Bridge Rivets/Bolts for Historic Structure
Bridge Rivets/Bolts for Historic Structure
(OP)
I have a historic bridge where rivets that are to be replaced. New bolt heads are required to have the appearance of the existing rivets(on both ends of the bolt). Historic Commission has input. I've been looking for TC bolts that would look like this. Anyone have any experience with this kind of bolt? Does it exist? I called LeJeune - no luck!
Thanks.
Thanks.






RE: Bridge Rivets/Bolts for Historic Structure
I don't see how it could exist. If your bolt head is just a button, then in order to tension the bolt you would need to twist it from the end of the bolt shaft, and that means a hex nut and a grippable spline on the end of the bolt shaft, going all the way through the nut. The closest you could come to capping the ends of the bolt would be making sure the shaft extends several threads beyond the nut, and then putting on some kind of cosmetic cap but (a) I don't know that you could get those on tight enough to be sure they wouldn't fall off, possibly creating a hazard to those below, not to mention a maintenance issue because you'd (presumably) leave unpainted steel where they came off (b) it still wouldn't look like a rivet, just a rounded cap on top of a hex nut. Unless someone sells some kind of cosmetic cap big enough to go all the way over the hex nut, but that would be really big and still not look like a rivet, and I'd still have my doubts about permanent attachment.
The historical society is going to have to compromise, or else find a modern-day riveting crew. (I hear Mass Highway uses them sometimes.) But good luck finding the AASHTO specs on design of riveted connections.
Hg
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RE: Bridge Rivets/Bolts for Historic Structure
you could use a conventional (hex) bolt head and nut with a plastic hemi-spherical cover.
this has been asked before ...
RE: Bridge Rivets/Bolts for Historic Structure
Alternate: "i guess you could make a bolt with a conventional external thread and add a stem onto a nut with an internal thread and have allen key sockets in both of them, with a plastic cover to add on after installation."
Try that, but make the "bolt" round-headed. Only two sides of the "round" bolt head are ground parallel across their midpoints. Thus a wrench can grip the two "almost flat" parallel sides, but the majority of the head looks round: the top is rounded and the other two ends of the bolt are round.
For the nut: It will need a two-sided "round" head like the bolt, and an internally threaded shaft that goes into the old rivet hole. Thus, you can tighten the bolt into the internally threaded part of the shaft, but have no exposed thread poking out of the end of the "round-headed nut".
RE: Bridge Rivets/Bolts for Historic Structure
I'm thinking the nut would look like the button end of a rivet, except it would have a hole in it for the bolt to thread - these would be TC twist-off type bolts, so the bolt end would shear off with the use of a Shear Wrench, perhaps leaving a flat face aligning with button bolt end/hole.
RE: Bridge Rivets/Bolts for Historic Structure
http://w
How big a shank do you need?
Mike Halloran
Pembroke Pines, FL, USA
RE: Bridge Rivets/Bolts for Historic Structure
(though beware that last comment in there about countersinking; that opens another can of worms)
2. I don't see how you can have a round nut. How do you turn it (or keep it still while the bolt turns, same thing)?
3. Huck bolt doesn't help with the nut side, as far as I can tell.
Hg
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RE: Bridge Rivets/Bolts for Historic Structure
RE: Bridge Rivets/Bolts for Historic Structure
"I have a historic bridge where rivets that are to be replaced. New bolt heads are required to have the appearance of the existing rivets(on both ends of the bolt). Historic Commission has input. I've been looking for TC bolts that would look like this. Anyone have any experience with this kind of bolt? Does it exist?"
2006 thread:
"I have an historic bridge where select rivets are to be replaced with high strength bolts. New bolt heads are required to have the appearance of the existing rivets (on both ends of the bolt). Anyone have any experience with this kind of bolt? Does it exist?"
Eerie.
Hg
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RE: Bridge Rivets/Bolts for Historic Structure
TobyT's profile shows that they haven't posted anything in a few years but still log in. Maybe they're reading this?
Hg
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RE: Bridge Rivets/Bolts for Historic Structure
You might be able to talk Huck into making a barrel of custom collars and a custom swaging die to form them into a more nearly rivet-like shape.
I agree, though, that you can't responsibly use a fully 'faux' solution; it still needs to be engineered to be as strong as a rivet, and to provide equivalent clamp load. I assume there's nothing in the budget for actually engineering the faux rivets, which leaves just the one choice; actual rivets.
Mike Halloran
Pembroke Pines, FL, USA
RE: Bridge Rivets/Bolts for Historic Structure
"2. I don't see how you can have a round nut. How do you turn it (or keep it still while the bolt turns, same thing)?
3. Huck bolt doesn't help with the nut side, as far as I can tell.
Hg"
No. That's why I said take a "round" (hemisperical) bolt head and grind flat two sides: Grind off about a 1/4 off each side and you a barely noticable "flat" on two sides that can be gripped by a wrench. If you make a specialized "wrench" you can even tolerate a slightly "sloped" side of the hemispere that won't slip too much if you push in towards the surface while turning, or holding, the nut and bolt.
RE: Bridge Rivets/Bolts for Historic Structure
Mike Halloran
Pembroke Pines, FL, USA
RE: Bridge Rivets/Bolts for Historic Structure
They are neat, weather-resistant, quite positive in locking and come in a good range of sizes."
RE: Bridge Rivets/Bolts for Historic Structure
Regards
Pat
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RE: Bridge Rivets/Bolts for Historic Structure
Cybo
RE: Bridge Rivets/Bolts for Historic Structure
A bit of putty and a dab of paint could make a hex nut look like a rounded one. Just a thought.