HomeDiagramsDatabaseMapsForum
     

Go Back   SkyscraperPage Forum > Global Projects & Construction > General Development

View Poll Results: Which transbay tower design scheme do you like best?
#1 Richard Rogers 38 7.74%
#2 Cesar Pelli 98 19.96%
#3 SOM 355 72.30%
Voters: 491. You may not vote on this poll

Reply

 
Thread Tools Display Modes
     
     
  #3301  
Old Posted Oct 8, 2018, 1:39 AM
viewguysf's Avatar
viewguysf viewguysf is offline
Registered User
 
Join Date: Jan 2007
Location: San Francisco
Posts: 1,833
“I think we are all lucky that there was not a collapse.”

https://www.sfchronicle.com/bayarea/...f-13267862.php
Reply With Quote
     
     
  #3302  
Old Posted Oct 24, 2018, 3:10 AM
mt_climber13 mt_climber13 is offline
Registered User
 
Join Date: Jan 2012
Posts: 1,210
Finally some accountability starts to kick in

https://www.sfgate.com/bayarea/artic...p?t=897153f4ac
Reply With Quote
     
     
  #3303  
Old Posted Oct 24, 2018, 8:02 AM
SFBuildings888 SFBuildings888 is offline
Registered User
 
Join Date: Apr 2018
Posts: 81
I wouldn’t be surprised if the Transit Center takes until next year to reopen given the seriousness of the situation.
Reply With Quote
     
     
  #3304  
Old Posted Nov 15, 2018, 12:38 AM
Pedestrian's Avatar
Pedestrian Pedestrian is offline
Registered User
 
Join Date: Dec 2016
Location: San Francisco
Posts: 8,756
Quote:
Expert believes SF transit center cracks a limited problem, not design flaw
Matier & Ross
Nov. 14, 2018 Updated: Nov. 14, 2018 4 a.m.

The investigation into the pair of cracked girders that forced the closure of San Francisco’s newly inaugurated, $2.2 billion Transbay Transit Center in late September is now focused on the composition of the steel and cuts or other rough spots that may have put stress on the beams.

But the building’s overall design does not appear to be an issue, according to a top expert called in to review the work.

That’s good news for the troubled transit hub. A design flaw might have meant the beams couldn’t support the weight of the building’s bus deck and three-block-long roof garden, and required a major redesign that could have shuttered the center indefinitely.

“There is zero evidence of that being the problem,” said Mike Engelhardt, a structural engineering professor at the University of Texas at Austin. “It seems to be a very fine design.”

Engelhardt chairs the five-member peer review panel hired by the Metropolitan Transportation Commission to look over the shoulder of the Transit Center’s own team of experts, which is analyzing the reason for the cracks . . . .

He likened the beam problem to a piece of glass with a line etched in it that snaps more easily when under stress . . . .
https://www.sfchronicle.com/bayarea/...a-13389677.php

Let's hope he's right because, since he's the guy hired to make the call, I assume the MTA will proceed to follow his recommendations.
Reply With Quote
     
     
  #3305  
Old Posted Nov 15, 2018, 8:54 AM
SFBuildings888 SFBuildings888 is offline
Registered User
 
Join Date: Apr 2018
Posts: 81
Quote:
Originally Posted by Pedestrian View Post
https://www.sfchronicle.com/bayarea/...a-13389677.php

Let's hope he's right because, since he's the guy hired to make the call, I assume the MTA will proceed to follow his recommendations.
Even with the good news, I still don’t see it reopening until next year.
Reply With Quote
     
     
  #3306  
Old Posted Nov 15, 2018, 11:28 PM
gillynova gillynova is offline
Registered User
 
Join Date: Mar 2017
Location: Bay Area
Posts: 417
Such a downer. Just stop and become positive about things.
Reply With Quote
     
     
  #3307  
Old Posted Nov 15, 2018, 11:39 PM
edwards's Avatar
edwards edwards is offline
Registered User
 
Join Date: Jul 2010
Location: Rincon Hill
Posts: 346
They were testing the gondola in the afternoon today.
Reply With Quote
     
     
  #3308  
Old Posted Nov 16, 2018, 7:50 AM
SFBuildings888 SFBuildings888 is offline
Registered User
 
Join Date: Apr 2018
Posts: 81
I’m not a downer. Just calling it as I see it.
Reply With Quote
     
     
  #3309  
Old Posted Dec 12, 2018, 5:24 AM
fimiak's Avatar
fimiak fimiak is offline
Build Baby Build
 
Join Date: Sep 2010
Location: San Francisco
Posts: 837
Some good news, several new retail stores are leasing space on the ground floor. Charleys, Tycoon Kitchen, and Foundation Cafe. That brings it to a total of 12 spaces out of 35 leased, across 9 tenants, with 47% of total retail square footage accounted for.

Additionally, the spaces that have been leased already are still being built out even during the temporary closing of the terminal. More info: https://www.bizjournals.com/sanfranc...g-closure.html
Reply With Quote
     
     
  #3310  
Old Posted Dec 12, 2018, 7:57 AM
viewguysf's Avatar
viewguysf viewguysf is offline
Registered User
 
Join Date: Jan 2007
Location: San Francisco
Posts: 1,833
Quote:
Originally Posted by SFBuildings888 View Post
I’m not a downer. Just calling it as I see it.
and you were, however unfortunately, correct!
Reply With Quote
     
     
  #3311  
Old Posted Dec 12, 2018, 10:28 AM
SFBuildings888 SFBuildings888 is offline
Registered User
 
Join Date: Apr 2018
Posts: 81
Now they are saying the building might not be open again until next summer.
Reply With Quote
     
     
  #3312  
Old Posted Dec 13, 2018, 6:58 PM
waterchicken waterchicken is offline
Registered User
 
Join Date: Dec 2015
Location: Marin County, California
Posts: 35
Quote:
Originally Posted by SFBuildings888 View Post
Now they are saying the building might not be open again until next summer.
Who is "they" and what is your source? I cannot find any reference to this claim.
Reply With Quote
     
     
  #3313  
Old Posted Dec 13, 2018, 7:57 PM
Pedestrian's Avatar
Pedestrian Pedestrian is offline
Registered User
 
Join Date: Dec 2016
Location: San Francisco
Posts: 8,756
Quote:
Originally Posted by waterchicken View Post
Who is "they" and what is your source? I cannot find any reference to this claim.
Quote:
Answers on Transbay Transit Center fracture problem expected in January
By Adam Brinklow Dec 12, 2018, 9:23am PST

On Tuesday, the San Francisco County Transportation Authority’s [SFCTA] deputy director for capital projects was supposed to provide answers as to when the still-shuttered Transbay Transit Center and Salesforce Park might reopen.

Instead, Deputy Director Eric Cordoba told the SFCTA board that he didn’t have much to report.

“Preliminary findings will be presented to the Transbay Joint Powers Authority this coming Thursday (today),” said Cordoba at Tuesday’s hearing, but confessed that a more in-depth analysis of the problem will only be ready to present “within the next month—or two months maximum (February).”

In a memo circulated ahead of the hearing, Cordoba explained that city organs are still busy testing the materials that compose the terminal’s faulty girders . . . .

All mechanical testing is anticipated to be complete by December 14. The final report on the root cause assessment is anticipated by early January 2019.

At this time, it is difficult to determine when the fix will be complete, since a lot depends on the lead time for the materials needed to implement the fix.
Cordoba writes that “structural engineers have developed and analyzed a variety of fixes,” but until someone figures out precisely which one the situation calls for, the best this preparation can do is “reduce the implementation time” in the future . . . .

Cordoba noted Tuesday that no additional cracks have been found anywhere and that inspections are ongoing.
https://sf.curbed.com/2018/12/12/181...meline-girders

I too recall reading--but I can't recall where--that the reopening might not happen until the "second quarter" of 2019. That could be as late as June.

But this piece from Curbed makes even that seem optomistic. If they don't have the results of the "in-depth analysis" until February and if they then have to order materials and schedule workers to do the repair, the lead time for which is unknown (and knowing as we all do how long things can take in this town), I'd cross my fingers even for June.

The good news: No new cracks.
Reply With Quote
     
     
  #3314  
Old Posted Dec 13, 2018, 11:01 PM
fimiak's Avatar
fimiak fimiak is offline
Build Baby Build
 
Join Date: Sep 2010
Location: San Francisco
Posts: 837
New info, and looks like they have a fix ready that does not involve too much jostling:

According to the team, the probable cause of the fractures appears to be “the formation of cracks in the girder weld access [holes]” that were cut prior to the beams being placed into service. More specifically for the engineers in the room:

1. Initially, shallow (micro) surface cracks developed during thermal cutting of the weld access holes in the highly hardened and brittle martensitic surface layer [of the beams].
2. Thereafter, larger pop-in cracks formed in two of the four flanges, potentially during butt welding of the flange plates.
3. Black, tenacious, high temperature oxide was present on both the shallow surface cracks and the larger pop-in cracks, confirming that both crack types formed at elevated temperatures.
4. The fracture origins were located in the mid-thickness of the flange where low fracture toughness, as confirmed by CVN [(Charpy V-Notch)] toughness testing, provided little resistance to rapid, low-energy, brittle fracture.
5. CVN testing was performed on all flange samples at the top, ¼ depth, mid- thickness, ¾ depth, and bottom. ¼ depth CVN results were found to be consistent with the project specification and girder plate mill certifications.
6. Rapid, low-energy fracture of the flanges occurred as the girder was subjected to service loading on top of the normal residual stresses due to welded fabrication.

While further material testing and stress analyses are underway, and will be considered in the final root cause assessment due next month, it appears that the cracked flanges, which have maintained “sufficient capacity to support the building dead loads and occupancy loads,” can be fixed in place.

As proposed by Thornton Tomasetti, the existing surface around the compromised flanges could be ground to a smooth surface, after which bolted cover plates would be installed above and below, restoring the beams to their original design capacity.



http://www.socketsite.com/archives/2...dentified.html
Reply With Quote
     
     
  #3315  
Old Posted Dec 14, 2018, 12:12 AM
Pedestrian's Avatar
Pedestrian Pedestrian is offline
Registered User
 
Join Date: Dec 2016
Location: San Francisco
Posts: 8,756
^^This more or less confirms what was hypothesized in my post #3304 above but what I haven't heard explained and don't understand is that if it was actually necessary to cut "welding access holes" in the beams, why such holes weren't "prefabricated" into the beams or at least factored into the original engineering and design. It still seems like somebody goofed--either the contractor by cutting holes they shouldn't have cut or the engineers by not taking the need to cut holes into consideration.
Reply With Quote
     
     
  #3316  
Old Posted Jan 8, 2019, 2:40 AM
Pedestrian's Avatar
Pedestrian Pedestrian is offline
Registered User
 
Join Date: Dec 2016
Location: San Francisco
Posts: 8,756
Quote:
Steel plates to reinforce cracked beams under Transit Center repair plan
By Laura Waxmann on January 5, 2019 10:58 am

Plans have been approved to repair fractured beams at the temporarily shuttered Salesforce Transit Center by reinforcing them with steel plates, Transbay Joint Powers Authority officials said Friday.

The repair plans were reviewed and approved last month by a peer review panel of the Metropolitan Transportation Commission, which is also developing recommendations guiding additional inspections at the center prior. No date has been set for the center to reopen.

. . . Plans for repair include reinforcing four beams — the two cracked beams on Fremont Street and two non-impacted beams on First Street — with four thick steel cover plates.

Four sets of the plates will be bolted together above and below the fractured areas of the beams for protection. A construction schedule to repair the beams is expected to be finalized in January 2019 . . . .
http://www.sfexaminer.com/steel-plat...r-repair-plan/
Reply With Quote
     
     
End
 
 
Reply

Go Back   SkyscraperPage Forum > Global Projects & Construction > General Development
Forum Jump


Thread Tools
Display Modes

Forum Jump


All times are GMT. The time now is 12:08 AM.

     

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2019, vBulletin Solutions, Inc.