Third Round of Federal Funding for WA Transit

11 Replies to “Third Round of Federal Funding for WA Transit”

1. Such a tunnel would be less steep, could be built more quickly, locally (rather than with Asian steel), less expensively, and would preserve the riverfront and salmon runs.

   There’s a lot of handwaving in your paean for an immersed tunnel at the I-5 crossing, Nathan. The engineers of both the Columbia River Crossing and the Interstate Bridge Replacement projects estimated the cost at roughly twice that of a bridge.

   Now we can go all Trumpy and charge them with cooking the books, but doing so requires ignoring the couple of hundred feet of post-Missoula flood silt at the bottom. The actual riverbed is almost two-hundred and fifty feet down, and putting a BART-tunnel like pair of sunken and then welded tubes in it would require driving splayed out supports for the tube segments unlike the SF Bay crossing which has the tunnel sections just sitting on the bottom of the dredged trench.

   A bridge will need the same sort of pilings, but only under the piers.

   The right thing to do is forget the LRT and instead add bus lanes between Vancouver and Hayden Island and extend MAX just to the island. Then run a couple of the Vine routes to the new MAX station.

   But most of all, make it an eighty foot clearance with a lift for the twenty or so openings a year that would still be required for tall vessels. That would solve the grades issue though it wouldn’t save money because of the lift machinery.

   1. I’ve clarified the post to make it clear that I’m not so sold on the tunnel option, but its proponents are making the claim.

      Personally, I would want to read more about the geotechnical design work to understand whether a submersed tunnel is actually feasible in the sediments of the Columbia River. Isn’t the hard part of a submersed tunnel not preventing it from sinking, but preventing it from floating?

      1. But it’s fairly clear that we’re going to get the IBR as currently designed, even though it’s mostly a freeway project spending lots of money on new interchanges in Oregon, and light rail tacked on as an easily-cut “cost saving” option instead of, say, not widening the freeway leading up to it.

      2. I agree. I think the tunnel idea is clouding the issue. I also think extending MAX is clouding the issue. Folks need to back up and look at the big issue here:

         This is way too big, and way too expensive.

         It is crazy that politicians constantly talk about aging infrastructure and then they build a giant, unnecessary expansion. It is like owning a couple old cars that keep breaking down but instead of fixing them you buy a Jeep. Eventually that car will need a repair, and you will be worse off.

         Anyway, it is worth looking at a tunnel option. Maybe it turns out that really is cheaper. But it is quite likely it isn’t, and it shouldn’t be the main option. They should consider options that are above ground but much smaller. This website has a pretty good summary or one set of alternatives (https://aortarail.org/site/assets/files/1044/csa2_overview.pdf) it involves the following steps:

         1. Build a new South Channel Bridge connecting Hayden Island with North Portland.
         2. Repurpose the existing I-5 bridge for local traffic between Hayden Island and Vancouver Washington (this actually saves money).
         3. Build a new I-5 freeway bridge, in addition to the existing bridge. This new bridge would be just upstream from the current bridge, and it would have 8 lanes for auto and truck traffic—four in each direction.
         4. Change the BNSF railway bridge, farther downstream. The 100-plus year-old swing span on this bridge would be replaced with a lift span that would be aligned with the high point of the current and new I-5 highway bridges. This alignment would eliminate over 90% of the lift events on the current bridge.

         I would add the following:

         5. Tolling. This should probably be the first thing. As soon as you start tolling, the idea that we need a bigger bridge starts to go away. Look at 520. Adding lanes at this point seems silly. Tolling works.

      3. A one- bridge-carrying-everything approach is a bad idea. Rail and highways have different design requirements. When the bridge fails or shuts down , it’s more than an I convenience if it’s not carrying everything..

         Another issue with I-5 in Vancouver is that it’s both an urban freeway and a long-distance truck route. 405 could have offloaded that but it doesn’t do enough.

         So I think something like Ross’ idea makes sense. It can be phased and it provides redundancy. It sets the stage for permanent tolling too — and helps to finance and undertake the construction in smaller parts.

         My only other comment is that any rail crossing should be able to accommodate high speed rail.

      4. Ross, the new bridge will only be four traffic lanes in each direction, so keeping the existing bridges, even with a slender breakdown lane, would be seven lanes each direction: four “through” I-5, two “local”, one for SR14 and one for downtown Vancouver, and a bus lane. THAT is a much greater increase in capacity than the three “through”, a slip between SR-14 / Downtown and Hayden Island and a “LRT” trackway (which should / will become a bus lane)

         Nathan, thanks for the clarifications. I would aesthetically much prefer the tunnel, but I’m not holding my breath.

         So far as “floating away”, yes, it’s possible to include floatation chambers in a twin-tube sectional tunnel. But it’s pretty sketchy to depend on flotation to keep the tunnel from sinking in the ooze. If a section springs a leak, patching and then removing the accumulated water would be um, “unpleasant”…😀

      5. Also, tolling is to start in 2026, several years before the bridge opens.

      6. > three “through i5

         It’s more than 3 lanes. The i-5 bridges they are building are the width of 6 lanes actually. The left most lane is the “bus on shoulder” but could probably be easily restriped to be an hov lane or just regular car lane. There’s 3 general through lanes in the middle. Then the auxiliary lanes. And then the right shoulder is large enough for another car lane.

         They’ll probably keep at least one shoulder — but I’d pretty shocked if they kept both of them and didn’t convert one.

      7. Would the tunnel option preclude bike access across the river? I haven’t heard of any highway tunnel with any non motorized accomodations.

      8. I’ve seen at least one proposal kicking around that would keep the newer of the two existing bridges for some local access and pedestrian access, if a high bridge were built. I would think they would do the same if a tunnel were built.

   2. There’s a bit that I don’t see being mentioned about the concept of an I-5 tunnel:

      They went through all this replacement bridge stuff before.

      They can’t build a high enough bridge for boat traffic at that location, because the airport approaches for both Pearson and PDX go through there. The current I-5 bridge towers would even be illegal under the current rules.

      They might be able to come up with something (moving a metal fabricator that sends large structures through the bridge by barge, and permanently closing Pearson airport have both been discussed, and I’d like to see them examine moving the main navigation channel to the south side of Hayden Island as that seems like the only practical option for a bridge) but there’s a lot more to this than bridge vs tunnel, which structure is more expensive. With the restrictions imposed on the last failed attempt, a bridge is not possible.

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