Vibration-based global long-term monitoring of the Maintalbrücke Gemünden using SSDD and numerical FE simulations

This contribution presents the implementation and evaluation of vibration-based structural health monitoring on the Maintalbrücke Gemünden, a semi-integral 299-meter-long reinforced concrete frame bridge located along the high-speed railway between Hannover and Würzburg in Germany. The monitoring concept is based on the Stochastic Subspace-based Damage Detection (SSDD) method, facilitating long-term and global surveillance of the load-carrying structure. Ambient vibration measurements are continuously recorded, supplemented by controlled load tests, to capture structural changes over time, including the effects of environmental factors such as temperature. To complement the bridge's real-world monitoring, a detailed finite element (FE) model of the structure was developed. Numerical SSDD analyses on this model enable investigation of potential causes for observed changes in the bridge’s global dynamic response. By simulating different scenarios and adjusting model parameters, it is possible to assess the influence of damage, sensor configurations, or external effects on the monitoring outcomes. This parallel approach allows the interpretation of measured data in light of physically plausible mechanisms identified in the simulations. The presented methodology supports a shift from conventional fixed-interval inspections toward predictive maintenance strategies, with data-driven intervention planning based on objective structural condition assessments. The combined use of SSDD for both empirical and simulation-based studies demonstrates high sensitivity to damage and provides valuable insight for the long-term stewardship of critical infrastructure.