Aspects of Prediction Accuracy in Human-structure Interaction

Structures such as grandstands in stadia and office floors in buildings are typically occupied by seated persons, and it is a challenge to predict the dynamic characteristics of these structures. This is because the structures and the seated persons interact when the structures undergo vibrations, basically with the effect that the seated persons influence the dynamic system. The mechanism of the interaction is not well understood, and there are a number of factors that might influence the mechanism of the interaction. Through experiments with a vibrating floor carrying seated humans, the paper looks into the mechanism of the interaction focusing on its effect on dynamic structural properties. It is investigated to which extent factors such as posture of the seated persons and the construction type of the seat on which the persons are sitting have a bearing on the structural frequency and damping. This provides useful insight into the uncertainties and errors that may be involved with predicting these structural properties from simple analytical models not accounting for the factors considered in this paper. The paper describes the conditions for the tests, the modal identification procedures, the test programme, and the test results are discussed.