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Forbes Avenue Pittsburgh bridge collapse

Started by davewiecking, January 28, 2022, 08:15:02 AM

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J N Winkler

Quote from: jeffandnicole on January 28, 2022, 02:02:37 PM
Quote from: formulanone on January 28, 2022, 12:09:19 PM
I'm surprised a span that long and wide was rated for only 26 tons.

A close call all the way around.

Because of the condition underneath.  Maybe it's more surprising they still permitted vehicles up to 26 tons to drive on it.

Since load-posting is a first step for bridges whose structural deficiencies are deemed critical, I expect the decision to post for 26 tons to be put under the microscope:  why not a lower weight, and why not close the bridge altogether?

Quote from: kalvado on January 28, 2022, 04:09:18 PMAnd regarding inspections...

QuoteEach of the fracture-critical inspection reports from 1994—2006 did note the presence of rust, corrosion, and section loss on gusset plates

I think the gusset plate issue must have been a continuing blind spot.  It wasn't just a question of failure to choose an adequate thickness--the original design was checked using a method that assumes gusset plates will have all the strength required and thus can be ignored.  MnDOT commissioned finite element analysis of the bridge before it collapsed and, from what I can tell, it did not surface the gusset plates as a problem in a way that would have told MnDOT it needed to take urgent action to forestall the collapse.
"It is necessary to spend a hundred lire now to save a thousand lire later."--Piero Puricelli, explaining the need for a first-class road system to Benito Mussolini

kkt

If the September inspection rated it "poor" is there a lower rating for "failure imminent, close the bridge today"?

Big John

Quote from: kkt on January 28, 2022, 05:49:38 PM
If the September inspection rated it "poor" is there a lower rating for "failure imminent, close the bridge today"?

NBI: 4=poor, 3=serious, 2=critical, 1-failure imminent.  The failure imminent rating calls for a immediate closure.

kkt

Quote from: Big John on January 28, 2022, 05:53:21 PM
Quote from: kkt on January 28, 2022, 05:49:38 PM
If the September inspection rated it "poor" is there a lower rating for "failure imminent, close the bridge today"?

NBI: 4=poor, 3=serious, 2=critical, 1-failure imminent.  The failure imminent rating calls for a immediate closure.

Thanks.

noelbotevera

Hey, I drove over this bridge back in December! Kinda crazy that it didn't collapse on me while I passed over it.

I'm surprised that a relatively new bridge like this collapsed, but considered the sad state of infrastructure...

tolbs17

Quote from: noelbotevera on January 28, 2022, 08:51:21 PM
Hey, I drove over this bridge back in December! Kinda crazy that it didn't collapse on me while I passed over it.

I'm surprised that a relatively new bridge like this collapsed, but considered the sad state of infrastructure...
And with that happening. Now I'm afraid to drive on the Alligator River Bridge because I feel like that one will collapse next; it's due for a replacement anyway.

zzcarp

The questions I'd like answered is where was this bridge ranked on the list for a major rehab or replacement, and when was that maintenance scheduled (if applicable). We can call for more infrastructure funds, and, for a locally maintained bridge, if it's not ranked in the top several, it's not going to get replaced even if it rains federal money on the local government.
So many miles and so many roads

roadman65

Shouldn't the recent transportation infrastructure cover this?
Every day is a winding road, you just got to get used to it.

Sheryl Crowe

rickmastfan67

Fixed thread title, as it's Forbes Avenue, not Forbes Road.

SteveG1988

Quote from: SectorZ on January 28, 2022, 04:34:06 PM
Quote from: tolbs17 on January 28, 2022, 03:03:09 PM
Fix ya bridges!

Florida pedestrian bridge,

And now this...

The Florida bridge was an engineering failure, had nothing to do with fixing anything.

yup, it was built in an extremely stupid manner, a concrete truss... it would have never worked.
Roads Clinched

I55,I82,I84(E&W)I88(W),I87(N),I81,I64,I74(W),I72,I57,I24,I65,I59,I12,I71,I77,I76(E&W),I70,I79,I85,I86(W),I27,I16,I97,I96,I43,I41,

MASTERNC

Replacement times were quoted as 1-2 years. With construction on the 376 bridge east of the Squirrel Hill Tunnel to start in 2025 (Forbes would be a natural alternative route), the clock is ticking.

zzcarp

Quote from: zzcarp on January 28, 2022, 11:20:47 PM
The questions I'd like answered is where was this bridge ranked on the list for a major rehab or replacement, and when was that maintenance scheduled (if applicable). We can call for more infrastructure funds, and, for a locally maintained bridge, if it's not ranked in the top several, it's not going to get replaced even if it rains federal money on the local government.
Quote from: roadman65 on January 28, 2022, 11:29:06 PM
Shouldn't the recent transportation infrastructure cover this?

The answer is apparently no, the bridge was not a priority, and it wasn't going to have this federal infrastructure money targeted to it to replace it or make repairs.

QuoteBut the bridge is not among the highway and bridge projects targeted for federal funding in the state's 2021 transportation improvement program.

City officials haven't said why the bridge, built in 1970, wasn't placed on the list for federal infrastructure funding.

The 447-foot, steel, rigid frame bridge had an overall 4 rating and was listed in poor condition, according to the Pennsylvania Department of Transportation. Ratings range from 0 to 9, with the highest number receiving an excellent score.

Specifically, the bridge was handed a pair of 4s for its deck and superstructure, but the substructure was rated 6, state transportation records show.
So many miles and so many roads

roadman65

To the smartass mod who keeps taking after FB Fact Check and trying to censor us ( I talked to one of the administrators to find out who you are but he couldn't) I wasn't being political or cracking a wise crack about the infrastructure bill, I was just asking why the commonwealth isn't responding to the money aid that is entitled to them via our government for roads specifically?

I wasn't poking fun at anyone specific nor making a typical Dan joke (that you seem to turn the other way at, that needs the owner himself to take action, but that's another story) when I asked about why the funding wasn't used.  You need to stay out of politics which is why you assume that. Also Mr. MOD keep your personal feelings out of this forum!
Every day is a winding road, you just got to get used to it.

Sheryl Crowe

Scott5114

Quote from: roadman65 on January 29, 2022, 11:38:34 AM
To the smartass mod who keeps taking after FB Fact Check and trying to censor us ( I talked to one of the administrators to find out who you are but he couldn't) I wasn't being political or cracking a wise crack about the infrastructure bill, I was just asking why the commonwealth isn't responding to the money aid that is entitled to them via our government for roads specifically?

I wasn't poking fun at anyone specific nor making a typical Dan joke (that you seem to turn the other way at, that needs the owner himself to take action, but that's another story) when I asked about why the funding wasn't used.  You need to stay out of politics which is why you assume that. Also Mr. MOD keep your personal feelings out of this forum!

According to the server logs, the only moderation that has taken place in this thread is rickmastfan67 changing "Road" to "Avenue" in the thread title.
uncontrollable freak sardine salad chef

J N Winkler

I am going to lay down a marker:  the eventual analysis of the collapse will focus on the Forbes Avenue viaduct being an early use of weathering steel in bridge construction, before the importance of drainage detailing was adequately understood.
"It is necessary to spend a hundred lire now to save a thousand lire later."--Piero Puricelli, explaining the need for a first-class road system to Benito Mussolini

Bitmapped

Quote from: J N Winkler on January 28, 2022, 05:24:04 PM
Quote from: jeffandnicole on January 28, 2022, 02:02:37 PM
Quote from: formulanone on January 28, 2022, 12:09:19 PM
I'm surprised a span that long and wide was rated for only 26 tons.

A close call all the way around.

Because of the condition underneath.  Maybe it's more surprising they still permitted vehicles up to 26 tons to drive on it.

Since load-posting is a first step for bridges whose structural deficiencies are deemed critical, I expect the decision to post for 26 tons to be put under the microscope:  why not a lower weight, and why not close the bridge altogether?

Weight-restricted bridges aren't particularly uncommon in Pennsylvania.

ixnay

Quote from: kevinb1994 on January 28, 2022, 11:53:12 AM
Quote from: empirestate on January 28, 2022, 11:47:33 AM
In any case, this will result in some very unpleasant detours. (Which color detour is designated for this eventuality?)  :hmm:
I suppose that the Blue Route (not the one in SEPA) will see the largest use.

:rolleyes:
The Washington/Baltimore/Arlington CSA has two Key Bridges, a Minnesota Avenue, and a Mannasota Avenue.

74/171FAN

An emergency project for the bridge replacement has already been entered into PennDOT's CE Expert System.
I am now a PennDOT employee.  My opinions/views do not necessarily reflect the opinions/views of PennDOT.

ixnay

Quote from: tolbs17 on January 28, 2022, 09:31:43 PM
Quote from: noelbotevera on January 28, 2022, 08:51:21 PM
Hey, I drove over this bridge back in December! Kinda crazy that it didn't collapse on me while I passed over it.

I'm surprised that a relatively new bridge like this collapsed, but considered the sad state of infrastructure...
And with that happening. Now I'm afraid to drive on the Alligator River Bridge because I feel like that one will collapse next; it's due for a replacement anyway.

I crossed (as a passenger) that bridge on US 64 in 2007 on a Carolinas vacation (making my way up from Charleston to our next stop, the OBX).
The Washington/Baltimore/Arlington CSA has two Key Bridges, a Minnesota Avenue, and a Mannasota Avenue.

ixnay

The Washington/Baltimore/Arlington CSA has two Key Bridges, a Minnesota Avenue, and a Mannasota Avenue.

tolbs17


tolbs17

Quote from: ixnay on February 01, 2022, 08:17:35 AM
The Fern Hollow bridge is now immortalized on Wikipedia.

https://en.wikipedia.org/wiki/Fern_Hollow_Bridge
Yes, and more was added to it. I see that photos were added.

rickmastfan67


MCRoads

I am very immature, I immediately saw the name of the park and started laughing my but off.

In all seriousness though, I'm very curious to see what happened. Why was this bridge not higher on the priority list? Was the collapse able to be predicted from the last inspection? If so, why wasn't the bridge closed? Guess I'll just have to wait for the NTSB report.
I build roads on Minecraft. Like, really good roads.
Interstates traveled:
4/5/10*/11**/12**/15/25*/29*/35(E/W[TX])/40*/44**/49(LA**)/55*/64**/65/66*/70°/71*76(PA*,CO*)/78*°/80*/95°/99(PA**,NY**)

*/** indicates a terminus/termini being traveled
° Indicates a gap (I.E Breezwood, PA.)

more room plz



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