West Seattle Blog... » Alaskan Way Viaduct http://westseattleblog.com West Seattle news, 24/7 Tue, 27 Jan 2015 08:21:39 +0000 en-US hourly 1 http://wordpress.org/?v=3.4.2 Update: Council’s longer-than-expected briefing on tunnel/Viaduct, and the 2 words repeated over and over http://westseattleblog.com/2015/01/happening-now-councils-longer-than-expected-briefing-on-tunnelviaduct-and-the-2-words-repeated-over-and-over/ http://westseattleblog.com/2015/01/happening-now-councils-longer-than-expected-briefing-on-tunnelviaduct-and-the-2-words-repeated-over-and-over/#comments Mon, 12 Jan 2015 21:02:11 +0000 WSB http://westseattleblog.com/?p=297901

(4:09 PM UPDATE: Archived video of the meeting now added above. The Viaduct discussion starts at 1 hour, 37 minutes in – you can drag the playback bar there)

1:02 PM: The City Council is already an hour and a half past the time it expected to conclude this morning’s “briefing” meeting. WSDOT has been on the hot seat since 11:15 am on the state of the tunnel-repair project and issues including a letter from SDOT in response to a report from WSDOT engineers around the time the repair pit’s status became an issue a month ago. Much discussion focused on the phrase “catastrophic failure” relating to the repair pit work – though it’s been reiterated over and over again that the Viaduct is safe, councilmembers want more assurance. Two more agencies are coming up now – SDOT and Seattle Public Utilities – so we’re putting the live window above, and will be adding the highlights of notes we’ve been taking (plus other coverage links) along the way.

1:29 PM: The meeting just adjourned. Here’s what’s transpired so far:

–Much discussion about the letter sent by SDOT to WSDOT and the engineering report that led to it. As far as we can tell, this was first reported by Sydney Brownstone of The Stranger. WSDOT opened its part of this morning’s meeting by sternly declaring that the city letter took the phrase “risk of catastrophic failure” out of context. This was repeated over and over again; the City Council, however, got stern right back – Councilmember Kshama Sawant, for example, noted that she formerly worked as an engineer, and engineers don’t use that phrase for no reason. Council President Tim Burgess asked WSDOT if it had the December 11th report handy, and when told, “yes,” stopped the meeting briefly so it could be given to a clerk who immediately made copies for the council. We’ve asked WSDOT for the document as well, and will add it here as soon as it comes in. (ADDED: Here it is; the “catastrophic failure” mention comes in the final paragraph. Note that WSDOT says this was a “draft” and has also sent a 12/19 “final” version [added]- here’s that one.)

Later in the meeting, WSDOT suggested that because of this “out of context” quoting, it might restrict city access to a system in which it keeps these reports, and several councilmembers voiced disbelief at that.

MORE AFTER THE JUMP

–Despite the use of that phrase, the Viaduct is not and was never at risk, WSDOT’s Viaduct/99 project leader Todd Trepanier opened. “At no time has there been a safety issue with construction of the access pit.”

–During a brief break in discussion of that situation, WSDOT’s Matt Preedy broke down the much-questioned number of the project being 70 percent complete. Yes, he said, tunnel digging itself is only 10 percent complete, but for example, the South Portal roadways – our side of downtown – are 82 percent complete, and that is 19 percent of the project. (Much math was required for a while during the briefing, including the rescue pit’s depth – they’re 98 feet down, but that’s also described at being a different number of feet below sea level. 98′ down is another “hold point” at which quality-control checks are being done. Still going for 120-foot depth. What if the tunnel machine can’t make it through the 20-foot concrete wall of the pit, when the time comes? There’s a plan for that too, WSDOT says.) Preedy said a “considerable amount of money” paid for advance procurement of tunnel components, many of which, he said, are being stored at Terminal 106.

–Assuming tunneling resumes, what happens when the Viaduct is closed while the machine goes beneath it? There’s no state money set aside for extra transit at that time, WSDOT said – and as for continuing other “mitigation” money for transit, that would have to be taken up with the Legislature (which just convened its new session today). Councilmember Rasmussen asked for elaboration on when the pass-beneath is expected. Still no clue on any dates for anything until the machine is back up and running, according to WSDOT. If and when tunneling does resume, there’s 500 feet to go – half again as far as it’s gone so far – before the machine starts going under the Viaduct.

-The proximity of the repair pit to the Viaduct remains a concern for Councilmember Mike O’Brien.

(still adding …)

-SDOT’s part of the briefing is detailed in the slide deck that was part of the agenda. It includes an independent assessment of the Viaduct that’s being funded by the city. (Seattle Times transportation reporter Mike Lindblom has more on that here.)

-Rasmussen asked Kubly what he would say to West Seattleites and others who use the Viaduct daily, regarding its safety. “Panic … is inappropriate,” the SDOT director replied. He went on to discuss the plans being made in case a longer-term or permanent closure is required, saying that while it sounds bureaucratic, it’s important that they’ve pre-positioned signage and pre-filled work orders. Capital improvements would take one to four months to build. A target list was worked on as recently as this past Saturday, with about half a dozen SDOT employees in a whiteboarding strategy session that afternoon (“before the game,” he noted).

-SPU said that it’s dealing with the settlement that’s potentially affecting water mains by creating an “isolation zone” in Pioneer Square, and reducing the amount of water flowing through it, but he insisted that is not affecting availability for key water uses such as firefighting, drinking, etc.

-The meeting wrapped up just before 1:30 pm – two hours longer than planned (though it should be noted, the SPD briefing on recent protest responses also ran overtime, about half an hour past what was scheduled). The council indicated it wants more frequent briefings on the Viaduct/tunnel/related-issues status.

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Speaking of pits: Hwy. 99 tunnel-machine-access digging resumes http://westseattleblog.com/2015/01/speaking-of-pits-hwy-99-tunnel-machine-access-digging-resumes/ http://westseattleblog.com/2015/01/speaking-of-pits-hwy-99-tunnel-machine-access-digging-resumes/#comments Thu, 08 Jan 2015 23:30:22 +0000 WSB http://westseattleblog.com/?p=297537

For the first time in more than two weeks, we have an official update on Seattle’s most closely watched pit – the one intended to reach the Highway 99 tunnel machine, so its cutterhead can be retrieved and repaired. WSDOT published the update this afternoon, saying that its contractor Seattle Tunnel Partners resumed digging today, and that: “Settlement levels near the pit have remained stable for more than six weeks.” The pit is 3/4 of the way to the 120-feet depth at which STP says it will pour a platform for the front of the machine to rest on, after it is turned back on to advance a short distance into the pit. Timeline? Nothing new yet, says WSDOT; you might recall, the most recent ballpark-guess tunnel-opening date was August 2017.

P.S. Reminder that seawall-and-tunnel-related work downtown will result in access changes at Colman Dock and Water Taxi Pier 50 starting tomorrow.

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Tunnel updates: Opening no sooner than August 2017; access-pit digging on hold again; new ‘settling’ info http://westseattleblog.com/2014/12/new-viaducttunnel-update/ http://westseattleblog.com/2014/12/new-viaducttunnel-update/#comments Mon, 22 Dec 2014 22:35:15 +0000 WSB http://westseattleblog.com/?p=296129

(Added: New screengrab from tunnel-machine-access-pit camera)
2:35 PM: Even if nothing else goes wrong with the Highway 99 tunnel project, it won’t be open for use any sooner than August 2017.

That’s an estimate made by the contractor Seattle Tunnel Partners BEFORE the recent discovery of “settling” in the area; WSDOT just disclosed the date today, as part of a general pre-holiday update. The update also says that while no new settling has been detected near the pit being built to retrieve the cutter head of the broken-down tunneling, machine, settling elsewhere “is greater and farther reaching than anticipated. Engineers are still evaluating whether other factors are involved that could explain the discrepancy. We will continue to conduct daily inspections of the viaduct and watch the survey data closely as STP moves forward with their work. As we write this, we’re on a conference call with other reporters and reps from WSDOT and STP – we’ll be adding more details shortly.

ADDED 3:19 PM: The conference call is over; from WSDOT, it included project executive Matt Preedy and spokesperson Laura Newborn, and from Seattle Tunnel Partners, executive Chris Dixon, plus local/regional/national reporters.

Among the many points of note:

-The August 2017 date that debuted today was described as coming from the “October update” by STP. We asked why it wasn’t mentioned before, not even during the official stakeholders’ briefing (at which we were the only news org on hand) in early December. STP explained that these updates – which WSDOT now plans to make public – take several weeks to assemble, so the “October update” is just being parsed now. (Which means, they acknowledged, we won’t know full details of the “November update” – which would still not include this month’s turbulence – until January, and so on.)

-The schedule will remain “dynamic,” said WSDOT’s Preedy, until the tunneling machine is back in operation. (In other words, even the new August 2017 date is nowhere near set in stone.)

-Excavation of the pull-the-cutter-head-out-for-repairs pit is on hold now for two weeks, and not expected to resume until early January. Digging stopped on Friday, about three days after WSDOT had said it could resume. Some non-structural pilings, explained in the official online update, are being pulled out before they start going to the next level. STP’s Dixon explained that digging had been done in stages, about six feet at a time, before an evaluation of where everything stood. At the completion of the most recent stage – to 90 feet in pit depth, aka “-74 in elevation” – they decided to pause for piling removal.

-Would it have been quicker, in hindsight, to approach the tunnel-machine repair project from the south/interior? STP insisted it’s happy with its choice to build the pit to try to hoist the cutter head out, even though it’s of a magnitude that has never been done before, given the machine’s record size, etc., and has “been more difficult than anticipated.”

-The settlement of the Viaduct itself, when recalculated as explained in the online update, will likely be a bit less than estimated, but the settlement causes in the area remain a mystery, and an investigation continues.

-As for the big issues – who pays for all this unanticipated work? – the state continues to point out that this is a “design-build contract” and that STP is expected to do whatever it takes to fulfill that. Pressed on certain specifics, WSDOT’s Preedy said he didn’t think it “appropriate for either party to speculate” on how it’s all going to be worked out.

-About the “70 percent complete” recent proclamation, today’s answer seemed to mostly boil down to, that’s the percentage STP has been paid.

P.S. To see the “October schedule” from which the August 2017 open-to-traffic projection was pulled, go here. WSDOT also has published the September schedule, which also seems to project that same month (albeit a couple weeks earlier than the Oct. “schedule”).

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Traffic alert: Crash on southbound Alaskan Way Viaduct http://westseattleblog.com/2014/12/traffic-alert-crash-on-southbound-alaskan-way-viaduct/ http://westseattleblog.com/2014/12/traffic-alert-crash-on-southbound-alaskan-way-viaduct/#comments Sun, 21 Dec 2014 03:58:48 +0000 WSB http://westseattleblog.com/?p=295963 If you’re heading this way from downtown or points north – note that there’s a backup on the southbound Alaskan Way Viaduct from just before the stadium zone, because of a one-vehicle crash. Kim reported it via Twitter:


No emergency vehicles at the time, but now they’ve been dispatched and reportedly will be checking a toddler for possible injuries.

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Today’s Viaduct/Tunnel update: Long FAQ including declaration of disappointment, threshold for ‘mitigation,’ more http://westseattleblog.com/2014/12/todays-viaducttunnel-update-long-faq-including-declaration-of-disappointment-threshold-for-mitigation-more/ http://westseattleblog.com/2014/12/todays-viaducttunnel-update-long-faq-including-declaration-of-disappointment-threshold-for-mitigation-more/#comments Thu, 18 Dec 2014 01:39:21 +0000 WSB http://westseattleblog.com/?p=295671

Today’s WSDOT update on the Viaduct/Tunnel project, posted late today, is a new, long FAQ attempting to answer some of the questions that have come up since the December 5th disclosure of “settling.” Read it in its entirety here. Some of what caught our eye on first look include:

Our contract with STP allows up to two inches of viaduct settlement before mitigation is required. Should it be necessary, a number of techniques could be used to strengthen the viaduct and keep it open to traffic until the new SR 99 corridor is completed. These techniques could include strengthening columns or other areas of the structure to provide additional support. We could also reinforce the viaduct’s foundation as we did in 2008.

Regarding the plan to reach, lift, and repair the tunnel machine’s cutter head, WSDOT writes, “We’re disappointed with STP’s progress to date …” while noting the pit is now three-fourths of the way to the expected 120-foot depth, and expressing optimism that even if the current rescue plan has to be abandoned: “At its core, this is an engineering problem, one that can no doubt be solved.” The FAQ reiterates, “No significant settlement has been observed in the area since Dec. 5.” And as for the biggest concern of all:

Our bridge experts have confirmed that the viaduct remains safe for day-to-day use. If we had any reason to believe it wasn’t, we wouldn’t hesitate to close it. It’s important to remember, however, that the day-to-day safety of the structure does not change the fact that the viaduct remains vulnerable to earthquakes. That’s why it’s being replaced.

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Today’s Highway 99 tunnel-project update: Pit-digging to resume http://westseattleblog.com/2014/12/todays-highway-99-tunnel-project-update-pit-digging-to-resume/ http://westseattleblog.com/2014/12/todays-highway-99-tunnel-project-update-pit-digging-to-resume/#comments Tue, 16 Dec 2014 21:01:23 +0000 WSB http://westseattleblog.com/?p=295569

(WSDOT photo from last week – assembly of what’s meant to lift tunnel-machine head from pit)
After Monday’s City Council session looking at the latest tunnel-related troubles (WSB coverage here), council president Tim Burgess declared it’s too late to turn back now. So, with no new settlement reported, onward it will go. WSDOT‘s tunnel update for today, just published here, says their contractor Seattle Tunnel Partners has the go-ahead to continue digging the pit from which they hope to pull up the tunnel machine’s damaged cutter head:

Excavation was stopped at WSDOT’s direction on Dec. 12. While no significant ground settlement had been observed since Dec. 5, we suspended excavation to give our team time to gather more survey data and review STP’s contingency plan for turning off the dewatering wells, should that become necessary. We have now reviewed STP’s plan and gathered additional data from the weekend that shows the recently measured settlement has stabilized.

The digging stopped about three-quarters of the way down to where they hope to reach the machine. The red lifting device is under construction (photo above) feet from the Viaduct, roughly parallel with King Street.

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Alaskan Way Viaduct & vicinity briefing @ City Council: ‘No continued settlement’ http://westseattleblog.com/2014/12/alaskan-way-viaduct-update-no-continued-settlement/ http://westseattleblog.com/2014/12/alaskan-way-viaduct-update-no-continued-settlement/#comments Mon, 15 Dec 2014 17:41:33 +0000 WSB http://westseattleblog.com/?p=295435

(ADDED: Video of this morning’s entire meeting, above)
9:41 AM: Ten days after concerns about “settling” related to the Alaskan Way Viaduct Replacement Project, WSDOT reps are briefing the Seattle City Council right now. Transportation secretary Lynn Peterson says there appears to be “no further settlement” since what was reported a week and a half ago, and no damage to buildings in the area. She says that while this is a “tense moment” in the project, WSDOT firmly believes it’s “less risky” to proceed than to rely on the earthquake-vulnerable Viaduct. She also vows that the contractor, Seattle Tunnel Partners, is being and will be held accountable for what they’re expected to do. And she says they can’t commit to any kind of timeline right now for completion, because the cutter head has to be retrieved for repair first: “This is a design-build contract and we have purchased a tunnel … the fix .. is the responsibility of the contractor. We do not own the machine nor the method” STP chooses to fix it.

WSDOT’s Todd Trepanier tells the council STP was asked to stop excavating, at least temporarily, on Friday, until getting a green light for resumption. He’s getting into more technical points; here’s the slide deck just added to the agenda.

You can watch the briefing live here. After WSDOT reps are done explaining, and answering council questions about, the “settling” situation, city reps are scheduled to talk about the status of plans in place in case a Viaduct closure was needed. We’ll have toplines of that later; you can preview the slide deck (which involves a 2005 plan centered on “what ifs” in case of an earthquake) here, plus a new city update on the “settling” situation here.

11:26 AM: The meeting, originally scheduled for about an hour, has now lasted for two and isn’t likely to end any time soon – again, it’s live at seattlechannel.org. Councilmembers continue to press for more specifics on Viaduct safety – a moment ago, Councilmember Kshama Sawant was asking what size of earthquake would take the AWV down; WSDOT says it doesn’t want to speculate but notes they all believe the structure “is vulnerable.”

11:30 AM: City reps are now coming to the table to discuss the status of plans in case it was determined the Viaduct had to be closed – not just transportation, but utilities.

SDOT director Scott Kubly says the “unified command structure” has been meeting at least once a day to talk about the situation. Seattle Public Utilities says it’s been monitoring utility lines and pipes in the area – they’re using a hydrophone to “acoustically” detect water leaks, as well as using closed-circuit video to watch the sewer lines. The presentation embedded above this paragraph shows all the utility info they’re presenting, including what types of lines are in the Viaduct/tunnel-pit area, as well as the transportation plan that SDOT will discuss shortly.

11:46 AM: Now it’s SDOT director Kubly’s turn, after a council question asking SPU who covers the cost if there are utility problems – answer: the state. Meantime, he says that they are in “good shape” if a Viaduct closure was necessary, because the 2005 plan is updated each year. The “variable message boards” on paths to The Viaduct would be called into action, as would equipment like barricades etc. which he says are “pre-loaded” onto vehicles and ready to go at a moment’s notice, if needed. He is followed by Seattle City Light with its plans. Meantime, the Department of Planning and Development hasn’t heard yet of any buildings that would be deemed unsafe, but if settlement was “a lot steeper in areas,” they have authority to “do various things depending on how much damage we see … (including) ordering vacation of (a) building.”

11:58 AM: Councilmember Tom Rasmussen asks how Metro works into this plan if the Viaduct had to close. Kubly says Metro is “at the table” and they are looking at “how would we speed buses” and “what detour routes would be in place … how (to) add service would depend on length of the closure.” Could the plan deal with all 60,000 people/vehicles that would not be able to use the AWV? Kubly says it would address elements such as possible restrictions on “non-essential construction,” changes in deliveries, and looking at ways to get more people carpooling, using transit, etc. (The funding for extra transit is “already gone,” the council is told.) WSDOT’s Trepanier is asked to come back to the table to answer some questions, such as what if there’s a long-term gap between the Viaduct going out of service and the tunnel coming into service. He says the Legislature made the decision not to use any more project money toward “transportation mitigation” (such as transit).

12:13 PM: The Viaduct discussion is over and the council has moved into a preview of its 2 pm meeting, which will include the White Center annexation proposal. When the video of this meeting is available, we’ll add it to this story.

3:18 PM: Just added the video.

8:18 PM: Mike Lindblom of The Seattle Times (WSB partner) reports on the downtown water main that needs replacement.

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Today’s Viaduct/tunnel pit update from WSDOT: No new ‘significant settlement’; no voids under King St. crack http://westseattleblog.com/2014/12/todays-viaducttunnel-pit-update-from-wsdot-no-new-significant-settlement-no-voids-under-king-st-crack/ http://westseattleblog.com/2014/12/todays-viaducttunnel-pit-update-from-wsdot-no-new-significant-settlement-no-voids-under-king-st-crack/#comments Sat, 13 Dec 2014 02:28:18 +0000 WSB http://westseattleblog.com/?p=295151 One week has now gone by since WSDOT disclosed new “settling” of, and near, the Alaskan Way Viaduct and the hole being dug to reach the Highway 99 tunneling machine for repairs.

After the ensuing week of various updates, discoveries, and concerns, today’s update is out, and in it, WSDOT says “to date, no significant settlement has been observed beyond the initial settlement we reported publicly on Dec. 5. The viaduct remains safe for travel.” The update also says that so far, ground-based radar hasn’t shown any “voids” under the crack scrutinized on King St. in Pioneer Square on Thursday. (E-mail from WSDOT to reporters adds, “The crack in the middle of King Street has been there for some time, as seen in a Google Maps picture from 2011. Given the absence of prior settlement data on this particular street, it may take a while to fully understand what may have caused pavement to shift.)

Meantime, the City Council‘s agenda for next Monday morning has been revised to start with WSDOT execs’ updating the council on the “settling” at 9:30 am, followed by a 9:50 am discussion with state and city officials about what would happen if the Viaduct had to be closed, short term or long term. The agenda section for the latter item includes this existing document that discusses closure in the context of an earthquake.

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Today’s Viaduct-and-vicinity updates: See the ‘settling’ map; King St. crack in Pioneer Square http://westseattleblog.com/2014/12/todays-viaduct-and-vicinity-update-see-the-settling-map/ http://westseattleblog.com/2014/12/todays-viaduct-and-vicinity-update-see-the-settling-map/#comments Thu, 11 Dec 2014 22:58:52 +0000 WSB http://westseattleblog.com/?p=294975 (SCROLL DOWN for newest updates)

2:58 PM: That map (click the image to see the full-size version) is the main Alaskan Way Viaduct/Highway 99 Tunnel update so far today, six days after first word that some areas in the vicinity have “settled” more than an inch. You might have seen a version of the map on Publicola this morning; the version released by WSDOT this afternoon has added context and a slightly different color scheme. It shows settling of almost an inch and a half in some areas, but does not show the areas of “uneven” settling, says WSDOT, and the text of their update makes it clear this does not show what’s happened on The Viaduct itself:

Crews from WSDOT and Seattle Tunnel Partners are conducting ongoing surveys of the Alaskan Way Viaduct and ground to determine whether settlement is continuing near the SR 99 tunnel access pit. In general, the surveys include:

Twice daily manual measurements at the bottom of both the east and west columns of the viaduct.
Approximately every other day measurements of deep survey points. These are survey points more than 80 feet underground.

Ground surveys of sidewalks and streets from Alaskan Way to Second Avenue and from Yesler Way to South King Street. Some areas are surveyed twice a day; other areas are surveyed once every two to three days.

Surveys of some buildings. Data is collected both manually and automatically and monitored daily.

The data from the ground surveys and deep survey points are represented on a survey point data map. This map does not represent data from building surveys or the surveys of the viaduct.

The map is a computer-generated approximation to show visually the survey results that were shared with the public on Dec. 5, which indicates approximately 1.4 inches of ground settlement near the access pit and a lesser amount of settlement in the surrounding area. It does not show differential settlement, which is uneven settlement that occurs underneath a particular building or structure.

Lastly, the map does not present conclusions about the effect of dewatering. Additionally, the colors have been modified to better show the change in settlement from high to low.

We asked WSDOT earlier today if the tunnel contractor was continuing with access-pit digging, estimated two days ago to have another day to go before they reached a point where they’d stop to evaluate. The reply said only that the December 9th update still applied. We’ve been watching the “live” construction camera, and the excavation equipment does seem to have been in action as the day goes on.

ADDED 4:15 PM: New development – a crack in King St. downtown, not far east of the “rescue pit.” A briefing by the mayor is expected soon.

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Tunnel-project update: Still digging ‘access pit’ – for at least 1 more day http://westseattleblog.com/2014/12/tunnel-project-update-still-digging-access-pit-for-at-least-1-more-day/ http://westseattleblog.com/2014/12/tunnel-project-update-still-digging-access-pit-for-at-least-1-more-day/#comments Tue, 09 Dec 2014 23:27:11 +0000 WSB http://westseattleblog.com/?p=294711

(Access-pit camera’s image from 3:20 pm today)
Again today, with the stalled Highway 99 tunnel project under the microscope more than ever before, WSDOT has just published a new update. This time, they’re clarifying the status of the access-pit dig intended to get to the tunneling machine’s cutter head:

Excavation continues on the circular pit (pdf 2.5 Mb) that will be used to access and repair the SR 99 tunneling machine. Seattle Tunnel Partners’ engineers have determined that continuing excavation to 84 feet, an additional 3 feet from the current depth, will not affect when and how the dewatering wells could be turned off. We anticipate excavation to this elevation will take approximately one day, at which time STP will inspect the shaft walls per their quality assurance procedures. Once they reach 84 feet, STP will review survey data and consult with their engineers and WSDOT prior to determining next steps. …

The update (which you can see in its entirety here) also mentions that work continues on the crane intended to lift the damaged machinery from the pit, and on the 1,000 feet of tunnel dug before the machine stopped work one year ago. The latter two points were also reviewed at the project stakeholders’ meeting we covered one week ago downtown, just a few days before WSDOT disclosed last Friday the “settling” that was causing concern, following up with a Sunday update, and then a City Council briefing yesterday.

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As-it-happened: City Council briefed on Alaskan Way Viaduct settling http://westseattleblog.com/2014/12/happening-now-city-council-gets-briefed-on-alaskan-way-viaduct/ http://westseattleblog.com/2014/12/happening-now-city-council-gets-briefed-on-alaskan-way-viaduct/#comments Mon, 08 Dec 2014 22:47:37 +0000 WSB http://westseattleblog.com/?p=294597 (TOPLINES: State insists Viaduct safe. Council wants to know specifics of what would make it unsafe. State says it’s up to tunnel contractor to figure out what happens next)

(Screengrab substituted for video window after meeting; will add archived video when available)
2:47 PM: The City Council regularly gets briefed on the Alaskan Way Viaduct Replacement Project, but with the disclosures of the past few days, the meeting under way now takes on extra weight. Watch in the video window above (click “play” for the live stream); we’ll note key points as it goes.

Regarding the “settling,” WSDOT officials say it does seem to have coincided with the “dewatering” process, which they explain involves a series of wells, to reduce the pressure as the contractor dug further down toward 120 feet in depth. This new settling, it’s explained, was detected by a wider swing in the survey area revealing “deep benchmarks” had settled – where they weren’t supposed to. “Local” settling is what they WERE expecting. But adding that to the “deep benchmark” settling, they came up with the inch of settling reported last Friday.

**AS-IT-HAPPENED COVERAGE CONTINUES AFTER THE JUMP**

They needed to figure out “what is really going on here, is it really tied to these dewatering wells?” so that’s why they did extra surveying over the weekend. WSDOT says that as they analyzed data over the weekend, they noted that “the Viaduct has experienced some settlement but it’s very uniform in nature and does not represent any form of safety threat for the Viaduct” but in the assessment of the “deep benchmark” settling, they could not confirm it was absolutely related to the dewatering wells, which have been in action for about three weeks. They’ve reiterated several times that they don’t believe there’s any safety risk.

As for shutting the wells off – “you don’t just flip a switch” to do that, it’s been explained, because if you did, you could damage nearby buildings or the pit itself.

2:59 PM: About 30 buildings in the “influence zone” have the one-inch settling situation, it’s just been explained. And they’re going to “kick up the surveying” beyond that zone. Now the briefing is moving to WSDOT’s Tim Moore, to speak to structural safety – “he knows the Viaduct better than anyone.” He says he’s been with WSDOT’s bridge office for more than 30 years. He reminds the council that the project is scheduled to tunnel underneath The Viaduct at some point once it restarts.

He talks about monitoring, saying they’ve surveyed over the east and west “gutter lines” since the 2001 earthquake, and did another such survey last Sunday morning “so we know how this structure has behaved (since then).” About the “differential settlement” – the uneven settlement that’s of concern,” which he describes as the “key component of whether this structure is going to see distress” – he says they’re not seeing that kind of distress so far.

They are surveying key points daily in a manner that can be done without closing travel lanes, WSDOT officials tell the council. Now Councilmember Jean Godden asks about the discrepancy between what was said long ago regarding 6″ settlement requiring shutting it down, and 6″ total settlement now being described as NOT requiring that. “Some of those large settlements in the past have been taken out of the picture …” because of strengthening, she is told. “It’s kind of like a start over.”

“I don’t think Viaduct closure is imminent,” Moore says.

Councilmember Sally Clark voices concern about settlement happening on one end and not the other, and won’t there be some “tugging”? Moore explains it’s really three spans that “act independently of each other.”

So what if you stop pumping the water and it comes back in? asks Councilmember Sally Bagshaw. A consultant takes that one on. He says most of the deep settlement seem to be happening “down in the glacial soils in the vicinity of where the water is being taken out.” He says it’s a “spring kind of compression” that might also rebound. “So what about the buildings on the surface?” she asks, if it’s “condensing and expanding, condensing and expanding.” They think “there’s a very good chance” the buildings will suffer “no lasting effects,” but they’re checking to be sure.

Councilmember Mike O’Brien notes that the 6″-settlement threshold is the only one they or we have ever heard, so if that’s not valid any more, WSDOT needs to articulate some better way for us to understand what *is* the safety threshold.

“Case by case,” he is told, “obtaining the information continually and timely” – assessing structures. “What can happen to a structure (then) and what cannot?” O’Brien presses.

Moore is asked for a scenario “that would lead you to concern,” then, to answer that. He mentions “fairly significant” structural cracks that are not getting in the way of the Viaduct to safely carry traffic, but would reduce its originally expected 75-year life span – though that’s beyond the time frame expected for it to be taken down. (It’s half a century old already.)

O’Brien is still pressing for clearer details on what would cause WSDOT to say it’s not safe any more. He wants to know specifics. “It’s really dependent on some characteristics … if it’s a slow settlement, the concrete can … dissipate some of that over time,” Moore explains. “(So far) we haven’t seen a huge buildup of strain in the reinforcing steel.” He reiterates, the Viaduct won’t make it to its originally planned 75-year life. And O’Brien still wants to know, what would push it over the limit? Moore says he just doesn’t have something specific to say in response.

Councilmember Sally Clark now points a question at SDOT director Scott Kubly, wondering who’s checking the state’s work as the plans for digging the hole are revised, and so on. Kubly says that’s a good question and backtracks to explain that Mayor Murray asked that SDOT and WSDOT set up a “unified command” as soon as the settling was revealed late last week. The “unified command” included utilities “because it’s the underground stuff that’s most of concern right now,” Kubly said. “We’re in the data-gathering and data-analysis phase” right now, he added. “… This is a really serious incident, and I think the city’s response reflects that.”

3:33 PM: O’Brien asked if SDOT has the expertise to independently look at WSDOT data and make its own conclusions on whether the situation is safe or not. “Right now we’re looking over their shoulder and following their lead – it’s their structure,” Kubly replied.

Councilmember Tom Rasmussen notes that he and his colleagues are frustrated at not being able to understand yet “what are the facts, what is the data needed to determine if they agree or disagree with WSDOT” regarding safety. Looking over shoulder’s not good enough – “you need to be at their sides,” he tells Kubly, next asking if SDOT has the kind of expertise to do that. “Yes, we do,” he replies.

In response to questions from Councilmember Kshama Sawant, WSDOT’s Moore details his resumé and past projects he’s worked on (including the Tacoma Narrows Bridge) and his expertise in analyzing the stress on concrete and steel in structures like this. He notes that the City of Seattle designed the section of Alaskan Way Viaduct that is still up; the state designed the section that has been demolished and replaced in recent years. He again mentions some cracking in The Viaduct that is the result of original design that wasn’t to the kind of standard that would be expected today, but it is still capable of carrying the load it’s expected to. Project consultant Red Robinson details his background in evaluating settlement and water challenges in tunnel projects.

3:42 PM: Councilmember Bagshaw asks “what is your confidence level” in The Viaduct right now? Would you allow your child to walk or ride under it? WSDOT’s Moore says yes, absolutely. He says he has 95 percent confidence in it right now. “We do have certain locations which are suspect and settlements of a large magnitude give us some concern.” Bagshaw asks, “What about that 5 percent?” Moore says, “It’s that earthquake probability … we all know we have ground issues, as well as issues at the joints.”

Councilmember Jean Godden invites them back next Monday to provide not only an update but also what would happen if The Viaduct had to be closed. The daily inspections/surveying will continue in the meantime, WSDOT says.

When was the 1 1/4″ settlement noticed? asked Councilmember O’Brien. Reply: This weekend. So what about the earlier reports that the information had been out for a while? Actually, the anomaly was picked up by the contractor just before Thanksgiving, and surveying was done the weekend after Thanksgiving, but WSDOT had not confirmed it until last week, he was told.

O’Brien bristles at this and says they should be told before 100 percent confirmation – “if there’s an anomaly, I want to know. … I would rather you err on the side of letting us know what’s going on and saying ‘we haven’t confirmed it’.”

Now he asks – are they still dewatering or not? “They are still dewatering,” is the reply. As mentioned earlier, it’s not something that can be stopped abruptly. They’re expecting they WILL stop – but that’s pending data, so there’s a chance they might not have to.

What about building settlement/damage? An unspecified media report is mentioned. WSDOT says they haven’t seen anything from outside, but they’re planning another round of checks, and they’re going to offer a hotline to building owners that might have something to report.

O’Brien now presses the point – are you sure it’s safe to have vehicles on The Viaduct, if it was going to be closed when the tunneling was happening beneath it? The reply notes that there will be definite ground movement when the machine goes beneath it – not the same situation as exists now – and they would want to be able to act quickly if stabilization were needed. This is not the same kind of fast-moving situation, they explain.

Rasmussen asks how all this might affect the schedule. Too soon to say, he’s told. Even before this, WSDOT says, the contractor had told them verbally that the March restart is not likely. And they won’t know for certain where they’re at until the tunneling machine parts to be removed are above ground and taken apart and assessed.

O’Brien goes back again to the issue of how much settling is OK – is it specified in the contract? he asks. Yes, there are some specifics, he’s told. They’d like to be briefed on that, he subsequently says.

Bagshaw gets back to the access pit. Are the last 40 feet of digging ‘doable’? she asks. Yes, says WSDOT, depending on how all these new discoveries shake out. Do you know what you’re going to do about the dewatering problem? she presses. WSDOT says that since it’s a design-build contract, it’s up to Seattle Tunnel Partners to solve the problem.

Next up – WSDOT promises updates if there’s anything major before they return to the City Council next Monday at 9:30 am to talk about what Councilmember Godden, chairing this meeting, describes as “what if – what if we need to shut it down for a time,” etc. They’re moving on now at 4:01 pm to talk about the seawall project; we won’t be chronicling that. Once the meeting is over, we’ll watch for the archived video to be posted at SeattleChannel.com and will substitute it above when available.

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Alaskan Way Viaduct ‘settling’ update: Tunnel contractor ‘will stop excavating’ after what today’s surveying revealed http://westseattleblog.com/2014/12/alaskan-way-viaduct-settling-what-todays-surveying-revealed/ http://westseattleblog.com/2014/12/alaskan-way-viaduct-settling-what-todays-surveying-revealed/#comments Mon, 08 Dec 2014 03:59:20 +0000 WSB http://westseattleblog.com/?p=294513

(Added: Screengrab from ‘access pit’ camera – see newest image here)
7:59 PM: After today’s early-morning surveying of the Alaskan Way Viaduct, following Friday’s disclosure of a new inch-plus of “settling,” WSDOT has just published an update. While continuing to say that it’s safe to use The Viaduct, WSDOT says its contractor plans to stop the “dewatering” that was under way in the pit being dug to get to the tunneling machine:

WSDOT and Seattle Tunnel Partners conducted additional survey work early Sunday morning to further assess the amount and extent of settlement that recently occurred on and near the Alaskan Way Viaduct.

Some of the data was inconclusive and analysis is still underway; however, WSDOT observed that a small amount of differential settlement is occurring near the access pit. Differential settlement is when the ground settles unevenly over an area. When the ground settles evenly or uniformly over an area, there is less risk of damage.

The additional survey work did not find that the differential settlement has caused any new damage to the viaduct nor have we observed any damage to buildings or utilities in the surrounding area. On-the-ground surveys will continue this week by historic architects and structural engineers.

Public safety is our top priority and while we have not seen any damage, Seattle Tunnel Partners is taking the prudent step to stop dewatering. The contractor will work with its geostructural designer to stop the dewatering in a deliberate manner in order to ensure worker safety and the structural integrity of the access pit and surrounding structures.

Data analysis, collection and monitoring will continue and we will provide updates as we have new information to share.

“Dewatering” was being done as part of the access-pit excavation; as Mike Lindblom reported at SeattleTimes.com (WSB partner) after Friday’s report of settling, “Within the pit, water must be removed so that excavation machines sit on stable ground and aren’t scooping out an endless slurry.” The question now: Can digging continue without it? Yesterday marked exactly one year since the tunneling machine’s work stopped, after 1,000 feet of northward digging. WSDOT promises more information once it’s available, and we’re likely to hear more when the City Council’s prescheduled Alaskan Way Viaduct committee meets around 2:30 tomorrow afternoon.

ADDED 9:31 PM: We asked Viaduct project spokesperson Laura Newborn, who sent the above update, if this means no more digging, for now. She confirms to WSB that the contractor “will stop excavating.”

ADDED 11:11 AM MONDAY: This morning, spokesperson Newborn says that means excavation stops if/when dewatering stops, but she doesn’t have information right now on whether that’s happened yet.

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Traffic alert for Highway 99/Viaduct because of downtown protest http://westseattleblog.com/2014/12/traffic-alert-for-highway-99viaduct-because-of-downtown-protest/ http://westseattleblog.com/2014/12/traffic-alert-for-highway-99viaduct-because-of-downtown-protest/#comments Sat, 06 Dec 2014 23:53:23 +0000 WSB http://westseattleblog.com/?p=294400 First we got a text saying that protesters downtown were blocking the Seneca offramp from the Alaskan Way Viaduct; minutes later, a tweet suggested the protest was wrapping up, but now Seattle Police just tweeted:


No word how long this might last, but if you’re downtown trying to get to The Viaduct or vice versa, now you know.

P.S. Just a reminder that a *scheduled* closure of Highway 99, both ways, is still on for late tonight/early tomorrow morning, 11:59 pm-5 am.

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‘One inch of ground settlement’ detected for Alaskan Way Viaduct, tunneling-machine repair pit http://westseattleblog.com/2014/12/one-inch-of-ground-settlement-detected-for-alaskan-way-viaduct-tunneling-machine-repair-pit/ http://westseattleblog.com/2014/12/one-inch-of-ground-settlement-detected-for-alaskan-way-viaduct-tunneling-machine-repair-pit/#comments Sat, 06 Dec 2014 01:13:48 +0000 WSB http://westseattleblog.com/?p=294311

(Added: Recent WSDOT photo of access pit, shared via Flickr)
5:13 PM: WSDOT says it will be inspecting the Alaskan Way Viaduct and vicinity this weekend after detecting more ground settlement. Seattle Times (WSB partner) transportation reporter Mike Lindblom reported it earlier this afternoon, and now WSDOT has this statement on its website:

Public safety is our top priority, which is why we installed a state-of-the-art settlement monitoring system as part of the SR 99 Tunnel Project. Recently, that system detected approximately one inch of ground settlement near the pit Seattle Tunnel Partners is building to access and repair the tunneling machine. We have also seen the same amount of settlement on the Alaskan Way Viaduct; the amount of settlement lessens in the surrounding area.

Some settlement was expected during tunnel construction and while the tunneling machine repair work was underway. This settlement appears to have occurred in the last month.

We have observed no new damage to the viaduct nor have we observed any effect on buildings or utilities in the surrounding area. WSDOT crews are conducting additional surveys this weekend to verify this information, including an inspection of the viaduct and a visual inspection of the adjacent areas.

While we are conducting this additional work, we are confident that there is no risk to public safety. We will provide an update early next week.

Even before the tunneling project began, Viaduct managers had noted ongoing settlement, usually described as minor (as in this 2010 report). Nothing about settlement was mentioned at the regional stakeholders’ meeting we covered last Monday, but we imagine it’ll come up when the City Council’s Viaduct Committee meets early next week.

6:08 PM: We asked WSDOT spokesperson Laura Newborn if this is the reason the Saturday night/early Sunday Viaduct closure was expanded to both directions, and she confirmed that was done “so extra survey work could be completed.”

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Traffic alert: 5-hour Highway 99 closure this weekend now both ways http://westseattleblog.com/2014/12/traffic-alert-5-hour-highway-99-closure-this-weekend-now-both-ways/ http://westseattleblog.com/2014/12/traffic-alert-5-hour-highway-99-closure-this-weekend-now-both-ways/#comments Fri, 05 Dec 2014 00:08:42 +0000 WSB http://westseattleblog.com/?p=294173 Update on the five-hour closure planned for the Alaskan Way Viaduct this weekend - WSDOT says it will close in both directions, not just southbound as originally announced. The time frame is the same, 11:59 pm Saturday night until about 5 am Sunday morning, closed between the West Seattle Bridge and the Battery Street Tunnel. WSDOT says the closure “will allow crews to move heavy equipment across the roadway and conduct survey work.”

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