oa Civil Engineer in South Africa - Economic and financial aspects of the tunnel
The Du Toitskloof Tunnel was first mooted as a solution to a more efficient link between Cape Town and its hinterland in the 1950s. Over time the Du Toitskloof Pass became increasingly inadequate as far as traffic capacity and road safety were concerned. Between 1970 and 1978 various designs were put forward for a tunnel through the pass. Initially the tunnel was planned to be a six-lane, twin-bore structure with dual carriageway approach roads.
In 1974 the National Transport Commission decided to scale down the project and build only one bore since the traffic volumes and growth rate were decreasing as a result of the fuel crisis and did not warrant this additional capacity. In 1978 the cross-section of the proposed tunnel was reduced to two lanes with a consequent saving of R20 million. The spacing between the first bore and a future doubling of the tunnel was also reduced, which enabled savings to be made on the approach fills and bridge structures. However, as the need for the tunnel was evident, construction began on the pilot bore in 1977 and was completed in 1979. Work began on the approach structures in 1980 and in 1981 the soft ground tunnelling was started. Both projects were completed early in 1982. Construction on the main tunnel contract started in 1984.
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