1931

Empire State Building

Homer G. Balcom (1870–1938)

For 40 years the Empire State Building in New York City held the record as the tallest building in the world. This was just one of many records it set.

Since the time of its opening in 1931, the Empire State Building has been considered to be one of the world’s great engineering achievements. It was originally designed by the architecture firm Shreve, Lamb, and Harmon; developed by John J. Raskob; and its chief structural engineer was Homer G. Balcom. The assembly process was highly tuned and impressively rapid—the elapsed time from first foundation work to completion was just 405 days. To make this kind of construction rate possible, the 58,000 tons of steel used in the building were all prefabricated into columns and beams in a factory, then trucked to the site—one of the early examples of just-in-time manufacturing. Workers used bolts and hot rivets to connect the steel pieces together. The rate of construction was 4.5 floors per week, with steel arriving at the site at a rate of approximately 10,000 tons per month.

Another key to quick construction was parallelizing the work. As workers finished each floor’s steel framework, it was covered in heavy wood planking to create a platform for the construction of the floor above. Plumbers and electricians followed the steel workers in close succession, and the construction of the outer cladding started just weeks after the steel framework began rising.

The engineering of the outer cladding itself contributed significantly to the construction speed. If you look at the building above the first few floors, you see a regular pattern of chrome trim pieces rising vertically. Then there are the 6,400 windows. Between the windows vertically are cast aluminum panels, and beside the windows are limestone panels. Behind the aluminum and limestone are eight-inch-thick brick walls made of ten million bricks resting on steel beams at each floor. Plaster covering the bricks forms the interior walls. Each floor is a concrete slab poured in place. Engineers have developed innovative modular building practices, setting new records many decades later, and making unimaginably tall buildings like Burj Khalifa possible. But given the technology available in 1931, the construction speed and height of the Empire State Building is still impressive even today.

SEE ALSO Tuned Mass Damper (1977), Burj Khalifa (2010), Instant Skyscraper (2011).

Aerial view of New York, focusing on the Empire State Building.