Pittsburgh bridge collapse 32

[Besserat]

It just happened

https://www.post-gazette.com/local/...int-breeze-squirrel-hill/stories/202201280075

 

[bones206]

The bridge collapsed as the city prepared for a visit from President Joe Biden, who is scheduled to speak about infrastructure Friday afternoon at Mill 19 in Hazelwood. Multiple officials said the collapse illustrated the need for infrastructure investment.

Glad nobody was seriously hurt, but truly this bridge had a sense of humor.

 

[JohnRBaker]

Karma...

John R. Baker, P.E. (ret)
Irvine, CA
Siemens PLM:
UG/NX Museum:

The secret of life is not finding someone to live with
It's finding someone you can't live without

 

[bradw1128]

Here is the element level data.

https://infobridge.fhwa.dot.gov/Data/BridgeDetail/22435238#!#NBETab

All 4 steel columns were at condition state 4 (severe)
2 of 4 movable bearings were at CS3 (poor)

I would expect that having a CS4 condition on a primary structural element like that would have triggered a more detailed structural review. I don't know the policies in PA though or how city-owned bridges might follow it.

Bradley Wilder, P.E.
Construction P.E. (KY), MBA
Bridge Rehab, Coatings, Structural Repair

 

[dik]

Old timber truss bridges are neat...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[timeforchili]

How are the reduced posted weight limits determined in these scenarios? Is 26 tons chosen through detailed structural analyses assuming certain failed members or is it a judgement call based on the types of vehicles that they want to prohibit?

 

[Sym P. le]

It makes one wonder how they decided that the cross member required supplemental measures but the column didn't.

 

[skewl]

How are the reduced posted weight limits determined in these scenarios? Is 26 tons chosen through detailed structural analyses assuming certain failed members or is it a judgement call based on the types of vehicles that they want to prohibit?

Someone would have had to completed a structural evaluation (inspection and analysis) to determine the load posting. They would have modelled failed connections, section loss, verified material strengths, etc.

 

[OHIOMatt]

I am not sure how we got to a point in the country were a bridge in a local municipality needs to be paid for by the federal government. I can see perhaps federal involvement on bridges in the interstate highway system. I think waiting for the benevolent hand of the feds to dole out money is never going to work. The local agency should be responsible. If they need to raise taxes or utilize tolls, so be it.

 

[CivilKeith]

How are the reduced posted weight limits determined in these scenarios? Is 26 tons chosen through detailed structural analyses assuming certain failed members or is it a judgement call based on the types of vehicles that they want to prohibit?

It goes through a certain structural analysis program for the load rating of bridges, in accordance with the FHWA and state DOTs.

 

[JLNJ]

Bill Watterson is the best!

 

[phamENG]

Well the feds aren't going to pay for it anyway because Congress can't get out of their own way, and the locals aren't going to raise taxes because then people might actually care about local elections and replace them.

So I think deficient bridges should simply be closed. Don't let people drive across them. Eventually people will be pleading the local government to take their money to make the repairs that are needed...or we'll all just wait in traffic for 2 hours to get to the grocery store. Either way, we get what we deserve.

 

[dik]

Without getting political, there's a real downside to Reaganomics; this is the beginning.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[la belle vie]

So I think deficient bridges should simply be closed. Don't let people drive across them.

Especially non-redundant ones.

 

[CWB1]

So I think deficient bridges should simply be closed. Don't let people drive across them.

As I often point out on disaster posts, this is how the existing process is supposed to work. Unfortunately nobody stateside seems interested in holding the muni engineers accountable for failing to close infrastructure before disasters like this, instead they spend hours blaming politics for lack of funding. Sorry not sorry but an engineer belongs in jail for this.

 

[JohnRBaker]

The infrastructure bill, that has already been passed by Congress, has almost #2 billion earmarked to replace/repair bridges in Pennsylvania, in addition to $4 billion for general road repair and maintenance.

John R. Baker, P.E. (ret)
Irvine, CA
Siemens PLM:
UG/NX Museum:

The secret of life is not finding someone to live with
It's finding someone you can't live without

 

[Red Corona]

When a bridge has important structural items at "needs fixing" it should surely be closed and fixed (or removed, if it's redundant) kind of immediately? There's no point having inspection regimes and rating of safety levels (which actually seem to have been followed quite well in this case) if you don't actually do the repairs they flag up.

Also, it seems like it would be a good idea for gas mains to have periodic auto-shutoff valves, or at least where they're built into a bridge, so if something bad happens to sever the line it doesn't allow lots of gas to escape.

 

[ACtrafficengr]

Especially non-redundant ones

Structurally non-redundant ones should be candidates for closure

But what we really need to do is shrink the system, as the Iowa DOT commissioner says some years ago. If we can't generate the revenue to maintain our roads and bridges, maybe we need to get rid of some

My glass has a v/c ratio of 0.5

Maybe the tyranny of Murphy is the penalty for hubris. -

http://xkcd.com/319/

 

[dik]

...and wonder what the effect of carbon footprint reduction will have on transportation.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[JohnRBaker]

Note the the only state with MORE substandard bridges than Pennsylvania is Iowa:

Iowa leads nation for most structurally deficient bridges

https://www.kcrg.com/2021/11/10/iowa-leads-nation-most-structurally-deficient-bridges/

John R. Baker, P.E. (ret)
Irvine, CA
Siemens PLM:
UG/NX Museum:

The secret of life is not finding someone to live with
It's finding someone you can't live without

 

[AutisticBez]

Well at least they could have closed a lane on each side. Damn. Also those columns are covered in rust. That break in the cross member should have been the moment you shut the bridge down and fixed it.

You know during COVID a bit of engineering work would be great. True? Stimulate the economy by building and fixing stuff.