Monitoring of Environmental Effects on Modal Estimates of Large Structures

This paper aims at describing some applications recently developed by the Laboratory of Vibrations and Structural Monitoring (www.fe.up.pt/vibest) of FEUP in which an accurate monitoring of the effects of environmental factors on modal frequency estimates was continuously performed, and appropriate statistical techniques were employed to remove or mitigate such effects, enabling a correct vibration based damage detection approach. The monitored structures are the Infante D. Henrique Bridge, the Pedro e Inês and the FEUP stress-ribbon footbridges, and the suspension cable roof of Braga stadium. The paper focuses on the effects of temperature on modal parameters.