While the strength enhancement was more pronounced for
specimens with circular cross section, specimens with square and rectangular cross sections exhibited larger ultimate axial deformations
without a substantial loss in strength. The efficiency of retrofitting was much more pronounced in the case of relatively lower strength
concrete. The proposed model, together with two other available models, were used for predicting the strength and corresponding axial
deformations of more than 300 specimens tested by other researchers, as well as more than 100 specimens tested by the writers during this
study and before. It was shown that the predicted results by the proposed model were in reasonable agreement with this extensive database
of experimental studies.