UPGRADING OF NONDUCTILE REINFORCED-CONCRETE FRAME CONNECTIONS

An innovative seismic upgrading technique for existing reinforced conc rete frame connections constructed prior to the 1970s using corrugated steel jacketing is proposed and evaluated. Six, one-third scale, rein forced concrete beam-to-column connections were tested under quasi-sta tic cyclic loading to study their seismic performance. The investigate d test parameters include the amount of joint and column transverse re inforcement, corrugated steel sheet thicknesses, and jacketing of colu mn only or of both column and beam. Test results demonstrated that exi sting reinforced concrete frame connections upgraded using corrugated steel jackets performed satisfactorily when subjected to high cyclic l oad levels. The corrugated steel jacket was found to be an effective s ystem of upgrading as it increases the joint shear strength and the en ergy dissipation capacity. A method for the design of the corrugated s teel jacket thickness and depth of corrugation is formulated.