A six‐and‐a‐half‐year Experience with continuous Strain Monitoring on a prestressed Concrete Viaduct

Prestressed concrete bridges are common on the road networks, especially in Europe, where a significant proportion of them were built from the 1960‘ to 1980‘. Thus, they reach the usual lifetime of prestressed concrete structures and deserve specific diagnosis and maintenance [1]. Structural Health Monitoring (SHM) with measurements gathered continuously over long periods is an emerging and relevant tool to get a consistent knowledge of the effects of ageing and loads on civil structures [2]. In this contribution, a recent case study is presented on a large prestressed concrete highway viaduct located in the French Alps. The 21 spans of the box‐girder deck have been monitored with 44 long‐basis optical strand strain sensors, from January 2018 to June 2024, gathering high volumes of data, since each passage of a heavy vehicle has been recorded on all sensors with a sampling rate of 100 Hz. We focus on the data analysis process to get useful knowledge on the mechanical behavior of the bridge from the raw strain data, including statistical indicators and synthetic indices, spectral vibration analysis, and the reconstitution of a full image of the movements of the bridge for specific load events.