Evaluating steel structural damping ratio using the fisher rule and nonlinear mapping based on experimental data

It is well known that the damping ratio of a steel structural building is affected by many factors such as the structural natural frequency, material used, foundation type and building size. This paper presents a method to evaluate the damping ratio of a building structure based on experimental measurements of other buildings, by applying the Fisher rule and the nonlinear mapping theory (NLM). The experimental data come from observations of real full-scale buildings. Firstly, the Fisher rule is applied to determine the λ value of each influential factor. The factors which possess high values of λ construct an M-dimension data space, which is then mapped to a low (2) dimension space by making use of the Mahalanobis distance. In the lower space, the building damping ratio can be evaluated more easily. An example is provided to show the calculation procedure. © 2007 Taylor & Francis Group.