User blog comment:Unownshipper/Metallurgists Wanted: Rapture's Natural Resources/@comment-8299550-20140811221953/@comment-75.36.139.127-20140812041613

Lots of curved surfaces to make use of compressive forces (just like an arch). Girders inside a shell to distribute the forces around the empty space within (some tension/shear force).

600 foot depth ~20 atm 280lb/sqin pressure still means massive (thick) supports no matter what its made of for large structures (versus 1 inch of steel for a (small ~12foot) curved bathysphere shell). Large flat panes of window -- bad very bad (as Epstein the Swami would say).

Lots and lots of massive concrete (including interior compression struts) - 'expensive' Ryanium around windows and thge few places 'thin' is desirable.

Rebar and fiber cement additives (often more to let the concrete set properly without stress crack formation)