Pneumatic Caissons: The Technology Behind the Tallest Buildings in the World

Darrin VonStein
Architectural Historian
Darrin VonStein, New York City

The Manhattan Life Insurance Building was the first building in New York City to employ a self-supporting iron and steel frame with non-structural curtain walls, fireproofing, wind-bracing, and express elevators, while incorporating innovative and extensive plumbing, heating and ventilation systems. All those components combined made this the most up-to-date building at the time of its construction, but what set this building apart from everything that came before it was that it incorporated pneumatic caissons for its foundation.

By the early 1890s, architects and engineers in Chicago and New York had embraced the technological and structural advances afforded by skeletal construction. As that technology eventually pushed the limits of pile, raft and grillage foundations, new solutions for stabilizing these massive new structures were required. Caissons immediately proved to be the pivotal technological application that allowed for greater distribution of building loads, speeding up the construction process and solving the problem of buildings settling in the soft clay and quicksand.

During the 1890s, both New York and Chicago would continue to develop and refine caisson foundations. By 1915, caissons would be applied to skyscrapers all over the United States and Canada, ultimately proving that the technology used in the Manhattan Life Insurance Building established the final, key component that would allow skyscrapers to reach unprecedented heights.