Cyclic seismic testing of steel moment connections reinforced with welded straight haunch

A simplified seismic design procedure as well as force transfer model for seismic steel moment connections using a welded straight haunch was recently proposed. As a follow-up study, cyclic seismic testing was conducted to verify the proposed procedure and to develop strategies that would prevent cracking at the haunch tip. All the specimens based on the proposed procedure effectively pushed the plastic hinging of the beam outside the haunch and developed satisfactory connection ductility with no fracture. A sloped edge combined with a drilled hole near the haunch tip, or a pair of stiffeners that partially or fully extended from the beam web, successfully prevented crack initiation at the haunch tip. The strut action of the haunch web, which had been predicted from the previous analytical study, was also identified through the strain gage readings in this experiment.