Seismic retrofit of riveted stiffened seat angle connections

Typical riveted stiffened seat angle connections taken from an 83 years old building were tested to investigate the actual hysteretic behavior and potential moment resistance of these connections and how they could be efficiently retrofitted with a minimum amount of structural modifications. This study shows that, in their as-is condition, these existing connections can develop a considerable moment resistance, but their pinched hysteretic curves indicate they have a relatively low energy dissipation capability. Therefore, two retrofitting schemes are proposed (ductile knee-braces and a 'selective welding' approach) and experimentally demonstrated to be effective.