Norwegian-American civil engineer and inventor (1876–1953)
Nils F. Ambursen (February 6, 1876 – January 17, 1953) was a Norwegian-American
civil engineer and
inventor. He was the founder of Ambursen Hydraulic Construction Company and was known for his influential
dam designs in the early 20th century.[1]
Working for the
B. F. Sturtevant Company in
Hyde Park, Boston,
Massachusetts, in 1903, Ambursen developed an innovative
concrete slab and
buttress dam for an industrial client in
Theresa,
New York.[3][4] Ambursen's design was for a
buttress dam requiring minimal buttress thickness in which the upstream part is a relatively thin flat slab typically made of reinforced concrete. Ambursen's concrete-slab-and-buttress design used far less material than a traditional
gravity dam making it both a significant engineering advance and cost effective for clients.[5]
Ambursen promptly filed a
patent on his own behalf and organized the Ambursen Hydraulic Construction Company, based in Boston. From 1903 through 1917, the company used the technique to construct more than one hundred dams in North America, most in
New England. The record-breaking 41-meter-tall (135-foot) La Prele Dam in
Converse County, Wyoming used 43 percent less concrete than an equivalent concrete gravity dam.
[6]
The structure allowed an interior hollow under the
spillway; the 1907
Bloede's Dam on the
Patapsco River in
Maryland housed its
hydroelectric power plant inside that hollow and therefore "under water". The company sued to preserve its patents fairly aggressively but with mixed success.[7] In some cases, the Ambursen dam became a more generic "Ambursen type", for instance at the 1911
Lock and Dam No. 1 on the
Upper Mississippi River between
Minneapolis and
Saint Paul,
Minnesota. Civil engineer George Freeman received his own November 1912 patent on a modified version of the concrete buttress dam used there.[8]
In 1917, Ambursen left his company, which has continued to bear his name for over a hundred years.[9] Today perhaps fifty Ambursen-type dams from the post-
World War II era stand outside the United States. The tallest example, 83 meters (272 ft), is the 1948 Escaba Dam (Dique Escaba) in
Tucumán,
Argentina.[10]
Hager, Willi H. (2015) Hydraulicians in the USA 1800-2000: A biographical dictionary of leaders in hydraulic engineering and fluid mechanics (Boca Raton, FL: CRC Press)
ISBN9781315680125