1934 Queensferries Road Bridge
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The growth in automobile traffic during the 1920s brought demands for road crossings of both the Firth of Forth and the River Severn. In January 1926, Great Britain’s Ministry of Transport retained the firm of Mott, Hay & Anderson to investigate a road bridge at the Forth. Borings suggested sites about 1.6 km on either side of the Rail Bridge and a third paralleling it. The upstream site was rejected because of deep rock beneath the south tower and navigation concerns.
Opposition from the railway to a parallel bridge was anticipated, and in spite of good foundation conditions, this scheme was dropped, a fortunate decision from the standpoint of aesthetics.
Mott, Hay & Anderson’s 1929 report recommended the downstream site for a 731-m suspension span carrying a 12-m wide roadway and cantilevered footways. The following year, the firm examined an upper road deck on the Forth rail bridge, but high costs and certain rejection by the railroad caused it to be scrapped.
In 1931, the firm of Mott, Hay & Anderson was again retained to examine another site, this time 800 m upstream of the Forth Bridge. Here, the south tower could be footed at a depth of 33 m. Preliminary plans called for a suspension bridge of 914-m span flanked by 41 1-m side spans. It would carry a 9-m wide roadway more or less on the line of the present day Queensferry Crossing, linking from the then A90 (now the B981) to the A904 at South Queensferry.
Simultaneously, Sir Alexander Gibb & Partners proposed a downstream span. The Depression curtailed further planning, but in 1934, the Ministry of Transport concluded both 1931 proposals to be economical, with similar costs of about $17 million each. The upstream scheme of Mott, Hay & Anderson was eventually adopted in 1939, but by this time war loomed. The 1936 spanning of the Firth of Forth at Kincardine 25 km to the west also removed some impetus for a new crossing
Mott, Hay & Anderson’s design
Elevation – looking downstream
Plan and cross sections
Crossing Site
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