Modal identification of a box girder bridge using optimally selected measured data from ambient vibration testing

In Colombia, construction projects for fourth generation (4G) roads are currently being developed on a large scale. For topographical and economic reasons, bridges in this kind of projects tend to be increasingly long, with high intermediate supports, and located mainly in intermediate and high seismic hazard zones. This article presents the modal identification results obtained in the Gomez Ortiz bridge using data measurements collected from ambient excitation sources. This bridge corresponds to a box girder bridge type and is located on Giron-Zapatoca road, in the department of Santander, Colombia. In the present study, an optimal sensor localization algorithm and a modal identification method previously developed and applied in several modal identification studies of bridges of different configurations are implemented. The results displayed in this article using a limited number of sensors show good correlation with the results used in the calibration of the numerical model of the previously developed bridge and that corresponds to the baseline of the bridge.