Numerical Model of the Load-Bearing Capacity of the Bottom Reinforcement Bars Passing over the Column

Complying with PN-EN 1991-1-7:2008 (EC1) and PN-EN 1992-1:2004 (EC2) additional reinforcement should be applied in reinforced concrete slab-column structures in order to protect them against progressive collapses. Some suggestions and instructions concerning the prevention of such situations are contained merely in CSA A23.3 and ACI 352.1R.The paper presents the numerical model which was developed in the program of FEM basing on laboratory tests performed on a simplified model of a slab-column connection with the structural integrity reinforcement. The aim of investigations was determine the value of the load at which the destruction of such a connection occurs due to the rupture of the bars above the column. The calculations have been carried out for the models with the reinforcement passing above the column consisted of bars with a diameter of ø8 mm, ø12 mm or ø16 mm. In respective models the column was situated axially or eccentrically with respect to span of bars. The calculations permitted to determine the relations between the exerted load and the displacement of the column in time, which was compared with the results of laboratory tests. Based on the results, the reduction of the load-bearing capacity of the reinforcement bars due to bending was determined. Moreover, the impact of the size of the diameter rebar at the carrying capacity of the connection has been determined. The impact of the eccentric loading effects on the slab-column connection has been specified, too.