Tacoma Narrows Bridge (Galloping Gertie)
(source: James Bashford (creative commons licensing))
Living in the Puget Sound area for a majority of my life, exploring, photographing, and documenting many parts of the Puget Sound for several years has been a fun hobby, but most of the time, this section of Puget Sound was recorded the most.
To find a major suspension bridge being constructioned in the 21st century in America is rare. A major suspension bridge hasn't been constructed since 1964 in the United States. While many major suspension bridges have been built in other parts of the world for the past several years, the lessons about the application and their design happend right here as American was getting involved in World War 2.
The first Tacoma Narrows Bridge was constructed in 1939 and went into service on July of 1940. When constructed, it was the third largest suspension bridge in the world. Only the Golden Gate and San Fransico Bay Bridge were larger.
Unlike the suspension bridges built in San Francisso, this bridge was built on a very low budget using cheap beams and girders to create a two lane bridge that looked like ribbon and moved freely in the wind.
Engineers didn't see a reason to test bridges in a wind tunnel. After the bouncing of the roadbed was reported to the engineer (Leon Moiseiff) he did indicate that the Bronx Whitestone Bridge and the Deer Island Bridge were doing the same thing, it became the responsibility of the state to find out why it was happening and how to prevent it.
University of Washington Engineering Professor Farquarson made a scale model of the bridge to test the affects of wind using a wind tunnel. To solve the bouncing, it was decided to add additional cables below the bridge and secure them using concrete block or cables connected to the towers. While this helped in 50 mph winds, early November was a stormy time of the year and eventually the cables broke (many bridges today use additional cable suports above the roadbed rather than below).
It was during this time that Profesor Farquarson would present his findings to the State of Washington. His suggesions were to either drill holes in the side beams or using fairings on the outer sides of the bridge to delect the wind. The state was interested in the fairlngs (they didn't want to drill holes in the bridge) and could have had the work copleted within 40 days but it was too late.
The center span of the bridge fell on November 7th 1940 at wind speeds that had gusts from 38-42 mph after the bridge twited from side to side for about 30 minutes.
The video produced by Barney Elliot shows the roadbed movement while a vehicle (left on the roadway) was left behind by Tacoma News Tribune reporter Leonard Coatsworth. Farquarson and others tried to get the dog, Tubby from the vehicle but the dog didn't want to get out of the vehicle biting those that tried.
Tacoma Narrows Today
It seems insane that anyone would design a two lane suspension bridge with the amount of traffic between Gig Harbor and Tacoma that uses this crossing on a daily basis. Thankfully, the second Tacoma Narrow Bridge (Sturdy Gertie) was completed in 1950 using the same supports the Galloping Gertie was built on and continues to handle traffic from Tacoma to the Olympic Pennisula to this day.
When the 50th Anniversary of Galloping Gertie was going on, The Tacoma News Tribune was reporting on either expanding the existing bridge to handle more lanes of traffic or build another bridge. The latter was chosen.
In July of 2007 the third Tacoma Narrows Bridge (now known as Greedy Gertie due to the tolls) took 6 years to construct due to safety and environmental concerns.
There are photos taken from the construction of the concrete towers, to the spinning of the suspension cables, to the assembly of the roadbed.
While taking these photos, the reamains of Galloping Gertie were found on the shore (Narrows Park on the Pennisula side) were they have stayed since they were jackhammered into the sound and it's shores below.
(Galloping Gertie remains on the shore (source: Tim Babcock))
The photo above is used for the Wikipedia page on the bridge while a digital video was shot of the remains for a You Tube to show it's construction.
The remains of Galloping Gertie rest in the Puget Sound and are protected as a historiccal monument (Historical Monument 92001068). The section of roadway that is at the Washington State Historical Museum in Tacoma was a section that was removed (near the location in the photo above). When the third bridge was built during the construction of the caissons.
Just before relocating to Oregon, the first year of the third bridge was spent taking photos in the area as it was easy to walk to from living on 6th Ave and Jackson in Tacoma. While the approaches to the third bridge were noisy, they have found some ways to baffle the sound.
Many bridges that were built with the design that Moiseiff created, have fairlings on the sides of the girders. Not only were these added to the Bronx-Whitestone and Deer Island Bridges in the 21st century, but the Liongate Bridge uses fairlings as well as the alternative to adding additional girdiers to stiffen the roadbed was affecting the lifespan of the roadbed (due to the weight) and had to be replaced.