Title:
Flat Plates in Seismic Areas: Comparison of Shear Reinforcement Systems
Author(s):
Carl Erik Broms
Publication:
Structural Journal
Volume:
104
Issue:
6
Appears on pages(s):
712-721
Keywords:
bars; ductility; flexural capacity; interstory drift; plates; seismic; shear; stirrups; studs
DOI:
10.14359/18953
Date:
11/1/2007
Abstract:
Four full-scale flat plate specimens, two with shear studs and two with ductility reinforcement, were tested for cyclic lateral displacement to simulate the behavior of an interior slab-column connection in a flat plate with the factored gravity load 10.5 kN/m2 (220 lb/ft2) during a major earthquake. Punching occurred for the specimens with shear studs at a 2% interstory drift ratio for recorded unbalanced moments that were considerably lower than the specimens’ nominal cyclic capacity according to ACI 421.1R-99. Although the specimens with ductility reinforcement were designed for gravity-type loading only, they endured a larger interstory drift than the specimens with shear studs. Their residual gravity load capacity after cyclic lateral displacements up to 5% drift ratio corresponded to all top flexural reinforcement over the specimen width reaching its ultimate strength. This indicates very good safety against collapse and offers a consistent design method for flat plates in seismic areas at which assessment of transferred moment between slab and column is not required.