111. The details oj an efficient structure.
If we assume now that an efficient building will be both compressive and continuous, we can obtain the main morphological features of its structure by direct inference.
i. Its ceilings, floors, and rooms must all be vaulted. This follows directly. The dome or vault shape is the only shape which works in pure compression. Floors and roofs can only be continuous with walls, if they curve downward at their edges. And the shape of social spaces also invites it directly—since the triangle of space between the wall and ceiling serves no useful purpose, it is a natural place for structural material.
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| Vaults. |
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CONSTRUCTION
3. Walls must all be. load-bearing. Any non load-bearing partition evidently contradicts the principle of continuity which says that every particle of the building is helping to resist loads. Furthermore, columns with non load-bearing partitions between them need shear support. The wall provides it naturally; and the continuity of the walls, floor, and ceiling can only be created by the action of a wall that ties them together.
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| Load-bearing avails. |
3. Walls must be stiffened at intervals along their length by columnar ribs. If a wall is to contain a given amount of material, then the wall acts most efficiently when its material is redistributed, nonhomogeneously, to form vertical ribs. This wall is most efficient in resisting buckling—indeed, at most thicknesses this kind of stiffening is actually required to let the wall act at its full compressive capacity—see final column distribution (213). And it helps to resist horizontal loads, because the stiffeners act as beams against the horizontal forces.
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| Vertical stiffeners. |
4. Connections between walls and floors, and between walls and walls, must all be thickened by extra material that forms a fillet along the seam. Connections are the weakest points for continuity, and right-angled connections are the worst. However, we know from the shape of indoor space (191) that we cannot avoid rough right angles where walls meet walls; and of course, there must be rough right angles where walls meet floors. To counteract the effect of the right angle, it is necessary to “fill” the angle with material. This principle is discussed under column CONNECTIONS (227).
| 2 o6 EFFICIENT STRUCTURE |
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| Thickened connections. |
| 5. Openings in walls must have thickened jrames> and rounding in the upper corners. This follows directly from the principle of continuity and is fully discussed in frames as thickened edges (225). |
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| Openings. |
Therefore:
Conceive the building as a building made from one continuous body of compressive material. In its geometry, conceive it as a three-dimensional system of individually vaulted spaces, most of them roughly rectangular; with thin load-bearing walls, each stiffened by columns at intervals along its length, thickened where walls meet walls and where walls meet vaults and stiffened around the openings.
continuity of material
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The layout of the inner vaults is given in floor and ceiling layout (210) and floor-ceiling vaults (219); the layout of the outer vaults which form the roof is given in roof layout (209) and roof vaults (220). The layout of the stiffeners which make the walls is given in final column distribution (213); the layout of the thickening where walls meet walls is given by columns at the corners (212); the thickening where walls meet vaults is given by perimeter beams (217)-, the construction of the columns and the walls is given by box columns (216) and wall membranes (218) ; the thickening of doors and window frames is given by frames as thickened edges (225); and the non-right-angled connection between columns and beams by column connection (227). . . .
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| 207 GOOD MATERIALS** |
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