The cover this week shows the Birchenough Bridge and is reproduced from a photograph provided by Dorman Long and Company Ltd. The building of this magnificent structure, the thrid longest single-arch span in the world, is described fully in a chapter in this Part. The bridge has a total length of 1,240 feet and the great arch rises to a height of 280 feet above the River Sabi in Southern Rhodesia.”
1,500 TONS OF STEEL were used for the arch span of the Birchenough Bridge. The same amount was used for the Victoria Falls Bridge, which has a span less than half the length. The total length of the Birchenough bridge is 1,240 feet, and the enormous arch rises 280 feet above the River Sabi.
The Birchenough Bridge 2:
THE ROADWAY along the deck of the Birchenough Bridge is 18 feet wide. On either side of this are the footways. The main cross girders of the deck can be seen projecting from the line of the roadway at intervals of 40 feet. The ends of these girders are suspended from the great arch by steel cables with a diameter of 2¾ in. These cables were used as anchorages suring the building of the arch. The same cables had been used in the building of the Sydney Harbour Bridge. Beneath the roadway and running the whole length of the deck is a huge horizontal truss, 48 feet wide, which keeps the suspended portion rigid against the pressure of the wind.
The Birchenough Bridge: 3
THE CABLEWAY ACROSS THE RIVER was suspended from two steel towers, 1,400 feet apart. The cableway was used to transport materials and plant across the River Sabi during the building of the Birchenough Bridge. Electric power for driving the cableway and cranes was obtained from two portable generating sets driven by high-speed diesel engines.