Strengthening of reinforced concrete corbels with GFRP overlays

Abstract

The strength and post-peak performance of reinforced concrete corbels, strengthened with epoxy bonded glass fi ber reinforced polymer (GFRP) overlays, were experimentally investigated. The test variables were the corbel shear span to depth ratio, corbel main reinforcement ratio, and the number and orientation of the GFRP fi bers. In total, 24 normal strength concrete, one-third scale, corbel specimens, without hoop reinforcement, were tested to failure under quasi-static gravity loading. Test results revealed that GFRP overlays can easily be used for the enhancement of corbel load bearing capacity, depending on the fi ber orientation. The main reinforcement ratio and the number of GFRP plies were found to be the two main variables affecting the level of strength gain in the corbel specimens. Notation a/d , shear span to depth ratio ; b , width of corbel (mm); d , effective corbel depth on the corbel-column interface (mm); f c ′ , compressive strength measured on 150 × 300 mm concrete cylinders (MPa); f sp , split tensile strength measured on 150 × 300 mm concrete cylinders (MPa) ; f y , yield strength of corbel main reinforcement or column longitudinal reinforcement (MPa) ; f yw , yield strength of column transverse reinforcement (MPa) ; h ′ , the corbel depth on the outer edge of the bearing area (mm); h , the corbel height (mm) ; H , horizontal load on the corbel (kN); H/V , horizontal load to vertical ratio ; P , applied load on the column ( V u = P /2) (kN) ; V , vertical load on the corbel (kN); V u , vertical failure load of a corbel ( V u = P /2) (kN); ε D , corbel concrete strain measured on 45 degree inclination with the horizontal (Figure 3); ε L , corbel concrete strain measured parallel to the corbel main reinforcement ( Figure 3) ; Φ , prefi x for reinforcing bar diameter in millimeters ; ρ , main reinforcement ratio measured on the corbelcolumn cross-section ( % ) ; τ , shear stress of the a corbel (MPa).

Behaviour of reinforced concrete corbels strengthened by FRP composites and steel bars: a critical review

“…On the other hand, the applicability of using epoxy bonded glass fibre reinforced polymer (GFRP) overlays in strengthening RC corbels was also investigated [24], as shown in figure 7. The a/d ratio, reinforcement ratio, and the quantity and direction of the GFRP fibres were all considered as tested variables.…”