Eccentric Punching Shear of Waffle Slab


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Title: Eccentric Punching Shear of Waffle Slab

Author(s): Ahmed Faleh Al-Bayati, Lau Teck Leong, and Leslie A. Clark

Publication: Structural Journal

Volume: 115

Issue: 1

Appears on pages(s): 163-173

Keywords: design; internal punching shear; moment transfer; plasticity; reinforced concrete; waffle slab

Date: 1/1/2018

This paper presents test results of six 1/10th-scale micro-concrete waffle slabs subjected to internal punching shear in the presence of moment transfer. Although the observed punching failure mechanism of a waffle slab was found to be very similar to that of a flat slab, the shear capacity is relatively reduced because some of the potential failure surface is lost when it extends into the waffle section. Because the current codes of practice do not consider the punching shear mechanism of waffle slabs, the comparisons with the test results revealed that BS8110 and EC2 overestimated the punching capacities of waffle slabs, whereas ACI’s prediction was conservative. A prediction model based on the upper-bound plasticity theory was proposed to predict the failure load, which gave good agreement with the tests.