Smart Monitoring by Fiber-Optic Sensors of Strain and Temperature of a Concrete Double Arch Dam

Abstract

Concrete arch dams are large constructions aimed at producing hydro-electricity, providing water for irrigation and controlling flooding. Since concrete dams in Italy are quite old-fashioned structures, it is a challenge to properly evaluate their conditions, manage maintenance interventions and optimize energy production for a more sustainable development. Traditional field monitoring carried out through visual inspections, topographical measurements and point sensors is complex and gives only discontinued spatial information. Recently, numerous innovative techniques have progressed greatly, and, among these, the use of Distributed Optical Fiber Sensors (DFOS) as detector of strain and temperature can be considered an attractive option, as it allows spatially dense measurements over large distances and with high resolution. To estimate the reliability and potentiality of this innovative system in monitoring the extremely low strains sustained by dams, a concrete double arch dam, namely the Ponte Cola dam in North Italy, was recently instrumented with two different types of DFOS (one for strain and one for temperature measurement) both in the foundation and along the crown of the dam. Several measurement campaigns were carried out and the data collected are briefly presented in this paper and are compared with those obtained through traditional monitoring techniques.