Jordan Journal of Civil Engineering

Effect of NSM technique on moment redistribution in top strengthened reinforced concrete continuous beams


Shady Salem; Amr Ibrahim; Mahmoud El-Kateb; Ayman Khalil; Mohamed Attia Fouda;


Numerous researches have been presented addressing strengthening of continuous reinforced concrete (RC) beams depending on moment-redistribution (MR) effect. Most of the research was backed on either strengthening the bottom surface of the beam or both top and bottom surfaces. As such, both techniques require full accessibility for the beam bottom surface which may not be applicable. This paper presents a novel strengthening technique using near surface mounted steel or fiber reinforced polymer (FRP) laminates. The presented study assesses experimentally/ numerically the behavior of RC continuous beams top strengthened at the hogging regions only. The experimental program includes testing five full scale RC continuous beams strengthened with either steel plates or carbon fiber reinforced polymer (CFRP) laminates. Moreover, the numerical model developed using finite element (FE) program was used for parametric investigation to assess the strengthening efficiency under different parameters. Strengthening using glass fiber reinforced polymer (GFRP) laminates was also investigated in the numerical analysis. Strengthening using steel plates caused up to fifty percent moment-redistribution with a significant increase in the load-carrying capacity of the beams. While CFRP and GFRP strengthened beams showed substantial amounts of moment redistribution, but without significantly affecting the load-carrying capacity.


Moment redistribution, Strengthening, Near-surface mounted, Numerical analysis, Steel plates, FRP laminates