Numerical Simulation and Theoretical Analysis of Flexural Strengthening of Undamaged RC Beams with Steel Strand...

The effects of practical parameters on the flexural behavior of reinforced concrete (RC) beams strengthened with steel strand mesh-reinforced engineered cementitious composite (ECC) were investigated, based on the finite element (FE) simulation. First, an FE model for strengthened RC beams was developed. The model was validated by comparing it with existing experimental data. Subsequently, the model was employed for parametric analysis on the flexural performance of the strengthened beams. The results showed that steel strand mesh-reinforced ECC significantly enhanced the flexural capacity, stiffness, and ductility of the RC beams, with improvements ranging from 7.81% to 61.84%, 6.35% to 40.90%, and 5.92% to 50.16%, respectively. As the reinforcement ratio of longitudinal steel strand, ECC thickness, and cracking strength increased, the flexural capacity increased. However, an increase in the reinforcement ratio of the longitudinal steel bars and the section height of the RC beam reduced the improvement in flexural capacity. The increase in the thickness of the strengthening layer and reinforcement ratio of the longitudinal steel strand enhanced the improvement of stiffness. Differently, an increase in the reinforcement ratio of longitudinal steel strand, concrete strength, and height of the RC beam diminished the improvement of stiffness. The enhancement of ductility increased with the concrete strength. Finally, formulas for calculating the bearing capacity and stiffness of RC beams strengthened with steel strand mesh-reinforced ECC and the limit of steel strand quantity were proposed. These formulas agreed well with experimental and numerical simulation FE results.