Influence of flexural reinforcement on the seismic performance of flat slab – Column connections

The behavior of flat slab – column connections under seismic-type loading is complex and not exhaustively studied. Among the many variables involved, this paper focuses on the influence of flexural reinforcement on the seismic performance of such connections. Three specimens were tested and analyzed in conjunction with two previously published specimens tested under similar conditions, under constant vertical loading and cyclic horizontal displacements, resulting in a total of five specimens. Among these specimens, the top flexural reinforcement varied from 0.64% to 1.34% and the approximate value of applied gravity shear ratio (GSR, equal to the ratio between the applied gravity load and the punching shear resistance) was around 55%. Two of the specimens (low and median reinforcement ratio) were also reinforced with headed studs against punching shear to study the unbalanced moment transfer capacity of the slab – column connections. The specimens are described and analyzed in detail. The results show that the performance under cyclic loading is affected by the amount of flexural reinforcement, even though GSR was almost the same for all specimens. It is shown that current code-based approaches for the estimation of unbalanced moment capacity, as well as drift capacity, are generally safe sided for the specimens under investigation but do not fully capture the trends observed in the experimental campaign.