Resistência à tração de pinos de ancoragem isolados e pré-instalados : Influência da armadura de flexão e de cisalhamento

Abstract

Fastenings inserted in concrete are used in order to allow the introduction of these components in concrete structures, enabling the structural link between metal structures and concrete foundation and between prefabricated components and fixing reinforcement elements. This work will study specifically an anchoring system pre-installed (cast-in-place anchor), consisting of single head studs with square head and subjected to tensile force. Assays were performed in 30 headed studs, using self-compacting concrete with compressive strength in the C-30 class. The main variables are the presence and rate of reinforcement, the arrangement of reinforcement in the blocks, and the influence of both the flexural reinforcement (longitudinal and transverse) and the shear reinforcement (hairpins) on the load capacity of the anchorage. The experimental results were compared with five methods of design found in the literature and show that the flexural einforcement has no effect in increasing the load capacity of the anchorage. The use of a shear reinforcement together with the flexural reinforcement can increase the capacity of the anchor up to 64%. Increasing the distance of the hairpins in relation to the head stud reduces the ultimate load achieved by the anchoring system while the increase in diameter and / or in the number of layers of hairpins can increase the ultimate load.