Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : NSM

Structural Behavior of Retrofitted Reinforced SCC Continuous Deep Beam With CFRP and Hybrid Techniques

Wisam J. Al -Bdari; Nabeel A. Al-Bayati; Ihsan Ali Al-Shaarbaf

Engineering and Technology Journal, 2021, Volume 39, Issue 7, Pages 1153-1163
DOI: 10.30684/etj.v39i7.1928

In this research, the results of experimental test of seven reinforced SCC continuous deep beams after being retrofitting by CFRP with different techniques. The main objective of the current research is to investigate the structural behavior in the shear performance and failure modes. The first beam tested up to failure and assumed as reference beam, while remaining six beams firstly loaded with 65% of ultimate load capacity then retrofitted by three systems namely: externally bonded reinforcing (EBR) by CFRP strips, near surface mounted technique (NSM) CFRP rods and the third system was hybrid technique by composite between EBR CFRP strips and NSM CFRP rods. The experimental results show that applying the EBR CFRP strips in a vertical direction improved the loading capacity in comparison with the horizontal direction. On the other hand, the NSM CFRP rods applied in horizontal direction presented higher values in both ultimate loading capacity and final deflection, where the increasing in ultimate load capacity about 43.48%, and the increasing in deflection about 33.5% compared with control beam. Therefore, it can be concluded that applying the hybrid technique is more efficient when the EBR strips and NSM bars applied in the vertical, and the horizontal directions, respectively.

Flexural Behavior of RC Beams Strengthened by NSM-CFRP Laminates or Bars

Ikram A. Saeed; Riadh Al-Mahaidi; Tareq S. Al-Attar; Basil S. Al-Shathr

Engineering and Technology Journal, 2018, Volume 36, Issue 4A, Pages 358-367
DOI: 10.30684/etj.36.4A.1

The strengthening and enhancing the structures represents an important aspect in the construction industry due to the growing need to increase the tolerability of origin to a specific level and within the required rehabilitation and maintenance work. This paper assessed the performance and effectiveness of the Near Surface Mounted (NSM) strengthening technique for the reinforced concrete beams. Three (140x260x2700 mm) reinforced concrete beams were strengthened in flexure with NSM strengthening systems using Carbon Fiber Reinforced Polymer (CFRP) strips, bars, and cement-based adhesive as a binding materials. The flexural behaviour of the beams was evaluated by testing the specimens under three-point loading to failure. The structural performance, deflection, ductility, stiffness, and modes of failure of the tested beams are presented and discussed in this paper. The test results indicate that using NSM-CFRP strips and bars is practical and significantly improves the stiffness and increases the flexural capacity of reinforced concrete beams. The strength increments were 48, 42, and 15 percent recorded with CFRP bars, rough strips, and smooth strips respectively. The deflection of the strengthened beams was reduced by about 66, 48, and 58 percent for CFRP smooth strips, rough strips, and CFRP bars respectively, compared with the control beam due to the increased stiffness of the strengthened beams.