When it's time to railroad, there will be sailboats...
Some of you may remember my discussion from the mid-1990s about how to create artificial islands. My idea was to use air-entrained concrete with Kevlar reenforcement to form large (50 x 50 foot) keyed hex-pads. These pads would drop into place working from the center out, relying on gravity to keep them locked. They would flex a bit yet support buildings, a runway and even lagoons. The effect over a mile or so would be like scum floating on the water. It would give a bit but dampen any waves.
My idea was to stack more layers under the larger buildings to support more weight. As building increased, more hex-pads would be lower into position under the keyed structure. The top would reflect what was under the water.
My approach was also to place the island in the doldrums, but to have a backup plan which was to create a "keel" underneath and a "fin" building above using these hex building blocks. The theory was to create the dynamic which would allow for VERY slow sailing when needed, maybe even the ability to sail slightly upwind.
These guys have a more grand and green design and say little about the structure. My idea was to make it large enough to land a 737 and grow some veggies for a military base or vacation resort for hire - politically independent, of course.
Green Float Design