Although this submarine bridge scheme is be- lieved to be without precedent, there is an exten- sive amount of experience available on immersed tubes, drilling rigs and other heavy marine struc- tures and Alan Grant and Partners believe that their proposal is a logical extension of known and
Submarine bridge plan for Messina
A submarine bridge devised by a British consor- tium has won one of six equal first prizes in an international competition of ideas for a permanent road and rail link between Sicily and the Italian mainland.
The consortium consists of Alan Grant & Part- ners (consortium leaders), Covell, Matthews & Part- ners (architects and planning consultants) and Ibucon International Ltd. (management consul- tants). The competition was sponsored by the Ita- lian Government Department responsbible for main roads in Italy and Sicily.
A standard bridge or tunnel link was considered by Alan Grant & Partners, but the disadvantages of these, such as expense, high wind dangers and in- terference with shipping led to the submarine bridge concept.
Three rigidly inter-connected tunnels are pro- posed, two to carry road and one to carry rail traf- fic under the Strait. The under-sea crossing would be between 3 000 and 9 000m, depending on the route selected, and the recommended depth is 40-50m below the lowest sea level, allowing vessels of any draft to pass with ample clearance.
The structure will be restrained from moving more than a calculated distance in any direction by means of a series of anchor cables attached to the bridge and secured to anchors drilled into the sea bed. In addition to these cables, ballast will be attached to counteract the natural buoyancy of the bridge.
Ventilation of the tunnel over such a distance could be satisfactorily provided by two ventilation stations, one on each bank. A supply of fresh air would be brought along galleries underneath and towards the sides of each roadway and then inject- ed into the tunnels at intervals. Air would be ex- tracted from the ends of the tunnels.
A sophisticated automatic alarm system for hold-ups and accidents would be provided, pro- bably in the form of closed-circuit television with cameras spaced at suitable intervals. An emergency telephone system to the control room would also be installed at a number of points along the tunnel as an additional safety measure and as reassurance to travellers.
Far East BUILDER, February 1971
Cut-away model of submarine bridge
well-tried techniques. The cost of the scheme com- pared with standard methods is believed to be substantially lower and the estimated construction time is three years, considerably less than a bridge covering the same distance.
University computer service
Engineers in many British industries are cur- rently benefiting from a university-run computer service which is said to be the most versatile in the UK for calculating stresses in a wide variety of structures.
Developed at Nottingham University, the sys- tem is founded on a series of general-purpose com- puter programs which utilise the stress characteris- tics common to more than one, and in some cases many, different structures. In this way much of the initial programming work which would otherwise face engineers working on a single project is elimi- nated, or at least a worthwhile saving in time and programming costs can be achieved.
The system, called PAFEC 70, is currently deal- ing with valve structures, a crane hook, roadway subsidence in mines and a multi-span bridge give examples of its scope.
to
Backed by a large library of different elements — including thin, thick, straight and curved beams, traingular and quadrilateral panel elements and shell and three-dimensional elements with straight and curved sides the system covers stress analy- sis, dynamics, thermal stress, determination of cri- tical loads and creep loading among a wide variety of calculations.
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These elements are used at the university to simulate the behaviour of a structure under stress. A car body, for example, is made
is made up of many dif-
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