Experimental investigation of RC full scale frame strengthened at the joints and columns with fibre reinforced polymers

This paper presents the strengthening procedure of a two storey RC full-scale structure tested on a shaking table. The bare frame, designed by using old European regulations, was subjected to a series of earthquakes until severe damage was caused in the joints. The strengthening strategy aimed to apply a minimal/optimal amount of CFRP sheets onto joints and columns so as to enhance their shear and flexural capacity and to transfer the plastic hinges from columns to beams. Construction details are given to show how joints and columns were strengthened and how the CFRP sheets were anchored on the external and internal joint faces. Two different strengthening methods using orthotropic reinforcement were examined. Some of the experimental results are shown focusing on the two principal natural frequencies and maximum absolute displacements of all floors for both bare and retrofitted frame. The behaviour of the building was successfully changed from the strong beam-weak column frame to a more ductile frame as the plastic hinges were transferred from the columns to the beams.