BEHAVIOR OF STRENGTHENED RC T-BEAMS

Twelve reinforced concrete T-beams were each strengthened in shear by the incorporation of additional stirrups in a thickened section cast using non-shrink grout. Another beam was strengthened by thickening the existing section only, without any additional reinforcement: The beams were simply supported and tested under a point load at midspan and their performance was compared with respect to cracking, deflection and ultimate strength. Separate tests were conducted to assess the contribution of grout to the shear strength of the beam, and accordingly a semi-empirical equation is proposed for the estimation of shear strength of the strengthened beams. The shear strengths of the tested beams compared well with the proposed equation, while they were generally underestimated by equations according to the codes of practice ACI 318 and BS 8110.