Experimental study of cyclic seismic behavior of steel moment connections reinforced with ribs

A simplified design procedure as well as load transfer model for rib-reinforced seismic steel moment connections was proposed recently. As a followup study, an experimental program was implemented to verify the proposed procedure and to develop schemes that would prevent cracking at the rib tip. All the specimens designed following the proposed procedure exhibited satisfactory levels of connection plastic rotation. A combined strategy of rib reinforcement plus slight trimming of the beam flange in the form of a radius cut pushed the plastic hinging and local buckling of the beam away from the rib tip and effectively reduced the cracking propensity at the rib tip. The strut action of the rib and resulting reverse shear in the beam web were also identified through the strain gage readings in this experiment.