Experimental resistance of slab-column connections with prefabricated truss bars as punching shear reinforcement

Abstract This paper presents the results of tests on slabs with punching shear reinforcement formed by prefabricated truss assemblies disconnected from the flexural reinforcement, developed to optimize the construction process. General guidelines for design, detailing, and assembly of this reinforcement are presented, based on the recommendations presented by ACI 318, Eurocode 2, and fib Model Code 2010. One slab without shear reinforcement and one slab with stud rails were tested as a reference for tests on two slabs with the prefabricated truss modules as punching shear reinforcement. The load-rotation response and the failure loads are presented and discussed in comparison with theoretical estimates obtained following the design codes. The profile of stress and strain distribution on the flexural and shear reinforcement are also presented and discussed. The slab with inclined prefabricated truss bars registered similar response and resistance compared to the one with stud rails. These tests confirm the effectiveness of this kind of punching shear reinforcement, as one of the slabs had almost twice the strength and more than three times the deformation capacity of the reference slab without shear reinforcement.