Modal Tests and Model Updating for Vibration Analysis of Temporary Grandstand

Temporary grandstands are subjected to dynamic loading due to the movement of spectators, and problems associated with the excessive vibration of these structures have been observed. In this context, since they can be used during design stage to address sueh problems, reliable finite element models of the structure are needed. In this paper, a finite element model of a temporary grandstand is developed while modeling effects are investigated. To do that, a temporary grandstand for about one hundred people was assembled in a laboratory. Modal tests were conducted to calibrate the numerical models of the whole structure. These models were developed by using various degrees of refinement in order to allow comparing the effect of modeling simplifications. The results evidenced that the modeling of connections and seat planks caused significant changes in natural frequencies. The complexity of the structure, with a significant number of parameters affecting dynamic behaviour, requires that modeling ideally start from individual structural components tested in separate.