Spectral analysis of sensor data in civil engineering structures

A system identification procedure is developed for processing structural response signals registered by sensors permanently installed for monitoring at critical locations of a structure. The procedure, which is based on spectrogram estimation and is applied within a sweeping window of signal samples, was built into a data processing software that allows the determination of the fundamental frequencies of vibrating structural members and can be used to identify the changing properties of instrumented structural systems through time. Field data obtained from strain sensors on a specialized bridge deck structural system that spans the Salmon River in Nova Scotia, Canada were used as case study for evaluating the performance of the proposed method. Successful correlation was obtained between theoretical and observed vibration characteristics, whereas several important features of the actual function of various bridge members were revealed through the analysis procedure.