To be fair, thousands of things are designed every day that are more the sufficient based on standards. It's like anything in life. No one is perfect.
Plus, we don't know if it was a design flaw.
Pedestrian bridge collapses at FIU
- Thread starter Cyclones_R_GR8
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To be fair, thousands of things are designed every day that are more the sufficient based on standards. It's like anything in life. No one is perfect.
Plus, we don't know if it was a design flaw.
That's what I thought when I heard it was designed/built whatever by the school. That has to be a black eye for the program.
Is there an update on the number of people hurt yet?
BBC News is saying 8 cars were trapped under the bridge. At least 10 people were hospitalized. 4 deceased.
https://www.yahoo.com/news/fallen-bridge-victims-found-officials-seek-answers-024716081.html
This article states that the bridge was in fact undergoing a stress test at the time. With an open multi-lane road underneath it.
FIU didn't design or build the bridge. Figg Engineering was the designer, and MCM was the contractor.
FIU's involvement was purely related to the Accelerated Bridge Construction (ABC) aspect of the bridge (the main span was built off on the side, and moved it into place as one big piece). The university has been a big proponent of ABC for many years.
Judging by what this article says "stress test" seems to be misused. It sounds like the bridge was post-tensioned. That is a common design technique where steel strands run through a structure and are tightened ("stressed") to give a structure added capacity/strength. From that article they say the strands had loosened (no mention if it was expected or not). Based on my experience, they were probably re-tensioning the cables to their design loads.
This article gives the impression they were somehow load testing the bridge above live traffic. That's unlikely, but not impossible to have occurred, and would go far beyond accepted practice.
FIU would never have designed or built the bridge. A university would never accept that kind of liability. FIU is the leading research institution into accelerated bridge construction (ABC). It's very likely FIU professors/staff were involved in the design development and construction planning, but FIGG would be the final engineering stamp for approval. Thus, FIGG and the Contractor carry liability. I'd be shocked if the university exposed itself through design or construction risk.
I also want to point out to those who are decrying "pushing the limits" or "going on the cheap." If these are big issues for you, you can contact your legislators about more infrastructure funding. It's a huge issue that doesn't get as much coverage as it should.
For those who live in Iowa, your state has one of the highest percentages of structurally deficient bridges relative to total inventory. The latest report out stated that 20.9% of the bridges in Iowa are structurally deficient (5,067 out of 24,215). The good news is Iowa just passed the $0.10 gas tax and now the DOT has a bunch more funding to use to improve the safety of bridges across the state.
If a story like this upsets you or brings this issue to the front of your mind, reach out to your legislators and let them know you don't want this happening in your state. It may not have prevented anything in this case, but it does highlight the need to improve our infrastructure across the board.
Yeah, they definitely don't quite have the technical details correct. They say the "cables that supsend the bridge" were being tightened, but later go on to say the main tower hadn't been constructed yet. Kind of hard to install cables without a tower to connect them to. They must have been adjusting the post-tensioning within the structure; not the main cables.
My guess is either the PT relaxed during roll-in or they were not required to be fully stressed until the bridge was in it's place. It wouldn't be unacceptable or out of the realm of standard practice to tension a bridge over live traffic. I'm really interested to hear what happened. I'm still surprised the thing failed with basically no load on yet aside from self-weight.
CBS News is running a piece about safety violations committed by Figg & MCM:
But just 10 days ago, the company was sued in South Florida by a TSA employee who was hurt at the Fort Lauderdale airport. The employee's lawyer alleges that a makeshift bridge MCM built for workers to use while the company does construction at the airport broke under his weight.
As for FIGG, a 90-ton portion of a bridge the company was assembling in Virginia in June 2012 fell apart while under construction. The Virginian Pilot reports four workers were hurt and that state regulators fined FIGG $28,000 for safety violations saying it was "pure luck no one was killed."
https://www.cbsnews.com/news/fiu-bridge-collapse-florida-international-university-deaths-miami/As for FIGG, a 90-ton portion of a bridge the company was assembling in Virginia in June 2012 fell apart while under construction. The Virginian Pilot reports four workers were hurt and that state regulators fined FIGG $28,000 for safety violations saying it was "pure luck no one was killed."
Interesting to see that. FIGG is one of the premiere concrete bridge designers in the world. I wouldn't be surprised if there's someone on this board that works for them. Will be interesting to see what the impacts are on their company long-term.
This is why I hate the speculation that comes from these kinds of articles - the writers don't understand the terms they are using, the general public doesn't understand the terms either, and conclusions get jumped to.
I agree completely. I've read a few of the comments on some of the articles and, as an engineer, they are frustrating to read. It's challenging to communicate these technical issues to non-technical folks. I've seen comments about how "accelerated bridge construction" sounds like a fishy way to build a bridge. ABC is widely accepted practice in the industry. Or this issue with a "stress test," that likely is related to post-tensioning (also very common). I do not envy the folks that will have to stand in front of the cameras and explain all this.
Years ago I worked some summers building office buildings with raised concrete decks for parking. When we poured those decks we ran cable through the floor and after the concrete was cured you would stretch the cables to get the proper tension. I imagine those are the cables they are talking about. Judging by one of the pictures I would guess these are what they are talking about.
Attachments
Now you know what it's like to be in aviation and see stories on accidents/incidents. You are lucky if they even put up a picture that is similar to the aircraft involved.
Oh believe me, I can relate. I worked in the petrochem industry for years.
CycloneErik
Well-Known Member
An old officer friend of mine who went SF always used to say "I take great comfort knowing that every piece of equipment I trust my life to was built by the lowest bidder."
Aren't the lowest bidders usually lowest for a reason, and not because they discovered cheaper, more efficient ways to deliver high quality?
This is correct. Those are the ends of the post-tensioning (PT) strands. There are also some running through the roof of the structure, if you look closely. If they were tensioning the bridge at the time of collapse, you might see a tensioning jack or other apparatus in some of the pictures, though I haven't seen one yet.