Abstract
Natural causes and high-speed train load will result in the structural deformation of long-span bridges, which greatly influence the safety operation of high-speed railway. Hence it is necessary to conduct the deformation monitoring and regular status assessment for long-span bridges. However for some traditional surveying technique, e.g. control-point-based surveying techniques, a lot of human and material resources are needed to perform the long-term monitoring for the whole bridge. In this study we detected the long-term bridge deformation time-series by persistent scatterer interferometric synthetic aperture radar (PSInSAR) technique using the high-resolution SAR images and external digital elevation model. A test area in Nanjing city in China is chosen and TerraSAR-X images and Tandem-X for this area have been used. There is the Dashengguan bridge in high speed railway in this area as study object to evaluate this method. Experiment results indicate that the proposed method can effectively extract the long-term deformation of long-span high-speed railway bridge with higher accuracy.
Highlights
Long-span bridges have complicated structure so that the safe operation of the bridges is sensitive to small deformations
21 interferometric pairs formed by 14 TSX images are used to detect persistent scatterers (PSs)
If the correlation coefficient of a pixel is more than the threshold, it is selected as a PS point
Summary
Long-span bridges have complicated structure so that the safe operation of the bridges is sensitive to small deformations. The deformation monitoring of long-span bridges needs high accuracy. Typical methods for the deformation monitoring are traditional engineering surveying techniques, methods using physical sensors and GPS surveying techniques. By these techniques, the absolute deformation information in local parts of bridges can be obtained. The absolute deformation information in local parts of bridges can be obtained These techniques need amount of manpower and material resources, and are performed by some control points so that it is difficult to achieve the deformation information for the whole bridge. Interferometric Synthetic Aperture (InSAR) technique has been often applied (Ferretti et al 2001, Berardino et al 2002, Lanari et al 2004, Hooper et al 2007, Liu et al 2009, Masahiro et al 2010, Zhang et al 2011, Ferretti et al 2011, Wang et al 2012) to solving these issues, because it can detect the deformation information for the whole target areas, and has high measurement accuracy and automatic degree, and few
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