Infrastructure Maintenance-Cost Calculations

https://www.cbsnews.com/live-updates/pittsburgh-bridge-colla…
A Pittsburgh bridge collapsed Friday morning, sending multiple vehicles and a public bus plummeting into a park below, officials said. Ten people suffered minor injuries and four people were taken to area hospitals, but none of the injuries were life-threatening, CBS Pittsburgh reports.

https://marginalrevolution.com/marginalrevolution/2022/01/ma…
At the link is a 3 year twitter comment about the bridge.“I hope someone is keeping an eye on the underside of the Forbes Avenue bridge over Frick Park? One of the big “X” beams is rusted through entirely(and yes, I see the cables, so its probably not a crisis.”

Those who are geezers may remember the Ford Pinto. I owned one. It was my first brand new car. There was a problem with gas tank when the car was hit in the rear. The beancounters determined that it was cheaper to let them burn, than fix the problem. Perhaps governments make the same sort of calculations.

https://philosophia.uncg.edu/phi361-matteson/module-1-why-do…
Ford knew that the Pinto represented a serious fire hazard when struck from the rear, even in low-speed collisions. Ford officials faced a decision. Should they go ahead with the existing design, thereby meeting the production timetable but possibly jeopardizing consumer safety? Or should they delay production of the Pinto by redesigning the gas tank to make it safer and thus concede another year of subcompact dominance to foreign companies? Ford not only pushed ahead with the original design but stuck to it for the next six years.

What explains Ford’s decision? The evidence suggests that Ford relied, at least in part, on cost-benefit reasoning, which is an analysis in monetary terms of the expected costs and benefits of doing something. There were various ways of making the Pinto’s gas tank safer. Although the estimated price of these safety improvements ranged from only $5 to $8 per vehicle, Ford evidently reasoned that the increased cost outweighed the benefits of a new tank design.

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At the link is a 3 year twitter comment about the bridge.“I hope someone is keeping an eye on the underside of the Forbes Avenue bridge over Frick Park? One of the big “X” beams is rusted through entirely(and yes, I see the cables, so its probably not a crisis.”

This was discussed on another forum I’m on, where one of the participants posted some of his own photographs of that bridge.

He reports that after the rusted-through beam was reported, maintenance folks DID come and remove it.

He thinks that maybe they should also have replaced it.

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maintenance folks DID come and remove it.

He thinks that maybe they should also have replaced it.

Good Lord. They didn’t think that perhaps the engineer had the beam in the structure for some purpose?

tjscott0 writes,

maintenance folks DID come and remove it.

He thinks that maybe they should also have replaced it.

Good Lord. They didn’t think that perhaps the engineer had the beam in the structure for some purpose?

Bridges typically have a factor of safety of about 3.0 in the design (i.e., engineers carefully calculate the loads and stresses on the bridge, size the beams, columns and struts, then triple the size of everything.

That doesn’t work in aircraft structural design. If you made everything on an airliner tripe the size, it would never get airborne. Those guys are flying on much thinner margins.

intercst

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maintenance folks DID come and remove it.

He thinks that maybe they should also have replaced it.

Good Lord. They didn’t think that perhaps the engineer had the beam in the structure for some purpose?

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Lets not jump to conclusions. Maybe the engineers were involved with the decision to remove a beam. The safety analysis currently being performed will reveal the cause of the failure.

Having lived in Pittsburgh (about 1 mile from the collapsed bridge) for about 3.5 years from 1968-1971 I know that many bridges are in poor condition. The city/county use a lot of salt on the roads in the winter. Exposed steel does not do well in wet salty environment. Because of all the steep hills/valleys in the city/county requires extensive clearing/salting roads and a major cost.

Jaak

The beancounters determined that it was cheaper to let them burn, than fix the problem. Perhaps governments make the same sort of calculations.

I believe it is crucial to force ourselves to remember that “Governments” do not make any kind of calculations – political people do and then the political mechanisms chew and chomp. Maintaining infrastruture is almost never subject to calculations, because the voters will vote “next November” and money used on infrastructural maintenance is money not available to make voters happy “next Tuesday”.

Only the publicly virtuous calculate for the long term good of all, and virtue is in rapid decline.

David fb

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