外贴纤维复合材料加固RC悬臂板的实验研究及简化计算

通过10个悬臂板的实验,对外贴玻璃纤维复合材料,加固钢筋混凝土悬臂板的受力性能,进行了研究.被加固构件的配筋率分别为0.28%、0.50%和0.79%,外贴纤维板的配置率分别为0.20%、0.41%和0.82%,采用一层或两层粘贴.实验中测试了板的挠度、材料应变随荷载的变化,观察了加固构件的破坏过程和破坏形式.实验结果表明,加固构件产生了两种破坏形式,即纤维拉断和粘接破坏,无论产生哪种破坏,构件承载能力均有明显的提高,但截面变形能力明显减弱.值得注意的是,在达到极限状态之前,有一个明显的局部粘结破坏产生和发展的过程,这对改善构件加固后的延性是有利的.另外,本文还采用数值分析方法,对加固构件的受力变形性能进行了计算,并在现行混凝土规范的基础上,提出了承载能力的简化计算方法,计算结果与实验结果吻合较好.

EXPERIMENTS AND SIMPLIFIED ANALYSIS FOR RC CANTILEVER SLAB STRENGTHENED WITH BONDED GFRP STRIPS

An experimental study on ten pieces of RC cantilever slabs strengthened with bonded GFRP strips is performed in the paper. Internal steel reinforcement ratio for strengthened Slabs were 0. 28% .0.5 % or 0.79% while their external GFRP reinforcement ratios were 0.20% .0.41% or 0.82% .The GFRP strips were made of one or two layers. The relationships of load versus deformation or strain are measured. Two failure modes are observed in the test: GFRP tensile rupture and debonding. Regardless of failure modes, the bearing capacity of all strengthened slabe is greatly increased, but their ductility is obviously reduced. Local debonding procession is occurred before the peak load, which improved the ductility of strengthened slabs. A numerical method used to predict the behavior of slabs is also presented. Another simplified method is given to predict the bearing capacity based on the Chinese design code for RC structures. The calculating results are matched with the test results well.