Diversity Fail? All-Women Engineering Team Blamed for Collapse of Miami Pedestrian Bridge

[Frank Cannon]

Zoom in on the picture and look with your eyes.

There is rebar all over that structure poking through the broken span.

Just watch the damn thing collapse. There is no way in hell the suspended walkway had any rebar in it. What little you see in the pictures is from some other aspect of that bridge.

[Frank Cannon]

You are so right.  Please do not walk across any bridge that I have designed.

Excellent.....now go get me a beer.

[Cyber Liberty]

So I watched some of the NTSB briefing.  They have a big blow up of one of the plans with Denney Pate's seal clearly on the bottom middle of the plans.  I cannot find him listed as a Florida engineer at all, which is weird to me.

Anyway, here's another video explanation of possible reason for failure.  Lots of F-bombs so not safe for work and not family friendly.


https://www.youtube.com/watch?v=KtiTm2dKLgU

This is going to be Hell to pat for whoever signed off the engineering. 

[DB]

The only reason an all-women engineering team would be important is if they were hired based on their sex and not their ability as the order of priority. If being PC came first then that is a big deal. And there's a lot of that going around these days, particularly in government.

[thackney]

You would think that an article claiming there was an all-woman design team, saying that such a team was touted, would provide some evidence that it was an all-woman design team, and that the company touted such.

Instead, the graphics provided do no such thing.

This is the original proposal for the bridge design in 2015.
https://facilities.fiu.edu/projects/BT_904/MCM_FIGG_Proposal_for_FIU_Pedestrian_Bridge_9-30-2015.pdf

The key leaders of the engineering design team are men.

[DB]

This is going to be Hell to pat for whoever signed off the engineering.

Assuming there wasn't a construction or materials error.

[thackney]

Just watch the damn thing collapse. There is no way in hell the suspended walkway had any rebar in it. What little you see in the pictures is from some other aspect of that bridge.

And your opinion of existence of rebar from the pictures in the following post?

...

[INVAR]

I'll repeat what I am reading and watching engineers say about this design:

There was no backup for the design, no redundancy of support, only a single column of concrete trusses to hold up the bridge.  No support steel in the construction, except for the single cable they had inside the trusses.

REBAR is not a support structure for a bridge span, regardless of what some might claim. 

Tonnage of concrete was being held up only by the single length of concrete angled W trusses that held both the walkway and the cement roof overhead.  As has been repeated by numerous engineers that are commenting on everything they are seeing from the briefings and the collapse itself - the entire bridge structure was wholly dependent upon the cable inside the trusses to hold the bridge up.  The moment any one of those cables failed inside the concrete trusses, the entire bridge was going to collapse exactly as it did.

There was no steel supports or redundant steel support outside of the single cable in the trusses.  And, if you want to count rebar as a structural support - I give you the collapse of this bridge as prima facia evidence of how absurd that assertion is.

[RoosGirl]

The only reason an all-women engineering team would be important is if they were hired based on their sex and not their ability as the order of priority. If being PC came first then that is a big deal. And there's a lot of that going around these days, particularly in government.

Not true at all.  I don't agree with awarding based on make-up of the ownership of the firm or design, but I can assure you that the FBPE does not award PEs to people based on their gender.  It's based on being able to pass the test or not.

[RoosGirl]

I'll repeat what I am reading and watching engineers say about this design:

There was no backup for the design, no redundancy of support, only a single column of concrete trusses to hold up the bridge.  No support steel in the construction, except for the single cable they had inside the trusses.

REBAR is not a support structure for a bridge span, regardless of what some might claim. 

Tonnage of concrete was being held up only by the single length of concrete angled W trusses that held both the walkway and the cement roof overhead.  As has been repeated by numerous engineers that are commenting on everything they are seeing from the briefings and the collapse itself - the entire bridge structure was wholly dependent upon the cable inside the trusses to hold the bridge up.  The moment any one of those cables failed inside the concrete trusses, the entire bridge was going to collapse exactly as it did.

There was no steel supports or redundant steel support outside of the single cable in the trusses.  And, if you want to count rebar as a structural support - I give you the collapse of this bridge as prima facia evidence of how absurd that assertion is.

Looked to me, based on the typical section I saw, there were two steel support rods inside each truss.

[thackney]

The collapse starts in the span where the workers are tensioning/relieving one of the canopy tendons.

[thackney]

I'll repeat what I am reading and watching engineers say about this design:

There was no backup for the design, no redundancy of support, only a single column of concrete trusses to hold up the bridge.  No support steel in the construction, except for the single cable they had inside the trusses.

REBAR is not a support structure for a bridge span, regardless of what some might claim. 

Tonnage of concrete was being held up only by the single length of concrete angled W trusses that held both the walkway and the cement roof overhead.  As has been repeated by numerous engineers that are commenting on everything they are seeing from the briefings and the collapse itself - the entire bridge structure was wholly dependent upon the cable inside the trusses to hold the bridge up.  The moment any one of those cables failed inside the concrete trusses, the entire bridge was going to collapse exactly as it did.

There was no steel supports or redundant steel support outside of the single cable in the trusses.  And, if you want to count rebar as a structural support - I give you the collapse of this bridge as prima facia evidence of how absurd that assertion is.

I count rebar as steel and as steel reinforcement, which your previous posts said did not exist.

As has been noted by engineers that section of concrete and rebar was from the right side of the span where it rested on and was anchored to the support pillars.

I am reading the incredulity of engineers that note that there is no steel reinforcement in the span itself.  The ONLY steel they could see in the span - was the single cable that was inside of the w-shaped trusses in a single line on the inside of the span.  Even the roof covering above the footbridge was solid concrete.

...There was no backup for the design, no redundancy of support, only a single column of concrete trusses to hold up the bridge.  No steel in the construction whatsoever, except for whatever cable they had inside the trusses....

[INVAR]

! No longer available

Of interest at the end of this video - the FIU brochure states that the bridge was designed using "new and environmental-friendly materials" as we are "reinventing the web-truss" More concrete, less steel.

[Suppressed]

So I watched some of the NTSB briefing.  They have a big blow up of one of the plans with Denney Pate's seal clearly on the bottom middle of the plans.  I cannot find him listed as a Florida engineer at all, which is weird to me.

@RoosGirl

Florida Professional Engineer licence #   34332.  Licence since 1984, expires 2019. 

You can search here:  https://www.myfloridalicense.com/wl11.asp

[DB]

The collapse starts in the span where the workers are tensioning/relieving one of the canopy tendons.

Thackney, doesn't it look like the first diagonal support on the left failed in compression and not in tension?

[Bigun]

Sorry but this is a load of crap. It doesn't matter if the engineers were all women, men, or RuPaul. Tolerance specs and testing and design software are highly accurate now and fairly universal. It sounds harsh, but sometimes crap happens. In something like this, one small weakness can be catastrophic- and it is highly doubtful that the weakness had anything to do with 'diversity' or women. There are so many factors in the supply chain and construction chain for something like this, it could be a multitude of problems, and possibly none of them are due to any specific identifiable human cause.

Blaming women in general (or women of color as some articles from questionable sources imply) is as bad as blaming all gun owners for gun crime. Even if one person screwed up, it is on that one person.

@AbaraXas

Perhaps that is true and perhaps it's not.  I don't know,  but as of today I would come down on the latter.

[Suppressed]

The key leaders of the engineering design team are men.

Exactly.

[Frank Cannon]

Has anyone looked in on what the Trilateralist were up to during the collapse? This could be a Red Flag event used to distract us from what they are up to.

[thackney]

Thackney, doesn't it look like the first diagonal support on the left failed in compression and not in tension?

Yes.  I've been reading on an engineering forum where I copied those about PT#11 being detensioned after transport.  The drawing below is shown from the other side so #11 is on the left in the video.



The following exaggerates the differences from transport to placement in how the trusses work differently in each case.

[Cyber Liberty]

Assuming there wasn't a construction or materials error.

Correct.  Or somebody made a change to the design after the sign-off.

[Cyber Liberty]

Has anyone looked in on what the Trilateralist were up to during the collapse? This could be a Red Flag event used to distract us from what they are up to.

I hope Trump has an alibi.

[thackney]

Thackney, doesn't it look like the first diagonal support on the left failed in compression and not in tension?

This stop motion shows where the tendon appears to fail, or at least fail in adhesion to strut, then the other end shoot off the top.

[WingNot]

I hope Trump has an alibi.

I'm not saying it was trumps fault, but it was Trump's fault!

[thackney]

For my fellow enginerds:





1. Transverse bottom-flange PT: 4x0.6" dia, 7-wire strands, GROUTED tendons @ 2'6" spacing. These tendons were fully stressed, capped and grouted BEFORE transportation.



2. Longitudinal bottom-flange PT: 10 groups of 19x0.6" dia, 7-wire strands, GROUTED tendons typically, except T6 were 12 strand tendons. These tendons were fully stressed, capped and grouted BEFORE transportation.



3. Longitudinal top-flange (canopy) PT: 4 groups of 12x0.6" dia, 7-wire strands, GROUTED tendons typically, except C3 were 7 strand tendons, GROUTED. These tendons were fully stressed, capped and grouted BEFORE transportation.



4. Truss diagonal member axial PT: 1-3/4" PT bar (probably Grade 150 ksi), probably full-threaded. I would expect that the majority of these PT bars would have been stressed, capped and grouted BEFORE transportation EXCEPT for the temporary PT in the end diagonals.

[truth_seeker]

Assuming there wasn't a construction or materials error.

Isn't that in part, what government agencies do with plan checks, inspections, materials tests etc?