化爆作用下FRP加固RC板的试验研究及动力响应分析

我国20世纪60年代、70年代修建的大量防护工程抗力等级较低,急需进行加固补强。进行了化爆作用下,外贴FRP条带加固钢筋混凝土(RC)双向板抗爆性能的试验研究。按介质-结构相互作用理论确定结构的爆炸冲击荷载,建立了加固板的三折线弯曲抗力模型,利用虚功原理建立了加固RC板的运动微分方程,按数值方法求解了外贴FRP加固双向板在化爆冲击波作用下的动力响应时程,分析结果与试验结果吻合较好。研究结果表明:外贴FRP条带加固可以有效延缓混凝土的开裂、限制裂缝的开展,提高RC双向板的刚度,减小结构位移,减轻结构破坏程度,外贴FRP加固RC双向板的抗爆炸冲击波能力得到了明显提高,外贴FRP条带在极限状态时发生了剥离破坏和断裂破坏。

DYNAMIC RESPONSE ANALYSIS AND TEST STUDY ON FRP STRENGTHENED RC SLABS SUBJECTED TO BLAST LOADING

The existing protection engineering needs reinforcement to upgrade the anti-blasting resistance so as to remedy the deficiency of strength. A test study was conducted on four reinforced concrete(RC) slabs strengthened with FRP strips subjected to conventional munitions explosion loading. Normal slabs were tested as control specimens. The failure mode and crack patterns were evaluated to determine the failure characteristic of the slabs. The blast resistances were studied. The blast impact load was determined by using structure-medium interaction theory. The analytical model to predict the bending resistance of an FRP strengthened slab was proposed. The motion equations for structures were established by using medium-structure interaction theory. The dynamic response analysis of an FRP strengthened slab under conventional munitions explosion loading were presented. The calculated results are in a good agreement with the experimental results. The experimental and theoretical analysis results show that FRP strips are effective to mitigate the concrete cracking, to improve structural rigidity and to reduce structural displacement. The results also show that the slab strengthened with FRP strips increase its blast resistance capacity. At the ultimate state, the FRP strips failed due to the debonding and fracture from the slab surface.