The Ingalls Building: The World's Enforced Concrete Skyscraper

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INTRODUCTION
The Ingalls Building is the world’s first reinforced concrete skyscraper, and is renowned for its construction methods in the use of reinforced concrete. The Ingalls Building is located in Cincinnati, Ohio, and is named after Melville E. Ingalls. The building was designed to house office spaces and is 16 stories or 210 ft. (64 m) tall (1). Construction on the building began on October 2, 1902 and concluded July 1903. It was designed by architects Alfred O. Elzner and George M. Anderson. Henry N. Hooper, a structural engineer, was the contractor. The Ingalls Building was named a Historical Landmark by the American Society of Civil Engineers (ASCE) in 1973. This report discusses two of the cutting edge techniques
The concrete for the slabs, beams, and columns for each floor were all poured at once and Ransome’s twisted steel bars were used in vertical and horizontal reinforcements. The column sizes were different depending on where on each floor a column was located and the load bearing strength it possessed. Between four and ten of these twisted steel bars would be placed inside of the columns. These reinforcing bars helped to resist tensile strains from wind pressures and the stress from the floor loads (2). The strength that the walls and columns were granted due to the reinforcing steel bars allowed for the Ingalls Building to be 210 ft. (64 m) tall. This framing system was used to handle different maximum loads as the floors went up. The first floor could resist a load of 200 pounds per square foot, the second floor could support a load of 80 pounds per square foot and the rest of the floors up to the roof could sustain a load of 60 pounds per square foot (3). The roof load was 40 pounds per square foot. (3). The steel bars hooked together to balance the weight that the concrete frame could support. Ernest Ransome’s twisted steel bar patent from 1884 shows how they were used in construction of the Ingalls Building. The left image shows how the bars were placed within the columns and the right image is of the
The groundwork laid by Ransome, Monier, Wayss and others was utilized by Henry Hooper to create the building that is still standing today. The Ingalls Building, now known as the Transit Building (3), still stands in Cincinnati today at the corner of 4th Street and Vine Street. The monolithic beam-column construction and the two-way reinforcing system worked together to showcase the benefits of using reinforced concrete in the construction of large scale buildings. The Ingalls Building paved the way for skyscrapers today which use reinforced concrete to achieve great heights. For example, the Petronas Twin Towers in Kuala Lumpur, Malaysia which stands at 1,483 ft. (452 m) high (5). The innovative knowledge gained during the design and construction of the Ingalls Building has been built upon and used in present day construction