Rules · Structure · Plans · Use
Span the whole depth of the building with the structure so that each floor is a single open plate, adaptable to uses that cannot be foreseen.
Pompidou: 48 m clear span between column lines, 13 bays of 12.8 m
The Centre Pompidou’s floors are carried by steel lattice girders spanning 48 m between two rows of columns. The girders rest on gerberettes, short cast-steel rocker brackets that pivot on the columns and are tied down at their outer ends: an idea of the engineer Peter Rice at Ove Arup. With the structure on the outside and the services beyond it, the interior is left as open as a warehouse. The dream of indeterminate, flexible space links Mies’s universal space to the high-tech hangar.
Frame a sphere by subdividing the triangular faces of an icosahedron and projecting the points onto the sphere; the triangulated net of short struts spreads loads through the whole surface and encloses the greatest volume for the least material.
full sphere of frequency ν: 30ν² struts, 20ν² triangles, 10ν² + 2 hubs
A saddle surface in which two opposite corners are raised and two lowered is a hyperbolic paraboloid; it contains two families of straight lines, so it can be formed with straight boards and yet has double curvature.
y = k·x·z (or any bilinear patch through four points not in one plane)
A thin curved shell carries load by the membrane forces in its surface, not by bending; so shape it to its loads and supports, and it can span great distances with a thickness of a few centimetres.
span ÷ thickness of a good shell ≈ 400–1000 (an egg: ≈ 100)
A fabric or cable-net roof is stable only if it is prestressed into an anticlastic (saddle) shape, curved upward in one direction and downward in the other, so that wind from either side meets a surface already in tension.
Move ducts, pipes, lifts and escalators out of the building’s core onto its exterior, colour-code them, and let them become the architecture, leaving the interior free and making the plant easy to reach and replace.
In a framed building the columns and beams carry every load; the outer wall can be reduced to a light cladding hung on the frame, floor by floor, and need grow no thicker as the building rises.
load-bearing wall: thickness grows with height · frame: cladding thickness constant
Cite this page Chris Paton, “Column-free floors for any use”, The Textbook of Architecture, https://textbookofarchitecture.com/rule/free-floor. Text, drawings and models licensed under CC BY-NC 4.0.