GB1280296A - Underwater structure - Google Patents

Abstract

1280296 Subaqueous structures G M J WILLIAMS 15 April 1970 [20 Jan 1969] 3176/69 Heading E1H To form a reinforced-concrete underwater tunnel-section a skin 2 of steel plate is first fixed to castellated rolled-steel-joists 4 or fabricated trusses 5, the upper portion of the skin being placed on the inner sides of the joists or trusses and the remainder being located on the outer sides and extended upwards to form reinforcements 9. A hatch 6 is then installed, walls 12 are inserted to form a ventilation channel 13 and traffic lanes 14, and temporary bulkheads are added to close the ends of said channel and lanes and thereby render the section buoyant. A protective layer 10 of concrete may be applied before the structure is floated to the. site. Finally, a concrete lining 11 is formed in stages, as shown, such that the joists or trusses are fully embedded therein so as to produce a "composite action structure", and ballast 15 is added to sink the completed section. Rods (21), Fig. 4 (not shown), to provide extra reinforcement may be included in the lining. The upper portion of the skin may be omitted to facilitate formation of the lining, Fig. 2a (not shown), and three walls 12 inserted so as to form two lateral channels 13 with the lanes 14 located therebetween. When the upper part of the lining has been formed a skin (17), of glass-fibre-cored bituminous-felt, Fig. 2d (not shown), is placed thereover to exclude water and the layer 10 is then completed so as to cover this skin. An open-topped structure to form a ventilation building for the tunnel may be constructed in a similar manner, Fig. 3 (not shown).