Structural Behavior of Strengthened RC Beams in Shear using CFRP Strips

Abstract

Carbon fiber reinforced polymers (CFRP) were widely used in strengthening of reinforced concrete members in the last few years. Experimental and theoretical investigations were carried out to find the behavior of reinforced concrete beams strengthened in shear by CFRP strips. Six beams measured of 200x300x2000mm were investigated. The variables investigated in this work are orientation (vertical and inclined) and the spacing between CFRP strips.It was found that the strengthening by CFRP strips increased the crack, yield and ultimate load by 10%, 71% and 77% respectively on average. Inclined CFRP strips show a better performance than vertical CFRP strips with same distances and increase the yield and ultimate load by 11% and 13% respectively on average. By covering all faces of specimen with CFRP strips, the yield and ultimate load increased by 82% and 95% respectively. Using the CFRP strips changed the failure model from shear to flexural by increasing the shear strength, so the ductility was increased by 198% on average. CFRP increased the strain in compression face of concrete and the value was greater than (0.003). For all strengthened specimens, there was no effect on CFRP strips.

Influence of Stirrup Spacing on the Strengthening and Rehabilitating of RC T-beams Using Near-Surface Mounted Carbon-Fiber-Reinforced Polymer Strips

“…Moreover, the shear strength increased with the increase in the NSM-CFRP laminates percentage, and this influenced the failure modes of beams. Al Rjoub et al [40] assessed the effect of changing the side concrete cover depth (20,30, and 40 mm), NSM-CFRP orientation (0 • and 45 • ), and the strip length on the shear behavior of strengthened RC beams with NSM-CFRP. The authors concluded that inclined strips were better than the horizontal ones, and the longer the strips are, the higher the shear capacity.…”

CFRP Strengthening of Beams in Reinforced Concrete Frames with Openings in Shear Zone

“…It was also noted that the load-carrying capacity increased due to strengthening of the openings in the shear zone with CFRP sheets. Amer et al [3] conducted theoretical and experimental studies on 2.00 meter long beams that are 200 x 300 mm in cross-section strengthened with FRP strips to enhance shear strength. The variables investigated included CFRP strip orientation (vertical and inclined) and spacing between strips.…”

Influence of Externally Bonded CFRP on the Shear Behavior of Strengthened and Rehabilitated Reinforced Concrete T-Beams Containing Shear Stirrups

“…Carbon fiber reinforced polymer (CFRP) composites proved their efficiency in strengthening concrete elements [1]. Previous studies focused on the flexural strengthening [2,3] and shear strengthening of RC rectangle sections [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22], T-beams [23][24][25][26][27][28][29][30][31][32], and prestressed beams [33] using externally bonded CFRP. The results indicated that using CFRP in different schemes improved the shear strength, as the capacity increased with the increase of the number of CFRP layers.…”