CFRP-圆钢管自密实混凝土复合加固RC方形短柱轴压性能试验研究

Experimental study on the behavior of RC square short columns strengthened with self-compacting concrete filled CFRP-steel tube under axial compression

提出CFRP-圆钢管自密实混凝土加固钢筋混凝土柱的复合加固方法。通过1根钢筋混凝土方形截面短柱和9根复合加固钢筋混凝土方形截面短柱的轴压试验,研究了CFRP-钢管自密实混凝土复合加固混凝土方形截面短柱的轴压性能,分析了CFRP层数、钢管壁厚对复合加固短柱的承载力、刚度和延性的影响。试验结果表明:随着CFRP层数的增大,复合加固柱的承载力和弹塑性阶段刚度显著提高;随着钢管壁厚的增大,复合加固柱刚度和延性显著提高;在其他条件相同的情况下,复合加固柱承载力的提高率将随钢管壁厚的增大而减小;当承载力提高幅度相同时,使用CFRP复合加固可以降低钢管壁厚,有效减少用钢量。在试验研究的基础上,建立了复合加固钢筋混凝土方形截面短柱的承载力计算公式,计算结果与试验结果吻合良好。

A composite strengthening method,in which the RC columns strengthened with self-compacting concrete filled CFRP-steel tube,was proposed. Based on one RC square column and nine compositely strengthened RC square columns,their behaviors under the axial loading were studied,and the influences of CFRP layers and the wall thickness of steel tube on the bearing capacity,stiffness and ductility of the compositely strengthened short columns were analyzed.The results indicate that with the increase of CFRP layers,significant increases in both the stiffness at elasto-plastic stage and the bearing capacity of compositely strengthened columns can be observed; with the increase of wall thickness of steel tube,significant increases in the stiffness and ductility of compositely strengthened columns exhibited can also be seen; with the same other conditions,the increasing ratio of bearing capacity of compositely strengthened columns may decrease with the increase of wall thickness of steel tube; for the same increasing rate,the wall thickness of steel tube can be effectively reduced if the CFRP composite strengthening method is applied. Based on the results,a formula was proposed to calculate the bearing capacity of the compositely strengthened short columns,and the calculation results agree well with the experimental results.