Análise experimental do desempenho de conectores de cisalhamento feitos em aço CA-50 para uso em estruturas mistas de perfis em aço e concreto armado

Abstract

The steel and concrete composite structures began to increase as a construction system over the years, due to their advantages both in their structural behavior and in their constructive aspects. These structures are those in which both materials (steel and concrete) work together, and for this to be possible, it is necessary to use connectors that combat the shear forces generated between the materials. There are several types of these connectors, but their goal is to make the structure solid and work monolithically. This work aims to experimentally analyze the performance of shear connectors, for use in steel and concrete reinforced composite structures, modifying geometries and arrangement of connectors composed of Ø 12.5 mm diameter CA50 steel bar bent in shape close to a truss, making a comparative to define which model offers the greatest contribution in the connection. Therefore, push-out tests were performed, following the procedure described in the European Standard Norm EN 1994-1-1 (2004), in 7 specimens, consisting of an 800 mm high welded I-metal profile, and two slabs of reinforced concrete, with dimensions of (600x600x150) mm, in contact with the top of flanges of the metallic profile, containing the welded connectors. Among the 7 models, 2 of them, named Isósceles Truss (IT) and Rectangular Truss (RT), were used as reference; in 4 of them were made variations on the arrangement of the connectors used on the reference specimens, which were named Slanted Isosceles Truss. (SIT), Slanted Rectangular Truss (SRT), Piramidal Isosceles Truss Type A (PIT A) and Piramidal Isosceles Truss Type B (PIT B), and in 1 was made a change on the geometry, which was named Straight Truss (ST). Regarding the load capacity, the ST connector presented a load gain of 10.82%, 32.94%, 19.53%, 34.51%, 30.98%, 23.14 % in relation to IT, RT, SIT, SRT, PIT A and PIT B, respectively. Taking into account the design resistance calculation (𝑃𝑅𝑑) of each connector according to EN 1994-11 (2004), the tested connectors had a load capacity 46.54% higher than 𝑃𝑅𝑑. The connectors, in their entirety, presented themselves as they are ductile in their breaking mode. Compared to the others, the RT connector presented a more rigid, and, the SRT, a more flexible behavior. Thus, it is observed that the proposed connectors presented a good performance in relation to the load capacity and rupture mode.