SHM deployments for two bridge structures: Assessing potential value

An approach for assessing the value of a structural health monitoring (SHM) system for a bridge prior to deployment has been developed. The methodology systematically obtains the views of three key stakeholders in bridge SHM management: the asset owner, the structural engineer and the SHM engineer.
The output of the methodology is a numerical value that indicates the approximate likelihood of a SHM system generating value for an asset owner. This paper applies this framework to two structures which span the River Thames in Central London, UK. The first structure is a 434 m long concrete, two-way road and footbridge, with a superstructure primarily comprising a concrete deck and two reinforced concrete box girders. In 2017, the bridge was the subject of a year-long monitoring programme which collected thermal and movement data to help refine structural models and inform maintenance repairs. The second structure consists of a pair of cable-stayed footbridges which are built on either side of an existing rail bridge. Each bridge deck is 300 m in length and is suspended from steel rods known as deck stays, made up of over 4 km of cable.
Initially, there were no prior notions about what system should be implemented, but after discussions with the asset owner, a system to monitor the tension in the cables is considered. From the resulting discussions, the retrospective application of the framework resulted in a value-rating (VR) of 3.8, whilst the second structure received a rating of 3.4. A detailed discussion on value monitoring from industry experts is presented.