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FIU had grand plans for 'signature' bridge. But the design had a key mistake

miamiherald.com

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Re: FIU had grand plans for 'signature' bridge. But the design had a key mistake

#131

Post by carapace »

LyndsySimon wrote: post #68
carapace wrote: post #53

Earlier quoted context omitted.

I think part of the problem with software is that it's effectively invisible to most people. Most of our software would look like Rube Goldberg Machines if we somehow made it physically manifest, and a lot of the problems would then be pretty obvious even to the proverbial untrained eye.

> Most of our software would look like Rube Goldberg Machines if we somehow made it physically manifest Now this is an interesting idea. I wonder if one write a static analysis tool that output a printable 3D model...

Hmm! Maybe print out layer: ASM on the bottom, and above it the C code structures (or whatever language.)

If you included all the software that ran just to service a key press, the OS, drivers, etc...

Thinking about it, I do believe that would be an ugly machine.

Re: FIU had grand plans for 'signature' bridge. But the design had a key mistake

#132

Post by sizzle »

beachy wrote: post #3

> But FIU's bridge was designed to mimic the dramatic look of a cable-stayed bridge, where the deck is suspended from cables fanning out from a tall mast. In FIGG's design, though, the "cables" — actually metal pipes — were mostly just for show. The diagonal, v-shaped struts of the truss did the structural work. I've always found it useful to hone in on anything that is done purely for aesthetic reasons. We build a h…

Your post reminded me of the fakery going on in Mcmansions.

http://mcmansionhell.com/

Re: FIU had grand plans for 'signature' bridge. But the design had a key mistake

#133

Post by Paperweight »

21 wrote: post #54
peterwwillis wrote: post #25

So many concrete bridges fail for so many reasons, it's kind of crazy that we keep building them. It's much easier to inspect and repair steel than concrete, and it fails more gracefully. Also, I'm not even an engineer and I can tell you that uneven strut design would give you uneven loading on the span. Christ. Why didn't they just build a damn cable stayed bridge?! If traffic was a concern, they could have built it…

> I can tell you that uneven strut design would give you uneven loading on the span A structural engineer is quoted in the article that this uneven strut design would have worked if if that end beam was more solid.

It still bugs me. Yeah, that part would work, at least until it got loaded weird by high winds or by being hit by a truck or something.

They were very unconventional in this design (new type of concrete, single row of struts, prefabricated construction, concrete instead of steel, uneven struts, computer-only analysis instead of civil engineering 101 static analysis) that it demanded extreme care.

Conventional bridge design patterns are robust as in they still work when they're old, under unexpected loads, analyzed by below-average engineers, or built with less-than-perfect materials. Deviating from them demands extra extra care, or people die. :/

Re: FIU had grand plans for 'signature' bridge. But the design had a key mistake

#134

Post by dsfyu404ed »

3pt14159 wrote: post #125
abduhl wrote: post #96

Earlier quoted context omitted.

I'm unaware of any liability that can be picked up through rendering an opinion on a design. I have participated in forensic engineering / expert witness cases in geostructural matters. In fact, the opinion of an engineer as an "expert witness" is often codified in law as retaining no liability. Asking questions and drawing conclusions is not something that presents any risks besides you being possibly proven wrong l…

I used to be a structural engineer in Canada (EIT, left before getting PENG) and one of the projects I was involved with was analyzing a collapsed building to determine fault. Being an expert witness is completely different than being an engineer talking to the public. Generally speaking an engineer close to the details of the project is going to know more than you. If you have concerns, you call up the engineer and…

So basically the code of ethics says you don't get caught arguing and doubting each other's work in public because it makes all engineers look bad. To me that sounds like a thin blue line, just not blue.

Re: FIU had grand plans for 'signature' bridge. But the design had a key mistake

#135

Post by jessaustin »

mcguire wrote: post #90
elefanten wrote: post #77

Earlier quoted context omitted.

Can you elaborate? This seems like a very perverse system. Why is criticism viewed to be so dangerous? As long as both the critic and the criticized are supporting their arguments with reasons and engaged in dialogue, the outcome should be net good for everyone.

On one hand, speculations during an ongoing investigation do not do anything good. Ruining someone's career without actually having all of the facts is poor form. On the other, criticising a collegue for a mistake that is only obvious in retrospect is also poor sportsmanship.

After you've dropped a bridge on dozens of occupied automobiles, your career is ruined, full stop. No one in TFA claimed that the mistakes were "only obvious in retrospect". All 4 experts independently identified strut 11 as being far too weak, after less than a weekend of study. The original engineer whose firm was paid millions of dollars should have performed the same analysis they did over the weekend, at least.

Re: FIU had grand plans for 'signature' bridge. But the design had a key mistake

#136

Post by jessaustin »

angersock wrote: post #105
tankerslay wrote: post #99

Earlier quoted context omitted.

"Scandal" should be avoided because it "degrades the trust of the public in the profession." An age-old saw trotted out to justify the cover-up of diverse kinds of negligence and malfeasance in all manner of professions the world over. It works precisely until there is a scandal too big to cover-up.

There are always degrees of uncertainty in any physical engineering project. It doesn't help anybody to have the general public being told to second-guess the work. Why do you think otherwise?

All four experts in TFA independently identified the same problematic strut, "11", after a weekend of unpaid work. That doesn't sound like "uncertainty" to me.

Re: FIU had grand plans for 'signature' bridge. But the design had a key mistake

#137

Post by oftenwrong »

jacobolus wrote: post #112
ScottBurson wrote: post #69

Earlier quoted context omitted.

Wow, I thought it seriously needed an editor to take an axe to it. I usually like long pieces, but this just seemed repetitive.

The way newspaper articles work, not every reader is expected to read the whole thing. They are structured to put critical information up front, so that a reader can stop whenever they lose interest without missing anything more important than what they already read, but include additional detail below for those who are more deeply interested. This leads to the same main points being repeated several times, which can…

It's known as the "inverted pyramid" style:

https://en.wikipedia.org/wiki/Inverted_pyramid_(journalism)

Re: FIU had grand plans for 'signature' bridge. But the design had a key mistake

#138

Post by ScottBurson »

jacobolus wrote: post #112
ScottBurson wrote: post #69

Earlier quoted context omitted.

Wow, I thought it seriously needed an editor to take an axe to it. I usually like long pieces, but this just seemed repetitive.

The way newspaper articles work, not every reader is expected to read the whole thing. They are structured to put critical information up front, so that a reader can stop whenever they lose interest without missing anything more important than what they already read, but include additional detail below for those who are more deeply interested. This leads to the same main points being repeated several times, which can…

Except it didn't seem like there was much more detail as I kept reading. That was my impression, anyway — I'm not inclined to reread it to see if I overlooked something.

Re: FIU had grand plans for 'signature' bridge. But the design had a key mistake

#139

Post by jessaustin »

21 wrote: post #52
ndespres wrote: post #19

> And in order to pull off the aesthetic, the bridge's designers had to make the diagonal supports beneath them a variety of different shapes and sizes. That complication may have led the designers to miss a crucial error, independent engineers who've examined the bridge's plans believe: One of the supports was not strong enough. They aren't joking about the "variety of different shapes and sizes" for the diagonal su…

> It's a false claim to structural integrity. That's a weird claim to make. False claim to who? Joe on the street?

Joe may be as dumb as you assume, but if he sees a truss bridge with one set of struts he might well wonder how safe that is compared to all the other truss bridges he has seen. If he sees another truss bridge with only one set of struts, but with cable stays as well, he might well think that is a safer bridge than the first. He believed the bridge's implicit claim about cable stays, which was false.
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