Comportamento de ligações mistas viga-pilar em perfis formados a frio com conectores de parafuso e rebite com rosca interna

Abstract

The non-linear behavior of the moment-rotation curve of composite beam-to-column connections of cold-formed steel structures is not known still satisfactorily, being the study of these connections still in an incipient knowledge phase. In this work, the results of the theoretical-experimental research are presented accomplished to study the behavior and the resistance of composite connections starting from semi-rigid bolted connections with extended plate of structures of low cost buildings with up to seven floors, in cold-formed profiles, using as shear connectors bolts and tubular rivets with inner threads. For the prevision of the non-linear theoretical behavior of the studied connection, in terms of Moment-Rotation relationship, the results of the experimentalresearch were used for the adjustments of the parameters i (i from 1 to 5) of Leon's equation, being obtained a good agreement of this with the test results. The calibrated model was shown valid for shear connectors with DIN 960 Class 5.8 bolts, with diameter of 12 mm, and rivets of the type RIVKLE M12x1,5 PO300 with inner threads, in SAE 1040 temperated steel, with tension resistance of 55 kN and torque resistance of80 kN.m, box beams with 150 mm of width and depth of 190 mm and of 250mm, plate with a minimum thickness of 2 mm, with yield stress among 300 MPa and 400 MPa and concrete with resistance to the compression between 18 MPa and 28 MPa. It can be concluded that studied connection is composite, being classified as semi-rigid as for therigidity and of total resistance in function of the presented resistance. The difference among the depth of the beams had little effect in the ultimate moment and in the capacity of rotation of the connection. However, it can be concluded that the initial rigidity of the connection was affected by the difference among the depth of the beams. Non-ductile limit states were not observed as, for example, rupture of bolts and of reinforcing bars. The obtained results can be used for the future revisions of technicalstandards, include the ABNT NBR 14762 - Design of cold-formed steel structures.