Miller Callaghan Engineering Services Limited was awarded the second phase of a seven phase refurbishment project on the Forth Road Bridge, near Edinburgh. The refurbishment replaced the steel walkways that form the access ways to the 200 panel points on the bridge. Having successfully completed phase 1, Miller Callaghan knew they required a scaffold contractor that would deliver to programme and have the necessary resource and expertise to build a complex scaffold in such an inhospitable environment.
The Suspended Span Under Deck Access (SSUDA) occupies a length of nearly 10km. It is used daily by engineers and maintenance operatives to carry out routine maintenance and inspections and is a vital component for ensuring the integrity of the bridge.
These walkways were installed in the early 1980s and were in need of refurbishment to extend their life. In order to reduce the environmental impact of the project, the existing steelwork was “upcycled” so that it could be reused and last for years to come.
The process required a specially designed hanging scaffold which was suspended from the underside of the bridge deck.
Denholm Industrial Services was approached by Miller Callaghan to design a scheme that would be fit-for-purpose for the operational and environmental conditions, offering a large work area in which to lay down the pieces of steel walkway, coupled with a fast erection and dismantling programme.
It was highlighted that the scaffolding components could have a tendency to fall from a great height down to the shipping lane beneath or into a Site of Special Scientific Interest (SSSI). Therefore the Royal Society for the Protection of Birds (RSPB) was also involved, given that the shoreline is a special protection area for several ground nesting sea birds.
The Glasgow based operation of Denholm Industrial Services designed a scheme that would see specialist rope access technicians commence work under the bridge with the installation of special material catching nets, slung and tied under the work area. These nets had to be specially designed to ensure they could be removed in high winds and offer the least amount of resistance to the continuous wind load that the bridge received. Once these nets were installed then a very experienced crew of scaffolders began the task of constructing the hanging scaffold. David Jackson, Denholm Industrial Services' General Manager in Glasgow, proposed a solution that utilised the branch’s stocks of traditional tube and fitting. This enabled a bespoke solution to be constructed beneath the bridge in the required timescale and meant it was also readily adaptable for any obstacles that needed to be overcome.
The original programme had called for the scaffolding to be complete in 14 weeks with sectional hand-over to the client. Denholm Industrial Services worked diligently and safely and completed the task in 12 weeks.