El monitoreo estructural garantiza que el Forth Road Bridge está en buena forma
Gigabytes of data are pouring off Scotland’s Forth Road Bridge (FRB) every day. The information is automatically collected, processed and analysed to help maintenance contractor Amey manage the A9000 trunk road across the Firth of Forth.
The data comes from 500 sensors installed on the suspension bridge. They monitor, among other things, temperature, wind speed, vehicle load and displacement, giving insight into its structural health and whether the road is safe for the public to use (New Civil Engineer July 2017).
The first set of these was initially required to monitor the behaviour of the bridge following the discovery of a fractured steel member, known as the truss-end link, in 2015. Initially, temporary splints were applied to the link, and seven similar ones. This was then followed by permanent structural repair to support the new truss-end post off brackets fixed to the towers (New Civil Engineer December 2016). The problem had been that a pin had seized up, causing large forces to pass through the original “link” member, causing the fracture. Access steelwork for the last of the truss-end arrangements was due to be completed in November as this issue went to press.
Instrumentation and sensors on the eight new truss-end posts at tower locations (see diagram) measure stress, bearing load, bearing wear and truss-end movement. They demonstrate that this solution is working as it should be. Sensors have also been placed on four similar details near the bridge’s side towers as well as on other key members to give the contractor a full picture of the bridge’s condition.