The Story of the Fall of the Tacoma Narrows Bridge

Sometimes even a structure that seems simple when we look at it from the outside was actually made as a result of difficult calculations. Especially if you are going to build a bridge, the calculations in question must be done much, much thinner. Designers and engineers of the Tacoma Narrows Bridge They did not do these calculations. They wanted to try a new design, but the results were not what they expected.

The story of the destruction of the Tacoma Narrows Bridge actually began even during construction. Even construction workers could clearly see the bridge swaying. No one was heeded and the world’s third largest suspension bridge was opened for public use. The bridge, which lasted only a few months, swayed and finally collapsed like a paper tower. To the story of the fall of the Tacoma Narrows Bridge let’s take a closer look.

The people of Tacoma need a bridge:

The idea of ​​building a bridge to the city of Tacoma in Washington state of the United States was first put forward by the Northern Pacific Railway company in 1889. Until 1920, there was no study on the subject. When we came in 1923 Tacoma Chamber of Commerce started to work on financing for the new bridge.

A team of many architects and engineers, especially Joseph B. Strauss, the chief engineer of the Golden Gate Bridge, worked on the new bridge. With funding provided in 1937, an offer was received from Clark Eldridge, a Washington State engineer. But for his project hundreds of millions of dollars and 8-foot beams had to be done.

Just then, New York bridge engineer Leon Moisseiff came up with a completely different project. Moisseiff’s project was unlike any before. This project, which is planned to absorb static wind in a different way, would be both cheaper and 2.4 meter beams would suffice. It was decided that the already limited funding would be invested in this project.

Construction of the Tacoma Narrows Bridge begins:

The bridge that will connect Tacoma and the Kitsap peninsula and will be built over the Tacoma Narrows strait, it would have a much more elegant appearance than traditional bridges. Two lanes were enough because not much traffic was expected. It was planned to be 1.8 km long and only 12 meters wide. The 2.4-metre beams would have been enough to hold him up.

Construction began in September 1938. However, there was a problem. Even when the deck area was being built It was noticed that the bridge swayed vertically as the wind increased. Many adjustments and damping measures were taken to improve the existing design. The Tacoma Narrows Bridge, the third largest bridge in the world, was now ready to open.

Good luck to the people of Tacoma:

Tacoma was a small region at the time. It was a wonderful thing to have the third largest suspension bridge in the world built in such a place. on 1 July 1940 The Tacoma Narrows Bridge was opened to the public of Tacoma. But it seemed to wobble a little. The bridge continued to be used, considering that it would improve over time and a few precautions were taken.

Although the Tacoma Narrows Bridge worried some, a large amount of money was spent to build it. All the financing spent was intended to cover the tolls. Work was underway on smaller models of the bridge. When the results of these studies were obtained, it was too late.

The fall of the Tacoma Narrows Bridge:

On the morning of November 7, 1940, the people of Tacoma awoke to a windy day. It was a normal situation. Those who looked at the Tacoma Narrows Bridge could not believe their eyes. Because this thin bridge was swinging so strongly that it was like one side was on the ground and the other side was in the sky. What happened when the wind reached speeds of about 64 kilometers per hour.

At around 11 noon, a large concrete mass collapsed in the deck area of ​​the Tacoma Narrows Bridge. A few minutes later, a 600-metre section was free. The bridge stretched like steel, continuing to rock back and forth. Since carbon steel was used in the bridge towers, there was no problem in that area. Soon, however, only a gap remained of the Tacoma Narrows Bridge.

Why was the Tacoma Narrows Bridge destroyed?

Countless mistakes were made even during the design phase of the Tacoma Narrows Bridge. Perhaps the biggest mistake was that the width of such a long bridge was so small. The fact that the beam heights were 2.4 meters was completely wrong. Moreover, these beams did not absorb the wind, they challenged it.

To give the simplest answer, the Tacoma Narrows Bridge couldn’t stand the wind. The wind wasn’t flowing through this structure, it was hitting it. After each blow of the wind, a frequency oscillation occurred on the bridge. It was inevitable that the swaying bridge would eventually collapse due to these vibrations coming in succession at high speed.

As luck would have it when this huge bridge collapsed Not a single person died. Who would want to drive their car over a bridge that wobbles like a cradle anyway? Only one dog died in this destruction. Because the dog stuck in the car could not be rescued.

The destruction of the Tacoma Narrows Bridge opened a new era in the engineering world:

Although the destruction of the Tacoma Narrows Bridge was considered a major failure, it was actually a major success. Because even today in the design of the bridge mistakes are taught in engineering faculties, and the reasons for collapse are taught in physics faculties. With the Tacoma Narrows Bridge, a new era in bridge designs has been opened and many designs are now standardized.

Sea creatures were the luckiest from the destruction of the Tacoma Narrows Bridge. Because the bridge collapsed into the sea as it was and remained there. World’s third largest suspension bridge now It’s the world’s largest artificial reef. Protected in 1992, the reef gives life to countless sea creatures. The remaining parts of the bridge on land were sold to scrap dealers.

Movie of the fall of the Tacoma Narrows Bridge:

When we think about 1940, when the Tacoma Narrows Bridge collapsed, almost miraculously. Two people recorded the event on their cameras. Films sold to Paramount Studios were copied and shipped around the world. These images are used even today in the courses of engineering, architecture and physics students.

While it was going to be the third largest suspension bridge in the world, it was disintegrating like a paper tower. We talked about the story of the destruction of the Tacoma Narrows Bridge. and we told you the details you need to know about this interesting event. Especially our engineer readers can share their thoughts on the subject in the comments.