Long-term monitoring of wind-induced responses of a large-span roof structure

A long-term monitoring of the wind acceleration responses of the World Cup Stadiumʹs roof structure in Jeju-do, Korea was carried out. Modal properties were extracted from collected data using the system identification technique, and variations of modal properties associated with the change in temperature and vibration amplitude (wind speed) were examined. The investigation indicated that up to a 5% increase in the natural frequencies was accompanied by a 27.2 °C rise in temperature. It also indicated approximately 5% decreases in the natural frequencies and increases of more than twice the damping ratios with an increase in five times the vibration amplitude. In addition, the reliability of the natural frequency prediction for this type of structures using the current analytical technique was examined by comparing with measured natural frequencies. In the FE model, nonlinear effects caused by the geometric stiffness and stress stiffening were included. The analytical natural frequencies showed good agreement with the measured values within a difference of 5%. An analytical prediction of wind-induced responses of the structure was made based on the wind tunnel test results, the analytical natural frequencies and mode shapes, including the added mass effect. Predicted wind-induced responses showed reasonable match with the measured accelerations during typhoons and winter storms.