Preliminary Results of a Shaking-Table Dynamic Test on a Repaired and Enhanced Reinforced Concrete Infilled Structure

Abstract

Although several post-earthquake surveys and previous studies have addressed the seismic vulnerability of infilled reinforced concrete (RC) structures built without proper seismic design, investigations have focused on repair and enhancement techniques only in recent years thanks to the development of new materials and the increase of public awareness. Moreover, experimental investigations have more commonly addressed strengthening techniques of pristine specimens rather than repairing solutions for damaged elements, because of the difficulty in defining a proper level of pre-existing damage. This paper describes an experimental campaign conducted at the EUCENTRE Foundation (Pavia, Italy) and discusses some preliminary results. The research work addresses the effectiveness of repair and strengthening techniques applied to a pair of identical structures through incremental dynamic shake-table tests. The specimens consisted of real scale threestory RC frames with clay masonry infills that were previously damaged up to two different levels to simulate two distinct post-earthquake conditions. The structures were repaired and enhanced depending on the preexisting damage and then subjected to the same loading protocol to allow a direct comparison on the effectiveness of the adopted techniques. The interventions involved the most vulnerable structural and nonstructural elements and can be summarized in: (i) strengthening of the first-story RC columns, (ii) repair and enhancing of first-story RC slab-column joints, and (iii) enhancement of the masonry infills for both in-plane and out-of-plane resistance.