Title: A New Technique for the Seismic Retrofit of Slab-Column Connections

Author(s): Dritan Topuzi, Maria Anna Polak, and Sriram Narasimhan

Publication: Structural Journal

Volume: 114

Issue: 6

Appears on pages(s): 1471-1481

Keywords: ductility; flat plate systems; flat slabs; punching shear; slabcolumn connections

DOI: 10.14359/51689500

Date: 11/1/2017

Abstract:
This paper describes an experimental investigation on the behavior of reinforced concrete slab-column connections retrofitted with a new type of shear reinforcement while subjected to a combination of constant gravity loading and increasing cyclic lateral drift. The testing program consisted of six specimens: five specimens retrofitted for punching shear with a combination of steel bolts and flexible washers and one unretrofitted control specimen. Washers of different flexibilities were used with the bolts to introduce a larger but limited opening of punching shear cracks. The results show that this type of shear reinforcement improves the lateral loaddeformation response of the connections, increasing the ductility without a commensurate increase in stiffness and strength. The lower joint stiffness results in lower shear forces transferred to the column, while the continuous opening and closing of cracks results in larger energy dissipation through friction within the crack interfaces.