Wind-induced response of a large cantilevered roof

Abstract

The subject of this study is to clarify aerodynamic properties of a large cantilevered roof. We conducted free vibration experiments in order to investigate effects of various parameters such as mass, pitch angle, and damping ratio to wind-induced vibration of the roof. In the experiments, we have found that the roof hardly vibrated at its natural frequency until a certain critical wind velocity, then a flutter-like vibration occurred and a sharp peak at frequency lower than the natural frequency appeared in a spectrum of the vibration. In the light of forced oscillation experiments, the frequency of the sharp peak was the natural frequency of the roof lowered by the positive aerodynamic stiffness. The lowered natural frequency synchronized with the frequency of the vortex shedding from the leading edge of the roof, which causes a negative damping effect of unsteady wind force.