Identifying the Frequencies of a Twin Steel Box Girder Viaduct By GPS Monitoring

摘要

The need to monitor bridge performance has been brought to mind with the recent bridge collapse in the United States in August 2007. With aging infrastructure and many bridges carrying loads that are far greater than predicted during their design, this has increased the need to monitor the performance of bridges. The knowledge of the resonant frequencies of a bridge is very important to bridge/civil engineers. These values are usually computed at the design stage using Finite Element Analysis (FEA). Changes in these frequencies over the lifespan of the bridge may indicate defects in the bridge structure. The use of GPS to monitor the deflection of bridges has been an ongoing research focus at the Universities of Nottingham and Brunel for about a decade [Ashkenazi et al, 1996], [Ashkenazi et al, 1997]. The work has focused on suspension bridges, and usually those whose movements are in the decimetre to metre range, such as the Humber [Brown et al, 1999] and Forth Road Bridges [Roberts et al, 2006a], as well as the London Millennium Bridge that saw magnitudes in the order of centimetres [Roberts et al, 2006b].