Other Concepts 
Thin Slab. A thin floating concrete slab has some qualities which 
commend its consideration as a MOBS platform. Firstly, there is a 
considerable savings in materials as compared to deeper draft platforms. 
A typical slab platform might have a total section thickness of 10 feet 
or less. The slab would be composed of solid top and bottom panels, 
each on the order of inches of thickness, supported between by transverse 
and longitudinal interior bulkheads. The latter would form a cellular 
interior, the voids of which could be filled with low density foamed 
plastic to insure floatation in the event of a breach in the outer slab 
panels. 
Full use would be made of pre-cast, prestressed panels in forming 
platform modules. The modules, formed in 100-foot x 100-foot, 300-foot 
x 300-foot or larger sections, could be constructed in a suitable dry 
dock, floated to the final assembly site and post-tensioned together to 
form a platform of practically any desired plan dimensions. 
Lately, considerable interest has been expressed in using thin 
concrete floating slabs for constructing offshore airports. For example, 
Shell United Kingdom Limited (1969) commissioned a study on the use of 
floating concrete slabs for constructing a new airport for the city of 
London. They recommended that the runways, parking strips, terminals 
and hangers be supported on a floating reinforced concrete pavement, 
the interior cells of which would be filled with expaned polystyrene. 
A typical pavement section, 3 feet 4 inches thick overall, would consist 
of a ''sandwich'"' of polystyrene between a 5-inch thick concrete top slab 
and a 3-inch bottom slab. Interior bulkheads would form cells approxi- 
mately 6 feet square. Estimates are that a ''seadrome'' assembled from 
100-foot x 100-foot precast modules would support the loads imposed by 
the heaviest aircraft now operational or planned for the immediate future, 
up to and including the proposed commerical version of the C-5A military 
transport. Due to the runway's extremely low freeboard, the designers 
suggest using a floating breakwater and wave deflectors mounted around 
the runway perimeter to prevent washing of the flight deck. 
In a study conducted at Rutgers University by the College of Engineer- 
ing and the Center for Transportation Studies of the Eagleton Institute, 
a proposal was made for developing a floating V/STOL airport (Nawy, 1967). 
One possibility envisioned was a 1,000-foot diameter, 21-foot deep re- 
inforced concrete, circular cylindrical platform having an interior 
deck for terminal facilities and aircraft storage. With a draft of 12- 
feet, it is claimed that this platform could be employed in practically 
any water area such as rivers, lakes and tidal estuaries. The entire 
structure would be pre-cast in a basin and then towed to its permanent 
location. 
As ecologic and aesthetic factors will undoubtedly play a more 
important role in the future planning of commerical airports; floating 
platforms such as the Shell and Rutgers concepts may yet prove to be 
more desirable alternatives to less costly terrestrial airports. There 
