Construction milestone: New 520 bridge pontoons reach midspan

Nov 17, 2014, 5:23 AM | Updated: 5:28 am
Drivers crossing the lake will notice an apparent milestone in the construction of a new floating b...
Drivers crossing the lake will notice an apparent milestone in the construction of a new floating bridge. (WSDOT Photo via Flickr)
(WSDOT Photo via Flickr)
LISTEN:

Drivers crossing Lake Washington on SR 520 will notice an apparent milestone in the construction of a new floating bridge. But actually driving on what your tax and toll money is paying for is still more than a year away.

Take a peek to the north as you pass mid-span. Those gigantic, connecting pontoons that will support the new bridge have reached the draw span of the existing bridge.

“Does that mean we’re halfway across the lake?” asked project spokesman Ian Sterling, with the Washington State Department of Transportation. “Well not necessarily, because you have these approach bridges that roll up to the actual floating portion of the bridge.”

Okay, but the floating section is half-way across the lake.

“Half of the pontoons needed to cross Lake Washington are now in place, in their permanent home, anchored and bolted together,” said Sterling. “Sixty-six of the 77 total pontoons need to build the bridge are complete and all of those are on Lake Washington.”

Every one of the concrete pontoons fabricated for the 520 project will be finished by early next year. That’s behind schedule because of cracks discovered in the first batch of pontoons due to a design flaw. The fix added $200 million to the cost of the project, according to Sterling.

Drivers should notice an obvious design change; the height of the bridge deck.

“We have road deck that’s going in on top of the pontoons, unlike the current bridge where you drive directly on top of the pontoons, essentially, (with) the new bridge pontoons, the road deck is suspended above the pontoons themselves,” Sterling explained.

The decking will sit 20 feet above the pontoons, keeping wave action off the roadway. The new bridge is designed for winds of 89 miles per hour and to withstand a 1,000-year earthquake.

One of the most common questions about the new bridge construction is how will drivers transition between the new six-lane bridge and the existing, four-lane roadway on the west side? Just like you’d think. Merging. New, west side connections are on a later construction schedule or not even funded yet.

“As we bring these improvements online, they go on one at a time, two at a time as soon as we complete them, we open them up,” said Sterling. “It’s not the perfect solution at this point in time, we’re just slowly marching along.”

The new floating bridge – originally scheduled to open next month (Dec. 2014) – is now due to open in April 2016, barring new delays.

“Of course, it’s construction,” Sterling cautioned. “Just like building a house, there is a chance, always, that things will change but at this point in time, it looks like 2016 (the bridge will open.)”

The new bridge will feature transit/ HOV lanes, wider shoulders and a 14-foot-wide bicycle and pedestrian path.

Funding for the ongoing construction comes from a 2003 gas tax increase, a 2005 transportation tax package and tolling. The overall budget for the new 520 corridor from I-5 to I-405 is $4.3 billion. Of that, $1.4 billion remains unfunded.

Local News

Washington state forest...
Dalton Day

Washington state to preserve, reseed two million acres of forest by 2040

The state Department of Natural Resources makes a substantial investment in its forests, pledging to preserve or restore 2 million acres of trees by 2040.
19 hours ago
homeless encampments...
Dalton Day

King County Council rejects attempt to remove public homeless encampments

King County Council ahs rejected a motion to codify procedure for removal of homeless encampments in unincorporated King county.
19 hours ago
Charleena Lyles...
MyNorthwest Staff

Seattle agrees to settlement in Charleena Lyles wrongful death lawsuit

The City of Seattle will pay a $3.5 million settlement to the family of Charleena Lyles, a Black woman who was shot and killed by Seattle police in 2017.
19 hours ago
charity, giving...
MyNorthwest Staff

Secretary of State warns Washingtonians about giving to fake charities

While it's the season for charitable giving, it's also the season for scammers. The secretary of state's office has tips to help protect your donations.
19 hours ago
Tacoma police, South King County...
MyNorthwest Staff

South King County mayors demand action from state to end rash of violence

Multiple mayors in South King County are banding together to combat a violent trend after seven people were shot in four days. 
19 hours ago
Seattle election...
Nick Bowman

How wealthy strongholds helped deliver Seattle’s 2021 election to moderate candidates

Seattle's moderate candidates prevailed in the 2021 election on the strength of wealthy neighborhoods along its eastern and western coastlines.
19 hours ago

Sponsored Articles

...
Experience Anacortes

Coastal Christmas Celebration Week in Anacortes

With minimal travel time required and every activity under the sun, Anacortes is the perfect vacation spot for all ages.
...

Delayed-Onset PTSD: Signs and Symptoms

Lakeside-Milam Recovery Centers SPONSORED — You’re probably familiar with post-traumatic stress disorder. Often abbreviated as PTSD, this condition is diagnosed when a person experiences a set of symptoms for at least a month after a traumatic event. However, for some people, these issues take longer to develop. This results in a diagnosis of delayed-onset PTSD […]
...

Medicare open enrollment ends Dec. 7. Free unbiased help is here!

Washington State Office of the Insurance Commissioner SPONSORED — Medicare’s Open Enrollment Period, also called the Annual Election Period, is Oct. 15 to Dec. 7. During this time, people enrolled in Medicare can: Switch from Original Medicare to a Medicare Advantage plan and vice versa. Join, drop or switch a Part D prescription drug plan, […]
...

How to Have a Stress-Free Real Estate Experience

The real estate industry has adapted and sellers are taking full advantage of new real estate models. One of which is Every Door Real Estate.
...
IQ Air

How Poor Air Quality Is Affecting Our Future Athletes

You cannot control your child’s breathing environment 100% of the time, but you can make a huge impact.
...
Swedish Health Services

Special Coverage: National Prostate Cancer Awareness Month

There are a wide variety of treatment options available for men with prostate cancer. The most technologically advanced treatment option in the Northwest is Stereotactic Body Radiation Therapy using the CyberKnife platform.
Construction milestone: New 520 bridge pontoons reach midspan