Ole Knutsen Singstad (June 29, 1882 – December 8, 1969) was a Norwegian-American civil engineer best known for his work on underwater vehicular tunnels in New York City. Singstad designed the ventilation system for the Holland Tunnel, which subsequently became commonly used in other automotive tunnels, and advanced the use of the immersed tube method of underwater vehicular tunnel building, a system of constructing the tunnels with prefabricated sections.
He also designed the Lincoln Tunnel, Queens–Midtown Tunnel, and Brooklyn–Battery Tunnel. By 1950, Singstad had designed and overseen the construction of more underwater tunnels than all other engineers combined. In 1946, the Triborough Bridge Authority under Robert Moses took over tunnel construction in New York, and Singstad was subsequently sidelined as Moses favored bridges over tunnels.
Early life
Ole Singstad was born at Singstad farm in the Lensvik area of Rissa Municipality (now part of Orkland Municipality in Trøndelag county), Norway. He was the seventh of nine children born to Knut Jacobsen Singstad (May 17, 1831 – November 24, 1906) and Anne Mikkelsdatter Auset Singstad (July 10, 1843 – April 30, 1947).
New York City tunnels
Singstad is widely known for work on the underwater road tunnels in New York City and for designing the ventilation system that made long underwater road tunnels possible, first used in the Holland Tunnel under the Hudson River. He began working under chief engineer Clifford Milburn Holland in 1915, and he finished directing construction of the Holland Tunnel after the death of Holland in the fall of 1924 and of Holland's successor Milton H. Freeman, who died in March 1925. the Queens–Midtown Tunnel, and the Brooklyn–Battery Tunnel,
In 1946, the Tunnel Authority was taken over by the Triborough Bridge Authority, forming the Triborough Bridge and Tunnel Authority, whereupon Singstad was fired, and the incomplete Brooklyn-Battery Tunnel was finished to specifications by TBTA chief engineer Ralph Smillie,
Other work
Singstad was instrumental in numerous underwater vehicular tunnels worldwide.
From 1930 to 1933, he designed and led construction of the Waasland tunnel under the Schelde River in Antwerp. The retreating French set explosives in the tunnel when the war began in 1940; the damage was repaired in weeks under German occupation. Later, the Germans tried again to explode the tunnel when they withdrew in 1944, and this time the tunnel was more seriously damaged. The tunnel was inundated with river water, and repairs took several years.
- He consulted on the Posey Tube, the second underwater vehicular tunnel in the United States and the oldest immersed tube vehicular tunnel in the world, which used the same ventilation system that he had designed for the Holland Tunnel.
- He consulted on the Detroit–Windsor Tunnel, the third oldest underwater vehicular tunnel, designed by fellow Norwegian-American engineer Søren Anton Thoresen, and designed the ventilation system.
- With Thoresen, he designed the Waasland tunnel under the river Scheldt in Antwerp, Belgium. On this project, Singstad designed the lining, the tunnel shield, the ventilation, and the equipment.
Singstad also designed tunnels in Argentina, Canada, Cuba, and Venezuela.
Pioneering techniques
Ventilating the Holland Tunnel
Thomas Edison had contended it was impossible to ventilate a tunnel with the volume of traffic envisioned for the Holland Tunnel. There were very few tunnels at that time that were not used by rail traffic; the most notable of these non-rail tunnels, the Blackwall Tunnel and Rotherhithe Tunnel in London, did not need mechanical ventilation.
In October 1920, General George R. Dyer, the chairman of the New York Tunnel Commission, published a report in which he stated that Singstad had devised a feasible ventilation system for the Hudson River Tunnel. Working with Yale University, the University of Illinois, and the United States Bureau of Mines, Singstad built a test tunnel in the bureau's experimental mine at Bruceton, Pennsylvania, measuring over long, where cars were lined up with engines running. Volunteer students were supervised as they breathed the exhaust in order to confirm air flows and tolerable carbon monoxide levels by simulating different traffic conditions, including backups. In October 1921, Singstad concluded that a conventional, longitudinal ventilation system would have to be pressurized to an air flow rate of along the tunnel.
Two thousand tests were performed with the ventilation system prototype. The system was determined to be of sufficiently low cost, relative to the safety benefits, that it was ultimately integrated into the tunnel's design. The public and the press proclaimed air conditions were better in the tubes than in some streets of New York City; after the tunnel opened, Singstad stated that the carbon monoxide content in the tubes were half of those recorded on the streets.
Prefabricated tunnel sections
During construction of Baltimore Harbor Tunnel from 1955 to 1957, Singstad adopted a cost-saving method for the construction of the tunnel in the river mud. Previously, hydraulic shields or pressurized caissons had been used — with the constant danger of divers suffering the bends, and the necessity for constant diligence. A sunk-tube method had been earlier proposed and used by Olaf Hoff on the Detroit River tunnel and Harlem River Tunnel.
Singstad advanced Hoff's ideas and proposed first digging a large ditch in the river bottom and lowering cable-suspended pre-fabricated tunnel sections in length (weighing 23,000 tons each) into the ditch from overhead barges. Interior chambers were filled with water to lower the sections, the sections then aligned, bolted together by divers, the water pumped out, and the tunnels finally covered with earth. This technique was followed in numerous later tunnel projects by other engineers, on the Chesapeake Bay Bridge–Tunnel, for example.
Personal life
In 1912, Singstad married Else Johansen He is buried in Brooklyn's Green-Wood Cemetery.
Honors and awards
Singstad received honorary doctorates from the Stevens Institute of Technology of Hoboken, New Jersey; St. Olaf College of Northfield, Minnesota; and in 2008, a lecture in his honor was held at the Museum of Modern Art.
Singstad was named 1933 Officer of the Order of the Crown of Belgium, and received the 1959 Chilean Order of Merit in the grade of commander.
At age 48, Singstad received the Royal Norwegian Academy of Science Society, an award normally reserved for much older people.