Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : Deep beams

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.

Retrofitting of SCC Deep Beams With Circular Openings Using CFRP

Nabeel A. Al-Bayati; Dhiyaa H. Mohammed; Nawfal A. Abdul Jabbar

Engineering and Technology Journal, 2021, Volume 39, Issue 7, Pages 1092-1104
DOI: 10.30684/etj.v39i7.74

The main objectives of this study are: encouraging the production and use of  self-compacting  concrete,  use  of  materials  which  are  lightweight,  easy to  use,  and  highly  efficient  in  the  retrofitting  of  reinforced  concrete buildings. Six deep beams specimens (L= length of 1400mm, h= height of 400mm,   and   b=   width   of   150mm)   were   cast   using   self-compacting concrete.  The  location  of  the  openings  is  in  the  middle  of  assumed  load path.  Five  patterns  were  adopted  to  arrange  carbon  fiber  reinforced polymer (CFRP) strips. The cylinder compressive strength of the concrete was  approximately  equal  for  all  beams  and  was  about  (44  MPa)  at  28 days  age.  All  the  beams  have  the  same  steel  reinforcement  for  shear  and flexure. There have been many tests for fresh and hardened concrete. The reinforced  concrete  deep  beams  were  tested  up  to  (60%)  of  the  ultimate load of control beams to simulate degree of damage, and then released the load. After that,the beams were retrofitted using (CFRP) strips, and then the beams were tested to failure. The study was focused on determining the vertical mid-span deflection, ultimate load, the load that causes first shear and flexural cracks, and mode of failure. Theresults showed that, the best increase in the ultimate failure load was (27.27%) and achieved using the inclined  strips  pattern  and  the  pattern  of  vertical  and  horizontal  strips together.  Reduction  in  the  deflection  values  for  the  retrofitted  beams compared  to  the  control  beam  by  about  (12-13%)  due  to  restrictions imposed by CFRP strips and the epoxy.