Pontoons take shape for SR 520 floating bridge

Construction is shaping up from the inside out on new pontoons for State Route 520. Local officials saw the first handful of precast concrete walls that soon will form the backbone of a new floating bridge across Lake Washington during a tour Friday.

September 26, 2011 7:09 pm
The mockup pontoon provides Kiewit-General crews the opportunity to implement the practices and lessons learned during the Advanced Construction Methods and Engineering process at Satsop in 2010. Here a crane operator carefully moves an interior wall segment into position.
The mockup pontoon provides Kiewit-General crews the opportunity to implement the practices and lessons learned during the Advanced Construction Methods and Engineering process at Satsop in 2010. Here a crane operator carefully moves an interior wall segment into position.

Construction is shaping up from the inside out on new pontoons for State Route 520. Local officials saw the first handful of precast concrete walls that soon will form the backbone of a new floating bridge across Lake Washington during a tour Friday.

The Washington State Department of Transportation (WSDOT) and contractor Kiewit-General (KG) recently completed the first precast interior wall pours, creating three 27-foot-tall, 11-foot-wide, 8-inch-thick walls that tip the scales at nearly 15 tons each.

Elected officials and media got a firsthand look at the behemoths during the tour.

In coming months, crews will construct thousands of the precast interior walls, using the sections create 33 pontoons in the casting basin.

ADVERTISEMENT
0 seconds of 0 secondsVolume 0%
Press shift question mark to access a list of keyboard shortcuts
00:00
00:00
00:00
 

“It was great to share our past successes and continued progress with elected officials from the region,” said Julie Meredith, SR 520 program manager. “Our focus is on maintaining this momentum to keep the project on time and on budget, while continuing to provide good, family-wage jobs in the Grays Harbor community.”

As pontoon construction ramps up, so will the number of people working on the project. When pile driving began to build the foundation for the casting basin this spring, 80 craft workers were on site.

Since then, the number of construction workers has more than doubled to 200 and counting – and that number will continue to grow as additional carpenters, ironworkers, laborers and operators are hired.

“This job site is buzzing with activity as workers build forms, tie rebar and get ready to pour months’ worth of concrete for the new floating bridge,” said WSDOT Principal Engineer Dave Ziegler. “It’s a mammoth task and the crews are hard at work.”

Crews will build pontoons in cycles, the first of which is scheduled to be complete in spring 2012. After that, pontoon cycles will be completed about every five months, with all pontoons finished by mid-2014.

More than 230,000 tons of concrete, 35,000 tons of rebar and approximately 2.4 million square feet of wooden formwork will be used to construct the pontoons.Work on the SR 520 Pontoon Construction project began in February as crews started work on the pontoon-casting basin.

For more information about the $367 million SR 520 Pontoon Construction project and to view project photos and the project webcam, visit www.wsdot.wa.gov/Projects/SR520/Pontoons.