Rivetted building truss design

[OldBldgGuy]

Maybe this should be in the fastener forum, but has anyone designed rivetted steel trusses for a small building? I have a client who wants to build a new building that looks like it was built in 1920; steel scissor trusses with all joints rivetted and wood T&G decking. I've worked on plenty of buildings like he's describing (coincidentally a 1928 one right at the present time), but I've not actually designed the trusses. The double angle chords are easy enough, and I can make assumptions about mild steel pins for connections but is anyone actually making rivets and is there data on them? The span is only about 36'. I told the client he has to find the fabricator if I do the design.

 

[JStephen]

Good question.
I see at least one source for steel rivets up to 1" size:

http://www.hansonrivet.com/rivets/solid-rivets/commercial-solid-rivets/

If all the riveting is shop-done, you might just ask this supplier who actually buys big steel rivets from them.
You can probably get design data from the older AISC books- I assume rivets were included about one edition after they had pretty well stopped using them.

One thing I would suggest is to make them the trusses just like you're thinking, only with high strength bolts in place of rivets. I don't know that the average non-engineer would really know the difference.

 

[OldBldgGuy]

Thanks for the link, that looks like a possibility as long as he can find someone to actually rivet them. The client absolutely wants the rivets for appearance, that's his whole point, so I can't use bolts. Believe me, he knows what he wants.

 

[thaidavid40]

How about using round-head tension control bolts, with acorn caps on the nut side? From 20 feet away, those would look a lot like rivets.
Dave

Thaidavid

 

[hokie66]

You could try this company.

http://www.hansenind.com/riveting/

 

[JAE]

Use all welded connections - then glue on rivet heads to make it look good!

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[dhengr]

OldBldgGuy:
I think JAE’s idea is the best. I suspect you will have trouble finding anyone who knows how to or wants to make riveted trusses, for all the trouble involved and special equipment needed. Weld them up, the weld isn’t all that obvious to the layman. Then find someone who will make round rivet heads with some small dia. tits on the underside and spot weld them in place for the cosmetics. Again, the layman will not know the difference, use six rivets at a few locations and 3 or 4 rivets at others, and be done with it. This rivet welding might be something akin to shear stud welding with less amperage, just to spot weld the tits to the base metal. The client wants it and he can pay for it.

As an aside, when I started at fabricators shop in the early 70's we had a whole wall in the shop that was lined with furnaces/ovens for heating rivets and round rods for heading bolts. We still had all the tools, and a few guys who knew how to do it, but we weren’t riveting anything any longer. The few times we had to fix a riveted joint we heated the rivet with an acetylene torch and drove and bucked it by hand.

 

[OldBldgGuy]

I'd thought about welded joints & tacked-on rivets as JAE & dhengr suggest, & that is probably the way to go, bit I think I'll first have to talk to the company hokie66 found. They're not that far away, I'm on the opposite end of Lake Erie from them and the project is on the west end of Lake Ontario.

I've done a fair bit of restoration work and designed another new "old" building for this client & he's more than a little anal about details, but I'll see if this will fly. He sees and rejects things that government employees on museum projects would accept, & he's using his own money while they're using ours, so I'm not complaining. It is nice to have a client with both the passion and the budget; usually the ones with the passion have no budget.
Thanks for all of the input.

 

[dik]

You need to take coupons to see if the steel is weldable.

Dik