03.25: On the seismic behavior of the HBS and RBS moment connections

Abstract

ABSTRACTAfter the earthquakes of Northridge‐1994 and Kobe‐1995, the reduced beam section (RBS) connections were proposed to improve the seismic behavior of moment connections. Afterwards, some major problems like high construction cost, remarkable reduction of stiffness along with lateral torsional buckling observed in this new connection type. Therefore, some researches completed recently to eliminate these objections. One of the novel suggestions in this way is heat‐treated beam sections (HBS). To form HBS connection, a region of the beam flanges at a short distance from column face is exposed to high temperatures purposefully followed by slow cooling. As a result, bending plastic hinges develop within this weakened areas of flanges. In the present article, the seismic performance of frames with heat‐treated beam section connections is compared with respect to the reduced beam section (RBS) connections. To this aim, first, finite element models of HBS and RBS connections are verified based on a chosen experimental program. Then considering connection of the beams with tube, box and I‐shaped sections to a box column, a parametric study is done by analyzing the finite‐element models using a quasi‐static loading protocol. Finally, the cyclic behavior of the HBS and RBS connections are judged with respect to some structural parameters like strength, stiffness, energy dissipation and hysteretic curves. Regarding to the unchanged properties of HBS connections like elastic stiffness and cross section area, it is concluded that the obtained results will show the superiority of the HBS connections.