Seismic Performance of Strengthened Slab-Column Connections in a Full-Scale Test

Funding Information: The SlabSTRESS (Slab Structural RESponse for Seismic European Design) experimental campaign is part of the Transnational Access activities of the SERA (Seismology and Earthquake Engineering Research Infrastructure Alliance for Europe) project. This project has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No. 730900. Publisher Copyright: © 2022 The Author(s). Published with license by Taylor & Francis Group, LLC.Strengthening of flat slab-column connections to resist imposed lateral drifts is often required for older reinforced concrete structures in which the flat slabs were typically designed to resist gravity load only or have been designed for less stringent requirements. The complex stress state around the columns means that strong experimental evidence is required for the repair and strengthening techniques to be adopted with confidence in practice. Although a significant amount of research has been devoted to strengthening of slab-column connections, a series of limitations still remain. A thorough literature review revealed that only relatively thin and isolated specimens have been tested under seismic-type loading and realistic strengthening scenarios. To overcome these limitations, a full-scale two-story flat slab building specimen was tested at the European Commission’s Joint Research Centre–ELSA Laboratory in Ispra, Italy. This paper describes and analyzes the results obtained from the last of a series of phases, on repaired and strengthened internal and external slab-column connections using post-installed bolts. Compared with previous tests, the full-scale building specimen has a thicker slab (200 mm), realistic slab continuity conditions and the connections were strengthened after they suffered damage from gravity loading and previous lateral loading phases. The results show that post-installed bolts are efficient even under the described conditions (i.e. damaged and repaired specimens with realistic thickness), and punching shear failure was prevented in the strengthened connections.publishersversionepub_ahead_of_prin