A new stress-strain model for FRP-confined concrete

External confinement of concrete using fiber reinforced polymer FFRP) composites has emerged as a popular method for retrofitting of existing reinforced concrete columns for increased strength and ductility. The paper examines the axial stress-strain behavior of FRP confined concrete, understanding of which is necessary for the design of FRP retrofitting measures for columns, particularly when the column is subject to combined bending and axial load and when seismic ductility is of concern. Presented is a new, accurate stress-strain model for concrete with a sufficient amount of confinement from FRP which leads to significant compression strength enhancement. The model is based on a careful interpretation of large test databases gathered from extensive surveys of the existing literature.