Temperature-based structural identification of long-span bridges using InSAR observation and meteorological shared data

Abstract

The Interferometric Synthetic Aperture Radar (InSAR) technology can be used for the health monitoring of long-span bridges, capable of measuring bridge deformations with millimeter-level precision. It is particularly effective for monitoring long-period temperature-induced deformations, providing valuable insights into abnormal changes in structural properties. However, few studies have focused on evaluating the condition of in-service bridges based on obtained deformations. Therefore, this paper adopts a temperature-based structural identification (TBSI) theory combined with InSAR technology for damage diagnosis in bridge regions. On this basis, the bridge structural temperature calculated from meteorological shared data and the displacement obtained through InSAR technology are used as the input and output, respectively, followed by an updated finite element model (FEM) of the bridge established for thermal-structural coupling analysis. The Differential Evolution (DE) algorithm is then applied to identify regions with abnormal thermal expansion coefficients, facilitating the localization and quantification of bridge damage. A case study of a long-span suspension bridge exemplifies the application of the proposed method, validating its accuracy in identifying assumed damaged regions and reflecting the structural health status, with damage quantification errors within 5%. This method provides an effective approach for the lightweight monitoring of bridge health.