001.16.2 | Deck fragment
1937, 20th century
21 x 8 x 70.5 cm
Gift of American Bridge
This artefact belongs to : © North Vancouver Museum and Archives
Keys to History
This original section of road deck shows the Tee-grid pattern, made by welding thin strips of steel together. Using Tee-grid proved to be a much lighter way of constructing a roadbed than the usual method of pouring slabs of concrete. It saved approximately 30 pounds per square foot (146 kg/m2), a significant difference for a suspension bridge. As well, no formwork was required, since the concrete was directly poured and levelled over the entire width of the road. Three decades later, the roadbed had deteriorated due to heavy use; the bridge was carrying triple the traffic for which it had been designed. The uncoated steel Tee-grid exacerbated this problem, since the rusting and flaking damaged the concrete. Local engineering firm Buckland & Taylor Ltd. assessed the condition and safety of all aspects of the bridge in 1972. Urgent repairs continued for years, and included replacement of the north end of the road deck.
Prefabricated sections of light steel grid, such as this, were welded together on-site to create the road deck, then filled with concrete.
This piece of road deck was taken from the south end of the bridge during its reconstruction. Normal procedure for pieces like this was to break out the concrete and to recycle the steel immediately by melting it in an electric blast furnace.
This section of the original road deck was removed from the bridge when the road was replaced in the summer and fall of 2001.
Workers cut up the road deck with a three-pronged tool, resembling large garden shears, that was made in Japan.