Vibration Performance of Lightweight Floor Systems Supported by Cold-formed Steel Joists

A study investigating dynamic characteristics of full-scale floor systems was performed for several laboratory-constructed and in situ floors. Floors were constructed with cold-formed steel joists and designed for residential mid-rise applications. Typical construction details including span, subfloor, topping, strongback and framing condition were varied, and their influence on fundamental frequency, damping ratio and deflection at mid-span compared. Changes in construction details which significantly increased floor mass, regardless of added stiffness, were found to lower the fundamental frequency. Adding a strongback with restrained ends provided a significant increase in fundamental frequency, stiffness and damping ratio. Laboratory tested floor systems were generally found to be the worst-case scenario for natural frequency and damping ratio