Tacoma Narrows Bridge
Facing west atop the Tacoma Narrows
Carries	State Route 16
Crosses	Tacoma Narrows
Locale	Tacoma to Gig Harbor, Washington
Design	Dual Suspension
Longest span	2,800 ft (853 m)
Total length	5,979 ft (1822 m)
Clearance below	187. State Route 16 is a State highway in Washington, USA It extends just over 27 miles (43 km from Tacoma in the southeast to Gorst Narrowsjpg|thumb|277px|right|The Tacoma Narrows as viewed from Tacoma facing northwest towards the Kitsap Peninsula Gig Harbor is a city in Pierce County, Washington, United States. This article is concerned with a particular type of suspension bridge the suspended-deck type 5 ft (57. 15 m)
Opening date	October 14, 1950 (westbound) July 15, 2007 (eastbound)
Toll	Eastbound only: $3. Events 1066 - Norman Conquest: Battle of Hastings - In England on Senlac Hill seven miles from Hastings, the forces Year 1950 ( MCML) was a Common year starting on Sunday (link will display the full calendar of the Gregorian calendar. Events 1099 - First Crusade: Christian soldiers take the Church of the Holy Sepulchre in Jerusalem after the final Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. 00 (cash/credit price), $1. 75 (transponder price)

The Tacoma Narrows Bridge is a pair of mile-long suspension bridges in the U.S. state of Washington, which carry State Route 16 across the Tacoma Narrows between Tacoma and the Kitsap Peninsula. This article is concerned with a particular type of suspension bridge the suspended-deck type The United States of America —commonly referred to as the Washington ( is a state in the Pacific Northwest region of the United States. State Route 16 is a State highway in Washington, USA It extends just over 27 miles (43 km from Tacoma in the southeast to Gorst Narrowsjpg|thumb|277px|right|The Tacoma Narrows as viewed from Tacoma facing northwest towards the Kitsap Peninsula The Kitsap Peninsula is an arm of land that is part of the larger Olympic Peninsula in Washington The first bridge opened to traffic on July 1, 1940 and became famous four months later for a dramatic wind-induced structural collapse that was caught on motion picture film. "July 1st" redirects here For the Ayumi Hamasaki song see H (song. Year 1940 ( MCMXL) was a Leap year starting on Monday (link will display the full 1940 calendar of the Gregorian calendar. Structural failure refers to loss of the load -carrying capacity of a component or member within a Structure or of the structure itself The original span's motion earned it the nickname Galloping Gertie.

The first replacement bridge opened October 14, 1950, and a parallel bridge opened July 15, 2007.

Westbound bridge

The westbound bridge, in 1988, when it carried traffic in both directions.

The current westbound bridge was designed and rebuilt with open trusses, stiffening struts and openings in the roadway to let wind through. In Architecture and Structural engineering, a truss is a structure comprising one or more triangular units constructed with straight slender members whose See also Strut (disambiguation StRUT ( St udents R ecycling U sed T echnology are three separate organizations It opened on October 14, 1950, and is 5,979 feet (1822 m) long — 40 feet (12 m) longer than the first bridge, "Galloping Gertie. Events 1066 - Norman Conquest: Battle of Hastings - In England on Senlac Hill seven miles from Hastings, the forces Year 1950 ( MCML) was a Common year starting on Sunday (link will display the full calendar of the Gregorian calendar. " Local residents nicknamed the new bridge "Sturdy Gertie", as the oscillations that plagued the previous design had been eliminated. This bridge along with its new parallel eastbound bridge are currently the fifth-longest suspension bridges in the United States.

When built, the westbound bridge was the third-longest suspension bridge span in the world. Wikipedia_talkFeatured_lists#Proposed_change_to_all_featured_lists for an explanation of this and other inclusion tags below -->This list of suspension bridges ^[1] Like other modern suspension bridges, the westbound bridge was built with steel plates that feature sharp entry edges rather than the flat plate sides used in the original Tacoma Narrows Bridge (see the suspension bridge article for an example). This article is concerned with a particular type of suspension bridge the suspended-deck type

The bridge was designed to handle 60,000 vehicles a day. It carried both westbound and eastbound traffic until the eastbound bridge opened on July 15, 2007. Events 1099 - First Crusade: Christian soldiers take the Church of the Holy Sepulchre in Jerusalem after the final Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. ^[2]

Eastbound bridge

In 1998, voters in several Washington counties approved an advisory measure to create a second Narrows span. Construction of the new span, which carries eastbound traffic parallel to the current bridge, began on October 4, 2002, and was completed in July, 2007. Events 610 - Heraclius arrives by ship from Africa at Constantinople, overthrows Byzantine Emperor Phocas See also 2002 (disambiguation Year 2002 ( MMII) was a Common year starting on Tuesday of the Gregorian calendar. The Washington State Department of Transportation collects a toll before entering the eastbound span, at $1. The Washington State Department of Transportation ( WSDOT) was established in 1905 75 for Good To Go! account holders with in-vehicle transponders and a $3. 00 toll for cash/credit card paying customers. The existing span has been toll-free since 1965, and will remain so. The new bridge marks the first installation of the new Good To Go! electronic toll collection system. Good To Go! is the Electronic toll collection system used by the Washington State Department of Transportation on all current and future toll projects in the state Electronic toll collection (ETC, an adaptation of military " Identification friend or foe " technology aims to eliminate the delay on Toll roads It is a

A group called "NarrowsBridgeLights.org" advocates illuminating both bridges with twinkling lights. The group recommends solar powered lighting, for both safety and beauty. ^[3]

Galloping Gertie

First Tacoma Narrows Bridge
The first Tacoma Narrows Bridge undergoes twisting mode resonance before collapsing.
Design	Suspension
Longest span	2,800 ft (853 m)
Total length	5,000 ft (1524 m)
Clearance below	195 ft (59. This article is concerned with a particular type of suspension bridge the suspended-deck type 4 m)
Opening date	July 1, 1940
Destruction date	November 7, 1940

Desire for a bridge at this location dates back to 1889 with a Northern Pacific Railway proposal for a trestle, but concerted efforts began in the mid-1920s. "July 1st" redirects here For the Ayumi Hamasaki song see H (song. Year 1940 ( MCMXL) was a Leap year starting on Monday (link will display the full 1940 calendar of the Gregorian calendar. Events 1492 - The Ensisheim Meteorite the oldest Meteorite with a known date of impact strikes the Earth around noon in a Wheat Year 1940 ( MCMXL) was a Leap year starting on Monday (link will display the full 1940 calendar of the Gregorian calendar. The Northern Pacific Railway was a railway that operated in the north-central region of the United States. The Tacoma Chamber of Commerce began campaigning and funding studies in 1923. Several noted bridge architects, including Joseph B. Strauss, who went on to be chief engineer of the Golden Gate Bridge, and David B. Steinman, builder of the Mackinac Bridge, were consulted. See also Joseph Straus Joseph Baermann Strauss ( January 9, 1870 &ndash May 16, 1938) was an The Golden Gate Bridge is a suspension Bridge spanning the Golden Gate, the opening of the San Francisco Bay onto the Pacific Ocean You may also be looking for David Steinman The Mackinac Bridge (ˈmækɨnɔː with a silent "c" at the end of the word is a Suspension bridge spanning the Straits of Mackinac to connect the Steinman made several Chamber-funded visits culminating in a preliminary proposal presented in 1929 but by 1931 the Chamber decided to cancel the agreement on the grounds that Steinman was "not sufficiently active" in working to obtain financing. Another problem with financing the first bridge was buying out the ferry contract from a private firm running service on The Narrows at the time.

The road to Tacoma's doomed bridge continued in 1937, when the Washington State legislature created the Washington State Toll Bridge Authority and appropriated $5,000 to study the request by Tacoma and Pierce County for a bridge over the Narrows. Pierce County is the second most populous county in the US state of Washington.

From the start, financing was the issue; revenue from tolls would not be enough to cover construction costs. But there was strong support for a bridge from the U.S. Navy, which operated the Puget Sound Naval Shipyard in Bremerton, and from the U.S. Army, which ran McChord Field and Fort Lewis in Tacoma. Puget Sound Naval Shipyard and Intermediate Maintenance Facility (PSNS & IMF is a United States Navy Shipyard covering 179 acres (0 Bremerton is a city in Kitsap County, Washington, United States. The United States Army is a military organization whose primary mission is to "provide necessary forces and capabilities. McChord Air Force Base is a United States Air Force base in Pierce County Washington. Fort Lewis is a Census-designated place and United States Army post located in Pierce County Washington, United States.

Washington State engineer Clark Eldridge came up with a preliminary, "tried and true conventional bridge design," and the toll bridge authority requested $11 million from the federal Public Works Administration (PWA). The Public Works Administration (PWA, a New Deal government agency headed by Harold Ickes, was created by the National Industrial Recovery Act in June But, according to Eldridge, prominent "Eastern consulting engineers" — led by New York engineer Leon Moisseiff — petitioned the PWA to build the bridge for less. Leon Moisseiff (1872 &ndash 1943 was a leading Suspension bridge Engineer in the United States of America in the 1920s and 1930s

Preliminary construction plans had called for 25-foot-deep (7. 6 m) girders to sit beneath the roadway and stiffen it. Moisseiff, a respected designer and consultant engineer of the famed Golden Gate Bridge, proposed shallower supports — girders 8 feet (2. The Golden Gate Bridge is a suspension Bridge spanning the Golden Gate, the opening of the San Francisco Bay onto the Pacific Ocean 4 m) deep. His approach meant a slimmer, more elegant design and reduced construction costs. Moisseiff's design won out. On June 23, 1938, the PWA approved nearly $6 million for the Tacoma Narrows Bridge. Events 1180 - First Battle of Uji, starting the Genpei War in Japan 1305 - The Flemish Year 1938 ( MCMXXXVIII) was a Common year starting on Saturday (link will display the full calendar of the Gregorian calendar. Another $1. 6 million was to be collected from tolls to cover the total $8 million cost.

The decision to use the shallower girders proved to be the first bridge's undoing. With the 8 foot (2. 42 m) girders, the roadbed was insufficiently rigid and was easily moved about by winds. From the start, the bridge became notorious for its movement. A mild to moderate wind could cause alternate halves of the center span to visibly rise and fall several feet over 4 to 5 second intervals. This led to the bridge being referred to as "Galloping Gertie" by the local residents, due to the apparent "galloping" motion felt by the drivers on the roadway.

Collapse

The wind-induced collapse occurred on November 7, 1940 at 11:00 AM (Pacific time), due partially to a physical phenomenon known as mechanical resonance. Events 1492 - The Ensisheim Meteorite the oldest Meteorite with a known date of impact strikes the Earth around noon in a Wheat Year 1940 ( MCMXL) was a Leap year starting on Monday (link will display the full 1940 calendar of the Gregorian calendar. For information on mechanical systems' absorption of energy at resonance see Mechanical resonance. ^[4]

From the account of Leonard Coatsworth, a driver who narrowly managed to escape the bridge before the collapse:

Tacoma Narrows Bridge collapsing

No human life was lost in the collapse of the bridge, though Coatsworth's cocker spaniel named "Tubby" was lost along with his car in the collapse. Theodore von Kármán, director of the Guggenheim Aeronautical Laboratory and world-renowned aerodynamicist, was a member of the board of inquiry into the collapse. The Guggenheim Aeronautical Laboratory at the California Institute of Technology ( GALCIT) was a Research institute created in 1926 at first specializing ^[5] He reported that the State of Washington was unable to collect on one of the insurance policies for the bridge, because its insurance agent fraudulently pocketed the insurance premiums. Washington ( is a state in the Pacific Northwest region of the United States. The agent, Hallett R. French who represented the Merchant's Fire Assurance Company, was charged with grand larceny for withholding the premiums for $800,000 worth of insurance. The bridge, however, was insured by many other policies that covered 80% of the $5. 2–million structure's value. Most of these were collected without incident. ^[6]

On November 28, 1940, the U. For the town in Argentina, see 28 de Noviembre. Events Year 1940 ( MCMXL) was a Leap year starting on Monday (link will display the full 1940 calendar of the Gregorian calendar. S. Navy's Hydrographic Office reported that the remains of the bridge were located at geographical coordinates 47°16′00″N, 122°33′00″W, at a depth of 180 feet (55 m).

Film of collapse

Footage of the Tacoma Narrows bridge wobbling and eventually collapsing. (19. 1 MB video, 2:30)

The final destruction of the bridge was recorded on film by Barney Elliott, owner of a local camera shop. A megabyte is a unit of Information or Computer storage equal to either 106 (1000000 Bytes or 220 (1048576 bytes depending on In 1998, The Tacoma Narrows Bridge Collapse was selected for preservation in the United States National Film Registry by the Library of Congress as being "culturally, historically, or aesthetically significant". The United States of America —commonly referred to as the The National Film Registry is the registry of Films selected by the United States National Film Preservation Board for preservation in the Library of The Library of Congress is the De facto National library of the United States and the research arm of the United States Congress This footage is still shown to engineering, architecture, and physics students as a cautionary tale. Engineering is the Discipline and Profession of applying technical and scientific Knowledge and The term architecture (from Greek αρχιτεκτονικήarchitektoniki) can be used to mean a process a profession or documentation Physics (Greek Physis - φύσις in everyday terms is the Science of Matter and its motion. A cautionary tale is a traditional story told in Folklore, to warn its hearer of a Danger. ^[7] Elliot's original films of the construction and collapse of the bridge were shot on 16mm Kodachrome film, but most copies in circulation are in black and white because newsreels of the day copied the film onto 35mm black and white stock. Kodachrome is the trademarked name of a brand of color reversal film sold by Eastman Kodak.

Cause of collapse

The bridge was solidly built, with girders of carbon steel anchored in huge blocks of concrete. Steel is an Alloy consisting mostly of Iron, with a Carbon content between 0 Concrete is a construction material composed of Cement (commonly Portland cement) as well as other cementitious materials such as Fly ash and Slag Preceding designs typically had open lattice beam trusses underneath the roadbed. This bridge was the first of its type to employ plate girders (pairs of deep I beams) to support the roadbed. I-beams (also known as W-beams or double-T esp in Polish and German) are beams with an I- or H-shaped With the earlier designs any wind would simply pass through the truss, but in the new design the wind would be diverted above and below the structure. Shortly after construction finished at the end of June (opened to traffic on July 1, 1940), it was discovered that the bridge would sway and buckle dangerously in relatively mild windy conditions for the area. "July 1st" redirects here For the Ayumi Hamasaki song see H (song. Year 1940 ( MCMXL) was a Leap year starting on Monday (link will display the full 1940 calendar of the Gregorian calendar. Wind is the flow of Air or other Gases that compose an Atmosphere (including but not limited to the Earth's) This resonance was transverse, meaning the bridge buckled along its length, with the roadbed alternately raised and depressed in certain locations -- one half of the central span would rise while the other lowered. In Physics, resonance is the tendency of a system to Oscillate at maximum Amplitude at certain frequencies, known as the system's A transverse wave is a moving Wave that consists of oscillations occurring perpendicular to the direction of energy transfer Drivers would see cars approaching from the other direction disappear into valleys which were dynamically appearing and disappearing. From this behavior, a local humorist coined the nickname "Galloping Gertie". However, the mass of the bridge was considered sufficient to keep it structurally sound.

Remains of Galloping Gertie

The failure of the bridge occurred when a never-before-seen twisting mode occurred, from winds at a mild 40 MPH. This is called a torsional, rather than longitudinal, mode (see also torque) whereby when the left side of the roadway went down, the right side would rise, and vice-versa, with the centerline of the road remaining still. In Solid mechanics, torsion is the twisting of an object due to an applied Torque. A torque (τ in Physics, also called a moment (of force is a pseudo- vector that measures the tendency of a force to rotate an object about Specifically, it was the second torsional mode, in which the midpoint of the bridge remained motionless while the two halves of the bridge twisted in opposite directions. Two men proved this point by walking along the center line, unaffected by the flapping of the roadway rising and falling to each side. This vibration was due to aeroelastic flutter. Aeroelasticity is the science which studies the interaction among inertial, elastic, and aerodynamic forces Flutter occurs when a torsional disturbance in the structure increases the angle of attack of the bridge (that is, the angle between the wind and the bridge). Angle of attack ( AOA, \alpha Greek letter alpha) is a term used in Aerodynamics to describe the Angle between the The structure responds by twisting further. Eventually, the angle of attack increases to the point of stall, and the bridge begins to twist in the opposite direction. For other uses see Stall. In Aerodynamics, a stall is a sudden reduction in the lift forces generated by an Airfoil In the case of the Tacoma Narrows Bridge, this mode was negatively damped (or had positive feedback), meaning it increased in amplitude with each cycle because the wind pumped in more energy than the flexing of the structure dissipated. Positive feedback, sometimes referred to as "cumulative causation" is a Feedback loop system in which the system responds to perturbation in the same direction Eventually, the amplitude of the motion increased beyond the strength of a vital part, in this case the suspender cables. Once several cables failed, the weight of the deck transferred to the adjacent cables which broke in turn until almost all of the central deck fell into the water below the span.

The bridge's spectacular destruction is often used as an object lesson in the necessity to consider both aerodynamics and resonance effects in civil and structural engineering. In Physics, resonance is the tendency of a system to Oscillate at maximum Amplitude at certain frequencies, known as the system's Structural engineering is a field of Engineering dealing with the analysis and design of Structures that support or resist loads Structural engineering is However the effect that caused the destruction of the bridge should not be confused with forced resonance (as from the periodic motion induced by a group of soldiers marching in step across a bridge). A soldier is a general English term that refers to a member of a land component of National Armed forces. Military step or march is a regular ordered and synchronized Walking of Military formations History The steady regular Marching ^[8] In the case of the Tacoma Narrows Bridge, there was no periodic disturbance. The wind was steady at 42 mph (67 km/h). (For the South African airport with IATA code "KMH" see Johan Pienaar Airport. The frequency of the destructive mode, 0. 2 Hz, was neither a natural mode of the isolated structure nor the frequency of blunt-body vortex shedding of the bridge at that wind speed. The hertz (symbol Hz) is a measure of Frequency, informally defined as the number of events occurring per Second. Vortex shedding is an unsteady flow that takes place in special flow velocities (according to the size and shape of the cylindrical body The event can only be understood while considering the coupled aerodynamic and structural system which requires rigorous mathematical analysis to reveal all the degrees of freedom of the particular structure and the set of design loads imposed.

In 1943, New York City's similarly slim Whitestone Bridge was retrofitted with a 14-foot deep Warren truss and diagonal stays to reduce deck oscillations. Year 1943 ( MCMXLIII) was a Common year starting on Friday (the link will display full 1943 calendar of the Gregorian calendar. The City of New York The Bronx-Whitestone Bridge, colloquially referred to as the Whitestone Bridge or simply the Whitestone is a Suspension bridge that crosses the East River and connects The Warren Truss was removed in 2001 and replaced with hydraulic dampers and deck-edge fairings to maintain stability.

Tubby the dog

Tubby, a black male cocker spaniel dog, was the only fatality of the Tacoma Narrows Bridge disaster. The dog ( Canis lupus familiaris) is a domesticated Subspecies of the gray wolf, a Mammal of the Canidae family of the order Leonard Coatsworth, a Tacoma News Tribune photographer, was driving with the dog over the bridge when it started to vibrate violently. The News Tribune is a daily Newspaper in Tacoma Washington, in the United States. Coatsworth was forced to flee his car, leaving Tubby behind. Professor Farquharson^[9] and a news photographer^[10] attempted to rescue Tubby, but the dog was too terrified to leave the car and bit one of the rescuers. Tubby died when the bridge fell, and neither his body nor the car were ever recovered. ^[11] Coatsworth had been driving Tubby back to his daughter, who owned the dog.

Coatsworth received US $364. 40 in reimbursement for the contents of his car, including Tubby. In 1975, Coatsworth's wife claimed that Tubby only had three legs and was paralyzed. ^[11]

Preservation

The underwater remains of the bridge act as a large artificial reef, and are listed on the National Register of Historic Places with reference number 92001068. An artificial reef is a man-made underwater structure typically built for the purpose of promoting marine life in areas of generally featureless bottom The National Register of Historic Places (NRHP is the United States government's official list of districts sites buildings structures and objects deemed worthy of ^{[12] [13]}

Plate structure in modern suspension bridges

A plate deck suspension bridge over the Yangtze River in China

Modern design, analysis, materials, and construction methods have now permitted the use of plate structures in suspension bridges. China ( Wade-Giles ( Mandarin) Chung¹kuo² is a cultural region, an ancient Civilization, and depending on perspective a National Rather than using aerodynamically unstable flat vertical sides the edges are now tapered (in cross section) to reduce vortex shedding and additional plate elements forming a box beam create a structure sufficiently ridged against twisting to avoid the problems seen with the Tacoma Narrows bridge.

Remains of Galloping Gertie

New bridge sections used in construction of the new span.

A panorama of Tacoma Narrows Bridge in 2007. In its most general sense a panorama is any wide view of a physical space

References

External links

• Color video of the original bridge's construction and collapse
• Color video of the original bridge's construction and collapse with narration

Coordinates: 47°16′05″N 122°33′02″W / 47.2681, -122.5506

• Physics behind the collapse of the bridge
• failurebydesign.info - physics presentation and resources
• Photos of the bridge and the new span under construction
• Tacoma Narrows Bridge (1940) in the Structurae database
• Tacoma Narrows Bridge (1950) in the Structurae database
• New Tacoma Narrows Bridge (2007) in the Structurae database

Historical

• History of the Tacoma Narrows Bridge
• University of Washington Libraries Digital Collection – Tacoma Narrows Bridge Collection More than 152 images and text documenting the infamous collapse in 1940 of the Tacoma Narrows Bridge. A geographic coordinate system enables every location on the Earth to be specified in three coordinates using mainly a spherical coordinate system. Structurae is an online Database containing works of structural and Civil engineering of all kinds such as Bridges High-rise buildings Structurae is an online Database containing works of structural and Civil engineering of all kinds such as Bridges High-rise buildings Structurae is an online Database containing works of structural and Civil engineering of all kinds such as Bridges High-rise buildings Also covers "Galloping Gertie's" creation, subsequent studies involving its aerodynamics, and finally the construction of a second bridge spanning the Narrows.
• The Tacoma Narrows Bridge Disaster, November 1940
• Images of failure
• Information and images of failure
• Firsthand account and images of the failure
• Official site of the Tacoma Narrows Bridge
• Timeline of the bridges
• Tacoma Narrows Bridge
• Suspended Animation - Failure Magazine (November 2000)
• Footage of the Tacoma Narrows bridge wobbling and eventually, collapsing, Stillman Fires Collection, in the Internet Archive. The Internet Archive ( IA) is a Nonprofit organization dedicated to maintaining an on-line Library and archive of Web and

Second span project

• Tacoma Narrows Bridge Project (WS DOT Web Page; information about the new bridge construction project)
• SR 16 - New Tacoma Narrows Bridge (computer projection of completed project)
• Puget Sound Transportation projects:Tacoma Narrows Bridge (unofficial site providing news, photos and information about the second span construction)
• Wind Tunnel Testing Summary from the National Research Council of Canada
• Wind Tunnel Testing Press Release from the National Research Council of Canada
• Tacoma Narrows Bridge Project (continuing coverage of bridge construction from The News Tribune)
• Bridge Workers are Walking Tall Above the Narrows Rob Carson (The News Tribune), Kitsap Sun, September 25, 2005
• Wire by wire, Tacoma Narrows bridge is built Mike Lindblom, The Seattle Times, October 15, 2005