Slenderness ratio
In architecture, the slenderness ratio, or simply slenderness is the quotient between the width of a building and its height.
In structural engineering, slenderness is a measure of the propensity of a column to buckle. It is defined as where is the length of the column and is the radius of gyration, the latter defined by where is the area of the cross-section of the column and is the second moment of area of the cross-section. Slenderness captures the influence on buckling of all the geometric aspects of the column, namely its length, area, and second moment of area. The influence of the material is represented separately by the material's modulus of elasticity .
Structural engineers generally consider slender those skyscrapers with a ratio maximum of 1:10 or 1:12. Slim towers require to adopt specific measures to counter the high strengths of the wind in the vertical cantilever, like including additional structures to endow greater rigidity to the building or diverse types of tuned mass dampers to avoid unwanted swinging.[1]
The most slender residential skyscraper in the world is the Highcliff of Hong Kong which, with 72 floors and a height of 252 metres (827 ft), possesses one of the most extreme slenderness ratios, 1:20. Its extreme slenderness is characteristic of Hong Kong, where there are more pencil-shaped buildings than in any other place in the world.[2]
Examples
| Building | Floors | Height (m) | Slenderness | Year |
|---|---|---|---|---|
| 111 West 57th Street | 82 | 438 | 1:23 | 2018 |
| Highcliff | 73 | 252 | 1:20 | 2003 |
| Sky Hous | 55 | 179 | Between 1:12 and 1:17 | Proposed |
| One Madison Park | 50 | 188 | 1:12 | 2016 |
| 785 Eight Avenue | 42 | 158 | Between 1:18 and 1:15 | Proposed |
| 432 Park Avenue | 85 | 425.5 | 1:15 | 2015 |
References
- ↑ Willis, Carol. "The Skyscraper Museum: SKY HIGH & the logic of luxury WALKTHROUGH". Retrieved 2016-01-24.
- ↑ Willis, Carol. "Presented by The Skyscraper Museum" (in inglés). Retrieved 2016-01-24.