On the rise in the U.S., residential floor collapse is associated with large gatherings in a single common space, overloading the flooring system. This can cause serious injury with people falling up to 10 feet, and in extreme cases “pancaking” failure, where several floors collapse due to the impact load. Dynamic occupant loads, such as rhythmic movements from dancing, jumping or bouncing, can exert higher forces on a structure.

Most floor systems are designed to carry a static crowd weight. Researchers M. A. Broers, A.M.ASCE; D. A. Bender, M.ASCE; F. E. Woeste; and A. R. Phillips, A.M.ASCE, investigated 15 cases of floor collapse to determine the effect of dynamic occupant load. Their research, “Residential Floor Failures from Dynamic Occupant Loading” in the Journal of Performance of Constructed Facilities, analyzed the case reports to determine common threads of collapses, including type of floor system, type of structure, movement of occupants, and geographic location of failures.

Learn more about their study and their recommendations for best design practices and future research to mitigate residential floor collapse, in the abstract below or by reading the full paper in the ASCE Library: https://ascelibrary.org/doi/10.1061/(ASCE)CF.1943-5509.0001581    


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.

Read the full paper in the ASCE Library: https://ascelibrary.org/doi/10.1061/(ASCE)CF.1943-5509.0001581