Minimum shear reinforcement for thick plates and two-way slabs

Abstract

Thick reinforced concrete plates of over 250mm thickness usually exhibit brittle shear failure under concentrated loads. Potential punching failures in the vicinity of concentrated loads have already been taken into consideration by conventional design methods. The current research is a continuation to previous work published by the authors on minimum flexural reinforcement for thick plates. The main focus of this research is to design adequate shear reinforcement for thick concrete plates. In this paper, new models are developed to calculate minimum shear reinforcements for thick plates, concrete plates and two-way slabs. Design guidelines as well as a design example for minimum shear reinforcement that the design engineers can follow are given. A comparison between the proposed formulae with experimental tests carried by different researchers is conducted. A comprehensive review of different design codes formulae is discussed and compared with the proposed formulae. The proposed formulae are simple and account for member size effect through fracture mechanics concepts. For all equations, (MPa) is used for stresses and (mm) for lengths unless otherwise noted.