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mahatmakanejeeves

(57,489 posts)
Tue Nov 7, 2017, 03:26 PM Nov 2017

Tough luck 77 years ago today, the original Tacoma Narrows Bridge:

The 1940 Tacoma Narrows Bridge, the first Tacoma Narrows Bridge, was a suspension bridge in the U.S. state of Washington that spanned the Tacoma Narrows strait of Puget Sound between Tacoma and the Kitsap Peninsula. It opened to traffic on July 1, 1940, and dramatically collapsed into Puget Sound on November 7 of the same year. At the time of its construction (and its destruction), the bridge was the third-longest suspension bridge in the world in terms of main span length, behind the Golden Gate Bridge and the George Washington Bridge.
....

The bridge's collapse had a lasting effect on science and engineering. In many physics textbooks, the event is wrongly presented as an example of elementary forced resonance, with the wind providing an external periodic frequency that matched the bridge's natural structural frequency. In reality, the actual cause of failure was aeroelastic flutter. The collapse boosted research into bridge aerodynamics-aeroelastics, which has influenced the designs of all later long-span bridges.
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Attempt to control structural vibration

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The Washington Toll Bridge Authority hired Professor Frederick Burt Farquharson, an engineering professor at the University of Washington, to make wind-tunnel tests and recommend solutions in order to reduce the oscillations of the bridge. Professor Farquharson and his students built a 1:200-scale model of the bridge and a 1:20-scale model of a section of the deck. The first studies concluded on November 2, 1940—five days before the bridge collapse on November 7. He proposed two solutions:

• To drill holes in the lateral girders and along the deck so that the air flow could circulate through them (in this way reducing lift forces).
• To give a more aerodynamic shape to the transverse section of the deck by adding fairings or deflector vanes along the deck, attached to the girder fascia.

The first option was not favored because of its irreversible nature. The second option was the chosen one, but it was not carried out, because the bridge collapsed five days after the studies were concluded.

Collapse

The wind-induced collapse occurred on November 7, 1940, at 11:00 a.m. (Pacific Time), because of a physical phenomenon known as aeroelastic flutter.

Leonard Coatsworth, a Tacoma News Tribune editor, was the last person to drive on the bridge:

Around me I could hear concrete cracking. I started back to the car to get the dog, but was thrown before I could reach it. The car itself began to slide from side to side on the roadway. I decided the bridge was breaking up and my only hope was to get back to shore."

"On hands and knees most of the time, I crawled 500 yards or more to the towers… My breath was coming in gasps; my knees were raw and bleeding, my hands bruised and swollen from gripping the concrete curb… Toward the last, I risked rising to my feet and running a few yards at a time… Safely back at the toll plaza, I saw the bridge in its final collapse and saw my car plunge into the Narrows.

Tubby, Coatsworth's cocker spaniel, was the only fatality of the Tacoma Narrows Bridge disaster; he was lost along with Coatsworth's car. Professor Farquharson and a news photographer attempted to rescue Tubby during a lull, 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 was ever recovered. Coatsworth had been driving Tubby back to his daughter, who owned the dog. Coatsworth received US$450.00 (US$7,700 with inflation) for his car and US$364.40 (US$6,200 with inflation) in reimbursement for the contents of his car, including Tubby.

The newsreel video:



Same footage, from British Pathé:



A short documentary:



APS News

November 2016 (Volume 25, Number 10)

This Month in Physics History

November 7, 1940: Collapse of the Tacoma Narrows Bridge

Washington State Department of Transportation, Tacoma Narrows Bridge: Lessons from the Failure of a Great Machine
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Tough luck 77 years ago today, the original Tacoma Narrows Bridge: (Original Post) mahatmakanejeeves Nov 2017 OP
something like this MFM008 Nov 2017 #1
Perhaps......... MyOwnPeace Nov 2017 #2
My uncle Richard was the last surviving person SonofDonald Nov 2017 #3
I used to live very near the bridge JonLP24 Nov 2017 #4

MyOwnPeace

(16,927 posts)
2. Perhaps.........
Tue Nov 7, 2017, 05:00 PM
Nov 2017

eliminating more oversights and regulations will make it easier for the 1% to make their profits and stiff the workers.

BUT, one thing we CAN count on:

IQ45 and the Congress will send their thoughts and prayers!

SonofDonald

(2,050 posts)
3. My uncle Richard was the last surviving person
Tue Nov 7, 2017, 05:11 PM
Nov 2017

That crossed the bridge right before it fell, in a Sunshine Bakery delivery truck heading from Tacoma to GigHarbor.

He said he looked through the windshield past his parent shoulders and saw sky, bridge, trees, sky, bridge, trees....

There were at least two books written about the bridge that I know of, "Catastrophe To Triumph, Bridges Of The Tacoma Narrows" by Richard S Hobbs.

And "Masters Of Suspension" by Rob Carson and Dean J Koepfler.

My uncle passed away in 2008, there are interviews with him in old issues of the Tacoma News Tribune.

I've been crossing that bridge for over fifty years myself, it's part of my life, it's where they will spread my ashes when I'm gone.

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