焊接不锈钢方管混凝土短柱轴压性能试验研究

通过对18根焊接不锈钢方管混凝土短柱模型试件的轴压试验，观察了各试件的破坏现象，分析了混凝土强度、试件高宽比和钢管板件宽厚比试件轴压承载力的影响，得到了荷载-位移曲线，荷载-应变曲线及柱截面应变强度分布曲线。根据试验现象，试件的破坏模式可以归为两类：一类为钢管在整个柱表面范围内发生局部凸曲，靠柱中焊缝破坏；另一类为局部凸曲未能发展到整个柱表面，在端部或者端部附近焊缝破坏。试验结果表明：混凝土强度越高，试件的轴压承载力越大，但钢管对核心混凝土的约束作用相对减小；焊接不锈钢方管混凝土短柱轴压承载力随试件高宽比的增大而增大，随钢管板件宽厚比的减小而减小；试件截面的角部存在应力集中现象，即截面角部的应力大于截面其余部位的应力；焊接不锈钢方管混凝土短柱具有很好的变形能力，其破坏属于延性破坏，具有良好的安全储备；焊缝强度是影响焊接不锈钢方管混凝土短柱承载力的一个主要因素。

Experimental research on static behavior of welded concrete-filled stainless steel square stub columns under axial compression

This paper describes an experimental study on the ultimate axial strength of 18 weld concrete-filled stainless steel square stub columns. The paper observes the failure phenomena of all the specimens, analyzes the influences of concrete strength, ratio of height to width and ratio of width to thickness on the axial ultimate compression of the specimens and obtains columns load-deformation curves, load-strain curves and load strain intensity distribution curves. According to the experiment, the failure modes could be classified into two categories: in one failure mode, local buckling spreads to the whole surface of the stainless steel tube and weld damage occurs in the middle of the column; in the other mode, local buckling does not spread to the whole surface of the column and weld damage occurs at the end of the weld or around the end. Analysis of the experimental results shows: axial compressive ultimate capacity of the specimens increases as concrete strength increases, while the steel tube exerts less restrictive influence on the core concrete; axial compressive ultimate capacity of the specimens decreases as the ratio of height to width increases or the ratio of width to thickness decreases; under axial compression these columns have a stress concentration at the corners, in other words, the stress at the cross section of the corner is greater than that in other places; the columns have a good plastic deformation capacity, and the damage is ductility damage, so the columns have a good safety margin; the ultimate capacity of weld seam is the main factor that affects the ultimate compressive capacity of columns.