爆炸荷载作用下外贴FRP加固钢筋混凝土双向板试验研究

Experimantal study on performance of FRP strengthened RC two-way slabs under explosion load

通过集团装药隔土爆炸荷载作用下4块外贴FRP条带加固钢筋混凝土双向板和1块普通板的对比试验,考察了裂缝的产生、开展过程及分布形状,分析了FRP加固板的荷载、位移、加速度、钢筋和混凝土以及FRP应变动力响应时程,研究了FRP加固板的抗爆破坏特征。研究结果表明:外贴FRP条带加固能有效延缓混凝土的开裂,限制裂缝的开展,改善钢筋混凝土板的抗爆性能;外贴FRP条带加固后,RC双向板的跨中位移响应、混凝土和钢筋应变响应明显降低,结构的抗爆炸冲击波能力得到明显提高;外贴FRP条带加固双向板在爆炸冲击荷载作用下的破坏形态有受弯破坏和弯曲屈服后的剪切破坏,外贴FRP条带在极限状态时发生了剥离及断裂破坏。

Using FRP laminates for strengthening existing structures in protection works has obvious advantages compared with other currently available strengthening methods.Based on the experimental results of four slabs strengthened with FRP strips and one as-built slab under conventional munitions explosion loading,the failure mechanism,development and distribution of cracks were studied.The dynamic time history responses of structural loads,deflections,acceleration and strains of steel reinforcement,FRP and concrete and the failure modes of the specimens were also investigated.Test results indicate that the strengthened slabs performed better than the normal RC slab.The FRP strips are effective in delaying the concrete cracking,limiting the development of cracks and improving the performance of reinforced concrete slabs under explosion.Strengthened with FRP laminates,RC two-way slabs exhibite a considerably enhanced capacity to resist explosive waves in that the mid-span deflections,the strains in concrete and reinforcing steel are largely reduced.The failure modes of two-way slabs strengthened with FRP laminates are flexural failure and shear failure after flexural yielding.At ultimate loading condition the FRP laminates fail due to debonding and fracture from the slab surface.