Operational Modal Analysis of the Grenland Bridge Using Wireless Accelerometers and One day of Measurement Data

A wireless monitoring system consisting of 20 triaxial accelerometers was mounted on the existing Grenland Bridge to characterize its dynamic behaviour. The system was mounted with short-term operation in mind and was planned for swift installation and dismantling, to minimize the interference with traffic and other operations on the bridge. The agile and simple installation ensured that all operations on site related to the monitoring system could be conducted without any additional closure of the bridge and with no interference with other planned tasks on the bridge (e.g., electrical maintenance, asphalting, inspections). The outcome of the campaign was one day of synchronized data that was used for automized operational modal analysis, to yield estimates of the probabilistic properties of the critical damping ratios.