Abstract
Hollow core slabs(HCS), as well as double tee slab, can offer improved span and load bearing capacity with a composite structural topping. To ensure a composite action between the precast concrete slab and cast-in situ concrete, shear connectors such as tie bars, shear studs and steel plates are required on the top surface of precast concrete slabs. However, the use of shear connectors is generally not practicable for HCS and shear reinforcement is likewise impossible. Therefore, the shear strength of composite HCS may be limited to the lesser of horizontal shear strength and web-shear strength. In this paper, the horizontal shear strength and web-shear strength for composite HCS with longitudinal groove at interface are evaluated. An experimental and theoretical study on the effects of roughened interface and concrete topping on the shear capacity of composite HCS is presented. It is concluded that the roughness of longitudinal groove can transfer the horizontal shear stress to obtain the composite action and the shear strength of composite HCS can be computed using Expression (11-12) of ACI 318-08 or Expression (6.4) of Eurocode 2.
