Bearing Capacity of Precast Hollow Core Slabs at Load Bearing Wall-Slab Joint

Precast/prestressed hollow core slabs are commonly used as floor members but may also be used as roof or wall members in many different types of construction projects. Hollow core slab benefits come from their longitudinal voids running through them reducing weight and material costs. However, due to this reduction in material, their bearing capacity under increasingly high loads may be of concern. This is of specific concern at the ends of the simply supported-members where load-bearing walls may sit on top of them and transfer the weight of the structure above through the slab into the walls below. An experimental program was conducted to determine the capacity of hollow core slabs under crushing loads at their terminal ends. A regional precast concrete manufacturer has supplied hollow core slabs for this project. A test frame was designed to simulate the desired loading conditions, and the slabs were setup with their ends abutting and 8" wide bearing area across the connection as they would be in typical design. The effects of multiple variables were tested to determine how they change the strength of the slabs. These included partially filling the cores with concrete, as well as grouting the area between the slabs to varying degrees to simulate field conditions. The capacity and failure mode of these slabs was determined for the different end conditions. These results give the insight into what is required to satisfy loading conditions, which will help to eliminate unnecessary costs and labor time from the production process of these precast elements in cases where additional core fill is not required.