Seismic-resistant connections of edge columns with prestressed slabs

This paper reviews the procedure developed by Megally and Ghali for the seismic design of nonprestressed concrete slab-column connections and investigates the validity of the same procedure for prestressed slabs. A series of full-size specimens was tested representing the connection of a prestressed slab, with post-tensioned unbonded strands, with an edge column. The amounts of the prestressed and the nonprestressed reinforcements were varied, while the flexural strengths were unchanged. The columns were subjected to an axial load of constant magnitude and unbalanced moment reversals, representing the effect of an earthquake, of increasing amplitude up to failure. The specimens were provided with the same amount and arrangement of stud shear reinforcement (SSR). It is concluded that the reviewed design procedure, intended for nonprestressed slabs, applies also to prestressed slabs having an average prestress of 0.4 to 1.1 MPa. The shear reinforcement, when necessary, can be designed according to ACI 421.1R-99.