An integrated approach for structural behavior characterization of the Gravina Bridge (Matera, Southern Italy)

Abstract

An integrated geophysical approach using non-invasive, non-destructive, and cost-effective seismic and electromagnetic techniques has been implemented to recognize the static and dynamic properties (i.e. eigenfrequencies, equivalent viscous damping factors, and related modal shapes) of the Gravina Bridge and its interaction with foundation soils. The “Gravina” is a bow-string bridge located on outcropping calcarenites in the city of Matera (Southern Italy) and develops for 144 m along a steel-concrete deck. The foundation soil characteristics have been evaluated by means of three high-resolution geo-electrical tomographies, one Vs velocity profile, and two site amplification functions. The main structural characteristics of the bridge have been estimated through permanent and on-demand monitoring using seismic and electromagnetic sensing. The former consisted of accelerometers and velocimeters installed with different geometrical arrangements for permanent earthquake and on-demand ambient vibration test recordings. The electromagnetic sensing was realized by a microwave radar interferometer placed below the deck to measure the displacements of the whole scenario illuminated by the antenna beam providing a continuous mapping of the static and dynamic displacements of the entire target. Acquired data have been analyzed in both frequency and time-frequency domain with the aim to study the stationary and non-stationary response of the monitored bridge. These experimental campaigns allowed us to assess the robustness of the proposed approach and to set up the zero-time reference point of the bridge dynamic parameters.

Damage Detection and Localization on Real Structures Subjected to Strong Motion Earthquakes Using the Curvature Evolution Method: The Navelli (Italy) Case Study

“…It is well known that the presence of damage on any type of structure is able to change the dynamic characteristics of the structural system. Several methods for damage detection are based on the evaluation of the variation of these characteristics, called modal parameters (frequency, mode shape, equivalent viscous damping) or non-modal parameters (e.g., operational deflection shapes) [18][19][20][21][22][23][24][25][26][27][28][29]. The presence of damage is detected by variations in these parameters in the damaged configuration compared to the reference state (undamaged) evaluated before the event (sometimes seconds before an event for continuously monitored structures).…”

Transport Infrastructure SHM Using Integrated SAR Data and On-Site Vibrational Acquisitions: “Ponte Della Musica–Armando Trovajoli” Case Study

“…The vibrational-based data (accelerometric and/or velocimetric data) provide information about the frequencies of structural vibration and their possible variation over time. Several studies demonstrate the possibility to use changing in modal characteristics of a monitored structure to detect damages and criticalities on both structural and non-structural components, see [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]). These in situ data have been provided by the Italian Civil Protection Department (DPC), through the Seismic Observatory of Structures (OSS) [24], a network of permanent seismic monitoring systems installed on public buildings, bridges and dams [25].…”