Vibration behaviour of steel-timber composite floors, part (2): Evaluation of human-induced vibrations

Abstract

The vibration of lightweight floors under service loads may cause annoyance to the occupants of buildings, particularly when the fundamental natural frequency of the floor is close to the range of frequencies 4–8 Hz to which the human body is sensitive. Accordingly, the vibration response of the floors is a governing factor in the structural design of steel-timber composite (STC) flooring systems, which have been proposed as an innovative alternative to conventional steel-concrete floors. The current study is part-2 of a comprehensive experimental and numerical study on serviceability performance of the STC floors under human-induced excitations. Natural frequencies are often used as measure of the acceptable vibration performance of the floors. Accordingly, the finite-element (FE) models calibrated and validated against the experimental results in part-1 are used to predict the natural frequencies of the typical STC floors with medium to long spans, and the effect of the geometry of the floor, the mechanical properties of the connections and the magnitude of superimposed loads on the natural frequencies of the STC floors are investigated through a paramtric study. In addition, dynamic analyses are carried out to predict the vibration response (i.e. displacements, velocities and accelerations) of the STC floors, developed in the parametric study, subject to human activities and the vibration performance of the floors with respect to acceptability criteria derived from various building codes is assessed. Lastly, some floor design recommendations are made to ensure satisfactory performance of the STC floors under human-induced vibrations according to the existing building codes.