The Quay Walls of Amsterdam, Netherlands: An Approach for Collapse Risk Mitigation at the Municipal Scale Based on Multisource Monitoring and Surveying Data

The City of Amsterdam is responsible for the maintenance of 600 km of historic quay walls, most of which are over 100 years old while others are 300 years old and are experiencing stability and degradation problems. A lack of knowledge about the as-built information and the current conditions of the retaining structures and their foundation systems exists, and very limited guidelines for the assessment of quay walls are available. Predicting the time when the quay walls are no longer safe is a key challenge in their end-of-life assessment. For this purpose, monitoring of the quay walls via conventional techniques (e.g., in situ surveys, topographic levelling and tachymetry) combined with satellite Multi-temporal Interferometric Synthetic Aperture Radar (MT-InSAR) data provides updated information on the displacements affecting the retaining structures and/or their foundations. This paper develops a multiscale methodology, consisting of three phases, that allow (1) the prioritization of the most exposed retaining structures (quay walls) at the municipal scale, (2) the retrieval of empirical relationships between different damage/movement indicators and quantitative displacement descriptors obtained via in situ surveys and terrestrial monitoring data, and (3) the identification of the most probable collapse mechanism by jointly analyzing the wall crack patterns and monitoring data. The results show that this approach could play a fundamental role to set up sustainable risk mitigation strategies at the municipal scale.