Part of my plan for a permanent civilization is to have buildings constructed to 10,000 year standards. When buildings are very permanent, the people using them can use their time more productively than constantly reconstructing their homes and other structures. In that very long period of time, a typical wooden structure would require replacement perhaps 100 times. Thus, if very long-lived structures could be built at a reasonable cost, they would prove to be more economical than current buildings. Stone domes are the strongest possible hollow structures; for example the Pantheon dome in Rome (at 41.8985, 12.4768) is almost 2,000 years old and is still in good condition and fulfilling its original purpose of displaying the Roman gods.
A sliced view of the Pantheon in Rome.
The largest concrete dome presently under construction is in located in Ensley, Alabama at 33.5146, -86.9261, which demonstrates just how big these things can get. However, it would be better, for my purposes, to build smaller domes of sandstone or granite because the manufacture of cement used in that dome requires the burning of large quantities of fossil fuel, which creates CO2 pollution. The typical future domes need not be nearly so large as the Pantheon or the Ensley dome, and they could be placed side by side touching together in rows and columns two wide by ten long with connecting doors between and side doors to the street. Or more easily as a paraboloid sectioned tube like the Orly dirigible hangers.
Orly airport dirigible hanger.
The domes are built up in a spiral, like an igloo, and could be constructed quickly by a three-man team from precisely shaped pre-made blocks. This requires the blocks to be made in a specialized modern factory that can control precisely the three-dimensional shape of each block. What I have in mind is to construct a circular base of bound together pre-cut stones to form a solid foundation and then to spiral upward toward in one continuous course to the top with these individually unique blocks. The finished profile would look like a parabola, similar to the St. Louis Gateway arch rotated around the center of its base, but usually only a portion of the arch and much smaller.
St St. Louis Gateway Arch showing the ideal dome shape in profile
Each block in the spiral would be unique, but with modern laser slicing and computer control that could be done with sufficient precision. Or a little easier would be to have each course of blocks identical, with a unique block only at the change point. The blocks are large at the bottom and smaller at the top, as seen in the St. Louis arch. At the bottom the blocks are simply set into place using a standard self-erecting crane positioned in the center of the base circle, and as the dome rises each new block is held in place by friction with the bottom and with the previously placed block beside it. As the dome rises the friction would not be enough to keep the blocks from toppling in so there are pre-positioned anchor points on the outside and inside of the foundation base with a cable strung over the top of each new block on the ascending spiral holding it in place. As each new block is brought up to its final resting place the cable which was holding the lower course block in place has its tension released and the cable is placed over the new block. As the spiral course is about halfway up there would be about 100 of these tension cables holding the top course in place. Nearer the top the new blocks will be held in place wholly by the cable tension, but when the annulus ring or topmost stone is in place there will be no more need for these tension cables and the dome will be complete and be very strong and permanent.
Because these stones are carefully cut to their special shapes there is no need for mortar between the blocks, but it would be necessary for weather-proofing to put a thin layer of tar between each of the joints. This very stiff tar could be pre-applied at the factory. Also it would be desirable to place locking stones into pre-drilled holes in the adjoining sides of the blocks to prevent movement during earthquakes and help maintain the blocks’ alignment for the very long expected lifetime of these domes. Each of these blocks could also have pre-drilled holes running through the blocks around the dome for the insertion of tensioning wires, if it were decided it was needed. Each block at the factory could also have pre-set anchor points built into each block and some permanent insulation fused glass-like directly onto the inside and outside surfaces.
The plan is to make these domes as permanent as possible with no need for maintenance or for outside energy to keep them either warm or cool, with opening and closing of heat exchanger equipped wind-holes being sufficient. Because this structure is so very strong, the roof can be covered over with soil and made into a garden with a greenhouse so there would be a garden setting for a restaurant gazebo and fresh vegetables available. If an annulus was built into the top, daylight could be brought in with sun-tracking mirrors so there would be less need for internal lighting.
This whole dome is easy to construct if the blocks are exactly fit to their place; therefore, what needs to be done now are the tests for shaping large blocks of sandstone or granite to precise dimensions. If that can be done cheaply enough, then this whole dome project becomes feasible and people could use these easily made and standardized structures for ten thousand years. Because each stone is unique it has no other purpose and will not be mined for other uses. However, the entire dome could be deconstructed and reconstructed at another site if needed. If during a war some of these domes were partially destroyed, new ones could be constructed from the surviving pieces if each of the thousand unique blocks had been made to standardized shape.
