The American Society for Civil Engineers publishes this report. I’m sure they’re all great people, but I take with a grain of salt any information that comes from an interested party.
The report is signed and stamped by the principal PE (professional engineer) not a construction company. These PEs are licensed by the state.
It’s linked in the thread and is very readable.
The report is rather matter of fact and lays out on page 7 what the problem was and what needs to happen to fix. This was 2018. Because a lot is unknowable these reports don’t tend to give a timeline for structural failure, but it does give some serious warnings.
> The US's bridges get a c+ according to the American Society Of Civil Engineers.
Which bridges, in which states, are we talking about here? I feel that these ratings are tossed around a lot, but there are a lot of bridges which are fallow/virtually unused in the U.S. by the nature of its evolution. It is conceivable that the average bridge is worse than the average overall risk from bridges (i.e. rating multiplied by proportion of miles/minutes on each bridge).
Unlike interest groups with mysterious names like "Amercians for Families and Fuzzy Kittens", it's pretty obvious what an engineering society is advocating and why.
The facts are mostly in their favor. How many interstate overpass bridges are there? Most have 35 year lifespans, and most are older.
In my area (Albany, NY) the State is just wrapping up a 6 year project to retrofit a major bridge that was a sister of the I-35 bridge in Minnesota that catastrophically failed a few years ago -- before that event, it was known to be in rough shape and nothing was done.
Also in my city, a century old storm sewer just collapsed last week, swallowing an entire street, taking out a primary water main and gas main in the process.
This sort of infrastructure is decaying all over the place, and even when not failing catastrophically, it causes other issues. For example, current standards are to separate storm sewers from sanitary (i.e. Poop) sewers. Most older areas end up overflowing storm drains into both systems, overwhelming treatment plants and dumping untreated waste. Increased sprawl and pavement mean more storm water -- so local rivers and harbors are fouled all over the country.
What has that got to do with anything? He got input from a range of sources including claimed structural engineers and correctly identified the point of failure during postensioning.
That's related, but it's not my point. Saying "decision-makers miss details in 100-page reports" makes it sound like the report is merely too thorough, and the inspectors did too good a job.
My point is the report's summary could have said "This bridge will fall down within 3 years" instead of obscuring the with vague, watered-down jargon like "structurally deficient"
Are they answering any important questions or just collecting data for data sake hoping something will be useful. Seems like this bridge was long identified as being at risk but simply never addressed. We don’t need novel techniques to make that assessment. At best they might be able to show a bridge is more at risk of failure but then what? The federal government only funds collapsed bridges so you need to collapse it or the local government will have to find it out of a non existent funding source.
I'll go out on a pretty small limb and say that the vast majority of Civil Engineering failings are not a matter of an incorrect safety factor, but are things that are explicitly not part of it.
1) Blunders. (Many places. You do the math wrong, or approve the wrong shop drawing, and no factor of safety is going to save you). (See the Hyatt Regency Walkway Failure)
2) Inadequate Geotech Info. (Basically every dam failure ever)
3) Genuinely new behavior. (Tacoma Narrows)
4) Contractors. (I-90 Bridge Sinking)
5) Deferred Maintenance. (Fatigue on bridges, Minneapolis)
"Professional engineers" in USA should make sure that structures are built well enough to be safely used by the public. They have no business weighing in on the sorts of issues addressed by Strong Towns. The fact that they have done so in the past is proof of this, because streets and roads in USA are organized very poorly when compared to those in similar nations.
I'm sure that there are organizations that will mess up if you give them enough rope. But that says nothing about the overpass itself and 'doesn't fall apart immediately' is not a standard that any civil engineer will want to be associated with, at least, not in the developed world and likely not in the third world either (but there due to resource constraints and corruption there may be a difference between what should have been done and what was actually done).
> stakeholders wanted an over-the-top bridge design [...]
Nothing wrong with that!
> They were so focused on building a nice looking bridge — and meeting deadlines
These are also good things.
To me sounds like the civil engineers started behaving more like software engineers. The independent peer reviewer they hired was not qualified to do the review.
> Louis Berger was not qualified by the Florida Department of Transportation to conduct an independent peer review and failed to perform an adequate review of the FIGG Bridge Engineers design plans and to recognize the significant under-design of the steel reinforcement within the 11/12 node, which was unable to resist the horizontal shear between diagonal 11 and the bridge deck.
This whole business of the engineers ignoring the cracks that the contractors kept needing reassurance about is also insane.
I have never expressed that opinion to any of them. I have a personal rule, which I'll break now because I am quite curious: why is a crappy old dangerous bridge better than a new safe bridge?
> Anyone can tell you about a bad bridge after it has failed. But it would take a bridge engineer to tell you that before it fails.
Right, especially since bridge engineers don't produce bridges, but rather produce designs for bridges, the quality of which can only be judged by other bridge engineers.
>We don't say "perfection is impossible" when it comes to bridges collapsing.
Yes we do. People on the internet might not but look at the formal documentation that goes with any bridge plans. It will talk about factors of safety, various loads, environmental conditions and establish a set of constraints outside of which the bridge is not expected to perform as advertised.
>speed traders are dealing with million-dollar stakes and a single mistake can make the news
It's really easy to put HFT a pedestal when you can't inspect it up close but I assure you that for every Citadel and P72 there is half a dozen firms with sloppy software that goes absolutely crazy if non-ideal but foreseeable things happen. These people are making money hand over fist (kind of) by building to the minimum. There's one firm I want to name because of how much everything they have is held together with duct tape but they're nice guys so I won't.
You should rethink that whenever you drive under a bridge or get on a boat. The reason they collapse or sink so infrequently is largely because engineers are accredited and held responsible.
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