In the Netherlands, as in many other countries, immersible road and metro tunnel elements are built in a dry dock. After completion of the reinforced concrete elements the dock is flooded and opened. The elements-lengths varying from 60 to 120m-are towed one by one to the building site, where a trench has been dredged in the bottom of the waterway, sunk by water ballast and subsequently provided with permanent ballast, generally concrete. The joints between the elements are made watertight by means of compressible rubber profiles - the so-called "Gina" - while a second rubber seal is usually applied to be quite on the safe side. Not only have these joints to be watertight, but so too must be the elements. The construction-method usually employed involves pouring first the floor and after this has hardened the walls and the roof. The differences in temperature and shrinkage of the floor and the wall concrete give rise to high longitudinal tensile stresses in the walls, which inevitably lead to vertical cracks penetrating the entire wall thickness. These cracks due to shrinkage permit leakage and make it necessary to apply a watertight covering, usually a bituminous lining. The lining is vulnerable and requires protection against mechanical damage.

  • Availability:
  • Corporate Authors:

    Morgan-Grampian Limited

    30 Calderwood Street
    London SE18 6QH,   England 
  • Authors:
    • GLERUM, A
  • Publication Date: 1973-7

Media Info

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Filing Info

  • Accession Number: 00047005
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Nov 14 1974 12:00AM