The Tacoma Narrows Bridge was an incredible engineering feat. It was the largest suspension bridge system in the world and it stood for just four months before collapsing. The structure was considered a failure because it didn’t last long enough to be useful but today we look back at this tragic event as an important lesson in how not to build bridges.
The Tacoma Narrows Bridge is a suspension bridge in the US state of Washington. It connects the city of Tacoma with the Kitsap Peninsula over the Tacoma Narrows strait, a narrow section of Puget Sound. The bridge was opened to traffic on July 1, 1940, after being constructed from December 1938 to May 1940. Less than four months later, on November 7, 1940, an intense windstorm caused one side of the bridge deck to wobble noisily and then collapse in an alarming fashion. Although engineers had not yet developed theories to explain this behavior at that time, they concluded that it was related to aerodynamic forces on tall structures; later research showed that wind-induced structural oscillations were common among such bridges and were known as “seiches” or “flutter”.
Tacoma Narrows Bridge
You have probably heard of the Tacoma Narrows Bridge. If you haven’t, it was the third-longest suspension bridge in the world when it opened. It was designed to withstand earthquakes and winds up to 170 mph (275 km/h).
It may be surprising for you to learn that this project had a reputation for problems. The construction of this bridge started off slowly and was delayed by several issues including cost overruns, weather delays, lawsuits from landowners whose property was seized for construction, and fires caused by welders who worked on pieces of steel being placed between two towers. These incidents were all blamed on faulty welding practices or workers who were inexperienced with welding techniques used at that time period because they did not know how hot temperatures needed to reach before using certain metals together during construction phases.*
Notable characteristics
The Tacoma Narrows Bridge has several noteworthy characteristics.
- The bridge’s length is 2,800 feet (853 meters).
- It rises more than 200 feet above Puget Sound.
- It has eight lanes of traffic and two pedestrian sidewalks.
Wind engineering
Wind engineering is a branch of civil engineering that applies the science of aerodynamics to civil engineering problems, such as structural design, construction planning, and assessment. Wind engineers often rely on wind tunnel testing in the early stages of development to reduce costs and increase quality.
The wind can cause problems such as vibrations, fatigue, and damage to structures. The distribution of forces caused by moving air masses on structures that are either natural or man-made has been studied since ancient times by various cultures across the world; however, it was not until the mid-1800s when scientific study into these phenomena began in earnest with scale models inside wind tunnels. Today there are several disciplines that make up modern-day wind engineering including aerodynamic analysis (which focuses on fluid flow through different types of cross-sections), structural dynamics (which focuses on the modal analysis), structural dynamics control methods (focused on damping out vibrations) plus many others
Collapse
The bridge was designed to withstand winds of up to 170 mph (275 km/h), yet on November 7, 1940, it collapsed in a 40 mph wind. The cause of the collapse was never determined conclusively. However, it is believed that the wind caused an aeroelastic flutter, which is when vibrations in a structure become unstable and lead to failure.
The bridge was designed by Joseph B. Strauss who submitted his plans for review by Theodore Cooper, an engineer with experience designing bridges and dams. Cooper rejected Strauss’ design because he thought its form would not withstand high winds well enough to be safe.[7] As a result of this rejection by Cooper’s firm, Strauss worked with other engineers from around the country until they came up with a design that met their standards.
New Tacoma Narrows Bridge
The New Tacoma Narrows Bridge is a suspension bridge crossing the Tacoma Narrows between downtown Tacoma and the city of Gig Harbor, Washington. It is owned by the Washington State Department of Transportation (WSDOT) and operated by the agency’s district offices in Olympia and Tacoma.
The original span was opened on July 1, 1940, with a ceremony that included marching bands and an estimated crowd of 50,000 people. Construction had begun on November 8, 1936, with workers paid $1/hour during its eight-year construction period. It cost $6 million to build at that time but would be worth at least $1 billion today due to inflation alone; however, this figure doesn’t account for maintenance costs which are significant considering how much traffic passes through these bridges on a daily basis.
The replacement bridge opened on October 14, 1950.
The bridge was designed by Charles H. Purcell, a professor at the University of Washington who had been involved in designing bridges at Tacoma Narrows. The bridge was designed to withstand winds up to 200 mph (320 km/h). It is also designed so that it could still carry traffic even if one of the two main cables broke.
The new bridge opened on October 14, 1950, and cost $8 million to build. It is 4,210 feet (1,280 m) long and stands 699 feet above the water.
Design and construction
The bridge was designed by Joseph B. Strauss, chief engineer for the project, who had previously worked on a number of other famous bridges. Construction began in August 1938 and ended in July 1940. The total cost of construction was $6.4 million (around $100 million today). This figure includes both design and construction costs, as well as labor and material used during those processes.
First bridge collapse
- The Tacoma Narrows Bridge was the first modern suspension bridge in the world.
- It was designed to withstand earthquakes and winds up to 170 mph (275 km/h).
- It replaced a ferry system that had been used for over 100 years.
Second bridge construction
The second Narrows Bridge was designed to withstand earthquakes and winds up to 170 mph (275 km/h). Although it was a suspension bridge, it did not have the usual stiffening trusses that were required for such bridges. Instead, David B. Steinman designed the structure with eyebar chains and large plates at each end of each span. He also devised a new type of suspension cable called a riband which allowed for lighter-weight cables than those previously used in other suspension bridges. The bridge’s main towers were made from concrete with an extra layer of steel on top to prevent corrosion over time; most of the tower’s strength came from its shape rather than its materiality or thickness.
The first span opened on July 1st, 1940 but only carried pedestrians due to wartime restrictions on construction materials like steel beams and rivets needed for building such structures as well as iron needed for railroads across America during World War 2 days when travel restrictions were enforced by law enforcement officials nationwide due primarily
to wartime concerns over national security issues related primarily directly related mostly specifically directly relating mostly exclusively almost solely primarily entirely 100%
Pedestrian and bicycle crossing
The bridge, which has been closed to all traffic since a storm caused it to collapse in May of 1940, is now open for pedestrian and bicycle traffic. The opening marks the beginning of an ambitious effort to revitalize the crumbling structure into what many hope will be a world-class tourist attraction.
The bridge was closed following the collapse; however, it remains accessible by boat and by foot. The pedestrian crossing is located on the east side of the Narrows Bridge where there are stairs leading down into Puget Sound between two piers that once supported one end of each span in 1940 when both spans fell into Elliott Bay during high winds.
Tacoma Narrows Bridge is an important part of American history.
The Tacoma Narrows Bridge is an important part of American history.
- It was the third longest suspension bridge in the world at its time of construction, and it held this title until 1964 when it was surpassed by the Verrazano-Narrows Bridge in New York City.
- The bridge was designed to withstand winds up to 170 mph (274 kph), which made it almost impossible for a windstorm that came through in 1940 to knock it down. The fact that it collapsed under 40 mph winds during that storm is one of many mysteries surrounding this bridge’s collapse.
- The Tacoma Narrows Bridge was also one of the first bridges built with a deck truss, a type of steel frame used for building girders over roadways or railways filled with concrete or asphalt. This design proved so successful that it became standard practice for building longer bridges from then on, including many modern skyscrapers built today.
This was the most difficult suspension bridge to construct.
While the Tacoma Narrows Bridge was certainly not the longest, tallest, or most expensive suspension bridge in the world, it was one of the most difficult to build. This was due in part to its design and engineering specifications.
The site chosen for this bridge was not only remote but also an unstable area prone to earthquakes. Additionally, standard suspension bridge designs were insufficient for such a long span; this required engineers to create innovative solutions that would allow them to take full advantage of their experience building shorter spans like New York City’s George Washington Bridge (1931). Because of this difficulty, there are many reasons why people might question whether it was worth it, and why it failed so spectacularly when opened for traffic in 1940.
The project had a reputation for problems.
The Tacoma Narrows Bridge, which opened in 1940 and was famous for collapsing from high winds in 2007, had a reputation for problems. Despite being built as an engineering marvel using the latest technology, the bridge was originally 1,800 feet long and 456 feet above the water below, it fell apart at its seams in less than four months of use.
The poor design of the bridge played a significant role in its demise. Engineers had placed too much stress on the suspension cables that held up the roadbed (which itself weighed 2,500 tons), causing them to snap when they couldn’t handle any more weight or vibration. The construction itself also contributed: The builders used small wire cables instead of large ones; they kept their costs down by not including bracing, and they cut corners with regard to safety measures like emergency vehicles that might be needed if something went wrong during construction.
The Tacoma Narrows Bridge designers were hampered by limited resources and even more limited access to their site.
The designers were hampered by limited resources and even more limited access to their site. The bridge was 120 feet (36 meters) high, 4,200 feet (1,300 m) long and 1,700 feet (520 m) wide.
The Tacoma Narrows Bridge was designed by Leon Moisseiff of New York City. He had built a similar but smaller bridge across another narrow channel in the Chesapeake Bay in 1923. His success with this design convinced him that a suspension bridge could be built over the deep waters of Puget Sound without support from piers or towers at either end of its span, that is, suspended in midair like a giant thread hanging from heaven. He believed that such a structure would have greater strength than one supported at both ends because it would have less weight to bear on its cables.
The bridge was 120 feet (36 meters) high, 4,200 feet (1,300 m) long and 1,700 feet (520 m) wide.
The bridge was 120 feet (36 meters) high, 4,200 feet (1,300 m) long and 1,700 feet (520 m) wide. It was a suspension bridge that weighed 562,000 tonnes. The towers were made of concrete and steel and stood 656 feet (200 m) above the water. The roadway across the bridge consisted of two decks – an upper deck for cars and trucks with a lower deck for railway traffic.
When it opened in 1940, it was considered the largest and longest suspension bridge system in the world.
When it opened in 1940, it was considered the largest and longest suspension bridge system in the world. The bridge was designed to withstand earthquakes and winds up to 170 mph (275 km/h).
It was designed to withstand earthquakes and winds up to 170 mph (275 km/h).
The bridge was designed to withstand winds up to 170 mph (275 km/h), earthquakes, and wind speeds up to 160 mph. The bridge was also designed with a very slim profile so that it could fit in between the Narrows.
The total cost of building the bridge was $6,400,000
As you can see, the cost of building this bridge would be over $6.4 million dollars in today’s dollars. If you were to build a similar bridge now, it would cost about $10 billion.
If you’re interested in learning more about Tacoma Narrows Bridge or other bridges and how they work, there are some great websites out there that will let you play around with different variables like length, width, and materials used in their construction so that you can see how these factors affect costs. And if this kind of thing sounds interesting to you at all then we have some good news: we’ll be talking more about bridges next time on Engineering Explained.
The bridge was designed by Leon Moisseiff, an engineer who had previously designed a number of other famous bridges throughout the world. Moisseiff’s design was a suspension bridge that featured concrete towers and steel cables. The bridge opened to traffic on July 1, 1940; just four months later it collapsed in what is known today as “Galloping Gertie. The new bridge is a testament to how important it is to keep up with the times. If you’re using an old method or product, make sure you consider upgrading if necessary.”
