Experimental and numerical investigation of strengthening effect of shear studs in RC flat slabs with multiple openings

Abstract

The punching failure, which is an abruptly developing brittle failure mechanism, is one of the most dangerous collapse mechanisms that can occur in beamless (flat) slabs. Therefore, it is important to consider both the ductility and strength in the design of slab-column connections. The effects of a strengthening technique using shear studs around the column perimeters of flat slabs are investigated experimentally and numerically in this study. The study is planned in two stages and involved fabrication and testing of twenty full-scale reinforced concrete flat slabs. In the first stage, ten reference test specimens and in the second stage, ten specimens that were strengthened with a shear stud were produced. In each series, one specimen without opening and nine specimens with double openings were designed. The presence of the opening, the size of the opening, the location of the opening, and the presence/absence of strengthening with shear studs were considered as the test variables. Based on the load-displacement graphs obtained from the testing of specimens, the maximum bearing capacity, initial stiffness, and energy consumption capacities of the specimens are calculated. Significant increases are obtained in the maximum bearing capacity, initial stiffness, and energy consumption capacities of the test specimens strengthened with shear studs. For numerical analysis, the test specimens were modeled in the ABAQUS finite element program, and a good agreement was observed between the experimental results and finite element predictions.