Title: Reinforced Concrete Slab Shear Prediction Competition: Experiments

Author(s): Thomas Jaeger and Peter Marti

Publication: Structural Journal

Volume: 106

Issue: 3

Appears on pages(s): 300-308

Keywords: deformation capacity; reinforced concrete; reinforcement; shear; slabs; stiffness; stirrups; strength; tests.

DOI: 10.14359/56494

Date: 5/1/2009

Abstract:
Twenty-eight large-scale tests were conducted at the Institute of Structural Engineering at the Swiss Federal Institute of Technology (ETH) in Zurich, Switzerland, to investigate the shear strength and deformation capacity of orthogonally reinforced concrete slabs. Test parameters included the slab thickness, the in-plane and the transverse reinforcement ratios, and the deviation of the principal shear (and moment) direction from the direction of the in-plane reinforcement. Eight of the 28 tests were used for an international competition to predict the expected load-deformation response. This paper presents the information on the test concept, the test specimens, and the test procedures given to the participants of the prediction competition and summarizes and discusses the results of the eight tests. It is shown that with a sufficient transverse reinforcement, ductile flexural failures instead of brittle shear failures occurred and, contrary to the specimens without transverse reinforcement, the shear strength of thick slabs was not reduced compared to thin slabs; that is, no size effect was observed for the specimens with transverse reinforcement. It is also shown that a deviation of 45 degrees of the principal moment (and herein, shear) direction from the reinforcement direction resulted in a significant decrease of the cracked slab stiffness, accompanied by a further strength reduction for the specimens without transverse reinforcement.