Ingalls Building

The Ingalls Building in Cincinnati, Ohio, is a sixteen-story skyscraper completed in 1903 and considered the first of its kind built of reinforced concrete. Named after Melville E. Ingalls, who had to convince the city government of the material's load-bearing capacity, the structure draws on the engineering principles of Ernest Leslie Ransome. Ransome had previously patented the use of twisted reinforcing bars, which made it possible to use reinforced concrete in large multistory buildings in the first place. Rising about 210 feet (64 meters), the building relies on the rigid membrane of its floor slabs to form a stable structure against wind loads. A landmark of national significance in both engineering and history, the building marks a decisive milestone in the development of modern skyscraper architecture.