Title:
Punching Shear Strength of Continuous Post-Tensioned Concrete Flat Plates
Author(s):
N. J. Gardner and Mahmoud Rezai Kallage
Publication:
Materials Journal
Volume:
95
Issue:
3
Appears on pages(s):
272-283
Keywords:
continous flat slabs; prestressed concrete flat slabs; punching shear; structural design
DOI:
10.14359/371
Date:
5/1/1998
Abstract:
This paper describes a test to failure of a two bay by two bay continuous, unbonded post-tensioned flat plate designed in accordance with the provisions of ACI 318-95, except that no supplementary bonded reinforcing steel was provided. The prestressing tendons were uniformly distributed in one direction and banded in span/3 column strips in the other direction. In both directions the average prestress on the concrete was 3.5 MPa. The dimensions of each bay were 2.7 m by 2.7 m, the slab thickness was 89 mm, and the mean concrete cylinder strength was 44 MPa. The load was applied monotonically until punching shear occurred at an edge column on the side parallel to the banded tendons. The failed column was shored and the slab reloaded until punching shear occurred at the interior column. Finally both the edge column and the interior column were shored and the slab loaded until a corner column failed. All the punching shear failures were violent and without warning. The literature was reviewed to locate experimental results of punching shear tests for isolated prestressed concrete flat plates, continuous prestressed flat plate systems and tests of flat plate column connections under shear and moment transfer. The measured punching strength capacities were compared to those calculated using the provisions of ACI 318-95, BS 8110-85, and a proposed method.