81–90 of 153 posts
> At least one said that if so, it constitutes an avoidable mistake on a bridge that should never have been so complicated. >“This is not a big project," Beck said. "It’s a darn pedestrian bridge.” There is something to be said about not over-complicating designs, whether it be in actual construction or in software.
Many people said the same thing about the Eiffel Tower ...
"But they suggested that over-reliance on the computer models, a common pitfall in the profession, may have played into it." It's very easy to be seduced into assuming a computer model's results are correct. Computer models of critical bits should always be double-checked by a separate independent calculation. For this bridge, a simple analysis of static forces should have been sufficient for a cross-check, despite t…
If you did find a way to design a structure so that analysis of the static forces was not straightforward, might that be a good indication that you shouldn’t build it at all?
"But they suggested that over-reliance on the computer models, a common pitfall in the profession, may have played into it." It's very easy to be seduced into assuming a computer model's results are correct. Computer models of critical bits should always be double-checked by a separate independent calculation. For this bridge, a simple analysis of static forces should have been sufficient for a cross-check, despite t…
Static force analysis only works when the materials being modeled are well known. Titanium dioxide concrete is a novel material—and, from the article’s text and subsequent research—appears to have a narrow effective range before integrity issues appear.
Designing how those members resist/react to those loads is dependent on the material though.
It is heartrending to realize that they were given one last chance to step back from the abyss, when cracks appeared, but they pressed on regardless. If something happens that you don't understand, it's time to halt and reevaluate. It bugs me that FIGG (one of the contractors) appears to be threatening the professional licenses of the engineers who helped the Miami Herald's investigation, by suggesting that doing so…
> It bugs me that FIGG (one of the contractors) appears to be threatening the professional licenses of the engineers who helped the Miami Herald's investigation, by suggesting that doing so was unethical. As a licensed Professional Engineer, you have to be quite careful criticizing other engineers. As long as the engineer signing off met "standard practices", he is covered and saying that he is not could get you in q…
Earlier quoted context omitted.
I am ignorant as to this whole story, but out of interest, why is it a bad thing to wait for the NTSB report? Often it is good to wait for an entire report to nail down the facts before the witch hunt should begin, is there something in this case that means this isn't the best idea?
I imagine the Herald doesn't believe that the NTSB (or any authority) necessarily has the canonical and final word on things, and thus the Herald sees itself as providing an independent viewpoint/assessment. One of the undercurrent themes of this story is that, according to the herald, the construction company and FIU officials are well-connected politically. Possibly related to this is the fact that the Herald is su…
"But they suggested that over-reliance on the computer models, a common pitfall in the profession, may have played into it." It's very easy to be seduced into assuming a computer model's results are correct. Computer models of critical bits should always be double-checked by a separate independent calculation. For this bridge, a simple analysis of static forces should have been sufficient for a cross-check, despite t…
Static force analysis only works when the materials being modeled are well known. Titanium dioxide concrete is a novel material—and, from the article’s text and subsequent research—appears to have a narrow effective range before integrity issues appear.
Earlier quoted context omitted.
I am ignorant as to this whole story, but out of interest, why is it a bad thing to wait for the NTSB report? Often it is good to wait for an entire report to nail down the facts before the witch hunt should begin, is there something in this case that means this isn't the best idea?
The families of the people that were killed want to understand what happened. Delays and silence will make their suffering worse. People are often very forgiving when they know what actually happened. But being shut out of the information flow is a problem. I'm not saying we need to find the guilty and punish them, but there are people that have a real stake in finding out the story.
Earlier quoted context omitted.
It always scares me that civil engineers and other real engineers (with professional engineer certificates) rely on software built by software "engineers" who may just be some kids out of high school that picked up coding. It's an extreme scenario, yes, as I'm sure/hope the software goes through rigorous testing.
When I was growing up I lived in a small town and the city planner had mocked the entire town in the original SimCity. The ongoing joke was that he would test any proposals in that.
Earlier quoted context omitted.
It was a cable stayed bridge. The bridge span was just put up. The tower and the cables were to be installed over the next few weeks. They allowed traffic under an incomplete bridge because money.
It specifically was NOT a cable-stayed bridge. It was a non-redundant truss bridge with a tower and faux stays that contributed nothing to the structural capabilities of the bridge. The arrangement of the truss structure mimiced the stay angles purely for aesthetics, not for any other reason. The choice to use a single truss structure rather than a more traditional redundant set of trusses was due to the desire for a…
The worst case would be a marching parade, on just one side, during a hurricane.
Earlier quoted context omitted.
> It bugs me that FIGG (one of the contractors) appears to be threatening the professional licenses of the engineers who helped the Miami Herald's investigation, by suggesting that doing so was unethical. As a licensed Professional Engineer, you have to be quite careful criticizing other engineers. As long as the engineer signing off met "standard practices", he is covered and saying that he is not could get you in q…
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 the other, criticising a collegue for a mistake that is only obvious in retrospect is also poor sportsmanship.