆钢管再生混凝土试件承载力影响较大，随长细比的增加，试件的承载力逐渐降低，而对方钢管再生混凝土试件承载力影响较小。基于计算结果，给出了2种截面形式的钢管再生混凝土轴压长柱的承载力及轴压刚度的设计建议。研究结果可为钢管再生混凝土结构的进一步研究和推广应用提供参考。

Experimental study and mechanical behavior analysis of recycled aggregate concrete filled steel tubular long columns under axial compression

Axial static monotonic loading test was carried out on 5 recycled aggregate concrete filled cycled steel tubular long columns and 5 recycled aggregate concrete filled square steel tubular long columns.The test parameters include section form,replacement rate of recycled coarse aggregate and slenderness ratio.The whole loading process and failure modes were observed.The important characteristic data were captured such as the yield strain,the peak deformation,the bearing capacity and so on.A series of important curves about load-deformation,load-strain and axial stiffness-deformation were plotted.The influences of the test parameters on the bearing capacity were analyzed.The bearing capacity and axial stiffness of two section types under the serviceability limit state were calculated by some related procedures.It is shown that the loading process of recycled aggregate concrete filled steel tubular long columns under axial compression is made up of elastic stage,yield stage and failure stage.The failure modes are mainly strength failure and failure of elasto-plastic instability.The influence of replacement rate on the bearing capacity is little.The influence of slenderness ratio on the bearing capacity of recycled aggregate concrete filled cycled steel circular tubular long columns is great.When the slenderness ratio increases,the bearing capacity will decrease.However,the influence of slenderness ratio on the bearing capacity of recycled aggregate concrete filled square steel tubular long columns is little.Based on the calculation result,the design suggestion is provided about the bearing capacity and axial stiffness of recycled aggregate concrete filled steel tubular long columns under axial compression.The research results can provide reference for further research and application of recycled aggregate concrete filled steel tubular structure.