(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:
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.