Enhancing urban resilience through Tomo-PSInSAR-based structural health monitoring

Structural health monitoring (SHM) is crucial for aging buildings, especially in areas with frequent seismic activities, but the cost is often prohibitive for most private property owners. This study explores the feasibility of large-scale SHM using tomographic persistent-scatterer interferometric synthetic aperture radar (Tomo-PSInSAR) within an urban planning context. By applying Tomo-PSInSAR to TerraSAR-X/TanDEM-X data over the Taipei Basin, a workflow is developed to assess building settlement and tilt rates. The analysis identifies 11.6% of building polygons as eligible for SHM, with 10.8% of these showing anomalous deformation. Peak settlement and tilting rates reach −14 mm/yr and 1/760 yr−1, respectively. Among buildings within urban regeneration plans, 9.4% are eligible for analysis, with 11.9% of them exhibiting deformation anomalies. Building age and soil properties partially explain variability in deformation anomalies, but additional factors are needed to fully account for it. For instance, the high deformation anomalies observed in buildings aged 30–50 years may be attributed to poor construction quality and the use of inadequate materials, such as sea sand in concrete. Several key factors affecting SAR-based SHM performance are identified: insufficient scatterers, uneven scatterer spatial distribution, the absence or geometric inaccuracy of building polygons, and missing age information. These limitations can be addressed through integrating SAR data from multiple viewing geometries, increasing acquisitions, and developing closer collaboration with government agencies.