Seismic Performance of Connections for Cellular Beams in Steel Moment Frames: Fid-Bau Portal

Seismic Performance of Connections for Cellular Beams in Steel Moment Frames

Smoke, R. P. / Dinehart, D. W. / Gross, S. P. / Yost, J. R.

Prior to the 1994 Northridge earthquake in California, steel moment frame buildings were thought to perform well under seismic loading conditions. Though none fully collapsed, over 200 buildings with steel moment frames as their primary lateral force resisting system experienced brittle fractures within column to beam connection elements. These fractures were typically initiated at the column-beam flange welds and many propagated into column faces creating an extremely hazardous, weakened condition. Much research has been conducted in order to better understand the behavior of steel moment frames, as well as to develop new connection types that demonstrate adequate structural performance under seismic loading conditions. Prior research suggests that cellular beams may perform well under such conditions due to inelastic deformation developed in the beam web away from the column face; however, no explicit testing has been conducted. The primary goal of this study is to gain an understanding of the behavior of steel moment frame connections using cellular beams. Presented herein is a preliminary finite element analysis demonstrating the adequate performance of a cellular beam connection subjected to cyclic load, as well as a proposed testing program which will be used to verify the analytical results. Both analytical modeling methods and full scale testing of beam to column connection assemblages are to be employed to demonstrate that such beams exhibit sufficient strength, ductility, and stable failure mechanisms under seismic loading. Ultimately, an AISC prequalified connection is desired to enable widespread use of cellular beams in steel moment frame construction in areas of high seismicity.