方钢管再生混凝土长柱单偏压性能试验研究

Experimental research on unidirectional eccentric compression behavior of recycled aggregate concrete filled square steel tubular long columns

文章以再生粗骨料取代率、钢管壁厚、长细比和偏心率为变化参数,通过对15根方钢管再生混凝土长柱进行单向偏心受压试验,研究了方钢管再生混凝土长柱偏心受压的受力性能。研究结果表明:钢管再生混凝土长柱偏心受压破坏分为端头压曲破坏和整体弯曲失稳破坏2个大类,方钢管对受压膨胀的再生混凝土有很好的约束作用,方钢管再生混凝土偏压长柱与普通钢管混凝土偏压长柱同样具有良好的承载力和变形能力;试件的承载力和初始轴向刚度随着长细比和偏心距的增大而减小,随着钢管壁厚的增加而提高;添加再生粗骨料导致试件承载力和初始轴向刚度降低,添加粉煤灰后试件承载力总体有所提高,添加膨胀剂试件的承载力有一定提高。

Based on the variation parameters of recycled coarse aggregate replacement ratio,steel tube wall thickness,slenderness ratio and eccentricity,the unidirectional eccentric compression tests were carried out on 15 specimens of recycled concrete filled square steel tubular long columns to study the eccentric compression performance of the specimens.The research results show that their failure modes are divided into two categories:end buckling failure and overall bending instability failure.The square steel tube has a good restraining effect on the compressed recycled concrete.Under the condition of eccentric compression,the recycled aggregate concrete filled square steel tubular long columns have good bearing capacity and deformation capacity as the square steel tubular long columns filled with ordinary concrete.The bearing capacity and initial axial stiffness of the specimens decrease with the increase of the slenderness ratio and the eccentricity,and increase with the increase of the wall thickness of the steel tube.The increase of replacement ratio of recycled coarse aggregate has adverse effect on their bearing capacity,and causes their initial axial stiffness to decrease.After the addition of fly ash,the bearing capacity of the specimens is improved in general,and the bearing capacity of the specimens added with expansion agent is improved.