Strengths of thick prestressed precast hollow-core slab members strengthened in shear

The prestressed hollow-core slab (PHCS) system is one of the most commonly adopted precast concrete flooring systems, which can optimize productivity and structural efficiency. Because PHCS members are typically produced by the extrusion method in long-line precast plants, it is extremely difficult to provide shear reinforcements due to the automated fabrication method for forming multiple hollow-cores in a cross section. However, the current ACI 318 building code stipulates that the web-shear capacity of hollow-core members over 315 mm (12.5 in.) thickness without minimum shear reinforcement should be reduced by half, which increases the demands of shear strengthening for a thick PHCS member at its end regions. In this study, the shear tests of thick PHCS members strengthened in shear, using various core-filling methods frequently used in the current precast industry, were conducted and a new analytical method was addressed to estimate the shear strengths of the PHCS members composite with core-filling concretes.