It was an unfortunate morning of 7th November 1940 when winds having speed of 42 miles per hour suddenly twisted the Tacoma Narrows Bridge and lead to its collapse. This accident though didn’t look any lives but it surely made the civil engineers to think new ways to combat bridge collapses.
Some of the important statistics of this bridge are –
It is located in Tacoma, Washington, USA and was completed in 1940. This was a suspension type of bridge with length of 7,392 feet and was built at the cost of $6.4million.It had the longest span of 2800 feet.
The bridge was designed by engineer Moisseiff who had strengthened it with a solid steel girder beneath the roadway.But the problems started soon it was opened to traffic.Under strong winds, it swayed much beyond the permissible limits and thus sent rippling waves along the deck. It took just 4 months before this bridge collapsed after its completion.
On investigating it was found that the solid steel girders provided to strengthen the bridge were actually blocking the wind which caused the bridge to twist.Due to this a swirling motion developed which ultimately lead to the collapse. After knowing the reason for collapse a new bridge was constructed which had a truss so that it can allow the passage of wind
This bridge also got the name “Galloping Gertie” due to its unusual twisting and rolling behavior.
See this video to see how this “Galloping Gertie” used to sway.
If you have a query, you can ask a question here.
nice effort
thanks fore the good page and interesting video link
it looks so funny surprised it lasted so long haha
new way of collapse , which is really give a impact to design engineers to give a alternate solution to wind load.
some explanation about form work, working stress method should be provided
the design engineer should predict that such kind of impact could happen there with bridge…he must check the last hard affectz of natural climate on that area..then by focusing these consideration he desigh the bridge or whatever he wantz to design..preplanning must be considered in the design…while economy iz also an issue…but money iz not more than humen life.
nice effort thanks for the good page and interesting video link..iI am surprised it lasted so long
nice videos for example
It looks that wind effect has not been taken into consideration up to the mark in its design.