Investigation of the Ultimate Capacity of NSM FRP-Strengthened Concrete Bridge Deck Slabs

Abstract

The use of near-surface-mounted (NSM) fibre-reinforced polymer (FRP) is a promising technology for increasing ultimate strength of concrete structures. However, the application of this strengthening method in concrete deck slabs is rather limited. This paper reveals a study of the ultimate capacity of concrete bridge deck slabs strengthened with NSM FRP rods. An experimental investigation on concrete deck specimens was carried out to identify the effect of NSM strengthening method on the failure mode and loading carrying capacity. The test results show that this strengthening procedure can increase the effective punching depth and enhance the punching capacity of concrete deck slabs. Interestingly, the NSM FRP strengthening strategy combined with arching action has a cumulative beneficial effect on the ultimate strength. Additionally, the ultimate strength of the test deck slabs was predicted by theoretical models reported in some reported studies. It is found that those methods yield highly conservative predictions. Subsequently, a modified theoretical model that takes into account of arching action is proposed. By validating the predicted strengths with the test results, the proposed method accurately predicted the ultimate strength of bridge deck slabs strengthened using NSM FRP.