THE INFLUENCE OF CFRP ON THE BEHAVIOR OF RE-INFORCED CONCRETE SUBJECTED TO BUCKLING
ABSTRACT
The most useful method ofstrengthening reinforced concrete columns consists of wrapping the columns with a Carbon Fiber Reinforced Polymer CFRP compared to others various methods such as retrofitting, filling new reinforced concrete or jacketing welded metal sheets around the column. This method proves to be fast and effective.
Strengthening using carbon fiber fabric plays an active role in flexural resistance (in-crease of the stiffness) particularly when the fibers are glued parallel to the longitudinal axis of the column [Verok 2005]. In the case of perpendicular gluing of CFRP, the resistance is consid-ered to be a passive. Therefore, the creation of lateral confinement occurs which prevents a con-crete from local swelling and bulging out.
For both cases, numerous studies have been reported the behavior of circular-columns subjected to a compressive loading [Chaallal & Shahawy 1999, Lorenzis 2001, Sause & Harries 2004]. However, limited studies on the behaviour of rectangular columns under the same type of loading have been published [Chaallal & Shahawy 2000]. Few investigations have considered the interaction of axial load and biaxial bending on the rectangular columns.
In this context, an experimental study of the behaviour of sixteen confined slender rein-forced concrete columns have been carried out. The results of only four columns with slender-ness ratio of l/h=22.8 (l/r≅79) are presented in this paper. To highlight the influence of the con-finement rate on the structural behaviour of the columns, the number of layers wrapped around the column was varied.
The columns were subjected to vertical compression loads with doubly eccentricity. The results of this study confirm that the increase in the confinement rate increased the strength capacity of the column, as well as its ductility. The experiments also show that the effect of CFRP confinement on the increase in slender reinforced columns strength is limited.
