Shear and Flexural Behavior of Reinforced Concrete Deep Beams Strengthened with CFRP Composites

Abstract

The current research studies the shear and flexural behavior of reinforced concrete (RC) deep beams strengthened with externally bonded carbon fiber-reinforced polymers (CFRP). Using two types of CFRP composites including sheets and laminates, different configurations for shear and flexural strengthening of deep beams were experimentally investigated. In total, twenty specimens of deep beams with cross-sectional dimensions of 190 mm width, 400 mm depth and an overall length of 1 900 mm were casted and tested to failure. Concerning the cracks' formation, failure's modes, ultimate strength and overall stiffness, the performance of the strengthened beams compared to the control beams were evaluated. From the test results, the effectiveness of CFRP technique on enhancing both the shear and flexural capacity of deep beams is verified; however, the efficiency differs variedly depending on the material and the strengthening scheme. Regarding the shear strengthening, using the continuous wrap of two sheets records the highest increase in the ultimate strength with a value exceeds 86% compared only to 36% with the inclined laminates. On the other hand, an enhancement of about 51% is achieved through the flexural strengthening with two layers of sheets and 26% when the laminates are used; both are accompanied by a divergent in the failure mode from flexure to shear.

The Influence of CFRP Orientation Angle on the Shear Strength of RC Beams

“…Al-Ghanem et al found that the presence of CFRP sheets and laminates can enhance shear and flexural capacity of deep beams. They reported that strengthening RC beams with CFRP sheets increased the shear strength to about 86% compared only to 36% with the inclined laminates [11]. Triantafillou tested eleven reinforced concrete beams strengthened in shear with CFRP at various area fractions and fiber configurations.…”

Shear strengthening and rehabilitating of reinforced concrete T-beams using externally carbon fiber reinforced polymer sheets

“…Carbon fiber-reinforced polymers (CFRPs) offer another way of rapidly repairing or reinforcing RC beams without interfering with the use of a framework or altering the geometry or weight of the repaired member [1]. Past studies of analytical solutions [2], experimental studies [3][4][5][6][7][8][9][10][11][12][13][14][15] or field applications have shown that the use of this technology has been extremely effective in practice [19,20]. Abdel-Jaber et al [10] investigated 38 rectangular beams in order to provide specific guidance for strengthening RC rectangular beams with FRP materials.…”

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.…”