More
than a half century ago, the dramatic collapse of the Tacoma Narrows Bridge
sparked a major investigation into the effects of wind on suspension bridges.
To coordinate the many activities that were to be undertaken, the Advisory
Board on the Investigation of Suspension Bridges was formed. The Board
was broadly representative of engineers responsible for specific suspension
bridges, research engineers having competence in aerodynamics and suspension
bridge theory, and representatives of industry with demonstrated ability
and leadership in the fabrication and erection of suspension bridges.
The Bureau of Public Roads (later the Federal Highway Administration),
embarked upon a broad research program which involved coordinating national
and international wind investigations, sponsoring contract research, conducting
laboratory and field studies in-house, and providing technical guidance
through committees, panels, or research councils.
The
Bureau made a careful survey of existing wind tunnel facilities in the
United States to determine if one might be adapted for the purpose of
studying the effects of wind forces on suspension bridges. The results
of the study determined that it would be more cost effective and expeditious
to build its own specialized facility. During the 1950's, the Aerodynamics
Laboratory and wind tunnel were designed, constructed, and placed into
service at the Turner-Fairbank Highway Research Center in McLean, Virginia.
The
facilities which have evolved from this research program are unique in
the nation. The Aerodynamics Laboratory is the only wind tunnel specifically
designed for and dedicated to ensuring the aerodynamic stability of transportation
structures, especially long-span bridges. The wind tunnel with its relatively
large cross section produces laminar flow and is very stable at low velocities.
Its size and velocity range enable both static and dynamic investigations
of large-scale section models of structures and structural components.
The significance of structural details can be evaluated as well. A computer-driven
turbulence simulation system is available to introduce properly scaled
gusting into the air flow during testing. This system was the first of
its kind in the world. To measure wind forces on sectional models, a high-frequency,
dual force-balance system is available. Although other wind tunnels use
high-frequency balances, ours is unique in that it is actually two matched
balances in one system and can be used to directly measure unbalanced
loads on the structural model.
To complement the research and development activities associated
with wind tunnel experiments the activities of the laboratory were expanded.
Over the years the laboratory activity has grown to include more and more
full-scale studies with many bridges across the United States being instrumented
and analyzed. In addition, in recent years, efforts have been under
way to develop numerical and computational modeling of fluid and structural
interaction in particular as applied to long-span bridges.
More
than a half century ago, the dramatic collapse of the Tacoma Narrows Bridge
sparked a major investigation into the effects of wind on suspension bridges.
To coordinate the many activities that were to be undertaken, the Advisory
Board on the Investigation of Suspension Bridges was formed. The Board
was broadly representative of engineers responsible for specific suspension
bridges, research engineers having competence in aerodynamics and suspension
bridge theory, and representatives of industry with demonstrated ability
and leadership in the fabrication and erection of suspension bridges.
The
Bureau made a careful survey of existing wind tunnel facilities in the
United States to determine if one might be adapted for the purpose of
studying the effects of wind forces on suspension bridges. The results
of the study determined that it would be more cost effective and expeditious
to build its own specialized facility. During the 1950's, the Aerodynamics
Laboratory and wind tunnel were designed, constructed, and placed into
service at the Turner-Fairbank Highway Research Center in McLean, Virginia.
The
facilities which have evolved from this research program are unique in
the nation. The Aerodynamics Laboratory is the only wind tunnel specifically
designed for and dedicated to ensuring the aerodynamic stability of transportation
structures, especially long-span bridges. The wind tunnel with its relatively
large cross section produces laminar flow and is very stable at low velocities.
Its size and velocity range enable both static and dynamic investigations
of large-scale section models of structures and structural components.
The significance of structural details can be evaluated as well. A computer-driven
turbulence simulation system is available to introduce properly scaled
gusting into the air flow during testing. This system was the first of
its kind in the world. To measure wind forces on sectional models, a high-frequency,
dual force-balance system is available. Although other wind tunnels use
high-frequency balances, ours is unique in that it is actually two matched
balances in one system and can be used to directly measure unbalanced
loads on the structural model.