Bridge Rivets 1

[TobyT]

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?

Thanks.

 

[UcfSE]

What do the rivets look like? F1852 twist-off tension-control bolts have a domed head but still require a hex nut. They are equivalent to A325 in strength.

 

[SlideRuleEra]

Try contacting a company such as Portland Bolt, they should be able to custom manufacture something similar to your requirements. Here is a link that may be of help

http://www.portlandbolt.com/products/bolts/custom_heading.html

http://www.SlideRuleEra.net

 

[HgTX]

A custom-headed bolt won't help you with the nut. I suppose a cap nut would be a little more rivet-like but (a) not really (b) I don't think structural fasteners come in cap nut form.

The only thing that will look like a rivet on BOTH sides of the connection is...a rivet.

I don't recommend trying to find a modern-day riveting crew.

So get an F 1852 button-head bolt and put the head toward the more visible side of the connection. Historic bridges all over the country have had rivets replaced with bolts, and the travelling public has not been injured in any way by the appearance of hexagonal nuts on one side of the connection.

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[rb1957]

if you start thinking that you could use a regular hex nut, and put a plastic dome over it (to look like a rivet); pretty quickly you end up with a standard hex bolt with a plastic dome over both the head and the nut.

 

[HgTX]

You will end up with really big plastic domes that will eventually fall off anyway.

For a 7/8" bolt or nut, distance across the flats is 1[ ]7/16". That's 1.66" tip to tip. Nut height is 55/64". Doing a little hand sketch of what seems to be an appropriately proportioned dome, I think you'd need to add another 3/4" to the radius of the dome, which brings you up above 3 inches in diameter.

Repeating the exercise for a 1/2" bolt (7/8" head, 31/64 nut height)...I get a dome about 2" across.

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[dimjim]

I cannot believe that a nut and bolt combination
like you are speaking of would have the strength
of the original rivets. Regular bolts and nuts
would of course and I think they tighten them
to yield. That used to be the practice. I do not
think you could do it with a thin nut head.
How do you drive such parts if the nut head does
not have a slot phillips or hex head or whatever
to restrain or tighten the parts.

 

[HgTX]

ASTM F 1852 twist-off type tension control bolt is a structural bolt that is available with a button head. There is a spline on the end of the bolt that is gripped by a tool that has both an inner socket (for the spline) and an outer socket (for the nut). Instead of turn-of-the nut, the spline twists off at a particular torque (which means that it is very important to maintain the as-manufactured condition of the bolt lubrication). When properly installed, they function just as well as ASTM A 325 bolts.

Hg

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[rb1957]

sort of like Hi-Lok fasteners (from Hi-Shear)

 

[HgTX]

LeJeune is probably the best known twist-off bolt, to the point that I've seen "lejeune" used as a generic term for this type of bolt.

Hg

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[DRC1]

We have done a lot of retro fitting where he have used standard 325 hex head bolts to replace rivets. Until you get close, you really don't notice and 95% of the public probably would not care.

 

[ozbridge]

if you want to go down the plastic cap line, chase up 'radolid'

http://www.apsonline.com/radolid.html

They are neat, weather-resistant, quite positive in locking and come in a good range of sizes.
Huck bolts have been used to give a good rivet-like appearance on one side. Other side apppearance is somewhere between bolt and rivet

 

[HgTX]

Huck bolts may or may not meet ASTM A 325 physical requirements or be acceptable for use in slip-critical connections. And AASHTO design criteria for edge distance, etc. will not be quite right.

Hg

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[ozbridge]

If you are replacing rivets with huck bolts (or other A325 bolts) you are stuck with the existing hole locations and if some code criteria are not satisfied 100% you have to be a bit pragmatic especially when you remember that the clamping force in a fully tightened A325 (or equivalent) is a lot higher than in a rivet.

 

[HgTX]

Do Huck bolts come in A 325 varieties--not just the properties of the steel but also the slip properties of the connection?

Because otherwise, my point is that you can't just do a standard AASHTO analysis of the connection and assume that's what you have.

Hg

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[ozbridge]

suggest you talk to Huck for details and clarification but there are Huck fasteners considered by various codes to be equivalent to "high strength friction grip bolts" in both properties and application.

also, one should realise that the sole function of a large portion of rivets is to stitch sections together so tightly that rust penetration is minimised

 

[evelrod]

Hg, from an old Texan that is old enough to have installed rivets first hand...The current trend in retrofit is the TC bolts to replace the bad rivets or, as is most common, to up date an existing bridge with additional structure. The last "real rivet crew" I came in contact with was out of Ironworker Local 433 in the mid 1980's...sadly, most are dead. Stick with the 'lejeune' and stear clear of the Huckbolts...I have some experience with them in smaller dia and, I doubt they would be viable on a RR bridge.
FYI, noise restrictions in Socal have made the TC fastener system viable and cost effective. I have no personal experience with A490 in the TC, but I am told they are now in use.

Rod

 

[HgTX]

ASTM F 1852 is the TC equivalent to A 325
ASTM F 2280 is the brand shiny new (April 2006) TC equivalent to A 490.

Hg


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[cage]

If you do end up going with custom bolts, you could reduce the required head and nut size by coutersinking them both, if the existing steel thicknesses will allow.