Shear Strength of Precast Prestressed Concrete Hollow Core Slabs

Abstract

Since early eighties, the precast prestressed concrete hollow core slab cross sections with non-circular voids became gradually popular, first in 400 mm thick slabs, then in 500 mm thick slabs. However, it is evidenced that this type of deeper slab sections have subjected to initial web shear cracking when they are provided longer supports and resist for higher line loads acting close to supports. Therefore, the objective of this study is to review the equations specified in American Concrete Institute (ACI), Eurocode 2 (EC2) and Canadian Standards Association (CSA) specifications to evaluate the shear strength of a member having no transverse reinforcement as in the case of hollow core slabs. For this purpose, the experimental test data on hollow core slabs are collected from past experimental programs and detailed finite element analyses are performed. Based on experimental and numerical results, it could be concluded that the evaluation of shear strength by the equations specified in ACI, EC2 and CSA specifications are conservative for the slab cross sections with circular voids while ACI and EC2 predictions are not conservative for deeper slab sections with flat webs. However, CSA predictions for all types of hollow core slab sections are more conservative than ACI and EC2 predictions.