Vibration Performance of Lightweight Cold-Formed Steel Floors.

A study investigating the modal properties and dynamic response of several laboratory-constructed and in situ floors supported with cold-formed steel C-shaped joists for floors was conducted. The tested floors were typical of residential midrise applications, with oriented-strand board, FORTACRETE, and cold-formed steel deck subfloors, both with and without lightweight concrete topping. Details including span, large lip-reinforced web openings, subfloor, topping, strongback, and framing condition were varied to observe their influence on the fundamental frequency, damping ratio, and deflection. Suggestions for the design and remediation of floors where vibration serviceability is a concern are given. Laboratory tested floor systems were generally found to be the worst-case scenario for the natural frequency and damping ratio. Furniture and finishes were found to not appreciably change the performance of a floor system. The responses of the floor systems tested in this study were evaluated against the ISO 2631 limit for maximum acceleration and Onysko’s static deflection limit, as presented in ATC Design Guide 1: Minimizing Floor Vibration. The in situ floors examined were found to have performed within the acceptable range, as defined by the two criteria. [ABSTRACT FROM AUTHOR]