Near Surface Mounted Shear Strengthening of Reinforced Concrete Beams


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Title: Near Surface Mounted Shear Strengthening of Reinforced Concrete Beams

Author(s): K.N. Rahal

Publication: Special Publication

Volume: 272


Appears on pages(s): 251-268

Keywords: beams; concrete; fiber-reinforced polymer; shear, stirrups; strengthening.

Date: 10/1/2010

Four reinforced concrete T-beams were tested to study their behavior when strengthened for shear using near-surface mounted (NSM) bars. The objectives were to study the effects of the type of bars used (carbon fiber-reinforced polymer (CFRP) and conventional reinforcing steel) and the effects of the load level at which the bars are installed. It was observed that the CFRP bars bonded at zero load increased the shear capacity by up to 92%, while those bonded when the precracked beam was under load increased the capacity by 77%. For the steel bars, these values were 75% and 57%, respectively. The CFRP strengthened regions showed a slightly more favorable response than those strengthened with conventional steel bars. Strengthening provided an improved control of the diagonal crack width. In the beams with closer spacing of NSM bars, the increase in shear strength allowed the beam to fail after considerable flexural deformations.