The Ingalls Building, built in 1903 in Cincinnati, Ohio, is the world’s first reinforced concrete skyscraper. The 16-story building was designed by the Cincinnati architectural firm Elzner & Anderson and was named after the primary financial investor, Melville E. Ingalls.
Image source: https://it.pinterest.com/pin/130041507960398258/?lp=true
The Ingalls is a massive structure, consisting of solid columns and foundations reinforced with the square-twisted steel bars that Ransome patented. According to the American Portland Cement Manufacturers Association, the Ingalls Building accounted for about one-half of one percent of all the cement used in the United States in 1902 to 1903.
Still in use today, the building was designated a National Historic Civil Engineering Landmark in 1974 by the American Society of Civil Engineers. In 1975, it was added to the National Register of Historic Places.
Info source: https://en.wikipedia.org/wiki/Ingalls_Building
Before the first bucket of concrete was poured, a major battle took place just to get the necessary permits to build the structure. Melville E. Ingalls, president of the Big Four Railroad and the building’s namesake, and Anderson fought for two years with Cincinnati’s building department before finally convincing them of the building’s stability and durability. Skepticism was high, because the existing height record for a concrete building was only six stories.
Legend has it that people were so sure the building would collapse that a local reporter once stayed all night outside the building, waiting for it to fall down.
Info source: http://www.asce.org/project/ingalls-building/
Why Reinforced Concrete?
Anderson chose concrete because it was fireproof and it would be less expensive to build a structure of this size with concrete than with steel. Henry N. Hooper of The Ferro-Concrete Construction Company in Cincinnati was the concrete contractor chosen to carry out Anderson’s vision. Hooper employed methods perfected and patented by Ernest L. Ransome, the man who had designed and built the world’s first reinforced concrete bridge, Alvord Lake Bridge, in San Francisco’s Golden Gate Park in 1889.
Image sourcce: wikimapia.org/14875621/Ingalls-Building
The amount of concrete produced during construction—100 cubic yards (76 m³) in each ten-hour shift—was limited by the rate at which the builders could place it. An extra wet mix was used to ensure complete contact with the rebars and uniform density in the columns. Rising at a rate of three stories per month, the Ingalls was completed in just eight months and has been in constant use ever since. It was the tallest reinforced concrete building in the world until the 281-foot tall Medical Arts Building in Dallas, Texas was built in 1923.
The Invention of Reinforced Concrete
Reinforced concrete development began with the French gardener Joseph Monier’s 1867 patent for large concrete flowerpots reinforced with a cage of iron wires. The French builder François Hennebique applied Monier’s ideas to floors, using iron rods to reinforce concrete beams and slabs; Hennebique was the first to realize that the rods had to be bent upward to take negative moment near supports. In 1892 he closed his construction business and became a consulting engineer, building many structures with concrete frames composed of columns, beams, and slabs.
In the United States Ernest Ransome, In 1884, patented the use of twisted steel bars for the reinforcing of concrete, following the paradigm of the steel frame. His pioneering efforts helped establish the viability of concrete for large, multi-level buildings.