Rapture Construction Domes

* See also Construction and Primary_Construction
* Reference to the Novel
* See also UnderWater_Construction
* See also Tunnels
* See also TechnicalDrawings
Seabed Domes Used During Rapture's Primary_Construction
 
Something mentioned in the BioShock Novel. Several "Domes" would be 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. ( Note that : for efficiency, MOST of the City Construction would actually be mechanized and semi-automated - Not done by some guys in suits 'riveting' girders"Riveting" is done with forming of hot metal rivets which DO NOT work underwater. Welding or screw-threaded Bolts would be used for something of THAT method. Example of the BioShock writers simply 'winging it' ... And NO, it is not Ryan using such ignorance in a museum exhibit because it was iconic -- as WELDING was well known by then being recognizable from endless WW2 production newsreel footage. together underwater - AS WELL AS : Being built mostly of Components manufactured above the water's surface. )
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BIG QUESTION - SATUARTION DIVING OR NOT ?? :
Saturation Divinghttps://dan.org/alert-diver/article/saturation-diving/ (in this context) is about the Construction Workers (below) continuously LIVING in a Compressed Environment for Extended Periods ( taking literally days to safely transition back to the Ocean Surface. ) (( This is actually done currently Today, so is NOT an impossibility IF the methodology was moved ahead by decades. ))
See real Scuba Decompression Charts https://www.bing.com/images/search?q=dive+decompression+chart( which stop at 190 - 150 feet ) - THAT is only ~1/3rd of the depth for my 600 foot Base City Depth. Beyond 'Scuba' depths ( which are 'really close' to the ocean surface ), the required diving process gets horribly more complicated.
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Problem : The Novel Has Ryan visiting the construction workings below, which precludes (as written) use of AT Depth Pressurization which WOULD BE the practical (non-magical) constructions solution. Going to a ~600 foot depth would literally require DAYS of Decompression if the construction facilities Ryan visits had ambient water depth pressure (280 psi).
We CAN discount this Novel (dubious Canon) account) IF it prevents the MMORPG from descending into Infinite BS-type lazy magic fantasy hokem.
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Novel Gives Details :
The "Bioshock:Rapture" Novel describes the Domes as being 200 foot across and 35 feet tall. And since I would prefer to not alter the structural requirement details much, I extended the floor downward into the seabed ( dug out of the Solid Rock and rock-wall-reinforced to withstand the all around 600 foot pressure ) so to significantly increase the space/volume available for the required equipment bays. Supposedly, the Domes were lowered down from the Ocean surface, and were embedded in the seabed, and then "pumped out". It would take a bit more than just dropping a Dome down in ~600 feet of water - The structures require fastening to solid Pressure Seals on the Dome's bottom edges against the rock (Pressure has no direction).
The Dome design would transfer a great deal of force of the external surface pressure thru compression of the curved structure onto its base, which then needs to sit on solid bedrock. Thick concrete works well for withstanding compressive forces. So instead of some thin metal Dome shell ( which would require alot of metalwork built precisely to maintain its dimensional stability ), a structure of thick (Ryanium and Steel Rebar) reinforced Concrete shell is more plausible. The structure would need many massive pillars/girders inside to support its domed ceiling. The mass of concrete would make the inside more like a beehive with 'cells' within a thick web of supporting concrete. 
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200 feet wide is rather huge to be pre-built in one piece ( or be transported by Ship ). Better would be : a frame bolted together and then concrete being poured/cast in place inside a thin metal prefabricated form. It could first be positioned on prepared/leveled Foundation footings ( with the internal support pillars pre-installed ). The form would be filled with a Rebar matrix and tied/joined to the footing, and then carefully filled with water-setting concrete. At least a month Later, after the concrete sufficiently set, the interior would be pumped out. As the stresses across the cast Dome shift, it would have special 'adjustment cells' filled-in with more Rebar and concrete/grout to make the structure permanently solid, so to hold out the Rapture Depth water pressure. The interior structures could then be built, and utility equipment moved in to make it habitable and functional for the workers.
A Dome designed for portability might have been used. Reuse would have been more difficult, with considerable complications every time it was repositioned. 
ARE These 'Domes' similar to a 'Caisson'https://www.bing.com/images/search?q=Caisson+deffinition -- which has pressure inside greater than the water's outside to keep the water out ? The Novel DOES NOT detail the 'Descent'/Ascent compression/decompression processes realistically required when Ryan visits the in-progress construction with McDonagh -- with a bothersomely and still dangerous slow decompression process such pressures require for the workers ( to avoid "the Bends" https://www.britannica.com/science/decompression-sickness which you can get even traversing to depths less than 100 feet too quickly ). The complexities involved would make all this Construction 'diving' activity the providence of expert technical labor, and NOT some grunt workers the game's story might imply.
A Saturation Diving habitat might be used by some workers, but preferably many other Construction facilities ( including Ryans visit ) would be kept at Sealevel pressures when much of the Construction was done with mechanized automation. 
Some smaller portable habitation units could be built for specialized uses. (( Later in Rapture's history, advances with the Tunnel Boring machines made it simpler/cheaper to just build a network of Tunnels to do many of the same tasks. ))
The first "Dome" would likely be installed near the Lighthouse to facilitate the transport/marshaling of construction materials down to the City Level.
No doubt many issues/problems would be discovered and require adjustments when the scale of construction greatly surpassed anything done previously.
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These Domes existed to facilitate building the City Foundations ( excavations and pilings and masses of concrete ) being built first, and followed by the careful placement of SURFACE prebuilt/modular building shells, and movement of the masses of machinery those buildings would require to become livable. Similarly, transportation systems would be built for moving materials from underwater production/assembly sources : all that cement and concrete, stockpiles of reinforcement components, and the many pre-formed components made up on the surface ( Ryanium wall sections, framed windows, etc ... ). The initial Train rail system that became the Atlantic Express would be built to speed movements of materials, and to move freight/personnel around the growing project.
The Domes Contained :
* Much of the Rapture Project's Construction machine maintenance and repair facilities, and spaces for local fabrication ( and for component assembly ).
* Living Space for the Workers ( all the usual facilities required for long-term habitation ). Each Dome could easily house 100 workforce personnel.
* Offices for organizing the Construction work ( literally tons of blueprints ... )
* Machinery to maintain the Living environment - fresh temperate air ( heating required because of the coldness of the water ).
* Domes had specialized equipment for doing specific jobs - equipment/machinery repairs ( which could NOT be done outside in the water )
* Airlocks for the tunnels and for Bathysphere/Equipment access.
* Pumps to handle the inevitable Seepage ( and the Airlocks operations ).
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Connections :
The connecting Tunnels ( reinforced tubes laid on the seafloor ) had (Novel detailed) Tram haulage tracks to help the equipment/tools/supplies/personnel move rapidly thru the narrow tunnelways between construction sites. Tubes with human accessible Interiors connecting parts of the construction project (even with Trams) were featured in the BioShock Novel. 
Power and Air would be generated elsewhere and be piped to each Dome -- Initially using diesel generator sets and compressors on the 'platform ship' (moored barges), and later on the Lighthouse_Island.
Waste Disposal ... ( pumped directly into the ocean ). The area around Atlantic Express in BS2 is littered with what might be construction junk.
The Tram system used in the construction transport tunnels were found to be very useful and simple to maintain ( and were integrated into the 'Street' structures for a myriad of utility uses ).
There should have been remote controlling of Submarines and various Remote-Controlled Construction Machinery ( with TV camera links ). My ( small 9 foot spherical ) Mini-Subs would act as attached control cockpits for all kinds of City Building Machinery, as well as be used for basic short-range in-sea transportation.
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Subsequent Use :
Look at the picture/diagram (above) -- the Dome is a fairly substantial building just by itself, and finding use for them after the city construction largely ceased would be quite logical. The domes would find a number of other uses :
* Some conveniently 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 accessible in the MMORPG ( Hmm, for once : a Rapture building with a circular shape, instead of all those 1930s style rectangular ones ).
Old (oldest in Rapture), and mysterious. More than a few Quest/Missions could be made dealing with the Construction Dome's histories.
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Proving The Systems Used For Rapture :
The Dome Complexes also would allow careful 'Proof Time' of various 'Sealing TechWatertight_Doors_and_Bulkheads' technologies, which were to be used for the rest of the city. Serious routine use would be a good way to PROVE the mechanisms and to be able to make adjustments to the systems which would subsequently be installed. These Rapture Construction Domes would likely be the largest deep underwater sites up to that time.
I have posited that Ryan Industries had previously done deep water work so to have the technology available when Rapture was built (starting 1946), but any serious engineer would want the actual systems ( upgraded with all the cumulative improvements ) would be actually thoroughly Tested, before the bulk of them were installed in the actual City project structures.
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The process of Positioning and Embedding of a "Dome" structure itself would be a 'Proving" process necessary to identify Construction issues ( which would NEED to be solved before the rest of the City was built ).
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