Development of a stand-alone vibration measurement system for bridge monitoring

The quality assurance of timber bridges is currently ensured mainly manually by regular visual inspections over the entire life cycle. To reduce this (cost) effort, the possibility of continuously recording the condition of bridges through monitoring is being investigated. This would also increase the confidence in the long-term load-bearing capacity of timber bridges among planners and public. In addition to the permanent recording of the wood moisture content, conclusions can also be drawn about the condition and even possible damage by recording the natural frequencies which depends on the stiffness. For this purpose, a stand-alone vibration measurement and evaluation system was developed, which is easy to handle and suitable for long-term monitoring due to its energy efficiency. Beside a first application on a low-traffic timber bridge for several months, the system was validated with investigations on various types of artificial damages on the natural frequency of timber components.