Primary Construction

* See also Construction
* See also Rapture Construction Domes
* See also Concrete_IS_Your_Friend
* See also UnderWater_Construction
* See also Water Depth
* See also Watertight_Doors_and_Bulkheads
* See also Prefabricated
* See also Rebar
* See also TechnicalDrawings (Diagrams)
* See also Windows
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The Skyline/CityScape of Rapture now being changed to be more realistic in height, and with the lighting toned down to reflect the very short-distance for light absorption through water.
Close up, a 12 story building still can look quite impressive ( consider how squat just about every inside part of Rapture we were in during the game, was ). A good MMORPG illustration would be YOU (on a Mission) having to traverse just 12 flights of stairs in some building where the elevators don't work ( very likely/typical ), and someone ( a NPC Team Lackey ) comments "Good thing it ain't 60 stories". 
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Ruling Factor About Rapture Construction :
600 feet deep = 280 lb/sq in external water pressure - greater than the steam pressure within most Steam Locomotive boilers. That's the magnitude of the water pressure pushing in on Rapture's buildings ( which needs to be CONTINUOUSLY handled by the building's structure -- NO WEAK SPOTS ).
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Steel For Rapture :
Sorry, No Steel-Plant at Rapture -- The iron ores ( and the limestone and coke and other fuel ) adequate to make Iron and turn it into Steel all come only from limited places/regions ON-LAND to practically make Steel of a large amount. The Steel Mills to make/roll Steel components (girders/plate/sheet/etc...) likewise. There is the added great difficulty of any steel-plant actually working down there ( Oh, and another thing : Steel-making requires ALOT of Air ). So you really need to produce it ON LAND, and ship it ( which BTW would take a fleet of ships, and not just 'The Olympian' ). Shipping to Rapture the far bigger bulk of Raw Materials would be EVEN more expensive. 
Also Don't Forget : It is Thousands of miles, not hundreds to transport All The Materials to Rapture ... You might as well transport the finished material itself.
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Metal Parts Little vs Concrete Much:
And as I mention the pre-made steel/aluminium(?) components for Rapture are nowhere near as huge a mass as the amount of Concrete components that would also be used. Aggregate (rock/sand ) for making Concrete might really be the only locally available materials. The other materials don't exist in the Ocean. Cement, like Rapture's Steel, is much easier/cheaper to MAKE at efficient land cement plants, with optimal material sources - the Fuel to make cement is also one of its bulkier raw materials.
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Poor People ?? Workers in Rapture's Population ...
 "Construction Workers" Would Mostly Be Use Up On The Ocean Surface
It is Logical to do prefabrication where it is easier at the Ocean surface, or even back on land, and not at some deep Depth where complications multiply many-fold and special equipment is needed for everything - deep diving Diving_Suits#Hard Suits are NOT used by 'Joe-Blow' workers.
SO : Less and less excuses (and the story's assumption) for so many 'Construction Workers' to be allowed into Rapture ( They are used in the game's plot as the excuse for all the 'poor' 'downtrodden' 'out of work' people who somehow prove Ryan (and Rapture's) Philosophy does not work. If they had instead worked on the surface/on-land, then they really never had to see Rapture ( and could be prevented from knowing what/where it was ). So not being immigrants, they didn't have to be allowed to live there, so they couldn't be there to 'reveal the secret' later. Most of the 'construction workers' who WERE let below would work more as Machine Operators and be Technical People, versus manhandler grunts/gophers. The workers let in would also be told that Construction would eventually end, and they had better be ready to take up new professions ( city maintenance would absorb more than a few doing similar type jobs ).
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A Solid Mass of Concrete is far simpler than a very complex network of girders and a metal shell to hold that water out. It would have Far LESS maintenance being involved ( a constant drain on city resources ... ) Thus most of the main structures of Rapture has the Pressure Containment Shell being thick walls/ceilings/floors of reinforced concrete, with concrete floor plates to do the transverse transmission of the external water pressure-caused forces ( and lots of 'fillets' to maximize the diagonally transmission/spreading of those immense forces into/across the interior of the building structure -- Usually across to the opposite side of the building, using its countering force, and exploiting the inherent compressive strength of the material ).
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Let's here try to lower Expenses to make it construction Monetarily possible. Use Mass Production techniques for one thing ... 
Bringing in components without giving away the secret - If Ryan had businesses building drilling rigs or something similar, that would help obscure the Rapture Project, but he could also just have the 'parts' built for 'building construction' in one city and shipped by water ( parts too big for Surface Railroad transport ) and just have them keep going out to sea.
It depends how large the prefabricated sections are. Sections of wall panels, the struts between the walls which compress to oppose the water pressure, etc... are still only 'pieces' and can look fairly generic. 
Now THOSE prefab sections can be assembled into larger assemblies onsite ( That Lighthouse means there IS a shallow zone where IT is possible to do alot of work at/near the ocean surface or partially on land ), and subsequently build into sections of buildings, which either could be lowered down to assemble into Rapture's buildings on the seafloor, or possibly smaller building structures could be assembled almost entirely at the Surface ( the work at less than 100 feet can use normal diving equipment, while at city depth, it requires really complex diving hardsuits - and ADAM doesn't exist at this point (1946) to bypass that fact ).
Anything/Everything ( factory, warehouse, personnel quarters, repair shops ) on the Ocean floor ITSELF has to be constructed FIRST. Any Factory 'down there' just adds to the cost overhead. Most raw materials simply wont be available 'locally'.
Sorry, no smelter, no steel-plant -- The ores adequate to make 'steel' ( and the limestone, and coke, and other fuel, etc ... ) all can ONLY come from certain places On Land to make steel practically, for the huge amounts required. So you might as well THUS produce it on land from established (efficient) industries, and ship it ( which BTW will take a large Fleet of Ships -- not just 'The Olympian' ). And if you are worried about the shipping costs, shipping an even bigger bulk of raw material ( to be processed/converted) would be EVEN MORE expensive to transport ( Besides the difficulty/impracticalities of any steel-plant actually working underwater -- Oh, and another thing : Steel-making needs ALOT of air ). And the transport distance is Thousands of miles ( not hundreds ) required to transport all this stuff to Rapture ( and that's just from the coast/ports ).
The pre-made steel/aluminium components are nowhere near as big a mass of materiale as the amounts of Concrete that would be used. The aggregate (rock/sand) might really be the only locally available materials ( and even then, likely was more efficiently produced ON LAND ). Cement, like the steel, is much easier/cheaper to make at efficient land cement plants, with optimal materials ( the fuel to make cement is also one of its bulkier raw materials ... assuming you had any of the other proper materials to 'refine' it from locally ).
Don't worry, there is still alot of work to do down below. The prefab components talked about so far is just the structural shells of the buildings. Those have to be joined to the Foundation and made water tight and pressure resistant. That's alot of positioning, fitting, joining to get done. There are the interiors to be installed, once the intact buildings are pumped out and dried and cleaned. There are many miles of pipes/conduits/venting/cabling to be installed and connected. Lots and lots of machinery that needs to be in the buildings. Add all the carpentry/plastering/insulation work which has to be done to the finish the inhabitable interior.
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RAPTURE - City Construction Requires Lots of Infrastructure :
All kinds of Temporary structures/rigging are required to facilitate the work :
* The early 'Construction Domes' used for Rapture's initial construction. First large-scale test of sinking large prefabs into place and digging/cementing a foundation. Reused when Construction phase completed.
* Remote Control systems for automated equipment - operator centers
* Mike Mulligan Steam Shovel equivalents 
* Dump Trucks ( rock is still heavy underwater ) - variable buoyancy 
* Retaining Walls to stabilize the parts of the seabed ( including when cutting out the Foundation volumes )
* Equipment for maintenance/servicing of all of the above
* Hoists and Derricks and Cranes - variable buoyancy lift
* Drilling Rigs ( for exploratory work to find conditions of seabed suitable for placing building )
* Haulage of Construction Supplies, components, personnel
* Diver Support ( hard suits for the grunts )
* Cement Mixing and transfer to work sites
* Interior repair/maintenance space/facilities
* Machinery recharging rigs for the self-contained units
* Power Line to get power to temporary in place equipment
* Worker/Staff Housing and Life Support ( sewage/sanitary/sleeping/eating/drinking/recreation/health maintenance )
* Local Project Coordination ( versus tracking/coordination from the Mainland )
* 'Pipelines' Transport ( ex- pneumatic transport of powdered cement from surface transport ).
* Initial lines of the Atlantic Express used to haul from fixed marshaling areas and component assembly plants ( ie- cement plant ).
Surface Facilities - Transport from 'Mainland' and transfer down to construction areas/stockpiles
* Breakwater and Anchorage
* Docks/Cranes
* Cargo Handling and Personnel Transfer Facilities
* Control and communications
* Small Boat servicing
* Bucket Tram down to Rapture ( containerized freight ) - the 600 feet difference made an AE type operation too long a track - impractical
* Power Systems - fixed generating units to make power - originating up on Lighthouse Island diesel engines
* Water desalinization plant ( most required for cement )
* Warehousing for cargo awaiting transfer below
* Fuel Dump
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Rapture's Inception - Considering IF an Undersea City is Even Possible/Feasable/Practical to Build
There is NO "Just Make It Happen". IF One thing doesn't work THEN the WHOLE THING wont work.
Technologies have to exist to make it possible and can take years/decades to create - So Rapture had to be built largely using materials/mechanisms/know-how/skills WHICH ALREADY EXISTED. A number of technologies Real World did already exist, but those would have to be pushed further in the Story to allow Rapture to be built.
To support this I theorize : Ryan's Industrial Empire had had goals of exploiting the Ocean and had already put in a whole lot of development work to make that possible. 
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Rapture Phase O - Site Discovery and Assessment, Surveying, Planning, Marshaling Resources
Looking For A Site For Rapture - Ryan's Surveyors Using Sonar Depth Soundings 
It takes a bit of Time to do a Search like this - even if the plans started years earlier (( This isn't "Oh we'll just let THAT get done in a few weeks" type Infinite Bullshit-type Fantasy Idiocy )).
Ryan would have a number criteria which narrowed down candidates ( specifics all identified 'from the start' ) :
* The geothermal requirement ( for the very critical self-sustained completely locally-sourced power )
* Hidden - Being too close to land would make Rapture too obvious, eventually (the security issue).
* Access to normal shipping lanes ( to build and populate Rapture ), but not on them ( Most North Atlantic traffic is directly between the US and Europe, and Rapture is well North of them ). Where they are, it is wide open, so surface activity wouldn't be easily spotted. 
* The maximum depth for which the construction could be engineered was another most important factor. SO starting with known 'shallow' locations ( ex- the Ocean depth around Rapture's Sea Mount quickly descends well below 3000 feet - and that's far too deep to build anything practical ).
Meanwhile Preparations for the Construction would be made :
* Construction Materials would start to be collected on the Surface in various Ports.
* Factories would be set up for producing the Pre-Fabrication of the City Structures and stockpiles of standard components would be built up.
* The Construction machinery would be built 
* Skilled/Specialist workers would be gathered. Additional training done for the required tasks
* Transportation infrastructure would be obtained and made ready.
Once found and approved, planning the actual layout of the City could then start. Building designs to match the site would be drawn up in detail and reviewed and Construction schedules established.
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Rapture Phase 1 - Initial Construction of the City - beyond Worker-Support infrastructure.
The Novel has some 'Domes' placed early on the seabed floor to act as housing and bases for construction machinery. 
Building in the area of Welcome Center, which would be some of the first facilities needed when large scale immigration started. Its proximity to the Lighthouse facilitated transfer of materials, supplies and personnel. It would be the first foothold of the normal building structure of the city.
Air circulated from intakes at the Lighthouse site would provide until the permanent systems were in place (the Farms)
Administrative Offices - operational coordination and control of construction
Monsenor Hotel - Allowed worker residences to be moved from the Work Domes to a more normal environment.
AE Station - link to the growing train system which greatly facilitated city construction.
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Establishment of Neptune's Bounty, Port Rapture, Hephaestus], and connections of them to the transport network followed to provide the basic resource needs for further expansion.
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NOT Any MASSIVE Water Pressure OUT
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"The Sinker" ( Beginning of Rapture's Underwater Construction ) :
Used to ferry men and supplies to the ocean floor and was positioned where a building was to be constructed.
Had living space for the crews doing the initial construction work and air/power supplies and space for storing/repairing various equipment.
Early 'Saturation Diving' would be used to alleviate the need for some of the cumbersome hardsuit work. Divers would stay down at the depth pressure for extended periods and then only decompress (very slowly) once when leaving for the surface.
The Sinker was used to prepare a site by cleaning off the seabed of silt and debris down to the rock and then digging out soft/broken material til the surface was solid rock. Digging down into the seabed would be done to form a solid anchoring Foundation for the buildings/structures. 
The Sinker platform had pile drivers ( and digging/drilling units for cement support pilings ) and these were used to make anchors for the forms used to pour the concrete building Foundation, and to guide prefabricated components being embedded.
A cement crane and either a tram or cable line was built to bring in cement/aggregate/freshwater from the production plant. The Concrete was mixed and poured in many repeated courses/layers, and would be built up to the required level ( cement takes time to set properly, and can create destructive stresses if made in one solid block ). Large boulders were often embedded to fill significant volume and save on cement.
After the Foundation was well started, 'The Sinker' was moved on to the next building site. Submarine handlers/operators in the mini-spheres controlled automated equipment that did the rest of the bulk/repetitious work ( boring anchors, digging, raising the forms, embedding tie-ins, pouring/tamping cement, placing filler boulders, repeat ... )
Later, more equipment was available to do similar work ( and the Construction Domes were built to house further construction personnel and do equipment maintenance ), but The Sinker itself was used to built many of the Phase 1 building foundations.
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Early Large Desalinization Plant in Rapture :
Not just for workers but all that Cement ( millions of cubic yards ) which uses alot of fresh water in its mix.
Such Desalinization plants used alot of Power, so the Operation at Hephaestus would have to be sufficiently done to accommodate the City's building phase. The City used many prefabricated concrete parts ( easier/cheaper to construct on land/surface and to source the materials ), but there was alot more concrete employed than for those used at the site ( which would have to be Rebar'd/mixed/set locally ).
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Per The Empire State Building Example :
It has a large central utility core within the building, with so many floors ( even with its thin walls, and with less utilities than the buildings in Rapture require ) which contains many elevators to access so many floors - Within a reasonable time ( capacity and average between-floors trip times - extra express elevators, etc ... ). That greatly cuts down the available interior space ( even more as the building thins towards the top ).
Some of the buildings seen in Rapture's Ocean Views look to be about 60 floors (by window count), which even though being less than half of the Empire State Building floors, still is of a similar 'tall' situation. Only a few of Rapture's buildings might be anywhere near that tall ( where you also have to worry about Rapture's depth and the clearance for any building's top being too NEAR the ocean surface -- which risks destruction by iceberg, as well as trying to anchor such a tall structure against ocean currents with so much leverage working against it. )
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Consider How Expensive Things Might Be - Like the Building of Rapture :
Mass production can greatly lower costs both of manufacturing and installation and maintenance. Remember Ryan was an industrialist and he fully understood this concept and how to apply it. He also could employ his still-owned industrial organization on the Surface to use Surface-World efficiency to build/obtain components for Rapture ( not just girders, but whole pre-made building sections and machinery ).
Example - Those vault-door-like pressure doors (ie- Securis Doors) would be very expensive, if only a few were custom built. Using industrial assembly-line techniques up there , with thousands produced ( as there would have to be in Rapture ), then the unit price drops considerably.
Likewise for any special materials used en masse, which such components are made out of ( like Titanium or Ryanium ) - they could be obtained also at Surface world economy-of-scale prices. Same goes for the machinery which sustains Rapture's terrestrial environment - Built on the surface using Ryan's existing infrastructure.
Inside Rapture cost of production was much higher - small production without much economy-of-scale ( or complete lack of it ), and hampered by lack of existing 'world-scale' material production methods/raw material supplies. Many common normally cheap materials thus would NOT be cheap IN Rapture, where such materials had to be found and transported in/down from the Surface ( lots of overhead costs ). 
This, of course, would also have been the years BEFORE the growth of ADAM (and other) technologies which might offer some in-Rapture cost-cutting improvements/new materials ( ?? or things later lost because of disruptions ).
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 "Reserved" :
In all of Rapture's Construction there would be space within the solid structure reserved for later potentially needed/required expansion of utilities systems.
Ryan ( and/or people who worked for him ) would definitely understand this concept as it is FAR more expensive to rebuild/retrofit such huge solid structures if a deficiency was later discovered.
Rapture's Pneumo System may have been planned for ( from the start when city was designed ), and space reserved for it -- As it uses good sized 'tubes' ( and the system's machinery ) which would run throughout the city's utility infrastructure. 
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BUT NOT FOR RAPTURE 
Above water, buildings have to hold themselves up against Gravity ( and to some extent Wind ). The steel girders in this picture hold everything UP. 
Underwater, you have to hold the Ocean's water OUT. It presses in on ALL sides, and with greatly increasing force as the depth increases. You cannot build underwater buildings like you do the ones above water.
Unfortunately, this fact was something the gamemakers did not seem to understand or care about, and the 'artists' even less.
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Surface Construction and moving the prebuilt sections to their place on the sea floor. Still plenty of work to be done, but doing too much down there just wasn't possible to get what the game shows you of Rapture.
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Phase 2 Construction
Later Construction ( Kunstruxion as called by some of the Engineers The Germans did more than a little Underground Construction during WW2. ) did a great deal of Tunnel building to add additional space for the City. Adjustments like additional Farm space.
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An Illustration :
Seeing Various Documentaries made me consider that building Rapture is similar to the building of huge dams - with the inside living space dealing with pressure problems in similar ways.
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