Performance enhancement of R/C building columns and beam–column joints through shotcrete jacketing

This paper investigates the effectiveness and suitability of shotcrete and cast-in-place concrete as means of retrofitting columns and beam–column joints in reinforced concrete frame structures, so as to improve their shear and/or flexural performance. Thus, the use of four-sided and two-sided reinforced shotcrete or cast-in-place concrete jackets has been investigated experimentally for the case of pre-earthquake retrofitting of columns and beam–column joints. Focus has been placed on studying their lateral performance and on comparing the effectiveness of the reinforced shotcrete jackets with reference to the corresponding cast-in-place ones, as well as that of the two-sided jackets with reference to the corresponding four-sided ones. All types of concrete jackets examined were found to be equally satisfactory in their ability to strengthen existing old frame structures.