Comparison of Long-Term and Ad-Hoc Monitoring Systems for System Identification in Structural Health Monitoring

The rapid development of new monitoring technologies in recent years is crucial for the wider implementation of Structural Health Monitoring (SHM), especially given the deteriorating condition of many bridges worldwide. This study contributes to this field by comparing a permanent long-term monitoring system and an ad-hoc monitoring system applied to a newly constructed steel arch bridge with a main span of 48.8 m and an arch height of 8 m. The bridge is equipped with several strain gauges used for continuous monitoring. In parallel with the permanent system, the ad-hoc monitoring system was deployed for a short-term, multichannel measurement campaign, during which Operational Modal Analysis (OMA) was performed using recorded accelerations. Natural frequencies obtained from both systems were compared to evaluate the effectiveness of each approach for system identification. The study highlights the advantages and limitations of long-term and ad-hoc monitoring and provides recommendations for optimal application in future SHM practice.