SDOT Considers Options for Replacing Bridge Connection to Ballard Locks

2
The current bike and pedestrian bridge along 33rd Ave W in Magnolia is due to be replaced. (Photo by Ryan Packer)

The conditions of the West Seattle high- and low-bridge, the Magnolia Bridge, and other high-profile bridges that carry vehicle traffic have been getting a lot of attention lately, with good reason. Seattle’s pedestrian bridges get less attention, but many of the 30 footbridges that the City maintains are reaching the end of their design life as well. One critical bridge in Magnolia, the 33rd Ave W bridge, is beginning to show signs of deterioration.

Made of timber, the bridge isn’t very wide and can get slippery particularly during autumn as wet leaves accumulate on the structure. (Full disclosure: I have definitely taken a spill here on my bike.) But it provides a great connection between the Ballard Locks and relatively new protected bike lanes on W Government Way and Gilman Drive up the bluff in Magnolia. Discovery Park is just to the west, and a Fort Lawton social housing project that will add at least 235 new affordable homes, too. Thankfully, Magnolia anti-growth advocate Elizabeth Campbell finally exhausted her predatory delay options recently.

The 33rd Ave W bridge provides a crucial connection between the Ballard Locks and the rest of Magnolia above. (SDOT)

The Seattle Department if Transportation (SDOT) is looking at how this bridge should be replaced. No money to construct a new bridge has been identified yet, but the department is planning to complete the design for a new bridge to get the project in the queue for construction funding. There is a survey up through June 8th asking for input on the new design for this crucial segment in Seattle’s bike network.

With so many competing bridge maintenance needs, the cheapest option is going to look pretty attractive. That option would consist of rehabilitating the existing bridge, keeping the superstructure but adding a new aluminum deck, widening the bridge from six feet to ten feet. But that wouldn’t make the bridge fully accessible, with the grade of the bridge still not meeting ADA standards. This new bridge would likely only last another 30 or 40 years, with frequent inspection and maintenance of the timber superstructure.

One option for replacing the 33rd Ave W bridge would be a rehabilitation of the existing bridge. (SDOT)
Rehabilitating the existing bridge with a new aluminum deck and railing would look like this. (SDOT)

A second option would completely replace the superstructure, which would allow a replacement bridge to be widened to 14 feet. This still wouldn’t have an ADA-compliant grade. A new bridge would have an expected lifespan of 75 years.

Another option for replacement would construct a new bridge in the same footprint. (SDOT)
A steel truss bridge like the one pictured here wouldn’t meet ADA standards for grade changes along the route. (SDOT)

The third, and best, option would be to construct a new ADA-compliant bridge, which would require an extension of the trail, a retaining wall, and an angled bridge to handle a more gentle grade. This bridge would also be 14 feet wide. The primary downside to this option will be cost.

The best option to replace the bridge would create a new angled bridge that meets ADA standards. (SDOT)
A concrete pedestrian bridge like this one could meet ADA standards and provide space for a 14-foot path. (SDOT)

Ultimately, ADA standards aren’t something that should be pitted against other considerations in the design of a project like this, so Option 3 should be the only one that remains on the table. Rehabilitating the bridge also may look like the most attractive option as the bridge projects stack up but it’s also the most short-sighted. If Seattle doesn’t have the resources to do a replacement like this correctly, that’s a big indictment of where we’re at as a city.

You can keep up to date about this project and take the survey through June 8th at the SDOT webpage.

We hope you loved this article. If so, please consider subscribing or donating. The Urbanist is a 501(c)(4) nonprofit that depends on donations from readers like you.

Ryan Packer lives in the Summit Slope neighborhood of Capitol Hill and has been writing for the blog since 2015. They report on multimodal transportation issues, #VisionZero, preservation, and local politics. They believe in using Seattle's history to help attain the vibrant, diverse city that we all wish to inhabit. In December 2020, Ryan started a three-month stint as editor of Seattle Bike Blog.

2 Comments
Inline Feedbacks
View all comments
asdf2

Option 3 has the advantage that a wider path and less steep grade will make it easier to bike (even if that isn’t the purpose of ADA), but I’m inclined to prefer option 1, so that the project savings can be re-invested in bike/ped projects elsewhere in the city. It also leads to less down time when the bridge is closed for construction.

nprws

I would tend to agree with asdf2 that in this era of coming up short on funding for capital projects, we go with projects that for now will extend the life and functionality of projects (Opt 1). Further, the City should examine designs that minimize the use of concrete given its impact on greenhouse gas emissions.