Mitigation effects of air-backed RC slabs retrofitted with CFRP subjected to underwater contact explosions

Reinforced concrete (RC) structures are commonly used in ocean engineering, and can be subjected to various blast scenarios. To evaluate the strengthening effects of the carbon fiber reinforced polymer (CFRP) on the blast resistance of air-backed RC slabs to underwater contact explosions, a numerical approach based on the coupled Lagrange-Euler (CLE) method is proposed. First, two blast tests with available experimental results are utilized to verify the numerical method. Then, numerical investigations are conducted on air-backed slabs retrofitted with CFRP subjected to underwater contact explosions using the verified analytical method. The retrofitting effectiveness of CFRP on air-backed RC slabs against underwater contact explosions are analyzed contrastively. In addition, the effects of various factors, namely, the retrofitted scheme, retrofitted thickness, retrofitted material, and charge weight, on the blast resistance of FRP retrofitted air-backed slabs are investigated. The results demonstrate that the CFRP retrofitting can significantly improve the blast resistance of air-backed slabs against underwater contact explosions by reducing deformation and catching flying debris.