STATS helps bridge a gap

Hertfordshire-based engineering consultantcy

has restored a Victorian footbridge in

, making it as sturdy as when it first opened 125 years ago.

Shaw Street footbridge, which crosses the Lancaster Canal in Lancaster city centre, was first built by Lancaster Corporation in 1882. The historic lattice braced wrought iron truss structure spans 19m between cut sandstone masonry abutments and carries a timber deck.

STATS worked with Lancashire County Council to devise a scheme to refurbish the bridge. This included installing bolted strengthening plates, refurbishment of the roller bearings, replacement of riveted connections, welding repairs, replacement deck and a high performance coating system for long-term corrosion protection.

Engineers replaced the corroded wrought iron with standard grade S355 structural steel, then hand-painted the entire superstructure with a special polyester coating system reinforced with glass flakes to prevent future corrosion. The coasting was applied at a thickness of 650 microns, which should mean no major maintenance would be required for 30 years or more.

Wherever possible, carbon steel was used for repairs throughout the main superstructure works to avoid any problems with galvanic corrosion that can occur between wrought iron and stainless steels.

To provide extended life to the components carrying the new deck, the structural supports under the bridge were hot dip galvanised for increased corrosion protection. The entire structure was then finished using a polyurethane-acrylic topcoat.

To ensure that the bridge refurbishment would provide a lasting solution to meet the council’s expectations, STATS also supervised the ironwork preparation, repairs, strengthening, prefabrication and installation of the steel deck, and protective treatment of the entire structure.