Corroded cables on Forth road bridge

FORTH Road Bridge chiefs have called for the installation of a £2m testing system to monitor corrosion in the structure’s main support cables after the discovery of broken wires.

The bridge’s manager, Alastair Andrew, said consultants suggested fitting an acoustic monitoring system of a type used on several similar bridges in the US.

The system is designed to help work out the extent and rate of deterioration and could be installed by the summer.

He admitted there seemed to be an "accelerated rate of corrosion" in the main cable and said one section of the bridge had 31 broken wires. But he stressed he had no concerns over safety.

"The worst section has 31 broken wires, but you must remember that the main cable consists of over 11,600 of these steel wires," he said."The fact that we’ve found 31 broken wires is a lot less than one eighth of 1% of the total."

However, he said US consultants Faber-Maunsell had not expected to see the level of corrosion discovered during the inspection of the 40-year-old structure.