Vibration frequencies of woodframe residential construction

Different methods of vibration measurement, such as ambient and forced vibration techniques, have been used in existing woodframe houses to determine fundamental frequency, but because of the highly nonlinear nature of this type of structural system, the reported results vary significantly. This paper discusses some of the differences of frequency values observed in various experimental studies, and identifies the source of these differences by relating the measured fundamental period to the level of shaking. The experimental results from different full-scale tests of woodframe houses and single wood shear walls are used in this paper to gain an improved understanding of the dynamic characteristics of this type of construction and to help explain the differences in results from ambient and forced vibration techniques. A simple equation to estimate forced vibration periods from ambient vibration periods is presented, and its possible application in engineering practice is discussed.