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采用FRP增强的混凝土柱在使用过程中,可能受到轴向冲击荷载作用,但目前这方面的研究基本处于空白。通过对7组21个大尺寸CFRP约束混凝土方柱进行落锤轴向冲击试验,研究倒角半径r对约束柱抗冲击性能的影响。试验获取了锤头冲击力时程曲线、压缩变形时程曲线、FRP表面关键点的应变时程曲线和整个破坏过程的高速影像等信息。试验结果表明,CFRP约束混凝土方柱的破坏是由试件中部倒角位置处的CFRP被拉断所导致的,试件的破坏现象与倒角半径r有关;倒角半径r对约束柱的冲击性能有显著影响,r越大,冲击应力峰值和能量密度也越大;CFRP约束混凝土方柱的动力增大系数(DIF)随倒角半径比rc的增大而减小,基本成线性关系,在1.23~1.82之间。
Concrete columns reinforced with FRP may be subjected to axial impact loads during use, but the research in this area is basically blank. The effects of chamfering radius r on the impact resistance of constrained columns were investigated by measuring the axial drop impact of 21 large-size CFRP-confined concrete square columns. The time-history curve of hammer impact force, the time-history curve of compression deformation, the time history curve of the key points of the FRP surface and the high-speed image of the entire destruction process were obtained. The experimental results show that the failure of CFRP-confined concrete square columns is caused by the CFRP pull-off at the chamfer of the middle part of the specimen, and the failure phenomenon of the specimen is related to the chamfer radius r; the impact of the chamfer radius r on the restraining column The larger the r is, the greater the peak value of impulse stress and energy density are. The coefficient of dynamic expansion (DIF) of CFRP-confined concrete square columns decreases with the increase of chamfer radius ratio rc, which is basically a linear relationship, Between 1.23 and 1.82.