Leon Moisseiff
Encyclopedia
Leon S. Moisseiff was a leading suspension bridge
engineer
in the United States of America in the 1920s and 1930s. He was awarded The Franklin Institute's Louis E. Levy Medal in 1933.
Born in Riga, Latvia into a Jewish family, Moiseiff started his education there and studied at the Baltic Polytechnic Institute for three years; he emigrated to the United States with his family at the age of 19 because of political activities. In the US, he graduated from Columbia University
with a degree in civil engineering in 1895.
He began his career in New York, and gained a national reputation as one of the designers of the Manhattan Bridge
over the East River. He also assisted chief engineer Ralph Modjeski
in designing the Benjamin Franklin Bridge
across the Delaware River.
He was an early advocate of all-steel bridges, which began to replace concrete and stone structures in the 1920s. He became known for his work on "deflection theory," which held that the longer bridges were, the more flexible they could be. Charles Alton Ellis
elaborated on Moiseiff's theories, and applied them in the design of the famed Golden Gate Bridge
. Moisseiff served as a consulting engineer on the bridge, but declined to speak up for his colleague Charles Ellis when he was fired from the project.
Moisseiff called the original Tacoma Narrows Bridge, the first bridge that he designed as the leading engineer, the "most beautiful bridge in the world." However, he lost his strong reputation when this narrow span across the Puget Sound in Washington State collapsed in a windstorm four months after it opened in 1940. The motion of the bridge earned it the name Galloping Gertie. The dramatic film of the bridge's collapse, as a twisting motion added to the stress of longitudinal waves along the span, is still shown to engineering
, architecture
, and physics
students as a good example of torsional flutter gone awry.
Moisseiff died of a heart attack in 1943. Though he had designed many other famous spans, the Narrows collapse overshadowed them all. It became a symbol of failed engineering and the dangers of arrogance in design. As tragic as this disastrous design flaw became to Moisseiff personally, it motivated the engineers to further research and substantially improve the design and safety of suspension bridges.
Suspension bridge
A suspension bridge is a type of bridge in which the deck is hung below suspension cables on vertical suspenders. Outside Tibet and Bhutan, where the first examples of this type of bridge were built in the 15th century, this type of bridge dates from the early 19th century...
engineer
Engineer
An engineer is a professional practitioner of engineering, concerned with applying scientific knowledge, mathematics and ingenuity to develop solutions for technical problems. Engineers design materials, structures, machines and systems while considering the limitations imposed by practicality,...
in the United States of America in the 1920s and 1930s. He was awarded The Franklin Institute's Louis E. Levy Medal in 1933.
Biography
Columbia University
Columbia University in the City of New York is a private, Ivy League university in Manhattan, New York City. Columbia is the oldest institution of higher learning in the state of New York, the fifth oldest in the United States, and one of the country's nine Colonial Colleges founded before the...
with a degree in civil engineering in 1895.
He began his career in New York, and gained a national reputation as one of the designers of the Manhattan Bridge
Manhattan Bridge
The Manhattan Bridge is a suspension bridge that crosses the East River in New York City, connecting Lower Manhattan with Brooklyn . It was the last of the three suspension bridges built across the lower East River, following the Brooklyn and the Williamsburg bridges...
over the East River. He also assisted chief engineer Ralph Modjeski
Ralph Modjeski
Ralph Modjeski was a Polish-born American civil engineer who achieved prominence as a pre-eminent bridge designer in the United States.-Life:...
in designing the Benjamin Franklin Bridge
Benjamin Franklin Bridge
The Benjamin Franklin Bridge , originally named the Delaware River Bridge, is a suspension bridge across the Delaware River connecting Philadelphia, Pennsylvania and Camden, New Jersey...
across the Delaware River.
He was an early advocate of all-steel bridges, which began to replace concrete and stone structures in the 1920s. He became known for his work on "deflection theory," which held that the longer bridges were, the more flexible they could be. Charles Alton Ellis
Charles Alton Ellis
Charles Alton Ellis was a professor, structural engineer and mathematician who was chiefly responsible for the structural design of the Golden Gate Bridge...
elaborated on Moiseiff's theories, and applied them in the design of the famed Golden Gate Bridge
Golden Gate Bridge
The Golden Gate Bridge is a suspension bridge spanning the Golden Gate, the opening of the San Francisco Bay into the Pacific Ocean. As part of both U.S. Route 101 and California State Route 1, the structure links the city of San Francisco, on the northern tip of the San Francisco Peninsula, to...
. Moisseiff served as a consulting engineer on the bridge, but declined to speak up for his colleague Charles Ellis when he was fired from the project.
Moisseiff called the original Tacoma Narrows Bridge, the first bridge that he designed as the leading engineer, the "most beautiful bridge in the world." However, he lost his strong reputation when this narrow span across the Puget Sound in Washington State collapsed in a windstorm four months after it opened in 1940. The motion of the bridge earned it the name Galloping Gertie. The dramatic film of the bridge's collapse, as a twisting motion added to the stress of longitudinal waves along the span, is still shown to engineering
Engineering
Engineering is the discipline, art, skill and profession of acquiring and applying scientific, mathematical, economic, social, and practical knowledge, in order to design and build structures, machines, devices, systems, materials and processes that safely realize improvements to the lives of...
, architecture
Architecture
Architecture is both the process and product of planning, designing and construction. Architectural works, in the material form of buildings, are often perceived as cultural and political symbols and as works of art...
, and physics
Physics
Physics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...
students as a good example of torsional flutter gone awry.
Moisseiff died of a heart attack in 1943. Though he had designed many other famous spans, the Narrows collapse overshadowed them all. It became a symbol of failed engineering and the dangers of arrogance in design. As tragic as this disastrous design flaw became to Moisseiff personally, it motivated the engineers to further research and substantially improve the design and safety of suspension bridges.