Measurement of Quasi-static and Dynamic Displacements of Footbridges Using the Composite Instrument of Smartstation and Accelerometer: Case Studies

Dynamic response monitoring of bridge structures has received considerable attention. It is important to synchronously measure both quasi-static and dynamic displacements of bridge structures. However, traditional accelerometer method cannot capture quasi-static displacement component although it can detect dynamic displacement component. To this end, a novel composite instrument of smartstation was proposed to monitor vibration displacements of footbridges. Full-scale experiments were conducted on a footbridge to validate the feasibility of the composite instrument-based monitoring method. Chebyshev filter and wavelet algorithms were developed to process the composite instrument measurements. Conclusions were drawn that the measurement noise of the composite instrument mainly distributed in a frequency range of 0 - 0.1 Hz. In two case studies with displacement peaks of 5.7 - 10.0 mm and 1.3 to 2.5 mm, the composite instrument accurately identified their quasi-static and dynamic displacements. The composite instrument will be a potential tool for structural dynamic monitoring with the enhancement of its overall performance.