椭圆截面钢管钢渣混凝土短柱轴压性能试验研究

Experimental study on performance of steel slag concrete filled elliptical steel tubular stub columns under axial load

目前我国钢渣累计存储量已超18亿吨,但是我国对钢渣的利用率目前仅为20%~30%,远低于发达国家的,钢渣堆积导致大量农地资源浪费,生态环境遭受较大污染。为提高钢渣的综合利用率,推广其在建筑工程领域中的应用,对采用钢渣替换混凝土粗骨料的椭圆截面钢管钢渣混凝土短柱轴压性能进行试验研究,得到轴压荷载作用下钢渣置换率和截面长短轴比等参数对椭圆截面钢管钢渣混凝土短柱破坏模式、承载力、刚度和延性等力学性能的影响规律,明确置换钢渣对椭圆截面钢管混凝土轴压承载力的贡献率,最终提出考虑钢渣置换和截面特征影响的椭圆截面钢管钢渣混凝土短柱的轴压承载力计算式。研究结果表明:在轴压荷载作用下椭圆截面钢管钢渣混凝土短柱的破坏模式主要包括钢管局部鼓曲、混凝土压溃和剪切破坏;采用钢渣逐步替换混凝土粗骨料可使椭圆截面钢管混凝土短柱轴压承载力提高2.0%~15.1%,刚度提升1.1%~16.8%,但其延性会随着钢渣置换率和截面长短轴比的增大而减小;经试验数据验证,提出的计算式可准确评估椭圆截面钢管钢渣混凝土的轴压承载力。研究结果可为钢渣废料在钢管混凝土结构中的应用和推广提供科学依据。

Currently,the cumulative storage of the steel slag in China has exceeded 1.8 billion tons,whereas the utilization rate of the steel slag is limited at 20%-30%,which is much less than that at developed countries.Hence,the cumulative steel slag results in massive waste of farm land and serious pollution on the environment.To improve the comprehensive utilization of the steel slag and to promote its application in engineering practice,this paper conducted an experiment study on the axial compressive performance of elliptical steel tubes infilled with concrete which uses the steel slag to replace the coarse aggregate.The influence of steel-slag utilization ratio and the aspect ratio on the failure mode,axial resistance,stiffness and ductility of the steel slag concrete-filled elliptical steel tubular(SCFET)columns was revealed.Moreover,the contribution of the steel slag on the axial compressive resistance of the SCFET stub columns was figured out.Finally,a design method for predicting the resistance of the axially-loaded SCFET stub column was proposed considering the effect of steel slag and the feature of the elliptical cross-section.The results indicated that the failure modes of the SCFET stub columns mainly included steel tube buckling,concrete crushing and shear failure.After the coarse aggregate of the ordinary concrete in elliptical steel tube was gradually substituted by the steel slag,improvements of 2.0%-15.1%in the axial compressive strength and 1.1%-16.8%in the stiffness were respectively obtained,while the ductility decreased with the steel-slag utilization ratio and the aspect ratio.The test results demonstrated that the design formulae proposed in this paper can predict the axial compressive resistance of the SCFET stub column accurately.This research may offer a scientific reference for the application and promotion of steel slag in concrete-filled steel tubular structures.