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Can you explain the difference some more? I think of a bolt as a pin with threads, that gets secured with a nut on the other end. A pin has no thread and gets secured by putting another piece through a hole in the end of it.

So they have different failure modes (a bolt can get its thread stripped, or vibrate the nut off) but otherwise can be used interchangeably. What's the structural difference you are referring to?



Bolts are (generally?) intended to apply force between two surfaces and not themselves act as shear resistance.

Whereas a pin is (generally?) entirely a shear-force resistance component.


Right. Bolts are usually weak in shear but strong in tension.Their job is to create high friction between two pieces; that friction joins the two pieces as one.


See this diagram: https://static.seattletimes.com/wp-content/uploads/2019/05/c...

I believe the metal sleeves that the bolts go into are the pins.

Edit: I probably shouldn't have said "sleeves". That has more than one meaning in this context. I'm talking about hollow pins, secured by bolts when I say "sleeves".


Wait... isn't that exactly what londons_explore says is wrong, and essentially the source of confusion in the first place?


I think it's right. He seemed to be describing hollow pins with threaded holes. The pins hold the sections together, the bolts screw into, and steady the pins.


Correct. What I said only applies to this particular use of bolts to hold pins in place, which in turn hold the truss together.


Watch this video for a good breakdown of what people think happened: https://www.youtube.com/watch?v=cexN2-T6dxY&feature=youtu.be he has a followup video with additional pictures sent in from the scene that seems to corroborate his thoughts




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