CFRP加固火灾后混凝土短柱抗震性能的试验研究

EXPERIMENTAL STUDY ON SEISMIC PERFORMANCE OF CONCRETE SHORT COLUMNS AFTER FIRE AND STRENGTHENED WITH CFRP

进行了1根未受火混凝土短柱、1根火灾后混凝土短柱、1根CFRP加固未受火混凝土短柱和3根CFRP加固火灾后混凝土短柱的拟静力试验,考察了CFRP的加固量和加固方式对火灾后混凝土短柱抗震加固效果的影响情况,建议了CFRP加固火灾后混凝土柱抗剪承载力的实用计算方法。研究结果表明:外包CFRP加固可将未受火混凝土短柱的抗剪承载力提高21.8%、可将火灾后混凝土短柱的抗剪承载力提升至未受火试件的111.2%~117.1%、可提高受火前后短柱的极限变形能力和累积滞回耗能。与未受火试件相比,外包CFRP不会提高火灾后加固混凝土短柱的割线刚度。对于相同的加固量,全包CFRP柱的抗剪承载力略优于条带包裹柱。受火前、后和外包CFRP加固前、后混凝土短柱的滞回规则均类似。

The pseudo-static tests of one concrete short column(CSC) without fire,one CSC after fire,one CSC without fire action and strengthened with CFRP,and three CSCs after fire and strengthened with CFRP were carried out to investigate the influence of CFRP usage and wrapping manner on strengthened seismic performance of CSCs after fire.A practical method to calculate the shear strength of concrete columns after fire and strengthened with CFRP was suggested.Results show that the shear strength of CSCs wrapped with CFRP is increased by 21.8% compared with those without wrapping.The shear strength of CSCs firstly exposed to fire followed by wrapping with CFRP is about 111.2%~117.1% of those without either fire action or wrapping.CFRP wrapping can enhance the ultimate deformation and hysteretic energy dissipation of CSCs both without fire action and after fire,but comparing to those without fire action,CFRP wrapping can't increase the secant stiffness of CSCs after fire.For the same CFRP usage,the shear strength of columns wrapped entirely is slightly better than those wrapped with strips.The hysteretic rules of CSCs for cases without fire action,after fire,without strengthening and with strengthening are similar.