https://www.bbc.com/news/articles/cqxjn3w9228o.amp
This photo suggests that the bridge consisted of three steel truss sections supported on abutments at the ends and two piers on the river bed. It looks to me like one of the two piers collapsed, probably undercut by scour exacerbated by the...
The big question here isn't whether they could successfully use a Vierendeel moment frame for one of the bays. Clearly they could, if they used enough steel to react the vastly increased bending moments in the chords and also keep deflection to an acceptable degree. And I don't think at this...
Just eyeballing it, I bet 4x4 fence posts with double-beveled ends, two each wedged into the open bays, would have had enough column strength to keep that mess in the air while they got their shit together.
Human909 your analysis appears to be a bit off. According to the photos, the omitted diagonal is in the second fully rectangular bay from each end, not in the third as your diagram shows. So you have underestimated the shear in the bay with the omitted diagonal.
Yeah, good question. My suspicion is that they wanted those clear spaces for services like HVAC ducting. And again, if they'd run them through the inboard two bays of the truss where the shear is negligible, the bending stiffness of the chords alone probably would have reacted what little shear...
Those missing diagonals probably converted the girders from structures into mechanisms. If they'd have put them in the middle where the shear is lowest, they probably would have gotten away with it.
https://www.news4jax.com/news/local/2023/09/12/part-of-parking-garage-collapses-at-ascension-st-vincents-riverside-hospital/
Best Reddit comment:
"Florida and shitty concrete work. Name a more iconic duo"
Tensile strength for raw carbon fiber of reasonable quality generally runs up to about 400ksi. When combined with a resin to form a composite, the tensile strength is of course reduced by the resin's contribution to the cross-sectional area.
The compressive strength of carbon fiber composites...
As reported in Composites World:
The operant part of that snippet is the direct quote from Mr. Spencer. It seems odd to me that they were given an OD not an ID to design to, but that's what's in the article. I have to assume that at least the direct quote is accurate.
Except, of course, the fact that according to design tools developed and used by folks who actually make DSVs, they used less than half as much carbon fiber as they ought for the specified parameters and safety factor. As discussed earlier (might be in Part 1), according to the CET tool, for a...
There are common techniques we use to reduce voids and entrapped air when joining assemblies with bonding paste. I was surprised to see in the video that they didn't do any such thing.
Just curious, what are typical bearing strengths for engineered epoxies like the Hysol EA9xxx series? In theory the bearing stresses at the interface between the Ti ring and the carbon barrel should be around 20ksi.
Except maybe the Advanced Unmanned Search System (AUSS) deep sea sub hull?
Huh. Sounds kinda familiar.
https://irp.fas.org/program/collect/auss.htm
Edit add: I'm guessing that this is the technical paper that Spencer used as the starting point for their hull design...
On bonding the titanium to the carbon, I sure would have wanted to see a lot more squeeze-out in that joint, as evidence of full coverage. Also, I rather wonder about the fiber orientations in their layup schedule. All they showed in the video was circumferential windings. That's all well and...
