Structural behavior of rc columns transversely reinforced with frp strips

Abstract

This paper presented the structural capacity of reinforced concrete columns transversely reinforced with FRP strips compared with the conventional carbon steel stirrups. Results were obtained through non-linear Finite Element (FE) simulation. Inadequate and improper design of transverse reinforcement includes the used of 90° hooks and large spacing between the stirrups may led to shear failure or even collapse of the whole building. Stringent requirements have been outlined for transverse reinforcement in seismic design codes to maintain structural integrity and provide sufficient ductility to the structure which includes the usage of 135° end hook and close spacing between stirrups in the potential area of plastic hinge is among the requirements given. However, in most construction, the requirements are not adhered. Based on literature reviews, FRP composites demonstrate excellent behavior in enhancing the overall load capacity and ductility of RC columns due to its high-strength- and stiffness-to-weight-ratio. FRP sheets has been mainly used as wrapping of RC elements for repair and retrofitting purposes, while FRP bars were used to substitute the conventional steel bars. However, limited study has been conducted in the application of FRP strips as transverse reinforcement in RC columns subjected to cyclic loading. Results from the numerical analyses shows that the RC columns transversely reinforced with FRP strips has 12.5% and 36.8% higher in the ultimate load capacity and lateral displacement, respectively compared to the one reinforced with carbon steel. It also has higher ductility ratio and energy dissipation capacity.