Design and implementation of a monitoring system applied to a long-span prestressed concrete bridge

Currently long-term monitoring systems are mandatory in major civil engineering structures like bridges, tunnels and dams. Generally, they monitor a set of physical, chemical and mechanical parameters in critical sections of the structure by incorporating appropriated sensors. The set of collected data demonstrates great potential in the prevention of damage and contributes to a more efficient maintenance of the monitored structures. This work presents the long-term monitoring system installed in the new Lezíria Bridge over the Tagus River in Portugal. The system was developed to control some aspects of the construction process and to survey the service life of the structure. A set of structural, durability and environmental parameters defining the bridge condition are remotely assessed in real time via a fiber optic network. Aspects like architecture, installation and functionalities of the monitoring system are discussed and the innovative aspects of the implementation are highlighted. In this context, the main goal of this work is to present the long-term monitoring system of the Lezíria Bridge, sharing the experiences, the solutions and the procedures adopted, given their potential usefulness in the implementation of similar projects.