It’s not quite spring, but heavy cleaning awaits SR 305 Agate Pass Bridge

By Doug Adamson

You wash your car and your dog. You wash behind your ears. But, washing bridges? It sounds odd, but the answer is yes. Washington’s aging bridges get a lot of exposure to the elements and occasionally need a bath. It is particularly true when key spans are near corrosive saltwater.

The Agate Pass Bridge requires a thorough inspection.
In order for that to happen, crews need to deep clean the bridge.

The reason for bridge washing, however, goes well beyond ‘keeping things tidy.’ Our inspectors are required to clearly inspect critical bridge elements, such as joints. That’s tough to do when those bridge elements are covered in a thick layer of gunk.

What are we doing? 
For 21 consecutive days beginning February 9, our bridge maintenance crews will deep-clean the Agate Pass Bridge on State Route 305. Workers also will inspect this vital link between Bainbridge Island and the Kitsap Peninsula. Crews will use three Under-Bridge-Inspection-Trucks (UBITs) to reach all areas of the bridge. UBITs have a crane-like arm that extends crew carriers over the side of the bridge.

What does this work mean for drivers? 
Crews will use three UBITs to clean and inspect Agate Pass
Bridge in February 2015. This photo shows a UBIT being
used to inspect the SR 167 Puyallup River Bridge.
Every day from February 9 through February 28, drivers will encounter single-lane alternating traffic
at the bridge each Monday through Friday between 8:45 a.m. and 3 p.m. On Saturdays and Sundays, single-lane alternating traffic will be in place from 7:45 a.m. to 3 p.m. Drivers who use SR 305 across the bridge should expect long delays during work hours. The work hours were chosen in coordination with the Washington State Ferries schedule to minimize impacts to ferry users.

Traffic impacts
There will be a lot of potentially frustrating traffic backups. That’s why we will need help from drivers. The Agate Pass Bridge is used by 22,000 vehicles per day.  During the seven hours between 8 a.m. and 3 p.m. - the times crews will work - SR 305 carries about 4,600 vehicles in each direction.

Planning ahead could help save you time and frustration.

Here’s a time-tested strategy:

  • Allow plenty of extra time to travel through the work zone.
  • If possible, travel early in the morning or later in the afternoon or evening. 
  • Consider rescheduling discretionary trips and telecommuting.

Why isn’t this work being done at night? 
The Agate Pass Bridge, built in 1950, is a critical link
between the north end of Bainbridge Island
and mainland Kitsap County.
Since one of our key goals is to keep traffic moving, we routinely schedule lane closures on state highways when traffic volumes are lower, typically at night. This project, however, is different. Workers need daylight to get this kind of work done. Motorists will see the bridge lined with three UBITs. An operator inside the truck needs to move in concert with workers inside a crew carrier to thread the truck’s crane-like arms through tight spaces under the bridge deck. The arm – that carries two crew members in a basket on the end of the arm – is delicately navigated through V-shaped steel portions of the bridge both above and below the deck. The operation has been compared to threading a needle when both the needle and the thread are moving. In this case, one person is holding the needle while a second is holding the thread.  Once the needle is threaded, daylight allows bridge inspectors to take an in-depth look at the bridge’s steel, checking for corrosion, cracks or other signs of wear.

We want to make sure that nothing, not the crews, the equipment, the driving public or the bridge, is damaged or injured in this process. In this particular scenario, working at night introduces unacceptable safety risks and inefficiencies.

Why don’t you just use the money to build a new bridge? 
The $200,000 cost of this work is akin to investing in your old, yet dependable car to keep it going. Reality is, the funds being used to clean the bridge wouldn’t pay even a fraction of the cost to build a new one.

Bridges and highways are significant investments in our state that were made by previous generations. We’re working to preserve the infrastructure – like the Agate Pass Bridge - for years to come.

Done with an eye toward protecting the environment 
In order to protect the environment, we have been working with the Washington State Department of Ecology (DOE) to do this work. During the work, we’ll hand-clean the bridge of debris followed by low-pressure flushing. The approach, approved by DOE following a pilot project, minimizes the impacts to waters flowing below the bridge. Sampling after this two-step approach has shown insignificant impacts to the environment. This option is also much less expensive since it doesn’t require crews to fully encapsulate the bridge in an oversized tent.

For more information about the SR 305 Agate Pass Bridge daytime closures, visit the project website.