Residential Floor Failures from Dynamic Occupant Loading

Abstract

Dynamic occupant action amplifies demands on structures compared to static loads and is often neglected in design. This paper focuses on 15 light-frame floor collapses caused by dynamic amplification of occupant loads, specifically rhythmic movements of jumping, dancing, and bouncing. This study investigates the increase in floor collapse cases due to occupant loadings near college campuses, their implications, and makes recommendations to reduce future collapse risk. Of the 15 cases studied herein, most failures occurred in multifamily structures within 1.6 km (1 mi) of a university in the East United States. All were determined by investigators and local building or city officials to be a result of dynamic occupancy overloads. Nine of the 15 (60%) overloaded floors were framed using metal-plate connected wood trusses. It is recommended that engineers elect to design multifamily structures in close proximity to universities above code live load minimums to counteract probable dynamic overload from gatherings.