Effect of Openings on Punching Shear Behavior of Concrete Slab-Column Connections
The flat plate floor system is a common design choice for multilevel buildings and car parks. Despite several advantages of the system, it has a tendency to fail in punching shear which is a brittle failure at the slab-column connection and often occurs at a load well below the flexural capacity of the slab. Openings often need to be constructed in the vicinity of slab-column connections for a variety of reasons including ventilation, plumbing, heating, air-conditioning and electrical purposes. When openings are constructed close to the slab-column connection, the volume of concrete resisting transverse shear is reduced, hence increasing the likelihood of punching shear failure of the connection. To strengthen flat plate slab-column connections and to provide adequate ductility, properly placed and anchored shear stud reinforcement (SSR) is often utilised. The focus of this paper is on the numerical analysis of slab-column connections with openings and SSR using the nonlinear Layered Finite Element Method (LFEM). Three parametric studies are conducted to investigate the effect of varying opening size and location as well as column aspect ratio on the punching shear behaviour of the slab-column connections. Results on the shear strength and deflection of the connections are compared and discussed in some detail. This investigation is an important step in determining the size and location of openings and the size of columns for the optimum structural performance of flat plate systems.
Australian Structural Engineering Conference 2005