EXPERIMENTAL STUDY ON THE MECHANICAL PROPERTY OF REDUCED BEAM SECTION CONNECTIONS OF STEEL FRAMES

Reduced beam section (RBS) connection of steel frame is one of the typical forms to move plastic hinge outward from the beam and column interface. Six specimens under quasi static load were tested to investigate their hysteretic behaviors. Five of them were designed with different depths, lengths and distances from column surface to examine their effects on failure mode, ultimate load, plastic rotation angle and ductility. One specimen with full welded connection acted as a counterpart. The test results show that the five RBS specimens have better ductility and larger capacity of consuming energy than traditional connections. The plastic rotation angles of the five RBS specimens exceeded 0.04rad, with ductility coefficient greater than 4.0，meeting the requirement for plastic rotation angles of 0.03rad and ductility coefficient of 4.0. As a comparison, the plastic rotation angle of the traditional connection was only 0.026rad, and the ductility coefficient was only 2.4. The main failure patterns of the five RBS specimens were lateral-torsional bulking (LTB) and crack in weld near beam-flange. It shows that RBS connection is effective to enhance the capacity of consuming energy for steel frame.