Vibration design criterion for wood floors exposed to normal human activities

Annoying vibration for occupant-induced footfalls is a serviceability limit state that must be considered in the design of structures, including resid ential wood floors. Recently proposed design methods addressing excessive f loor vibrations require knowledge of the dynamic characteristics of the flo or system, such as the fundamental frequency or the root-mean-square accele ration (a(rms)). A finite-element approach was utilized to model wood floor systems under dynamic loads resulting from normal human activities, and de sign curves relating a(rms) to floor fundamental frequency and mass are pro posed. Predicted behavior from the design curves was compared with behavior observed from an experimental study and the two sets of results were found to be in close agreement. From the results, it is concluded that current v ibration criteria based upon static properties or fundamental frequency are inadequate for preventing undesirable floor vibration. To obtain an accept able value of a(rms) for a floor, it is shown that a stiffer floor with a h igher fundamental frequency is required. It is also concluded that a proper floor design may be achieved through the use of the proposed design curves .