Web-shear capacities of composite hollow-core slabs with core-filling and topping concretes

This paper presents an experimental shear test performed to investigate the web-shear capacity of composite hollow-core slabs (HCS) with cast-in-place (CIP) concrete. Five HCS specimens are fabricated, and the presence of a topping slab and number of cores strengthened by core-filling concrete are set as key test variables. The shear force–displacement responses of the specimens, patterns of cracks occurring in the HCS and filled cores, strain behavior of stirrups, and composite action between the HCS and CIP concrete are measured and analyzed comprehensively. In addition, the web-shear capacity of the composite HCS with CIP concrete is calculated based on elasticity theory and the transformed area method, in which the residual stress ratio factor is introduced to reflect the shear contribution of the core-filling concrete after its shear cracking. Moreover, a practical equation is proposed to allow structural engineers to easily perform the shear-strengthening design of HCS via the core-filling method. The detailed model and the simplified equation accurately evaluate the web-shear capacities of the HCS specimens.