Retrofitting of Moment Connection of I-Beam to Double-I built-up Column using Vertical Stiffeners

Double-I-built-up columns are used in most of existing steel moment frames. The traditional moment connection of I-beam to these columns is made using flange plates. Due to flexibility of column cover plate, these connections behave as partially restrained, semi-rigid and brittle connections. Vertical stiffeners are proposed for upgrading the connection.
To compare the behavior of the connection before and after upgrading, non-linear finite element models of one-sided sub-assemblage is being analyzed under cyclic loading. Hysteretic moment-rotation curves and stress and strain contours of traditional and retrofitted models were compared. The results show that, vertical stiffeners modify the force transferring mechanism and reduce the deformation of column cover plate, which improve connection behavior considerably.