Abstract
The composite interface should be able to transfer the horizontal shear force to possess the efficiency of a monolithic member for the composite floor with HCS(Hollow Core Slab). This research is about the horizontal shear capacity on the stripe-type and grid-type surface roughness of HCS. 20 specimens for each type were tested in single shear and double shear method. As the results of stripe-type tested in single shear method is larger than the results of grid-type tested in double shear method, it is found that the single shear test is a desirable method to evaluate the horizontal shear capacity in the interface between HCS and topping concrete. The horizontal shear stresses range $0.85{\sim}2.88N/mm^2$ and $0.86{\sim}3.80N/mm^2$ in stripe-type and grid-type interface separately. The horizontal design shear stresses are analyzed with a probability density function called the Weibull function. The characteristic strengths corresponding to the 5% fractile are $0.73N/mm^2$ and $0.95N/mm^2$ on the stripe-type and the grid-type respectively, which are 1.3 and 1.7 times larger than $0.56N/mm^2$ of horizontal shear capacity prescribed by KCI(2007) and ACI(2008).
