Analytical model for shear strength of prestressed hollow-core slabs reinforced with core-filling concrete

The core-filling method, one of the shear strengthening methods of prestressed hollow-core slabs (PHCSs), has been widely applied on construction sites because of its easy reinforcement procedures. However, since there are no details for sufficient composite behavior between PHCS and core-filling concrete at the inner surface of the hollow core, interfacial cracking or separation may occur when a large shear force acts on the member. Such damage at the interface can negatively affect the shear strength of the member. In this regard, this study aims to propose a shear analysis model for PHCSs with core-filling concrete that considers the composite performance between PHCS and core-filling concrete based on previous shear test results reported by the authors. In the proposed model, the shear demands of PHCS and filled cores are calculated based on nonlinear flexural analysis, and the shear force at which one of the shear demands reaches the corresponding potential strength is regarded as the shear strength of the member. In addition, the change in the shear strength of the member according to the interfacial shear properties of the PHCS and filled core is analyzed in detail. The analysis results show that the shear strength of the members is reduced as the stiffness of interfacial shear stress–slip relationship between the PHCS and filled core decreases, and that the proposed model can quantitatively estimate the shear contributions of PHCS and filled cores.