Opportunities of light jacketing with Fibre Reinforced Cementitious Composites for seismic retrofitting of existing RC columns

Abstract

A new jacketing technique consisting in a thin layer of Fibre Reinforced Cementitious Composites (light FRCC jacketing) in replacement of the original cover has been recently proposed for increasing durability and load bearing capacity of existing reinforced concrete (RC) structures. Although the advantages in terms of durability have been widely investigated, the behaviour of retrofitted columns under cyclic loading still deserves attention. This paper deals with the seismic response of RC columns retrofitted with a light FRCC jacketing. To this scope, flexural and shear critical RC columns were retrofitted and tested under load reversal. The resulting damage pattern was analysed by means of the Digital Image Correlation (DIC) technique. The cyclic response of the FRCC jacketed columns was compared with that of bare columns, to assess the suitability and effectiveness of the FRCC jacketing as a seismic retrofit technique. The experimental results demonstrated that the FRCC jacketing can represent a valid strengthening solution for shear critical members. In the case of flexural columns, the FRCC jacketing was able to provide an increase in ductility but induced a rocking behaviour. Preliminary modelling considerations for assessing the seismic response of FRCC jacketed columns have been finally provided, based on experimental evidences.