内填料石钢管混凝土中长柱轴压性能试验研究

Experimental study on axial compressive performance of stone prism and concrete-filled steel tubular slender columns

为研究内填料石钢管混凝土(SCFST)中长柱的轴压性能,对12根内填料石钢管混凝土中长柱进行单调轴压试验,研究内填料石尺寸、钢管壁厚和长细比对SCFST中长柱受力性能的影响。试验结果表明:内置料石提高了SCFST中长柱的承载力,且增幅随料石尺寸的增大而提高,最大增幅达87%;内填料石尺寸相同时,SCFST中长柱承载力随钢管壁厚的增大近似呈线性增长;随着长细比的增大,SCFST中长柱破坏形态逐渐从轴压破坏转变为压弯破坏,承载力逐渐降低。根据试验结果,对GB 50396—2014中CFST柱相关设计模型用于预测SCFST中长柱承载力的可行性进行评估,预测结果与试验结果误差为-18%~24%,不能较好预测SCFST中长柱的承载力。

To further study the axial compressive performance of stone prism and concrete-filled steel tubular(SCFST) slender columns, a total of 12 slender column specimens were tested under axial compression. The main test parameters were the dimension of infilled stone prism, the wall thickness of steel tube and the slenderness ratio. The test results indicate that the infilled stone prism increases the ultimate strength of the slender composite column. The axial compressive strength of SCFST columns tend to increase with the increase of the stone-prism dimension, and the maximum strength increase was 87%. With the same stone-prism dimension, the axial compressive strength of SCFST columns showed a linear increasing trend as the wall thickness of steel tube increases. With the increase of slenderness ratio, the failure modes of SCFST columns shifted from strength failure to instability failure, and the axial compressive strength decrease consequently. Based on the test results, the feasibility of using the available design code GB 50396—2014 for CFST members to predict the axial compressive strength of SCFST slender columns was evaluated, the error between the predicted values and the experimental results is-18-24%, which cannot redict the ultimate strength of the SCFST slender columns precisely.