SUBSTANTIAL repairs are needed on White Bridge in Upper Beeding, a popular route for schoolchildren.
Works began recently on the footbridge across the River Adur, north of Bramber, to replace the decking timbers and improve accessibility on the approaches.
But workmen found rotting timber and surface corrosion of the steelwork, far worse than had been expected.
David Barling, West Sussex county councillor for Bramber Castle, said: “Regrettably, having started these works, concerns for the integrity of the structure have arisen due to corrosion of some of the steel elements. These have been found beneath the lifted decking timbers.”
The extent of the problem has now been identified and the result will be substantial further maintenance works.
The county council is now consulting both the Environment Agency and Southern Gas Networks and awaits their consent in due course.
Mr Barling added: “Once received, the contractor can order and prepare the appropriate materials, together with setting up the scaffolding that will be needed.”
He said the damage was ‘typical of what happens when timber is fixed direct to steel without much in the way of effective corrosion protection to the steelwork’.
“The narrow gaps between the steel and timber allow the build up of moisture, and prevent circulation of air to dry the moisture,” he added.
“This leads to both rotting of the timber and surface corrosion of the steelwork, which can be accelerated by chemicals (tannins) within the timber.”
He said the corrosion appeared to have badly affected the steel angles forming the bottom chords of the main deck trusses, in particular the horizontal leg.
The parts that support the longitudinal timbers were generally in fair condition, but were more heavily corroded at the contact area, where the ends are fixed.
Mr Barling said: “I am doing all that I can to press WSCC to get these works done as quickly as possible and to get the bridge open again.
“It is an important crossing point, and in particular, a route to school from Bramber and Upper Beeding to Steyning.”