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BUILDING
FOR THE FUTURE:
A
REMARKABLE BRIDGE
By
Marty
Baker
Welding plays an important role as one of the most
remarkable bridge stories of our time continues to unfold in
western Washington State – the Tacoma Narrows Bridge – that
spans across the Puget Sound. On July 1, 1940, then the
third longest suspension span in the world opened. Just
four months later, a windstorm was blamed for its dramatic
collapse. Engineers learned much from this lesson and the
failure led to safer design and construction of suspension
bridges. On October 14, 1950, a new Tacoma Narrows Bridge
opened as the 5th longest (2800 feet) suspension bridge in the
United States. Ironworkers and steelworkers –
“bridgemen” – welders -- contributed much of the labor,
risking their life or serious injury performing the difficult
and dangerous work. It is said that they had “nerves of
steel”.
Today, improved standards make the jobsite a safer place to
work as Washington State Department of Transportation (DOT) and
the Tacoma Narrows Constructors build yet another Tacoma Narrows
Bridge. Construction on the structure began in October
2002 and is expected to be complete in early 2007. 18,000
tons of steel – 46 “slices” each weighing 450 tons and
measuring 120-feet long – will be fabricated and moved into
place with gantry cranes. The orthotropic steel deck and framing
will act as one with the truss structure. The completed
bridge deck will be 5,400 feet in total length.
Washington State DOT requires compliance with all existing
standards including the Bridge Welding Code (AWS
D1.5: 2002) that was developed and published in partnership with
the American Association of State Highway and Transportation
Officials (AASHTO). This standard covers structural and
welded joint details, workmanship, qualification, and inspection
for AASHTO welded highway bridges made from carbon and low-alloy
constructional steels.
WHY ANOTHER BRIDGE?
Increasing congestion on Washington’s State Route 16
corridor is one of the factors that led to the addition of
another bridge that is being built parallel to the existing
bridge. The current bridge was designed to carry 60,000
vehicles per day, not the 85,000 to 90,000 that pass over it
each day. The new bridge will provide two general lanes
and an High Occupancy Vehicle (HOV) lane for eastbound traffic
and a separated path for bicycles and pedestrians. This
design-build project provides the option to accommodate a second
deck in the future. The existing bridge will be
reconfigured to provide to general purpose and a HOV lane for
westbound traffic. Separating oncoming traffic will
improve safety by providing wider lanes and safety shoulders and
relieves congestion for travelers.
TRAINING
The Structural
Welding Program at the Hobart Institute of Welding
Technology is the path to follow if this work sounds
interesting to you. The 21-week program prepares people to
weld on bridges, construction, job shop and fabrication work.
You can learn more about this at http://www.welding.org
or call HIWT at 1-800-332-9448 or (937) 332-5300 for a printed
catalog.
WEB SITE AND FACTS
The Washington State DOT maintains an interesting web site
for this project at http://www.wsdot.wa.gov/projects/sr16narrowsbridge/.
Included there, along with the history of the project, were some
facts concerning “Women of the Bridge”. It indicates,
“women make up eleven percent of construction employees, but
only 2.4 percent of all skilled trades.” The “Tacoma
Narrows Bridge Project outdoes the nation with [women] a full 10
percent of the laborers and field engineers on the job.”
These females range in age from 23 to 61 with anywhere from one
to 24 years of construction experience.
For further information, contact:
WSDOT Tacoma Narrows Bridge Project Office
3214 50th Street Court NW
Building D, Suite 302
Gig Harbor, WA 98335
E-mail orfeedback@wsdot.wa.gov
Phone: 977-762-7769
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