The work will be carried out using an unmanned DJI Matrice 350 RTK aircraft equipped with LiDAR technology and an RGB camera. The flights will produce a high-density three-dimensional point cloud and extensive photographic documentation, which technicians will use to create a georeferenced digital model of the entire bridge and its abutments.
The analysis will assess the condition of the stonework, structural cracks, the presence of vegetation and possible scouring around the piers. Erosion, wear and the detachment of stone blocks from the left abutment will also be examined, with the aim of obtaining an accurate diagnosis for the preliminary plans for comprehensive rehabilitation.
IN-DEPTH INSPECTION AHEAD OF THE PILAR FESTIVITIES
To ensure safety during the flights, the Stone Bridge will be closed to vehicular and pedestrian traffic this Wednesday, September 30, between 10:00 a.m. and 5:00 p.m. A safety perimeter will also be established along the Paseo de Echegaray y Caballero, the Paseo de la Ribera and the banks of the Ebro beneath the structure. If weather conditions prevent the flights from taking place, alternative dates will be arranged.
Zaragoza City Council has scheduled the operation before the Pilar festivities, as the stalls and decorative elements installed on the bridge during those days would make it difficult to collect accurate data using LiDAR technology. As the bridge is listed as an Asset of Cultural Interest (BIC), the future project must also address issues such as mobility in the surrounding area and improvements to the ornamental lighting.
The inspection will also focus on common and pallid swifts nesting in cracks in the stonework. A map of the existing nests will be drawn up, along with an appendix detailing the protection measures to be applied during future works. The technical assistance contract for drafting the preliminary plans has a four-month deadline, while the future rehabilitation has initially been valued at approximately 750,000 euros, including VAT.
