Seismic and Vibration Performance Rehabilitation for an Industrial Steel Building

A rehabilitation plan is presented for a two-story industrial steel structure in Iran. The building was found to have unsatisfactory performance: The first-floor two-way composite slab was prone to uncontrollable vibrations during normal operation (forklift vehicles), and the lateral load resisting system did not comply with current seismic code provisions. Notably, a recent vibration rehabilitation attempt applied to an almost identical structure had added columns and struts of nearly 120 tons of steel with little improvement. To resolve this twofold problem while respecting the minimum disruption requirement for a facility that operates nearly 24/7 and the height/width clearance restrictions due to existing industrial machinery and vehicle traffic, a combined rehabilitation scheme was proposed that involved: (1) keeping the extra columns of the failed rehabilitation scheme, (2) stiffening the joists, (3) adopting toggle-brace dampers in the main girders, and (4) strengthening the existing lateral X-braces and their connections. (c) 2020 American Society of Civil Engineers.