Assessing Displacement Estimation from Velocity vs. Acceleration: Effectiveness and Limitations for SHM Applications

Accurate displacement measurements are critical for the health monitoring of civil structures. Displacement time series can be retrieved in many ways, such as via time integration of acceleration or velocity series. These integration processes, however, are known to be susceptible to significant inaccuracies, since time integration amplifies noise and baseline drift, leading to cumulative errors. Various procedures and data processing algorithms can be used to mitigate such errors. In this context, a research project was initiated with the aim of analysing some of the aforementioned approaches, using experimental data retrieved from tests performed on full-scale structural components, to show potential and criticalities of different data processing techniques. Specifically, tests were performed on reinforced concrete beams instrumented with co-located accelerometers, velocity seismometers, and displacement transducers, and subjected to different loading protocols. During tests, sensors recorded the complete transient response, which served to assess the methodologies used to obtain displacement from time integration of acceleration or velocity. This work presents preliminary results of the aforementioned investigation. Discussions are provided on the comparison between displacement values measured by displacement transducers and those obtained by time integrations, considering effectiveness as well as limits of the adopted sensors and data processing approaches. Preliminary findings provide a basis and may offer some guidance on improvements required for achieving reliable displacement-based monitoring procedures.