West Seattle Bridge Community Task Force, report #2: Cost-Benefit Analysis review

(SDOT video of Wednesday’s full Community Task Force meeting)

By Tracy Record
West Seattle Blog editor

A day and a half after receiving the information-dense Cost-Benefit Analysis reviewing West Seattle Bridge options, Community Task Force members got their first chance to ask questions about it.

The 89-page report was almost done before the ballyhooed new “rapid span replacement” possibility went public, so the discussion took place somewhat in its shadow, and immediately after the first half of Wednesday’s CTF meeting was spent on a presentation on that unvetted option (WSB coverage here) – something that hasn’t been done for any of the other possibilities, so far.

SDOT‘s bridge-project leader Heather Marx opened with a warning: “None of the numbers you see here should be referred to as ‘estimates’ SDOT would have preferred ranges but this type of study requires choosing a number, she said. She also stressed what the CBA is not:

Then, a presentation of the studied alternatives’ toplines, from SDOT’s Greg Izzo. #1, shoring, “did not perform very well overall.” #2 is repairs:

Izzo said a big question mark remains regarding how long repairs would last. This would likely be designed to 30 percent, with a contractor then brought in to work on the remaining design as well as construction, which would bring “more assurance’ in terms of risks and costs. Repairs would have challenges including seismic performance, future flexibility (a reference to a repaired bridge’s inability to include light rail), funding not as available as it would be for an immediate replacement.

#3 was dropped earlier in the process, as described at an earlier meeting. #4 – superstructure replacement – was the “highest performing” alternative, Izzo said. Unlike repairs, it wouldn’t have significant maintenance costs in the ensuing years.

Though the projection in the CBA is that superstructure replacement could take until 2026, he said they’re becoming more and more confident they could get a replacement up and running sooner. The archetype used in the CBA would be another box girder bridge and that would require foundation strengthening. Some of the costs here are to cover the possibility the USCG could require a higher bridge.

#5 – Full replacement, including piers that would be pushed back to get them away from the water: This is less likely to facilitate an accelerated schedule.

A cable-stayed bridge – the prototype in the CBA – could require some FAA consultation, Izzo said in response to a question from CTF co-chair Greg Nickels.

#6 – Immersed tube tunnel (which SDOT added to the study after community clamor): The CBA says this would cost the most and take the longest. “There’s a lot of issues and a lot of risks we’d have to investigate, including to secure land (for) a new casting facility [to build the “tube”] … that’s a huge monetized risk that we’d have to capture. ” Izzo also mentioned the possibility of “underground surprises” on Harbor Island.

Izzo also noted that SDOT has no experience on maintaining something like the ITT.

In “attribute performance,” here’s how the alternatives stacked up:

In short:

Izzo threw in more words of warning about repairs, saying that “some of what concerns us most about (repairs) is that we would still potentially have an unplanned closure” at some point afterward, mandating replacement anyway.

TASK FORCE Q&A AND COMMENTS: Bicycling/environmental advocate Peter Goldman expressed some skepticism about the duration and cost estimates for the ITT, given projects elsewhere in the world – the 1959-built Fraser River tunnel in BC, for example, and dozens of tunnels in Europe and Asia. He suggested that in-water work is not necessarily out of the question because the port already does a lot of dredging in the area. He said he feels “we’re missing a great opoortunity” to accelerate light rail by linking it into the project. He also said an “integrated vision’ would be “easier to sell to the federal government.”

State House Rep. Eileen Cody noted that nothing so far has taken into account the projected lifespan of what the bridge connects to – the Spokane Street Viaduct. SDOT is “working on a resiliency study for the whole corridor,” Marx said, but otherwise they have to “limit our focus to the emergency project at hand.”

West Seattle Bridge NOW‘s Jen Temple observed that page 57 of the CBA says there’s a “very low risk” that the bridge repair would not last 40 years. Marx retorted, “There’s a very low risk of the repair failing … that’s not the same as a very low risk of the bridge failing.” Izzo added that it’s a separate question to evaluate – “how does the bridge perform as a system?” Wouldn’t that be the same as reusing the substructures for span replacement? pressed Temple. Izzo replied that the substructures – the foundations of the bridge – “are not in bad shape.”

Seattle Port Commission president Peter Steinbrueck echoed that it was “befuddling” to compare the two concepts of repairing or replacing PART of the bridge. He said it looks like those two alternatives, 2 and 4, are the best, but they need a “much more detailed analysis” of the permitting, environmental-review, and funding processes.

Marci Carpenter from WA Federation for the Blind asked about the complications mentioned regarding demolition. This would be the first structure of its kind in the region to be demolished, replied Izzo. Replacement designer HNTB’s Ted Zoli – who gave the ‘rapid span replacement” briefing earlier in the meeting – said same goes nationwide, adding, ‘a lot of the repairs we’re putting in place now, we’d have to undo to demolish the bridge. … That adds to the risk and challenge.”

Jill Mackie of Vigor wondered how these stack up to the mayor’s goals. “Speed and certainty” are critical in those, Marx observed, and obviously repairs and “rapid replacement” would address the first; regarding certainty, she said, “once we intervene in that bridge, (that) it’s the last time for a long time” is a key goal.

The question of a full CBA analysis for the “rapid replacement” concept came up again, from Tim McConnell of West Seattle Runner (WSB sponsor), especially considering CTF members are expected to offer their recommendations next week. Not enough time to do one, said Marx.

SDOT director Sam Zimbabwe added that they’re still strengthening the bridge so it’s too soon to really say how repairs would likely perform.

A few other notes from earlier in the meeting:

BRIDGE UPDATE: Marx provided a quick look at the stabilization work:

She described the often-mentioned “post-tensioning” as ‘steel rope to hold the bridge together.”

RECONNECT WEST SEATTLE UPDATE: SDOT’s Sara Zora showed a list of some of what has been done so far:

And she updated the low-bridge steps toward automated enforcement (as reported here earlier in the day), all to get ready for $75 ticketing starting in early January. The low-bridge subcommittee has its second meeting on Tuesday.

Dan Austin from the West Seattle Chamber of Commerce asked about the status of some proposals such as a possible NB freight lane on West Marginal. “We’re now getting into the point of more targeted engagement,” replied Zora. Austin stressed that he hopes there’s more time for community input. Deb Barker of the West Seattle Transportation Coalition asked if there’s going to be a separate group discussing the West Marginal proposals; Zora said no.

WHAT’S NEXT: The CTF meets again next week, noon Wednesday, October 28th. Given this meeting’s last-minute change in viewing links, we’ll mention a tip that helped us find the new one even before SDOT sent out a hasty update – the streams are handled by Participate Online and if you can’t find it, you can go to that service’s YouTube channel.

34 Replies to "West Seattle Bridge Community Task Force, report #2: Cost-Benefit Analysis review"

  • KT October 22, 2020 (9:31 pm)

    Blah, blah, blah, blah, blah …..

  • SDOT’s bias is destroying public confidence October 22, 2020 (10:14 pm)

    This CBA process has been horribly depressing. SDOT’s bias toward replace taints this report and their commentary. This does not serve us as West Seattleites at all. And yet even with the negligent omission of the real economic impacts of the bridge being closed for years, the CBA clearly spells out as the repair being the smart choice. Now if they got honest about the cost being cheaper than their disclosing, being faster than their estimating and buried in the footnotes is the real probability of the repair lasting for 40 more years at 95% or better, the decision is vividly clear. Repair is the only responsible decision fiscally and it’s the best solution for the people and small businesses of our community. Cut the bs and get the bridge reopened as soon as possible Mayor Durkan. Please, we need you. 

    • Mr. Belvidere October 22, 2020 (10:43 pm)


    • Alki resident October 22, 2020 (11:49 pm)

      Well said!!!! SDOT is dragging their feet and more worried about implications on them. I have this weird feeling the bridge is not as bad as they say but they’d look like idiots if they admitted it. Repair the bridge! Most will agree it may never be able to hold traffic like it did before but get us all moving over it, and continue using Marginal as well. Monitor and continue planning for a future replacement. 

    • Chemist October 23, 2020 (12:11 am)

      From a the technical advisor chair at an earlier meeting, it sounded like they had a decent idea of what was causing the failure, but then when WSB followed up and basically got a lot of backpedaling on indicating any cause.  Maybe there’s some things you can guess about and feel 90% sure that scares someone to pin a failure on in a way that could cause lawsuits.  Alternative 2 calls out additional ground reinforcement needed around pier 18.    I don’t have a lot of confidence in re-using the box structure for 40 years, but I also think it’ll take at least 10 years for SDOT to get their ducks in a row about a replacement bridge project (hopefully not in the exact footprint of the current high bridge to minimize full closure) and it’s wrong to make West Seattle wait for that. 

      ABOUT THE CAUSE:  Another followup question we asked was for elaboration on Technical Advisory Panel co-chair Barbara Moffat‘s mention during last week’s meeting that they now understand what went wrong with the bridge. Here’s the reply we got, also today: “While our confidence in our understanding of the physics affecting the bridge has grown with time as we’ve been able to test our advanced engineering modeling by watching the bridge behave as predicted in response to seasonal temperature changes and our initial stabilization efforts, it may never be possible to determine with 100% certainty a single underlying cause of the bridge cracking, or even if there was a single isolated cause.” We’ll keep following up.

    • AA October 23, 2020 (8:22 am)

      Agree completely. It is clear reading between the lines that SDOT would prefer to replace, despite the CBA findings pointing to repair. For one, funding for replace could likely come from more external sources than the repair option. Second, replace would “bury the corpse” (hey, it is almost halloween) on this colossal failure, sparing them answering difficult questions. As Chemist pointed out, they know what happened but are reluctant to say.

  • Mr C View October 22, 2020 (11:05 pm)

    Couldn’t have said it better. SDOT’s gain is our pain. Time for the electeds (Durkan, Herbold, Constantine) to step up and listen to the community and put these administrators in check. 2026 is too long to wait for superstructure replacement. The rapid replacement option needs to be vetted before it can be selected as there are major risks and unknowns that could result in costly delays.  Vet it – if it pencils out the community will get behind it, but don’t ram it down our throats. The decision to replace or repair will be made by the mayor but the recommendations to replace are being developed internally at SDOT  by unelected self interested administrators that aren’t impacted by their decision.  The social and economic costs to the community increase from an extended closure. A choice to not repair given the CBA and engineering data presented  is a conscious choice to do harm to the people of West Seattle (euphemistically called a trade off  in the biz). That this is being done mainly so that administrators at SDOT can “feel confident” about future funding for maintenance makes me want to pull my hair out. Replace the bridge when Sound transit has rail in place if maintenance costs become excessive. You have a half fixed bridge right now. Can’t we just finish the job? We have all suffered enough in 2020, please don’t add to the misery. Seattle has a long history of corruption, fortunately that has abated in recent decades. When I see public servants getting dazzled by the once in a lifetime big dollar shiny object it makes me nervous.

    • Stevie J October 23, 2020 (11:50 am)

      “Seattle has a long history of corruption” – care to share any examples or citations to this claim?

      • Rick October 23, 2020 (2:31 pm)

        Boy, that’s an outdated argument. How many dollars do you stand to make out of this? We all know what it’s about.

      • JW October 23, 2020 (3:24 pm)

        “1968: A ballot measure approves $16.7 million in funding for a new, higher bridge. A company charging triple the cost of three other potential applicants has its bid selected to design the bridge.It’s later discovered that the company not only had close financial connections to the Speaker of the state House of Representatives, but was also involved in a bribery scandal with the head of the state House Transportation committee.The ensuing controversy leads the state to withdraw funding for the bridge.“10 years later a ship would magically collide with the old bridge and force a replacement, but the first attempt to build the bridge was killed due to corruption. The viaduct replacement was filled with controversy before, during, and still. I’m sure it’s not uncommon with large scale public infrastructure projects. Take a dive into Sound Transit finances if you care to see some real garbage. 

  • Smittytheclown October 23, 2020 (6:27 am)

    47 million in up front costs for a 40 year repair ready by early 2022?Discussion over. 

  • Steve October 23, 2020 (7:38 am)

    Leave W. Marginal alone!  A single lane for cars?  I swear…are they trying to make life any worse for us than it already is?

  • Kyle October 23, 2020 (8:02 am)

    Please repair it, and make the decision quickly. The CBA, while insightful, looks like a report of quality that could have been completed months ago. I thought this was an emergency. The bias towards replacement negates the risk to schedule and the ongoing impact on the lives of those living in West Seattle.

  • Sunchaser October 23, 2020 (8:20 am)

    The “estimated total ownership” figures are very partial as they only reflect the view of SDOT. There should be a similar figure taking into account the cost to the businesses of West Seattle resulting from the lack of the bridge. This would more properly reflect the “estimated total ownership” as seen by the population and businesses of West Seattle. 

  • Anne October 23, 2020 (8:22 am)

    Really -did people read the risks associated with repair?? Although the repair option says it could last 15 years-the risk is -no confidence in that . Seismic performance lower than replacement-not to mention funding issues -WS continues to build & grow- unless city puts moratorium on building(never happen) more folks means more traffic( truth Jort) Build a new bridge that will accommodate WS needs-   Does anyone truly think bridge replacement will be easier to swallow later??  How is that logical? 

    • Fix it! October 23, 2020 (12:17 pm)

      The report clearly says the bridge is 95%+ chance of 40 years or beyond with an equivalent seismic rating as replace. And 10-15 years from now we’ll be connected by light rail… that is huge! The reality is a $47m (hugely padded number) or $400m for a bridge we don’t need. The “stabilized” West Seattle Bridge will be drivable by the time they start tearing it down! Do you get that? They will be demolishing a drivable Bridge?!? Federal money or not spending money on this seems wrongs. I don’t know how you could argue we don’t have higher priorities. 

    • JT October 23, 2020 (12:52 pm)

      A replacement will not have ANY additional capacity for more traffic, so it’s not a better option for a growing WS population.  They need to repair now so we have time for light rail to be built, increasing much-needed capacity and creating some redundancy for decades from now when a replacement may actually be required.

  • Repair The Bridge Now October 23, 2020 (8:31 am)

    So well said. In the meeting a bright, shiny object was presented without due diligence and from someone unfamiliar with our City and how long it takes to get things done. It definitely worked to distract people from the reality of our options. A repair continues to be the smart choice so we can take the necessary time to plan and permit for a replacement WITH light rail, and possibly buy ourselves 40 years! PLEASE Mayor Durkan, make the right choice and repair our bridge!

  • JT October 23, 2020 (8:46 am)

    Echoing some of the sentiments here, the repair is the most fiscally responsible and viable option.  Yet SDOT is clearly pushing for vaporware in the form of a “rapid replacement” that has no vetting and could take much, much longer than the pie in the sky timeline that was presented.  Our elected officials need to step up already and get moving with the repair.

  • L October 23, 2020 (8:55 am)

    Repairing the bridge is the only fiscally responsible choice here.   Let’s not waste another day … I agree with the sentiments in these comments that the mayor needs to step up and lead.

  • Mj October 23, 2020 (9:43 am)

    Repairing the bridge should be a no brainer decision.  The repair has 95% confidence to last 40 years.  In 10 years Light Rail should be serving WS.  And I anticipate technologic improvements, aka autonomous driving vehicles, will significantly increase capacity of existing infrastructure.  Thus in the future instead of 6 lanes 4 could suffice for example. 

    It’s time to get the bridge repaired, and if SDoT had not failed WS residents and businesses in the first place, via not conducting maintenance in 2014 when a issue arised, this conversation would not be happening.

  • Colonel Mustard's Wrench October 23, 2020 (11:22 am)

    Mayor Durkan, we have lost patience and respect for SDOT. 

    Please repair this bridge.

  • Zark00 October 23, 2020 (11:30 am)

    This is about WSDOTs budget. The repair is clearly the correct option, but it doesn’t land a $1.2B project for SDOT, they need more. I’m not sure if it’s relevant, but the huge 2005 TPA was a 16 year expenditure plan, seems weirdly coincidental that 2021 is the 16 year mark. Maybe it’s nothing, or maybe if SDOT doesn’t fill their pipeline with high dollar projects they won’t have the budget to sustain their expansion over the past decade or so. 

  • Matt P October 23, 2020 (12:06 pm)

    This whole thing is a farce.  7 months to tell us that replace is the best option but they don’t really know but they probably do and just don’t want to tell us because it will make them look bad?  Start repairing the bridge ASAP.  Oh and the the tube tunnel opton seems like they threw on an absurdly high cost so people would forget it because they didn’t really want to consider it.  It has been used in many other places and it was chosen for its reduced cost and longevity yet here an extremely complicated bridge is somehow cheaper.

  • Rick October 23, 2020 (2:39 pm)

    Why has West Seattle looked at seceding from the city of Seattle twice since I’ve lived here? I know it wouldn’t be practical but is this fiasco? I guess we’re not one of the elite neighborhoods. Or politically correct.

    • AMD October 23, 2020 (4:39 pm)

      West Seattle hasn’t.  A handful of noisy people on the internet have clamored about it.  Our taxes would go through the roof if we seceded, anyway.  And they’d stay super high since the new West Seattle overlords would insist on no new housing (and thus a forever-small tax base), and all road repairs being done within the hour, no matter what the overtime or other costs associated with their impatience.

  • FixOurBridge October 23, 2020 (3:48 pm)

    Call Durkan. Call Herbold. Call SDOT. Do it today. Leave a vm. Demand they repair the bridge. Otherwise we will all suffer for years and years and years while SDOT makes mistake after mistake. Also, why is SDOT playing such a large role in this? They do what Durkan tells them to do. If the mayor says fix it then fix it. SDOT is not elected. They should have no say over this. None. So undemocratic. Durkan was elected, she needs to decide. Now. So call her. Please!

  • Anne October 23, 2020 (4:07 pm)

    Totally disagree with repair.  Replace  bridge.

    • Derek October 26, 2020 (9:08 am)

      And I, my wife, and many, many of my neighbors disagree with you. Repair. Replace with new one alongside after. 

  • Who wants to pick up the tab? October 23, 2020 (5:30 pm)

    Have you even been to dinner with others you know but may not be really your friends?  If you can’t get separate checks how do you decide who pays the bill?  I also believe with many other folks in this thread that it is about the money.  To repair the bridge is less money up front but requires longer term maintenance and money.  It is not explicitly stated in the cost-benefit analysis but I suspect an underlying concern and reality is that the City of Seattle and SDOT have a lot of longer term maintenance that they cannot afford in part because they don’t even budget (set aside the money) for it.  Since the West Seattle Bridge belongs solely to the City of Seattle, maintenance and repair is entirely their (money) problem, just like the Magnolia Bridge and other 70 plus structures that they don’t maintain well on an annual basis because they don’t set aside the money and/or pass the problem to the next set of leaders (for example the stuck Pier 18).  Replace also costs a lot of money, but less in long term maintenance and more in up front cost, which the City of Seattle hopes will find a (money) savior in the form of Federal and State allocations.  The less the City of Seattle has to pay for and the less SDOT has to maintain the less behind in budget (money) for maintenance they can be before they pass the problem on to the next set of leaders.

  • Chemist October 23, 2020 (6:37 pm)

    Speaking of stuck bearings, SDOT was saying in their weekly bridge update from Monday “release the restrained bearing at Pier 18 as soon as the end of the week.”

  • dsa October 24, 2020 (12:17 am)

    Too bad HNTB did not do the original design.  They have ruled engineering for decades. 

  • The Angry Civil Engineer October 24, 2020 (1:03 am)

    The repair now option in the CBA has the lowest total life cycle cost (if I recall correctly) and that includes full replacement in a few decades and all the additional maintenance to keep the bridge operable. SDOT’s consultants WSP who stamped the CBA report are  professional civil and structural engineers. They would have been obligated  to rule out Alt 2 as infeasible if they
    thought the bridge could not be safely strengthened. That they did
    not means it is  very likely to be repairable. That a reputable engineering firm would stamp this report and put their reputation on the line is signficant. Things can always change later but we
    know more about Alternative 2 than anything else the City has
    presented. There is a lot of unlocked value in an alternative that has fewer unknowns on
    risky projects like this.
    I think the issue is that SDOT leaders don’t want to believe the CBA numbers about future maintenance costs provided by their consultants.  The sudden gravitation to the unvetted fast replacement and sexy video we saw when it was presented are  both highly suspicious. The problem I see, beyond the lack of vetting,  is that the rapid replacement concept is not coming from the CBA team, its coming from a  company that has huge financial interests in replacement  and administrators eager to justify a costly fix regardless of the impacts to West Seattle so their future capital spending is “more predictable”. Can we trust that SDOT has  our best interests in mind? Do the rest of the people in Seattle want to pay close to a billion dollars  now, put ourselves at risk for cost and schedule overruns when much less expensive and lower risk options are on the table and light rail is 10 years out? Can we trust that HNTB won’t give campaign donations (aka legal bribes) and overcharge like it did in Charlotte NC  and elsewhere? (https://www.wcnc.com/article/news/investigations/investigators/same-company-that-overbilled-charlotte-has-89-million-worth-of-contracts-with-city/275-a3784c1e-ffab-4011-8c07-497efe12eeae)  SDOT has a legitimate concern over seismic risk and a responsibility for public safety associated with its infrastructure.  If repair is unsafe replacement is the only acceptable option, but that is not the case. According to the CBA, repair is feasible and safe. The question is what is the acceptable level of risk to the community  and how much impact the citizens of Seattle need to bear?  SDOT has lived happily with the high bridge engineering risks and would continue to do so had the issue we are facing not developed. I personally would prefer a safer bridge but as a long time resident am also comfortable with the CBA data on rolling the dice for a couple  more decades. Let’s not forget, the cost to the community of the closures has yet to be properly quantified.For those outside the PE and public works world, professional civil engineers (aka PE’s) must pass an arduous technical and an ethics test to become licensed. Once licensed they are required to  hold the public’s interest paramount. SDOT’s contractors working on the stabilization and CBA are providing their best professional judgment on top of their decades of expertise solving problems like this. To their credit SDOT’s staff are being timely and transparent with their findings. I am happy they caught this before  failure and saved lives by closing the bridge. But the leaders at the top are not engineers. That isn’t necessarily an issue as long as the recommendations of the engineering experts are fully considered  but at present I am not seeing enough information to be confident that is the case.  Of course engineers aren’t perfect. They can be overly cautious and deliberative and in the worst cases arrogant and dismissive, maybe a little angry :) But good engineers  know how to solve problems creatively,  ethically, responsibly and effectively. 2020 has had enough politics, listen to your engineers, and fix the GD bridge already!more info:Sam Zimbawe, SDOT Director (https://sdotblog.seattle.gov/2019/02/01/meet-sam-sdots-new-director/)Heather Marx, Project manager, (https://www.linkedin.com/in/heather-marx-all-in)

  • wlcg06 October 25, 2020 (11:37 am)

    The rapid span replacement concept looks too promising to ignore. The timeline is just 1 year different from the repair, maybe less as the Champlain bridge was done in 18 months, over a wider span. I think we HAVE to take a little more time get the CBA on this one as it sounds like a great solution. 

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