Undersea Windows

* See also Real Physics
* See also REALISTIC WINDOWS IN RAPTURE
* See also Ryanium
* See also Construction
* See also Seascape View Around Rapture
* See also Windows
NEED TO CONSOLIDATE ^^^^ 
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Windows Out Into The Sea :
External Windows in Rapture are NOT like ones on Surface buildings/Skyscrapers. They have to be significantly stronger ( like by 2 or 3 Magnitudes ), and strongly supported by the building's wall structure.
Rapture Sea Windows have to be integrally built/embedded into the thick structural walls/ceilings. They would get installed during surface construction to strongly seal the building section before it was lowered to the final installation site. You only see a small part of their metal framing structure, which has to be sunk DEEP into the adjacent wall's concrete to distribute the force of the water pressure upon the window. The larger in area the window is, the thicker the glass needs to be to hold up against the increasing leverage force pushing into the middle of each pane ( and acting to bend/force it inward ). 
The oversized windows first seen in Neptune's Bounty
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Dim, Dimmer, Dark :
One Problemo with Rapture's stylish Art Deco cityscape skyline is : Due to the short distance over which light gets completely absorbed in water, any tall/fancy buildings/decorations/towers/signs dwindle away with distance into darkness VERY FAST, and can hardly be seen a hundred feet away. So, you don't get much "Bang for your Buck" if you are styling them "for effect", especially when the costs of undersea building Construction is MANY times of what it is up above the Ocean surface.
This then loses much of the decorative aspect of what we think of as Art Deco type architecture for Rapture buildings. Interior use of 'external' type architecture is hampered by the need to contain them within limited open space volumes - when attempted it often leading to a great deal of huge unused space ( as was seen in BaSx ).
Note - Any attempt using ultra bright lights to illuminate things for longer distances would be too intense for anyone close up. Remember that Bright Sunlight dwindles to nothing within a few hundred feet in water. chart
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Those Fricken Huge Windows :
Real World buildings at Rapture's time generally did not have huge windows. And in Rapture, buildings cost many times as much to build as in any Surface city ( not just the difficulties of its undersea location, but also that the windows have to be overbuilt beyond the strength of German WW2 bunkers to withstand the ocean depth's pressure ). Big windows require big more complicated frames of metal reinforcement.
It was not just because of the expense, but because they were a liability - even ones above the surface just from wind ( and that's hardly with some 280 pounds per square inch constant water pressure pushing on them from the outside, as they are in Rapture ).
SO, you would have SMALLER well-supported windows. The window panes transferring the water pressure forces - inward compression onto the building's shell structure -- Embedded within a strong metal frame's tension (tensile strength) pulled towards the inside. The wider the 'Glass' is, the harder it is to make it stay flat and not bend/bulge inwards at its center where the potentially destructive leverage is maximized. The window's design must work against those forces. AND The force involved increases linearly with the window's size.
Few composite windows we saw were curved or domes ( which act as arches to horizontally transfer the in pressing force ). Most important would be many of the glass panes themselves having that shape - Employing curves to oppose for the pressure forces. We saw some ROUND windows, in Paupers Drop, which helps assist in minimizing the force leverage at the window pane's center.
Neptunes Bounty had huge windows ( needlessly, except to 'look good' for the game scene ). Even more HUGE windows were seen after the 'Big-ification' in the BaS DLC -- Infinite-itus where they got stuck on a style of huge volumes, for a place which should have been more closed-in, as per the original/previous visions of Rapture.
The Reinforced Concrete supporting the metal Window Frame itself would be heavily reinforced with Rebar. These Windows/Frames/Concrete-backings would be carefully pre-built at the Ocean surface, using many prefabricated components pre-assembled on land. This would allow proper Construction with inspection and testing - Something which would be horrendously difficult and expensive if attempted down in the deep ocean water.
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Window Fun In The Deep Blue Sea. Diagram of pressure forces stressing a square Window Pane. Note -- in the pane's middle, the inward pressure force is MANY MANY TIMES AS GREAT as at the edges -- It is the leverage of the force pushing in at the center of all that unsupported 'glass'.
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The Thick Glass Problem : 
( Depth 600 ft = 280 lb/sq in pressure on one side ) - Why Those huge Windows are problematic.
* Glass Strength - its Tensile Strength is fairly low : magnitude of 30 vs 400-550 for structural steel
* Its Shear (force) Strength likewise is bad ( glass generally is not ductile like metals )
* "Toughened glass", heated and chilled which closes off defects improving strength up to 5 X ( expensive and hard to do in large panes )
* Poly-Carbonates (a plastic) are less resistant to chemicals, cost alot more, but do have much higher strength ( but lose strength at a significantly lower temperature - melting ).
* Curves are better for handling compression across the window material's shape ( versus Flat panes with their increased shear effects ). Curves give a partial 'arch' support effect (compression strength being utilized).
* Consider what happens to glass when you try to bend it ?? Not good.
* These are windows, so the optical quality is very important ( If poor enough then is no point having a window ). The required non-fantasy thickness accentuates that issue.
* Windows Suffer a similar effect for any 'framing' when multiple panes are used. The required supports ( if they also aren't to bend ) have to be as massively strong as the main structural walls - more even, as the window edges have transmitted to them ALL the pressure force from that window's surface, which is NOT supporting itself directly.
Conclusion - Many Smaller windows for Rapture, and some larger ones ( still FAR smaller than the absurd ones seen a few places ) would be reserved for special things deserving their great expense.
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Massive Pressure Requires Proper Construction Design :
Curved Windows - An Arch Design Helps Alot - Distributing Force to the Buildings Structure. 
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