Comparison of confinement models for fiber-reinforced polymer-wrapped concrete

Fiber-reinforced polymer (FRP) wrapping of reinforced concrete columns is rapidly gaining acceptance as all effective rehabilitation and strengthening technique. Over the past 20 years, numerous analytical models have been presented in literature to predict the stress-strain behaviour of concrete confined by FRP wraps. These models have generally been derived empirically from relatively small samples of experimental data, and there appears to be little consensus among researchers as to which confinement model(s) consistently yield the most accurate results. In this paper various available analytical models are evaluated in light of a large database of test results on FRP wrapped columns. In addition, several of the existing models are modified herein to provide the best fit to the experimental database. Because of the variability observed in the test data, however it appears impossible to develop simple empirical models based oil the current database with less than approximately 14% mean absolute error for ultimate strength. and 35% mean absolute error for ultimate strain. Existing design guidelines are presented and discussed in light of the experimental database.