The other day I got curious about what goes into determining optimal skyscraper height, and went down a rabbit hole. Apparently, most of our understanding of skyscraper economics is based on a book written in 1930 by W. C. Clark and J. L. Kingston (CK), an economist and architect, respectively. Titled
The Skyscraper: A Study in the Economic Height of a Modern Office Buildings, the book aims to figure out the height of a given skyscraper that would maximize returns, given rents, cost of land and construction costs. They refer to this as the "Economic Height".
The authors mostly examined Manhattan, but their methodology has since been applied all over the world and has been found to hold true. The gist of it is that the main driver of skyscraper height is economic growth and urbanization. There's a feedback loop in play: the number of tall buildings in a city, as well as their collective heights, tends to be the greatest predictor of the number and height of future skyscrapers. This is good news for us here in Austin because it means there are more supertalls in our future.
The other interesting thing I found was a comparison of cost-per-floor numbers across Asia vs. the United States. The Burj Kalifa, which is the world's tallest building at 163 floors, cost only $1.5 billion, which comes down to $9 million per floor. In contrast, the 58-story Bank of America building in New York cost $1.76 billion, i.e. $37 million per floor. Apparently the difference can almost entirely be attributed to labor and material costs between the two locations. Indeed, this appears to be one of the reasons Asia has built so many supertalls over the past 100 years:
The other interesting bit I found was a breakdown of materials used in the construction of skyscrapers over time:
Not sure what "composite" stands for — I can only assume it's reinforced concrete or something similar?