Reinforced Concrete

It is a large, imposing structure (over a dozen rooms and spacious halls) dominated by a four-story octagonal tower at one corner and a second shorter square tower at another corner containing tanks for potable and fire-fighting water supply.

The Salginatobel Bridge, spanning the Salgina Valley ravine, is the earliest surviving three-hinged, hollow box arch bridge designed by  Robert Maillart.

The Kamehameha V Post Office is the oldest surviving public building in the U.S.  constructed with reinforced concrete. The success of this early structure helped establish the value of reinforced concrete as a durable construction material.

Brickmaker J.G. Osborne was chosen to provide design and construction. He  immigrated to Hawaii from Yorkshire, England, and was aware of the recent  development of Portland cement and its expanding use in Europe. It is believed that the leaders of Hawaii were anxious to adopt British skills, which influenced their selection of Osborne.

The 16-story Ingalls Building, still in use today, was the world's first reinforced concrete skyscraper. Its success led to the acceptance of high-rise concrete construction in the United States.

Melville E. Ingalls, for whom the building is named, spent two years convincing city officials to issue a building permit. Skepticism was high, because the existing height record for a concrete building was only six stories.