Title:
Seismic-Resistant Joints of Interior Columns
with Prestressed Slabs
Author(s):
Ramez B. Gayed and Amin Ghali
Publication:
Structural Journal
Volume:
103
Issue:
5
Appears on pages(s):
710-719
Keywords:
flat plate; post-tensioning; prestressed concrete; punching; shear; slab
DOI:
10.14359/16923
Date:
9/1/2006
Abstract:
A procedure is developed for the punching shear design of post-tensioned slab-column connections subjected to gravity loads combined with lateral displacement-induced unbalanced moments due to earthquakes. The procedure is based on existing design recommendations for nonprestressed slabs, on a series of seven full-scale tests presented in this paper of interior column connections with post-tensioned slabs and on a companion similar series on edge column-slab connections. In the seven tests, the ratio of prestressed to nonprestressed reinforcement was varied, while flexural strength was maintained the same. Columns were subjected to a constant axial force, simulating gravity load effect, combined with cyclic displacement reversals of increasing amplitude up to failure. The slabs were reinforced with stud shear reinforcement. The tests, supplemented by analyses, indicated that the existing design recommendations for nonprestressed slabs can also be used for post-tensioned slabs having an average effective prestress of 0.4 to 1.4 MPa (60 to 200 psi). Prestressing mitigates degradation of the stiffness; however, energy dissipation is better in nonprestressed connections.