Periodic Characteristics of Environmental Effects on Modal Frequencies of a Cable stayed Bridge

Abstract:

Based on a 5 year field measurement data from the structural health monitoring system and the toll gate of Donghai Bridge (DHB), this study focuses on the dependency of the structural frequencies, including the first vertical/lateral bending modes as well as the higher modes, on the temperature and traffic loading in the prospect of periodic characteristics. The environmental effects on the frequency variation are compared by the stepwise regression analysis on such dominating periods as 1 year, 1 week, 1 day and 0.5 day. Results of this study show that the variations of temperature, traffics and modal frequencies have some long period components, and the relative importance of temperature and traffics is different for each individual period. Based on the long term field measurement data, the analysis herein can advance the understanding on the periodic variation of structural frequencies, and may lead to more reliable assessment of structural conditions.