Updated: Feb. 2, 2013
Follow along with WSDOT as we continue to build, tow and assemble pontoons for the new SR 520 floating bridge.
Click image to enlarge
Pontoon towing update
- On Thursday Jan. 31, crews floated out the last two supplemental pontoons of the second construction cycle in Tacoma.
- Between Jan. 29-31, a total of six pontoons were towed out of the basin. Watch the time-lapse video on YouTube.
- At around 6 a.m. on Saturday, Feb. 2, the first of two pontoons left Tacoma. You can track the tugboat Terilyn as the pontoons makes its way to Lake Washington.
- The first pontoon is currently planned to arrive at the Hiram M. Chittenden Locks in Ballard around 3:30 p.m. on Saturday, Feb. 2.
- To track the second pontoon's transit to Lake Washington, track the tugboat Solana. It is expected to arrive at the Hiram M. Chittenden Locks in Ballard around 6:30 p.m. on Saturday, Feb. 2.
- The Locks grounds are open from 7 a.m. until 9 p.m.
- The four remaining pontoons will stay in Tacoma until additional longitudinal pontoons arrive on the lake.
- Check out photos of the float-out on our Tacoma Flickr page.
Pontoon transit route
Pontoons for the new floating bridge are being constructed in two different sites in Washington state: Aberdeen and Tacoma. When pontoon construction is complete and they are ready for assembly, they will be brought to Lake Washington through the Hiram M. Chittenden Locks in Ballard.
If you are interested in viewing the pontoons as they make their way to Lake Washington, see our map of suggested viewing locations (pdf 2.5 mb).
Build-your-own pontoons for the floating bridge
The floating bridge pontoons represent a key milestone in a critical safety project. Using the printable pontoon templates linked below, you can build your own bridge that follows our progress with the construction, transport and final positioning of floating bridge pontoons.
- As we complete the construction of each pontoon and bring them to Lake Washington, we will post new templates here. Each pontoon is labeled according to its location within the final bridge structure.
- For each pontoon, download and print the template file (each pdf is approximately 400 kb), cut along the indicated lines, and then fold your pontoon for final construction.
- We will maintain the links for each pontoon template, so that you can catch up with any you might miss.
Aug. 11, 2012: Pontoon V
Aug. 14, 2012: Pontoon W
Aug. 18, 2012: Pontoon V-NW
Aug. 19, 2012: Pontoon V-SW
Aug. 22, 2012: Pontoon U
Sep. 22, 2012: Pontoon V-NE and Pontoon V-SE
Sep. 30, 2012: Pontoon U-NE and Pontoon U-SE
Types of pontoons
The new SR 520 floating bridge will be supported by three types of concrete pontoons:
Longitudinal pontoons (21)
These are the largest pontoons at approximately 360 feet long. They form the backbone of the bridge and support the roadway superstructure.
- Constructed in Aberdeen facility
- Weight: 11,100 tons
Cross pontoons (2)
These mark the ends of the floating bridge section and the transition to the East and West Approach structures.
- Constructed in Aberdeen facility
- Weight: 10,100 - 10,550 tons
Supplemental stability pontoons (54)
These smaller pontoons help stabilize and support the weight of the new floating bridge.
- Constructed in Aberdeen facility (10) and Tacoma facility (44)
- Weight: 2,500 - 2,820 tons