Details:
The alluvial event of Scrivia stream in November 2002 caused the undermining and consequent failure of a central pier (P3) of the bridge of the provincial road SP140 that connects Arquata Scrivia with Vignole Borbera. Due to the serious injuries caused to the protected building, the demolition and subsequent faithful reconstruction of the central pier and of the arches under it, after consolidation of the adjacent piers P2 and P4 by means of tying, has been planned.
For the execution of these works in safety, given the conditions of high danger of collapse of the arches, it was necessary to monitor the structural stability. Therefore, were installed inside the piers adjacent to the P3 two 2D DMS columns with a length of 6 m each in order to monitor in continuous and in real time the two vertical between -1 and -7 m from the driveway. The control unit provided for the management of the alarm thresholds with automatic triggering of an acoustic warning device in case of exceeding the threshold values for the alert of the workers operating near the bridge. The stability monitoring so implemented allowed to work on the instable artifact, guaranteeing workers and technicians to operate in safety.