Modern structures like high-rise buildings, suspension bridges and offshore windmill turbines are becoming more flexible and their lifetime is typically governed by structural vibrations caused by external forces which lead to metal fatigue. During the design of these structures the lifetime is assessed based on statistical models that are rarely validated. By measuring the vibrations of these structures, a more accurate state of health may be obtained. The work in the PhD project proposed and demonstrated a set of tools that may be useful within this field