North Washington St Bridge

AmericanFolkLegend

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A tiny nitpick: by "the engineer" you mean the bridge design firm ("bridges as structural art," per their own branding). It was very unlikely a single structural engineer made this design choice to put form over function, though I'm sure one or more was tasked with figuring out how to make the design work after it was aesthetically conceptualized (and ultimately someone signed off on it).
That's a fair distinction. I'm sure Rosales isn't the EOR (didn't stamp any of the drawings). I think I remember Benesch being the structural engineer and GZA being involved with the foundation design. There were like 6 stamps on the construction drawings if I recall correctly. So Rosales probably prescribed the individual piers and then it fell to Benesch to make that work and still meet seismic loads.
 

intellirock617

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That's a fair distinction. I'm sure Rosales isn't the EOR (didn't stamp any of the drawings). I think I remember Benesch being the structural engineer and GZA being involved with the foundation design. There were like 6 stamps on the construction drawings if I recall correctly. So Rosales probably prescribed the individual piers and then it fell to Benesch to make that work and still meet seismic loads.
The design was joint Rosales and Benesch. Someone from Benesch is the EOR I'm pretty sure. The piers were prescribed to create an inverse of the Zakim bridge as noted previously. The design is certainly unconventional and challenging which has led to many frustrations throughout construction.
RE: Your previous comments regarding the diaphragms ... there are several full depth/full height pieces spaced throughout.
 

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Rhino

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Alright, I did some more digging and found out what's going on with the welds. Kind of interesting actually:
  • The bridge piers for this project are actually four individual piers at each location. This was a design choice made by the engineer.
  • Most large bridges have monolithic bridge piers (the first two at this link) or at least individual piers that are tied together with a concrete cap (the last example at that previous link).
  • A monolithic bridge pier provides better resilience against seismic loads.
  • The design of the N. Washington St bridge piers can't meet the seismic loads required. So they need to make it up by overengineering the diaphragms that connect the tub girders to meet those loads above the piers.
  • So they've got these super thick diaphragms that they are supposed to connect to the tub girders with a full pan weld. Fine, that can be done, just takes a long time to heat up the steel and get it super hot for the entire thickness of the diaphragm.
  • Problem comes when the super thick/hot weld cools down. If it cools down too quickly it cracks. That seems to be what's happening here.
So MADOT (who is administering the job on behalf of the COB) flipped out. They completely shut down the project. Curiously, they're kind of treating it as a safety issue - like it would be too dangerous to have anyone working on the bridge. Which is just silly because they let guys crawl all over the project to install the diaphragms in the first place. Anyway, the contractor (JF White) will need to come up with a procedure to keep the welds from cooling down too quickly and cracking. My guess is MADOT will make them prove the procedure works with a sample weld off the bridge. This problem will only be exacerbated in the winter. So we could be in for several months of no progress on the bridge.

TL/DR - There are QA/QC problems with some of the bridge welds. Don't expect any work on this bridge for weeks or months. 😥
AFL, do you happen to have an update on this? I really appreciated your original detailed explanation/update, btw.
 

AmericanFolkLegend

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AFL, do you happen to have an update on this? I really appreciated your original detailed explanation/update, btw.
I talked to an exec at JF White (the general contractor) maybe a month ago. He said the welding company assumed it was a welding issue and the engineer assumed it was a design issue (he brought this up to point out how rare it was that both parties initially blamed themselves!). All parties (GC, welder, engineer, COB and MADOT) agreed to take samples of the welds under the same conditions and send them to their preferred testing lab. From that they hope to be able to determine if the issue was with the steel, the weld, or the design of the weld.
Frustratingly he said, "Don't expect to see much work on the bridge for 6 months." They're still doing utility work and some other miscellaneous work, but I doubt any of it is "critical path" to the schedule.
 

Rhino

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I talked to an exec at JF White (the general contractor) maybe a month ago. He said the welding company assumed it was a welding issue and the engineer assumed it was a design issue (he brought this up to point out how rare it was that both parties initially blamed themselves!). All parties (GC, welder, engineer, COB and MADOT) agreed to take samples of the welds under the same conditions and send them to their preferred testing lab. From that they hope to be able to determine if the issue was with the steel, the weld, or the design of the weld.
Frustratingly he said, "Don't expect to see much work on the bridge for 6 months." They're still doing utility work and some other miscellaneous work, but I doubt any of it is "critical path" to the schedule.
Ugh, that's extremely frustrating to hear. But again, I really appreciate your update - the updates they provide to the community are essentially pointless and never discuss setbacks like this or impacts to the schedule.
 

Rhino

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http://charlestownbridge.com/2022/0...e-replacement-due-to-defective-weld-in-beams/

Based on AFL's inside info, I left Dan Fielding (listed as the MADOT contact person for the project) a voicemail expressing my concerns about the lack of transparency on this issue and also emailed the editor of the local papers about what I had heard. They posted a quick article about the issue yesterday and we're able to get an acknowledgment from MADOT that they did indeed encounter the exact issue that AFL disclosed to us. Unfortunately and frustratingly, they never acknowledged that this was discovered over 2 months ago and they also are still not able (or willing) to provide any updates on potential schedule impacts.
 

C-Town_Jeff

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http://charlestownbridge.com/2022/0...e-replacement-due-to-defective-weld-in-beams/

Based on AFL's inside info, I left Dan Fielding (listed as the MADOT contact person for the project) a voicemail expressing my concerns about the lack of transparency on this issue and also emailed the editor of the local papers about what I had heard. They posted a quick article about the issue yesterday and we're able to get an acknowledgment from MADOT that they did indeed encounter the exact issue that AFL disclosed to us. Unfortunately and frustratingly, they never acknowledged that this was discovered over 2 months ago and they also are still not able (or willing) to provide any updates on potential schedule impacts.
I was wondering why this has not been in the paper for so long and then all of a sudden was. I was hoping that it was because a solution had been found and they didn't want it in the paper until they could also follow up with the good news. Hopefully if we poke this with enough sticks we will get some more action on this.
 

Rhino

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I was wondering why this has not been in the paper for so long and then all of a sudden was. I was hoping that it was because a solution had been found and they didn't want it in the paper until they could also follow up with the good news. Hopefully if we poke this with enough sticks we will get some more action on this.
Yep, I sent Dan Ryan an email about it as well to see if he can push for at least the testing to be expedited. I'd also love to see some discussions and proposals regarding how they can reduce some of the delays with future work (approve longer work days, weekend work, etc.) - one thing I'd love to see is if they can work to open up the bridge to pedestrians/bikes prior to finishing the road part.
 

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AmericanFolkLegend

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Update as of last week:
  • JF White has submitted their "position paper" on why the weld cracks were not their fault.
  • JF White very recently submitted their proposed procedure for installing the diaphragms without weld failures.
  • MADOT is looking at the procedure and likely will have an answer in early to mid May.
  • Once all the parties agree on the welding procedure, they will do test welds which will then be examined (i.e., x-rayed).
  • If the test welds pass, production welding can begin in earnest.
  • "Don't expect to see any serious work on the bridge before the end of May at the earliest."
 

Jahvon09

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The project seems to have gone stone cold. What seems to be the holdup? :unsure:
 
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Patrick Winn

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It’s frustrating that this project in particular got screwed up so badly. The N. Washington St. bridge connects Charlestown to the north and West End via the freedom trail which is used by so many tourists. The temporary bridge is sketchy walk and the intersection by North Washington and Chelsea is basically a combat zone for pedestrians. Traffic over the temporary bridge is predictably bad. This is a really bad project to botch. Would like to know who’s responsible.
 

AmericanFolkLegend

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the intersection by North Washington and Chelsea is basically a combat zone for pedestrians
I will say, at least they finally changed the walk signal so that it's all directions at once. It used to be that you'd need to wait a light cycle to make it to a traffic island. Then wait for another light cycle to make it to another traffic island. It was the epitome of prioritizing cars over pedestrians.
 

Rhino

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Update as of last week:
  • JF White has submitted their "position paper" on why the weld cracks were not their fault.
  • JF White very recently submitted their proposed procedure for installing the diaphragms without weld failures.
  • MADOT is looking at the procedure and likely will have an answer in early to mid May.
  • Once all the parties agree on the welding procedure, they will do test welds which will then be examined (i.e., x-rayed).
  • If the test welds pass, production welding can begin in earnest.
  • "Don't expect to see any serious work on the bridge before the end of May at the earliest."
AFL, do you by chance know if MADOT has provided feedback on JFW's proposed procedure yet? Again, I really appreciate all the inside-info/detail you've been able to provide.
 

Lrfox

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Not to drift too far from the debacle with the bridge construction, but does anyone know how long the N. Washington/LoveJoy Wharf stairs have been open? When I stopped at Night Shift last summer, they were still closed. I just happened to notice during some b-roll footage prior to a Celtics game last week that the stairs were open and being heavily used.
 

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