The steel skeleton frame

Assembled from 20 blocks · 2 evidence · 13 related

1. Story
2. A three-dimensional cage of metal columns and beams that carries the entire weight of a building, including the weight of its own external walls, floor by floor. Its consequence is categorical rather than incremental: in a load-bearing masonry building every extra storey thickens the walls at the bottom, so height is bought by losing ground-floor area, and a sixteen-storey masonry building such as Chicago's Monadnock Block ends up with walls roughly two metres thick at street level. In a frame, the wall carries nothing but itself and the wind, so it can be thin, or glass, or hung from the frame like a curtain. The frame also needs lateral bracing against wind, fireproofing of the metal (early frames were clad in terracotta or concrete because unprotected steel loses strength in a fire), and a mechanical way of reaching the upper floors. The system spreads from Chicago and New York in the 1880s and 1890s and is still the basis of tall building construction.
3. Knowledge
4. The steel skeleton frame
5. Structural steel
6. Connections
7. Load path
8. Structural steel
9. The curtain wall
10. Home Insurance Building, Chicago
11. The Home Insurance Building is completed in Chicago
12. Demolition supplies the evidence for the claim
13. The steel skeleton frame
14. Reinforced concrete
15. Bessemer describes the converter to the British Association
16. The Hennebique system makes reinforced concrete a frame
17. Burj Khalifa opens at 828 m
18. Evidence
19. Jenney's Home Insurance Building (1885) is conventionally identified as the first tall building carried on a metal skeleton frame, and the claim is qualified in the scholarly literature. Supports the frame, elevator and Chicago School records. V55 verification basis: the site was not reachable in this session; entries are cited by title from established record.
20. Standard structural history of Chicago commercial building, including the composition of the Home Insurance Building frame as established when the building was demolished in 1931, and the qualifications attached to the "first skyscraper" claim. V55 verification basis: real and standard, not consulted in this session.