102 / 2022-04-21 17:55:17

Bending behaviour of corroded RC continuous beams with C-FRCM strengthening system

Carbon-Fabric Reinforced Cementitious Matrix (C-FRCM), Continuous Beam, Finite Element Analysis (FEA), Interface Performance, U-Shaped Wrapping.

The durability of reinforced concrete (RC) has always been one of the major concerns in construction, especially for offshore or coastal engineering where the RC structures are prone to long-term erosion of chloride salts. Fiber reinforced cementitious material (FRCM) strengthening technology can effectively solve the durability problem of corroded RC structures. This paper presents a numerical investigation into the bending behaviour of strengthened RC continuous beams, considering interface performance (Fig. 1). The numerical load-displacement curves (Fig. 2), failure modes (Fig. 3) and moment redistribution values of the RC beams in the loading process are validated against those obtained from experiments. After parametric study and evaluation of flexural capacity according to codes, it can be concluded that the carbon-fabric reinforced cementitious matrix (C-FRCM) strengthening system as a strengthening method is feasible for RC beams and finite element analysis (FEA) can effectively predict the failure mode and strengthening performance of specimens.



In view of the member ductility discussion, the ductility of RC beam retained well with one or two layers of carbon-fabric (CF) mesh (Fig. 4), yet the combination of the C-FRCM plate and the U-shaped wrapping as the end anchorage is more effective than the C-FRCM plate only. The increase of the layer of CF mesh in the C-FRCM plate or U-shaped wrapping will enhance the strengthening effect (Fig. 5).



Given the parametric study on 35 supplemented FEA models of RC beams, the effectiveness of C-FRCM strengthening system is verified and demonstrated. The theoretical flexural capacities of RC beams with C-FRCM strengthening system are assessed according to the existing codes and compared with those obtained from numerical analyses.



By evaluating the flexural capacity of RC beam with C-FRCM strengthening system, the design formula for flexural capacity of RC beam is proposed by introducing the correction factors that considered the layer of CF mesh and U-shaped wrapping as well as degree of corrosion of steel bar. The modified calculation method for Bulletin 14 can provide more accurate estimation on RC beams considering the effects of the layer of CF mesh and U-shaped wrapping, and the degree of corrosion of steel bar.