Structural Health Monitoring of a Wooden Mast Structure Based on OMA Techniques

Structural Health Monitoring (SHM) using OMA techniques utilizes the dynamic characteristics, as indicators of the health state of the monitored structure. In fact, changes in these dynamic properties can reflect either a potential degradation of the structural integrity or a change in the environmental conditions (e.g., temperature, humidity, etc.). Therefore, to apply a successful SHM approach to the monitored structures, the damage detection technique must identify and clearly separate the different sources of changes in the monitored dynamic properties. In this context, the present study aims to detect structural changes in a structure exposed to ambient vibrations and varying environmental conditions. The investigated structure consists of a wooden mast and a steel frame topside that is clamped to a concrete block at the bottom. In the monitoring campaign of the wooden mast, the vibration responses are collected by means of a measurement system whose sensors are placed at strategic locations on the topside, whereas the environmental conditions are recorded by a nearby weather station. The collected data is utilized to (i) estimate the environmental conditions; (ii) remove their influence from the estimated modal parameters, and finally (iii) detect structural changes induced by damages added with different severities to the mast.