Seismic retrofitting of pre-1970 RC bridge columns using innovative jackets

Abstract

The efficiency of an innovative seismic retrofit scheme, proposed for the improvement of the overall lateral performance of poorly detailed existing reinforced concrete structures, is herein experimentally investigated. One original cantilever column sub-assemblage with continuous longitudinal reinforcement, representative of the best construction practice regarding columns found in bridges designed for gravity load only in the 1950s-1970s period, was subjected to cyclic lateral loading to failure. The column was subsequently retrofitted with a high performance steel fibre concrete jacket. No conventional reinforcement was used for the construction of the jacket. The fibre volume fraction was equal to 1.50%. The post-earthquake enhanced specimen was subjected to a large number of inelastic cyclic deformations. Test results clearly demonstrated the reliability of the proposed retrofit scheme, which successfully prevented the brittle shear failure of the enhanced column and ensured a desirable ductile behaviour under reversed lateral deformations of the earthquake-type loading.