Early 1900's Bldg - Flat Head Rivets? 2

[anchorengineer]

Hi,
I've not come across this before but understanding early 1900's steel construction is constantly presenting something new/old to me. I've googled and found "flat head" rivets but I've only come across them for the first time on a rehab project. They are not in critical connections but I'm wondering if they should be replaced. At first I thought they were just a bad install but now I suspect that due to rivets adjacent to these, there was a clearance issue of the rivet gun, so they made the head flat. Other than the fact that they look ugly, I am wondering if they really need to be replaced. I've attached a sample photo (flat head rivets on right). Thoughts?

 

[Lomarandil]

I didn't even think that they'd be able to create a flat head by overdriving a rivet. Not with a pneumatic riveter.

 

[hokie66]

A pneumatic riveter was not used. All by hand, and the hammer was perhaps a bit overly applied in flattening the head.

 

[GeorgeTheCivilEngineer]

Agree it was likely done at construction.

If the heads are intact there's no reason to replace. Rivets wiggle their way into misaligned holes so bolts need to be drilled through, making an inferior connection.

 

[bridgebuster]

From the Carnegie Pocket Companion c1914. The same table appears in the 7th Ed. of AISC.

 

[anchorengineer]

Thanks @bridgebuster. It looks like a flat headed rivet was not necessarily a mistake.

 

[bridgebuster]

you're welcome anchorman. I've seen a lot of rivets but never flattened heads.

If you do a lot of work with riveted structures you might find the attached drawing helpful. It's criteria for rivet replacement. I don't know the origin of the drawing - and neither does anyone in my age - but it's been around before I started working in the late 70's. Slightly different versions show up occasionally in NYSDOT bridge rehab projects. This is the version I used recently; I tweaked some of the text about 10 years ago. What's interesting is that I came across a study on rivet by USACOE a few years ago and their results correlated closely to the numbers shown.

 

[anchorengineer]

Thanks again @bridgebuster!

 

[bridgebuster]

You're welcome anchorengineer