Abstract:
Concrete structures reinforced with a combination of steel and fiber-reinforced polymer (FRP) bars can effectively solve the durability problem of steel-reinforced concrete (SRC) structures and the brittle failure problem of FRP-reinforced concrete structures. It has been widely used in civil engineering. In order to study the explosion resistance of hybrid FRP-steel-reinforced concrete (hybrid-RC) slab, the close-in explosion tests of hybrid-RC slabs and SRC slabs at different scale distances were carried out to compare and analyze the difference of explosion resistance between the two slabs and determine the failure mode of hybrid-RC slab. When the scale distance is 0.684 m/kg
1/3, The maximum displacement of hybrid-RC slab is 19.2% larger than that of SRC slab, but the residual deformation is 27.3% smaller than that of SRC slab. The explosion recovery index is introduced to evaluate the explosion recovery capacity of concrete slabs. The explosion recovery index of hybrid-RC slabs is larger than that of SRC slabs. Hybrid-RC slabs have excellent explosion recovery capacity. The cracks on the back of the hybrid-RC slab depicts multiple vertical cracks and diagonal cracks, while the cracks on the back of the SRC slab depicts one vertical main crack and multiple diagonal cracks radiating outward. With the decrease of the scale distance, the failure mode of the hybrid-RC slab develops from the whole bending failure to the coexistence of the bending failure and the local concrete failure. According to the test data, the prediction formula of the maximum support angle is proposed. It provides a reference for the explosion design of hybrid-RC slab.