Pittsburgh bridge collapse 32

[Besserat]

It just happened

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

 

[dik]

It is... and the comments do not detract from it... I recall a first year engineering class titled, "Engineering and Society."

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

-Dik

 

[bridgebuster]

As Dirty Harry said "...are you feeling lucky...?" It's possible but it shouldn't be done. I'm sure PennDOT is similar to NYSDOT, which prohibits postings without calculations.

I don't believe the city just pulled a number out of their @$$. According to the bridge data posted by bradw1128, the design live load is H20 (for the uninitiated, that's a 40K vehicle with two axles spaced at 14', from axle is 8k; rear axle is 32k). The Inventory Rating is 17.2 Metric Tons (slightly less than the weight of an H20 truck, which does indicate some deterioration.) and the Operating Rating is 29.9 MT. The posted load of 26 T is less than the Operating load, which is SOP.

Again, for the uninitiated:
Inventory Rating Level - The inventory rating level generally corresponds to the customary
design level of stresses but reflects the existing bridge and material conditions with regard to
deterioration and loss of section. Load ratings based on the inventory level allow comparisons
with the capacity for new structures and, therefore, results in a live load which can safely utilize
an existing structure for an indefinite period of time.

Operating Rating Level - Load ratings based on the operating rating level generally describe the
maximum permissible live load to which the structure may be subjected. Allowing unlimited
numbers of vehicles to use the bridge at operating level may shorten the life of the bridge.

 

[ATSE]

There's no problem with invoking politics in this forum. Civil engineering and public policy are inseparable.
The problem lies with selective facts and selective outrage and the inference that if only (x) wasn't governor, or the cost of jet fighters, or whatever if right in front of you isn't the way you think it should be ... then the bridge would have been maintained, and these failures wouldn't be happening so often.
That thinking is plain silly.
There's probably two or three main culprits for this bridge failure, but 100+ reasons why there was lack of correct and appropriate funding to minimize the risk of collapse.

 

[bones206]

My comment on spending wasn't specific to this bridge failure. More of a general observation of spending priorities on a macroeconomic level over the course of history. Obviously there are specific reasons for this particular bridge failing that have no direct link to the national budget. I just disagree with the premise that road infrastructure in-and-of-itself was a high priority in the past. I think the military wanted it so the military got it. I don't think that particular dynamic has changed much.

 

[dik]

There was no outrage... simply an observation.

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

-Dik

 

[bridgebuster]

Close to 30 years ago, I had to take over supervision of a street reconstruction project in NYC - a lot of problems political and technical. Before taking over, I had to go for an interview with the City's borough engineer. Initially, he was reluctant because my background was mainly bridge work. He said to me "...keep in mind, bridges don't have constituencies; nobody lives on a bridge; people live on streets."

No one cares about bridges until they can't use them. There's a limited pot of money; for decades politicians have been robbing Peter to pay Paul for programs that buy them votes. States rely heavily on Federal money. In the past, the Federal funding formula didn't cover maintenance. At least things are changing somewhat. FHWA does recognize the need for "preservation." IN NY for example, the number of preservation projects that have been let has increased noticeably. we're making progress.


Federal funding for transportation come from the gasoline tax. We're still robbing Peter to pay Paul on transportation funding through the gas tax. That money is also used for things like bikeways, greenways, trails, etc. These are worthy project - I enjoy biking - but they're not bridges. Nobody lives on a bridge

 

[FacEngrPE]

The funding issues here may have more to do with local budgets. Pittsburgh population is about 1/2 of it's population in the steel hayday. The road network is still about the same or even larger.

Pittsburgh was reported in 2006 to have 446 bridges in its 55.38 sq mi, serving ~ 300,000 people.

 

[phamENG]

Ha...that's about 673 people per bridge. So just tax them when the bridge needs to be fixed: hello, citizen, if you don't pay your $3k share of the $2M repair and maintenance for this bridge in 2 weeks, your commute to work will quintuple when we close the bridge. Yikes.

 

[spsalso]

Some of the bridges are owned and maintained by "other owning entities": Railroads come to mind.



spsalso

 

[Cool_Controls]

Corporations are people to (that's what I've been told), but they tend to get tax breaks to move into certain locals, individuals not so much.

 

[CWB1]

Ha...that's about 673 people per bridge. So just tax them when the bridge needs to be fixed

That's essentially what happens under normal circumstances - local taxes cover infrastructure, failure to pay leads to failures which cost locals more later. Paying a federal employee to pay a state employee to pay a city employee to pay a contractor to fix this bridge makes no sense, yet that's how we shuffle money then wonder why it disappears. Its much like blaming the military for their budget after your local politicians created jobs by forcing the military to hire local-yokels at $100k+ to do the simplest support jobs that the military already did for $40k to a much higher standard.

 

[spsalso]

Corporations are people to (that's what I've been told), but they tend to get tax breaks to move into certain locals, individuals not so much.

My point was that bridges that are owned by railroads in Pittsburgh are not maintained at the expense of the City. If getting "...tax breaks to move into certain locals..." negates that statement, I would like to see the logic. Those bridges are repaired and maintained at the expense of the stockholders, not the City of Pittsburgh.

spsalso

 

[Cool_Controls]

It's not always about you spsalso, I was responding to a prior post. No doubt privately owned bridges should be maintained by the parties to whom they belong.

 

[Milliontown]

It looks like Pennsylvania has a history of diverting bridge funds away from bridges.
[URL unfurl="true"]https://www.lehighvalleylive.com/lehigh-county/2019/04/42-billion-diverted-from-penndot-road-and-bridge-repairs-to-fund-state-police-new-audit-reveals.html[/url]

 

[SnTMan]

Well, govt finances are largely about robbing Peter and not paying Paul

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[spsalso]

Cool Controls,

I reread your post and do now see what you are getting at: corporations in Pittsburgh are getting financial breaks from the city, and should not be.

I hope I've got that right.

I do hope the citizens and the government of the city will take heed. I would have thought the city government explored the profit/loss numbers before approving of these tax breaks, and decided that more income to the city would be generated than the breaks cost. Perhaps they were in error.



spsalso

 

[dik]

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

-Dik

 

[bridgebuster]

Nothing new. In PA, our gas tax is almost $0.59/gallon; 3rd highest in the US. When the legislature passed the infrastructure bill about 10 years ago, doubling the tax, the money was supposed to go into a lock box (shades of Al Gore?). Just like legalized gambling was supposed to lower the school tax.



I would venture to say that today railroads only maintain bridges carrying their tracks. In NYC, there are a fair amount of bridges - rail and vehicular - that were constructed by the railroads in the 19th & early part of the 20th Centuries. As the railroads starting going bankrupt after the war the ownership of the vehicular bridges was transferred to the city and state, mostly in the 50's/60's. Even in the 80's to get plans for these bridges we had to go to the railroad for them. A bit of history.

 

[spsalso]

I doubt there were many railroads that included vehicular pathways on their railroad bridges. Safety comes to mind. Plus: why would they do that?

Not saying it didn't happen, but I see it as quite rare.

However.

Transit rail is another thing. I do not view that as "railroad". For example, they are generally not common carrier. There was, for example, transit rail on the San Francisco Bay Bridge. I do wonder what, if anything, that carrier paid the "authority" for usage.

By now, most/all transit rail has been rolled into government ownership/support. So they wouldn't appear to be sources of more funding for bridge maintenance.

However.

In this case, we're talking about Pittsburgh, and its 400+ bridges. Separating transit rail from common-carrier rail, I wonder which bridges handling the latter do also support vehicular traffic.


spsalso

 

[CWB1]

PA also has their famous turnpike. About ten years ago my wife wandered onto the NE extension on a trip from DC to NY. I remember marveling from the passenger seat at the nice new road and a sign that must've been 10' tall bragging about ~$100M in construction, we thought PA was pretty ok until she had to pay $70 in tolls for her commuter car.