By Tracy Record
West Seattle Blog editor
Tired of getting just toplines about the West Seattle Bridge “final repairs” that are getting under way now?
The project manager from repair contractor Kraemer North America presented a detailed briefing during this month’s West Seattle Bridge Community Task Force meeting Thursday evening – the video recording should open below to the start (55 minutes into the meeting):
The key points and images from his presentation top our report:
CONTRACTOR PRESENTATION: Adam Dour, Kraemer’s project manager for the West Seattle Bridge Corridor projects, spoke – he said he was also involved with the rehab work last year, First, he described his company as a “bridge contractor – our specialty is bridges – we’ve been doing this for 110 years.” They’ve worked with state and local agencies around the region and country. He presented an overview of both the high and low bridges
For the high bridge, the green line on the top graphic is the pst-tensioning, and the blue and purple (interior) highlighting shows the epoxy injection and carbon-fiber polymer wrapping.
Other improvements – the project includes bridge deck overlay on the west end (Fauntleroy), removal and replacement of existing expansion joints, while some will be rehabilitated – “Bridge 131EA” will get some wrapping too near SR 99. “Not shown but equally important,” as Dour described it, the replacement of 4,000 feet of jersey barriers and 10 overhead sign structures.
As for the schedule – intermediate timelines – they have 280 working days after the June 30th “substantial completion date” to finish anything that doesn’t affect traffic (in other words, work that would be done after the bridge reopens).
Right now, they’re relocating utilities, doing the hydro-demolition for access holes as well as platform hanging. They’ll be assembling the platforms in December/January – west side platform should go up last week of December, followed by east side when permission from the railroad is in. Then “we’ll restore the deck to service and get traffic back on this thing.”
On the low bridge, they’re working on material procurement right now, with platform assembLy/raising due in February. More exterior wrapping, improved electrical systems.
Here’s the maintenance work schedule:
He included various reassurances along the way in his briefing, such as: “Once we put traffic on the bridge, we’re not going to take it off, I want to make that very clear,” he said. The only notable work that might have to happen after June 30th is the new overhead signage. If they had to slide that to post-reopening, they’d narrow lanes down on an “overnight basis only” to get the structures in. But again, “once we give that traffic back to West Seattle, we’re not going to take it away.”
He explained how the work will be done and how the platforms work, “designed specifically” for this bridge. The winching systems are on site and they’re opening the last access holes.
Hydrodemolition – which was happening when we visited the bridge last week – involves “eroding the concrete” with water that’s 8,000 punds per square inch but not damaging anything else. “Once we open up these openings, we have a perfectly preserved rebar, PT strand … we’re trying our darnedest to make sure we’re improving the bridge, not making more work.” They’re opening some of the larger access holes right now.
The platforms go up in minutes and attach to hangers off the bridge. They’re designed to be mobile. The raising will happen on evenings or weekends so as to not affect traffic, Dour said. The platforms help crews reach the spots they need to get to for the project. “It’s a challenge to get work access up so high.”
Here’s what carbon-fiber wrap looks like:
Explaining this reinforcing, Dour said, “it’s in a way like the Superman of wallpaper … a carbon-fiber weave that’s put together, abut as strong as steel when it comes to being able to be pulled apart …” It’s bonded to the concrete with a :high-speed epoxy “so that at the end of the day you have concrete that wants to crack, it absolutely can’t … the carbon fiber is holding it together to be sure those cracks don’t open back up.” Existing cracks, meantime, are being filled with epoxy; then the CF wrap is applied to a smoothed-over concrete , and it’s painted with a solution to prevent “degradation.”
Regarding post-tensioning, the cables will be placed “throughout the structure”:
They’ll be “pulling the bridge from end to end tighter together, forcing the concrete to push in on itself and make sure we don’t have cracks that open up.” They’re installing 24 new post-tension tendons but inducing “an additional 20.8 million pounds of force into the structure … equivalent to 1,600 African elephants standing on top of your head, or 40 fully loaded 787s, or launching a car in a slingshot halfway to the moon … To handle that sort of force, we have to do some core drilling in the existing piers – 6″ diameter.” Properly modeling this in the design process was vital – “could do a lot of damage if we didn’t put it in the right place.”
Also planned: Concrete deviator blocks, to realign interior aspects “to make sure the bridge stays in the geometry it’s supposed to stay in,”
For the low bridge, work platforms will be raised through existing holes in the hollow structure so new holes don’t have to be made. That work will happen while surface and maritime traffic continues flowing above/below.
Where’s our biggest risk on the project? asked CTF co-chair Greg Nickels. “The unknowns,” replied Dour. “Supply-chain issues throughout the industry” for one, but they’re working as hard as they can to get the materials “here on time and get the ball rolling in the right direction.” So you have a tracking system that’ll tell you if something’s behind? Yes, there’s a scheduling tool updated weekly. You’ll let the community know if something’s running behind? Yes, Dour said. Task-force member Anne Higuera asked if the carbon fiber wrap is a new or old technology, Been around for 30 years, commonly used for about the past 15 years, said Dour. She also asked about inspections – who inspects this for permits and approvals? SDOT’s Heather Marx replied that the work is self-permitted because it’s their right of way, but they do have inspectors and “we’ve brought in additional help to support them,” with a contract soon to be signed for that outside help. What kind of weight will be added to the bridge? asked task force member Dan Austin. Dour said some items will add weight – the post-tensioning and deviator blocks, for one – but “not a significant total when you look at the global weight of the bridge.” Austin asked a question we had asked during the recent briefing with the mayor, whether there are incentives for early completion. No, in part because of federal funding rules, Marx reiterated. SDOT director Sam Zimbabwe also said the same thing he said at the media briefing – “everyone’s very committed” to “doing everything we can to meet the schedule” but trying to speed it up beyond that “would send the wrong message.” Also asked: Is the bridge opening in the same lane configuration? Yes, but it will have a “wider westbound shoulder” for safety, Marx said, while noting that’s probably nothing that anyone will notice. What number of workers, what hours, where are they parking, how are they getting there? asked task force member Deb Barker. At peak, 50 workers at any one given time, said Dour. They will be parking on the high bridge. The construction vehicles will not be putting added traffic on the low bridge, he added. They’ll be working generally 6 days a week, 10 hours a day, with some nighttime shift for certain things.
Here’s what else happened in the meeting, mostly before the contractor’s presentation:
OPENING BRIEFING: SDOT’s Marx led off the presentations. “Final repairs are under way,” she declared. She showed a graphic she says will be updated every briefing – showing where the work actually is happening:
Some of what she had to say was later eclipsed by details from the contractor. But she also showed a basic construction timeline:
This is all to be done by the end of June, and then, she said, “commissioning” will take a “couple days.”
LOW BRIDGE: Marx said this “rehabilitation” will start in the first quarter; “ongoing preventive maintenance” continues now. Here’s what’s ahead:
The cylinder replacement that was supposed to happen next month – requiring the low bridge to remain in a fixed position – has been delayed, because of the “machining of cylinders,” she says. Once it happens, it’ll last 72 hours – affecting maritime traffic. Also ahead, getting ready for the low-bridge work and ensuring it can handle work platforms will require testing with no traffic for about half an hour at a time – dates and times are not set yet but they’ll be on Sundays to have the least impact.
Later in the meeting, task force member Austin asked about the problem that took the low bridge out of service last month. Marx recapped that the problem required early completion of a planned repair, which is now done and is permanent,
Low-bridge access will change at the first of the year – even authorized restaurant and retail users will be asked not to use it between 10 am and 3 pm, “especially eastbound.”
RECONNECT WEST SEATTLE: As we’ve reported, the Duwamish Longhouse signal is now in operation, Also, as readers pointed out already, another lane has opened on SR 99. The Flip Your Trip program is up to 2,700 registrations, “3,000 trips used.”
TASK FORCE MEMBERS’ THOUGHTS/QUESTIONS: This was a time for general questions early in the meeting, Yes, the repair contract has milestones, was the response to a question from task force member Barker. Task force member Marci Carpenter asked about the Water Taxi shuttles, which don’t run during all of the expanded winter service times – only am and pm peaks. Chris Arkills from King County said the problem is a driver shortage, though they’re still trying to staff up so that they can add middays too. The Water Taxi shuttles are driven by Hopelink employees, it was noted.
TASK FORCE’S FUTURE: Co-chair Nickels, a former mayor, says there’s no word yet from incoming mayor Bruce Harrell‘s administration on whether the task force will continue – they’re working on much higher priorities. So the Task Force is going to formally ask for clarification, while reserving a meeting time next month in case they’re asked to continue. SDOT director Zimbabwe said he and Marx have briefed the transition team on the project. Just in case this was the last meeting, there were lots of warm words from and for task force members including co-chairs Nickels and Paulina López. Marx had noted the hours the task force has put in, and other stats:
MAYOR DURKAN’S FAREWELL: Also during the meeting, outgoing Mayor Jenny Durkan dropped in to express thanks to the CTF for its advisory work as well as to SDOT. Recounting the day (March 23, 2020) she had to order the closure, she said, “Getting that call [that the bridge needed to close] was no fun,” but she was grateful they caught the accelerated cracking before catastrophe. After that, she said, the community input provided by the CTF was invaluable – “rais(ing) good questions and bring(ing) good ideas to the table.” She declared, “This bridge WILL open next year,” and that all indications are it will then last the rest of its originally expected life. She also apologized to West Seattle and the Duwamish Valley for the impacts of the long closure. Before Durkan left the meeting, City Councilmember Lisa Herbold jumped in to thank her too, as did outgoing Seattle Port Commissioner Peter Steinbrueck; both made an extra point of thanking her profusely for choosing “repair” over “replace.”
WHAT’S NEXT: Since they don’t know yet if the Harrell administration wants the Task Force to carry on, they’re not sure if there’l be another meeting, but noon January 12th is penciled in.