This article described the design and construction of the Hugo's river viaduct which carried the N1 freeway across Hugo's river valley between Paarl and the Du Toitskloof (Huguenot) Tunnel. The 535 m long viaduct consisted of a girder type bridge deck supported on tall slender piers. The depth of the box was 3.3 m, and the cantilevers are 3.8 M long. Pier height varied from 13.6 m to 43.6 m. Horizontal curvature was of 597.3 m radius, vertical gradient 5.675%, and superelevation 9.8%. In order to increase resistance to sabotage, the piers were filled with mass concrete up to 3 M above ground level. Piers 4-8 were fitted with fixed bearings, and the remaining piers and abutments were fitted with one uni-directional and one multi-directional bearing each. The viaduct was constructed by incremental launching uphill. Because of the sheer mass of the bridge (15000 T), the gravitational force was 8500 kn, and the maximum frictional force was 5250 kn. The method of centre-hole jacks mounted on the abutment face, launching cables and pulling sticks was used. Five jacks of 3300 kn force were provided. The deck shutter was built on the same curvature and gradient as the bridge deck. Temporary bearings used were reinforced concrete with a steel plate on the top surface. To reduce the forces on the side guides that maintain the bridge on the correct path, the upper surfaces of the temporary bearings was sloped 2% towards the centre of the circular curve. (TRRL)

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  • Corporate Authors:

    South African Institute of Civil Engineers

    9 St Davids Place, Parktown, P.O. Box 62129
    Marshalltown,   South Africa 
  • Authors:
    • Mills, H B
  • Publication Date: 1988-4

Media Info

  • Pagination: p. 204-207
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00493084
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Files: ITRD, TRIS, ATRI
  • Created Date: May 31 1990 12:00AM