Aftermath The original Tacoma Narrows Bridge deck is still submerged in Puget Sound, producing an artificial reef, and its side spans were melted down for steel during WWII. State officials eventually authorized a replacement bridge, which was built in 1950 and christened "Sturdy Gertie."
This new bridge was also a cantilever, but one made of concrete instead of steel. It had three main sections: the central section was 112 feet long and had a clear span of 75 feet; on each end of this center section were towers that reached 315 feet high. The whole structure was covered with decorative panels painted red, white, and blue to mark its opening- Day-Dawn-Cantilever-Concrete.
This new bridge lasted nearly half a century before it collapsed in 1975, killing 38 people. The cause was determined to be overloading. The first sign of trouble came when some trucks driving over the bridge saw warning lights go on at the top of one of the towers. When officers went to check out the scene, they found heavy traffic congestion and no one in charge. Then the tower started to wobble and finally fell into the sound.
The disaster led to many changes. First of all, the center portion of the old bridge was removed so that it would not be used by any future bridges or tunnels.
The Tacoma Narrows Bridge, often known as "Galloping Gertie," was erected in 1940 and was recognized for its peculiar, undulating movement. A standing wave looked to have developed between the bridge's two towers. This image is from a 1950s photograph that has been enhanced for clarity.
The phenomenon of standing waves has been known for quite some time. Isaac Newton described it in his 1687 book Opticks: "If you tie a string to a bobbing ball and then walk around with another string tied to your foot, you will find that the ball follows your footsteps." In other words, if you walk in a circle around something, the object will stand still at the beginning and end of your journey but will be bobbing up and down in the middle.
Newton also noted that if you throw a rock into a pond, it will create a series of concentric circles of water that reach maximum amplitude at the center and die out again as you move away from there.
In general, anything that creates a disturbance at one end of a liquid body will cause a similar disturbance at the other end, passing over any given point twice. For example, if I throw a stone into a pond, the water near the shore will rise up and fall back again, while more distant parts of the pond will remain unaffected.
Tacoma Narrows Bridge, a suspension bridge in the U.S. state of Washington, fell in 1940 due to poor aerodynamic design. This caused aeroelastic flutter, which nearly destroyed the bridge. Collapse was even shown on video, and since then, all huge bridges have been constructed in wind tunnels. The Tacoma Narrows Bridge was the first major American bridge to be designed with this new technology.
It is also considered one of the first modern bridges. It connected the cities of Puget Sound and Lake Washington for almost 12 miles (19 km). Its length at collapse was 1,929 feet (580 m). Today, after 70 years, it has been replaced by a new bridge called "New Tacoma Narrows Bridge".
The old bridge was built in 1937-40 as a toll bridge. When it collapsed, it was the longest suspension bridge in the world. The new bridge is not a replica but an innovative structure using many advanced materials including fiberglass and carbon fibers. It's expected to last longer than any other bridge of its kind.
The disaster that killed 46 people has never been fully explained. Contributing factors include bad design, wind load, and maintenance errors. Some researchers believe the fatal vibration may have been triggered by a fire on one of the towers during renovation work.
In addition to the loss of life, the collapse also damaged or destroyed much of the surrounding area.
On July 1, 1940, the first Tacoma Narrows Bridge opened to traffic. Four months later, on November 7, 1940, at 11:00 a.m. (Pacific time), its main span fell into the Tacoma Narrows due to aeroelastic flutter triggered by a 42 mph (68 km/h) wind. The bridge collapse has long-term consequences for science and engineering. Before the incident, engineers had not experienced a large-scale structure fail because of its strength and design. The event forced them to reexamine their assumptions about what could be done safely. It also caused them to consider new methods for maintaining structures to prevent similar accidents in the future.
The disaster killed 41 people and injured another seven. It is considered one of the worst transportation disasters in U.S. history.
After World War II, when the nation's highway network was being built out, many bridges were constructed with poor choices of materials or techniques that no longer met modern needs. The Tacoma Narrows Bridge was no exception; it used thinner-than-required girders that were prone to flutter under certain conditions. When winds increased beyond a threshold value, this motion became amplified and the bridge collapsed.
Although this accident happened four decades before the first American suspension bridge collapsed during a hurricane, its implications for modern bridge engineering was immediate. Engineers now knew that if they made bridges too thin, they were asking for trouble.
The Tacoma Narrows Bridge, a historic failure in engineering history, was the first suspension bridge across the Narrows of Puget Sound, linking the Olympic Peninsula to the mainland of Washington State, U.S. It was constructed by the California Division of Bridges and Structures, using funding provided by the War Department during World War II. The main span of this wooden-stringer cable-stayed bridge is approximately 750 feet long and consists of four sections each with three spans, with total length being 22,400 feet, with deck width of 35 feet.
This bridge has been called "the most expensive footrace in history" because both it and the Golden Gate Bridge were built as part of a war effort. The Tacoma Narrows Bridge was opened to traffic on May 17, 1946, just five months after the opening of the Golden Gate Bridge. It replaced an earlier road bridge that had been destroyed by the same earthquake that caused so much damage to its replacement. The old bridge had been deemed unsafe by the state department of highways and was removed after the end of the war emergency.
Although this bridge was intended to be temporary, plans were already underway for its permanent successor, which would become one of the great wonders of the world, the George Washington Memorial Bridge.
The West Seattle Bridge, which closed in March due to severe cracking, may have been doomed from the start in 1984. According to one popular explanation, the 220,000-ton bridge was gradually weakened due to long-term shrinkage of concrete within the twin girders that hold the mainspan above the Duwamish Waterway. However, a more thorough investigation by the Washington State Department of Transportation (WSDOT) concluded that there was no evidence of structural damage before the bridge collapsed. The WSDOT report also noted that although the main cause of the collapse was likely mechanical failure, heavy rainfall may have played a role.
In addition to its age and original design, another factor contributing to the West Seattle Bridge's demise was political: The $7 million dollar replacement project was not approved by voters. In fact, the only people who actually supported the replacement plan were the engineers who recommended it. Opponents argued that building a new bridge was not necessary because there were already plans in place for major improvements to I-5. They also claimed that the city didn't do its fair share of pollution control because the majority of funds from car taxes went toward paying for the new bridge instead of improving air quality.
In the end, community opposition caused the city to abandon the plan. Instead, they decided to repair the existing bridge until it could be replaced later this decade. Costs are expected to reach $50 million dollars.
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