February 2012
Progress at the site:
- Crews are constructing the first pontoons at the casting basin. Six pontoons are being built and are on track to be completed in April 2012.
- Crews installed the gate to the casting basin in November 2011. The gate is 110 feet long, 30 feet tall and 10 feet thick, and weighs about 150 tons.
- Crews completed placing approximately 11,200 cubic yards of concrete have to construct the pontoon casting basin floor.
- Crews completed excavating approximately 280,000 cubic yards of material that had to be removed to construct the basin.
- Crews completed driving the 874 piles needed to construct the pontoon casting basin's foundation, crane beams and bulkhead wall.
- View photos of the construction.
Overview
WSDOT is advancing pontoon construction to restore the SR 520 floating bridge in the event of a catastrophic failure. If the SR 520 bridge failed, it could take several years to construct pontoons and restore the bridge for drivers.
WSDOT and contractor Kiewit-General (K-G) are currently building a casting basin facility at the 55-acre Pontoon Construction Project site in Aberdeen. The facility will feature a concrete batch plant, on-site water treatment and a 4-acre casting basin, where pontoon construction will occur.
Crews will construct and store 33 pontoons, 21 of which at 360 feet long, 75 feet wide, and nearly 30 feet tall, are the largest ever built in Washington, for planned replacement of the SR 520 Bridge. If the pontoons are not needed immediately for this purpose, they will be stored at a location within Grays Harbor.
Why is WSDOT
building pontoons for the SR 520 Bridge?
Pontoons are the foundation of a floating bridge and can take several years to construct. They are large, hollow concrete structures designed to support the weight of the road, plus the cars, trucks and buses that use the bridge daily.
The Pontoon Construction Project is a critical step toward restoring the existing SR 520 bridge as soon as possible in the event of a catastrophic failure.
The timely availability of new pontoons is a critical element of restoring the bridge for drivers and maintaining a critical link -- the SR 520 corridor -- to the region's transportation system and economy.
The End Result
If the SR 520 bridge were to fail, we would be prepared with pontoons to replace the floating section of the SR 520 bridge in a timely manner. If the SR 520 bridge does not fail, we would store the pontoons until they are needed for the planned replacement of the SR 520 bridge in 2014.
Project Benefits
Safety
The pontoons for the SR 520 bridge will be designed and built to:
- Withstand a 1,000-year earthquake event.
- Withstand windstorms up to 92 mph.
Reliability
Currently, 115,000 vehicles cross the SR 520 bridge each day. There is not an available detour designed for or capable of accommodating additional traffic at equivalent speeds or travel times.
Economic and social impacts on the region are likely to be substantial if the SR 520 bridge were to fail. Advancing pontoon construction would allow the region to avoid an additional three years of SR 520 bridge closure and the resulting adverse effects on the transportation system and economy.
What is the project timeline?
- 2009 - Innovative pontoon construction testing.
- 2010 - Publish draft environmental impact statement.
- 2010 - Issue final environmental impact statement.
- 2011 - Receive Record of Decision from FHWA.
- 2011 - Begin and complete casting basin facility construction.
- 2012 - Begin pontoon construction.
- 2014 - Complete pontoon construction.
Financial Information
The project is funded through the following sources:
With the passage of ESHB 2211 in the 2009 legislative session, WSDOT is authorized to collect tolls on the SR 520 floating bridge beginning in 2011. This will expedite the replacement of the SR 520 floating bridge and allow us to move forward with pontoon construction.
How can I get more information?
Contact:
For comments and questions about the project, or to be added to the mailing list or e-mail list, please e-mail pontoons@wsdot.wa.gov.
To listen to a recording of the latest project information and leave a verbal comment or question, please call the project hot line at 1-360-591-8012.
To contact the project office by mail:
Pontoon Construction Project
600 Stewart Street, Suite 520
Seattle, WA 98101
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