Spencer Group were appointed as Principal Contractor by Transport Scotland to repair the truss ends on the Forth Road Bridge, following a high-profile fracture in the North East main span link that connects the tower to the road deck, forcing the bridge to close for three weeks. The works involved replacement of seven truss ends which connect the bridge deck to the tower.
We were tasked with cutting out the obsolete sections and replacing them with a sliding bearing system. This required removing the temporary solutions on the main deck and installing bearings, as well as installing both the temporary solutions and the new bearings on the side decks. We also strengthened tower cells to take the combined 14 tonne weight of the support bracket and new sliding bearing. To enable the installation of the new bearing, the current truss was modified, with a section of the end post and bottom chord cut away and replaced with new sections.
We also conducted modifications to make future works on the bearings considerably easier, this included installation of new access stairs and permanent access platforms to allow easy maintenance all year round, reducing disruption to bridge users during future repairs/maintenance.
A number of key challenges were overcome in order to successfully deliver the project, this included working safely on an operational bridge and at height. For example, temporary scaffolding was required 50m above the River Forth and traffic management measures were implemented on the bridge to reduce speed restrictions and the number of vehicles on the bridge.
Furthermore, the Forth Road Bridge, is located within a Site of Special Scientific Interest, we therefore coordinated all work with the Scottish Environmental Protection Agency to ensure our works had no adverse environmental impacts.