Rapture Construction Domes
Construction Domes diagram http://img189.imageshack.us/img189/4712/constructiondomex.png
20 Domes were built early in the Rapture project to house workers and construction equipment on the seabed, and with pressurized tunnels interconnecting them and the various worksites.
The Bioshock:Rapture Novel describes them as being 200 foot across and 35 feet tall (and since it would not alter the structural requirements much, I extended the floor downward into the seabed (dug out of the solid rock) to significantly increase the space available for the equipment bays. Supposedly the domes were lowered down from the surface and imbedded in the seabed and then "pumped out" - with alot of pillars/girders inside to support the domed ceiling. It would take a bit more than that in ~600 feet of water - requiring solidly pressure sealing the bottom edges against the rock.
The Dome design transfers alot of force of the surface pressure thru compression of the curved structure onto its base which sits on solid bedrock. Thick concrete works well for withstanding compressive forces. So instead of a thinner metal Dome requiring alot of metalwork built precisely to maintain dimensional stability, a thick reinforced (Ryanium and Steel rebar) concrete shell was built. It was poured/cast in place inside the thin metal prefabricated form - first positioned on the prepared footing (with support pillars pre-installed), filled with a rebar matrix and tied/joined to the footing, and carefully filled with water-setting concrete. Later after the concrete sufficiently set, it would be pumped out and as the stresses shifted would have special 'adjustment cells' filled with more rebar and concrete to make the structure permanently solid, holding the pressure. The interior structures were then built inside and equipment moved in to make it habitable.
A portable Dome design might have been used, but would have been more difficult, with considerable complications every time it was repositioned (this is not the same as a caisson which has pressure inside greater than there is outside to keep the water out). Some smaller portable dome units were built for specialized uses. Later, advances with the tunnel boring machines made it simpler/cheaper to just build a network of tunnels to do the same tasks.
The Domes existed to facilitate building the City Foundations (pilings and masses of concrete) built first and then the shells of buildings and movement of the masses of machinery those building would require to become liveable. Similarly, transportation systems would be built for moving materials from underwater production sources (cement and concrete), stockpiles of reinforcements and pre-formed components made on the surface (Ryanium wall sections, framed windows, etc..). The initial train system that became the Atlantic Express was built to speed movements of materials, freight and personnel around the growing project.
The Domes contained :
- Much of the Rapture projects machine maintenance and repair facilities, and spaces for local fabrication (for component assembly).
- Living space for the workers (all the usual facilities). Each Dome could easily house 100 personnel.
- Offices for organizing the construction work (literally tons of blueprints...)
- Machinery to maintain the environment - fresh temperate air (heating required because of the coldness of the water).
- Some Domes had specialized equipment for doing specific jobs (which couldnt be done outside in the water)
- Airlocks for the tunnels and for Bathysphere access.
- Pumps to handle the inevitable seepage (and the airlocks).
The connecting tunnels (reinforced tubes laid on the seafloor) had Tram haulage tracks to help the equipment/supplies move rapidly thru the narrow tunnelways.
Power and air would be generated elsewhere and piped to each dome (initially diesel generator sets and compressors on the 'platform ship (moored barges) and on the Lighthouse island.
There was alot of remote controlling of submarines and various construction machinery (with TV links). The small 9 foot spherical mini-subs would act as control cockpits for all kinds of machinery, as well as basic sea transportation.
The Tram system used in the transport tunnels were found to be very useful and simple to maintain, and subsequently were integrated into the 'street' stuctures for a myriad of utility uses.
Look at the picture/diagram -- the Dome is a fairly substantial building just by itself and finding use for them after city construction largely ceased would be logical. The domes would find a number of other uses :
- Some convienently located Domes were used to house 'railroad' construction workers until the work moved on.
- Many would remain as Maintenance bases (including for Big Daddies).
- Some would be enlarged (by digging down into the bedrock with little dome structural change required.
- A few were damaged and abandoned.
- Old unused equipment is stored in several.
- At least one was turned into a submarine 'garage' for one of the 'Cab' companies.
- Another became a sea-agriculture laboratory for Ryan Industries.
- One became a smugglers base, until it was discovered.
There should be at least one of these Domes in the MMORPG (for once a circular shape, instead of all those rectangular ones).
Old (oldest in Rapture) and mysterious, more than a few quest/missions could be made dealing with the Construction Dome's histories.