Shear resistance of slab-corner column connections

Abstract

This thesis studies the potential failure by punching of concrete flat slabs at their connections with corner columns. The design procedures according to the Canadian, American, and European codes are critically reviewed. As well, theories proposed by several researchers are discussed. The writer tested seven full size corner slab-column connections to failure. The connections were initially submitted to a service loading. The column ends were then cycled through deflections of up to 3.0% of the column height to simulate the lateral deformation caused by an earthquake. Finally, the load was increased to failure while maintaining the same eccentricity as the service load. The test parameters that were varied were the provision and extent of the shear reinforced zone, the column cross-sectional shape and the load eccentricity. The shear reinforcement used in the experiments, called shear studs, was in the form of vertical bars with forged heads at one end and welded to a flat strip at the other. It was shown that the provision of these shear studs increased both the strength and ductility of the connections. The experimental failure loads were compared with the connection strengths predicted by the various theories and design equations. Most of the design equations predicted very conservative failure loads. This was due to overestimating a coefficient Yv, which is the fraction of the applied moment resisted by eccentricity of shear. A new equation is proposed to calculate Yv·