Facile Retrofit of Shear Tab Connections for Enhanced Lateral Resistance of Steel Gravity Frames

Abstract

A facile and effective method for retrofitting simple shear tab connections in a steel gravity frame is presented to improve its overall lateral force-resisting capacity. At a target shear tab connection, the existing gap between the beam flange and column face is snugly filled with a tapered steel plate, which is then field-attached to the column face. When a steel gravity frame is subjected to lateral loads (due to, for example, earthquake and strong wind), the retrofitted shear tab connection deforms and promptly engages the beam to bind the column via the filler plate, thereby exerting a horizontal thrust to the column at the retrofitted beam flange level. Hence, the moment arm between horizontal reactions increases and so does the flexural capacity of the connection. Numerical results from detailed finite-element analysis confirm the role of beam binding action enabled by the present method in satisfactorily enhancing both the strength and stiffness of shear tab connections as a gravity frame deforms laterally.