多边多腔钢管自密实高强混凝土短柱轴心受压性能试验研究

摘要

Aiming at the colossal columns of Goldin Finance 117 tower in Tianjin,seven 1/20 scale polygonal multi-cell and self-compacting high-strength CFST columns were prepared.Based on axial compression tests,failure patterns of the specimens were investigated;the load-deformation curves and the load-strain curves were measured;the influences of factors such as concrete strength,thickness of steel tube and existence of steel reinforcement cage on the bearing capacity of column specimens were analyzed.The results indicate that there are four phases during the entire axial compression process of the column specimens;the shape of specimens remains almost unchanged until 90％ of the ultimate bearing capacity is reached.Concrete strength contributes most to the enhancement of the bearing capacity of column specimens;while the steel reinforcement cage contributes little to the enhancement of the bearing capacity;increasing the thickness of steel tube can not only enhance the bearing capacity of specimens,but it may also improve the ductility of specimens.Based on the test results and referring to the domestic and overseas design codes,a practical calculation formula for the bearing capacity of short multi-cell and self-compacting high-strength CFST in axial compression was put forward,and it was recommended for practical engineering design.%以天津高银117大厦巨型柱为原型,按1/20缩尺设计制作7个多边多腔钢管自密实高强混凝土短柱试件.通过轴心受压试验,考察了试件的破坏形态,实测试件的荷载-变形曲线、荷载-应变曲线,研究了试件轴压性能,分析了混凝土强度、钢管壁厚度、有无钢筋笼等参数对试件承载力的影响.研究表明,多边多腔钢管自密实高强混凝土短柱轴心受压全过程大致分为四个阶段;在达到90％极限承载力之前,试件外形无明显变化;提高混凝土强度对试件承载力的提高作用最为明显,有无钢筋笼对试件承载力的影响不明显,增加钢管壁厚度不仅可以提高试件承载力,而且可以显著改善试件延性.基于试验结果,参考国内外相关规范,建立了多边多腔钢管自密实高强混凝土短柱轴心受压承载力实用计算公式,可供实际工程设计参考.