What to do with a pontoon construction site when you are done making pontoons

After completing the last three pontoons for the new State Route 520 floating bridge last month, work at the Aberdeen Casting Basin is winding down. Contractor Kiewet General is preparing the

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Triple play on the way as final pontoons for new SR 520 bridge leave Aberdeen

As baseball fans cheer the start of a new season, the Washington State Department of Transportation is celebrating a major milestone for the new State

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Fourth cycle of State Route 520 pontoons leaving Aberdeen casting basin April 15

The fourth cycle of pontoons headed for the State Route 520 bridge will be floating out of the Aberdeen casting basin late tonight. Deputy Executive Director at the Port of Grays Harbor Leonard Barnes told commissioners last week, the giant concrete structures will be floated to other terminals for inspection and preparation. Some are stored at a moorage facility in the harbor, North of John’s River until they are towed 260 nautical miles around the Olympic Peninsula to Lake Washington for the new State Route 520 floating bridge. Ian Sterling with WSDOT tells KBKW they have another six pontoons for the new SR 520 floating bridge ready to float out from the casting facility in Aberdeen. Crews plan to work through the night on Tuesday, April 15, with the first pontoon scheduled to leave the casting basin close to midnight to coincide with the high tide necessary for float-out. These six pontoons represent the fourth cycle built in Aberdeen, meaning two-thirds of the 33 pontoons being constructed there are now complete. Other bridge pontoons are being built in Tacoma. All told, 52 of the 77 total pontoons needed for the new bridge are now complete.
Six more SR 520 pontoons wait for high tide in Tacoma
Six more SR 520 supplemental stability pontoons are towed out of their Tacoma casting basin in pairs each evening, as the high tides allow.

Fourth cycle of SR 520 supplemental pontoons nearly complete in Tacoma

OLYMPIA, Wash – Washington State Department of Transportation crews move closer to another project milestone as the finishing touches are made to the fourth cycle of Tacoma-built pontoons

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SR520 Pontoons on the move in October

ABERDEEN – Two new State Route 520 bridge pontoons left Aberdeen for Seattle this weekend, while another two pontoons will follow next week. 

Currently, eight pontoons are located in the Grays Harbor area: two pontoons completed in Cycle 2 – longitudinal pontoons Q and R – and six pontoons completed in Cycle 3 – longitudinal pontoons M, N, O and P and supplemental stability pontoons BSW and BSE. 

The Cycle 2 pontoons are currently at a moorage site in Grays Harbor, while the Cycle 3 pontoons are at the Port of Grays Harbor. Pontoons BSW and BSE were towed last weekend, and pontoons Q and R will leave next week. Pontoons M, N, O and P will move to the Grays Harbor storage site. 

Third cycle of SR 520 pontoons complete in Aberdeen

ABERDEEN, Wash. - Another six State Route 520 bridge pontoons floated out of the Aberdeen casting basin today, marking completion of the third of six total pontoon cycles to be built in Grays Harbor. 

“With the third cycle complete, we’re halfway done in Aberdeen,” said Julie Meredith, SR 520 program director for the Washington State Department of Transportation. “We’ve now finished 38 of 77 pontoons needed for a new SR 520 floating bridge that will serve the region for 75 years or more.” 

The third pontoon construction cycle included four longitudinal pontoons and two supplemental stability pontoons. The 360-foot-long longitudinal pontoons will help form the backbone of the new bridge, while the supplemental pontoons provide additional stability and flotation. 

Each longitudinal pontoon in this cycle includes transverse post-tensioning, a concrete strengthening technique endorsed earlier this year by a pontoon expert review panel. WSDOT managers, who conducted preliminary examinations in the casting basin, report the pontoons are performing as expected. The pontoons show no signs of the spalling that occurred in the first pontoons built last year, and end-wall cracking appears limited to predicted and acceptable levels. 

Repair Work to Delay Float-Out of Pontoons

Seattle, WA- With the heavily planned and much anticipated 520 floating bridge pontoon construction project underway the Washington State Department of Transportation are now facing a delay of the float-out of SR 520 bridge pontoons built in Aberdeen after damaged concrete was discovered.

Work is planned on four of the six concrete pontoons under construction in Aberdeen and is preliminarily expected to take four to six weeks to complete. As a result, the completed pontoons are not expected to be towed out of the casting basin until July or August, depending on favorable tides. 

The Washington State Department of Transportation is working with contractor Kiewit-General to analyze the cause of the damage "We have a plan, and by making these repairs and modifications before the pontoons leave Aberdeen, we can assure that the new SR 520 floating bridge will safely carry traffic for 75 years or more," said Julie Meredith, WSDOT SR 520 program director.

The damage was discovered May 11th after construction crews completed post-tensioning on a longitudinal pontoon measuring 360 feet long, 75 feet wide and more than 28 feet tall. Crews plan to de-tension the steel tendons, remove concrete and add steel rebar reinforcement needed to contain the steel tendons. 

WSDOT and contractor KG are focused on making the modifications carefully and swiftly, but say it is too early to say how much the repairs will cost or how costs will be assigned.

Aberdeen-Built Pontoons Head to Hoquiam June 1

ABERDEEN, Wash. - Replacement pontoons for the State Route 520 floating bridge will begin their journey to Lake Washington this summer, but June first, they leave the casting basin in Aberdeen and make a short trip to Hoquiam.
We have the contract to get them to the Port, then there's another contract to take them up the coast. We're thinking WSDOT that we're working with here will buy the pontoons within 24 hours - Project Director Phil Wallace
Wallace, with Kiewit General, told Port Commissioners on Tuesday that the six pontoons will rotate out of Terminal 4 in Hoquiam while the Washington State Department of Transportation works on towing the biggest pontoons every built 260 nautical miles around the Olympic Penninsula to Lake Washington.

Pile Driving Begins on Pontoon Construction Site in Aberdeen

ABERDEEN, Wash. - The sounds of progress start echoing through the State Route 520 Pontoon Construction project site this week as crews begin to drive hundreds of support pilings to form the foundation of a pontoon casting facility.

The Washington State Department of Transportation (WSDOT) and contractor Kiewit-General (K-G) are constructing the foundation for the casting basin where they will build the concrete pontoons that will form the backbone of a replacement SR 520 floating bridge. Crews must drive as many as 900 steel piles 125 feet into the ground. During the three-month process, K-G will have up to 20 pile drivers working at the site, and nearby residents and businesses will notice hammering sounds.

“This work is critical in that it literally lays the foundation for the pontoon construction that will start later this year,” said Dave Ziegler, WSDOT principal engineer. “As we finish sections of piles, we’ll begin excavating the site to create the basin.”

SR 520 pontoon project open house Wednesday in Aberdeen

ABERDEEN – The Washington State Department of Transportation (WSDOT) and its contractor, Kiewit-General Joint Venture (K-G), invite the public to a pre-construction open house for the State Route 520 Pontoon Construction Project in Grays Harbor. Now that federal approval has been received, construction is expected to begin at the Aberdeen Log Yard as soon as mid-February.


When: 4 – 7 p.m. Wednesday, Jan. 19


Where: Aberdeen High School Commons, 410 N. G St., Aberdeen


Speakers: WSDOT and K-G staff will be on hand to provide detailed project information and explain how to stay informed during the project. Representatives from local unions will also be available. There will be no formal presentation.


Visuals: WSDOT and K-G will have displays of the casting basin and staff to explain the casting basin and pontoon construction.


For more information about the project and the open house please visit: www.wsdot.wa.gov/Projects/SR520/Pontoons.