rivets in a 1926 building 4

[ronster]

I am investigating a building constructed in 1926. How do I determine the diameter of a rivet from the head size? Is there any way to verify the material, if it is A-502 grade 1 or 2 or was some other material used at that point in time?

 

[diamondjim]

You might try the old standard which was
1.75 times the diameter as a general guideline.
There really was no standard back then.
The diameter to the head would be the reciprocal
of 1.75 or .5714 times the head diameter.

 

[Qshake]

Ronster, I told you someone here would know a thing or two about rivets....

I agree with Diamondjim. Having had an opportunity to check in my old drafting book, I found that for an American Standard small rivet the diameter of the button head would be 1.75 times the shaft diameter. Also note that the height of the rivet head will also be 0.75 times the shaft diameter. This is only for the button heads and four additional types are depicted. They include flat, countersunk, pan and truss (or wagon box). Each has differing characteristics.

The book is Engineering Drawing by Thomas French, 6th Edition 1941.

 

[diamondjim]

The book I was citing from was
dated 1934, Design of Machine Elements,
by Faires. The following had 1.75 times D,
the rivet diameter: Straight Base Button Head,
Cone Head, Pan Head, Button Head, and Flat Head.
1.9 times D for Double Radius Button Head,
2.0 times D for Steeple Head,
1.7 times D for Countersunk Head.
It gives the general guideline that the dimensions
may be increased, but must not be decreased
more than ten per cent.

 

[Qshake]

Good Stuff, Jim!

 

[svc430]

According to the 1923 Edition of the “Pocket Companion”, published by the Carnegie Steel Company, the American Bridge Company Standard for structural rivets was as follows:

Diameter of full driven head = 1.5 times rivet diameter plus 1/8”.
(ie: diameter of full driven head of a 1” rivet = 1.625”)

Depth of full driven head = .425 times head diameter.
(ie: depth of full driven head of a 1” rivet = 11/16”)

Diameter of a countersunk head = 1.577 times rivet diameter.

Depth of a countersunk head = .5 times rivet diameter.

This same reference lists the ultimate tensile strength of rivet steel for buildings and bridges as 46 ksi to 56 ksi, with the yield strength (elastic limit) as one half of the tensile strength (23 to 28 ksi).

Also included in this reference was the American Bridge Company Specifications for Steel Structures (adopted 1912), which lists the following allowable stresses for rivets:

Shear on shop rivets = 12,000 psi
Shear on field rivets = 10,000 psi
Bearing pressure on shop rivets = 24,000 psi
Bearing pressure on field rivets = 20,000 psi

For comparison purposes, the former ASTM A141 rivet steel (comparable to present day A502 Grade 1), has an ultimate tensile strength of 52 to 62 ksi.

Hope this helps.

 

Another important issue here is the quality of the rivet stock itself; specifically, non-metallic inclusions. Manufacturing processing techniques employed at the turn of the century were especially prone to entrapment of slag. This slag, which is of course a necessary product of steel making, can give rise to substantially lower performance from the rivet. I am a recognized expert in fasteners and rivets and a member of the SD-7 Maritime Forensic Committee – which investigates failures such s the Titanic. An investigation of the fasteners obtained from the floor of the ocean revealed the presence of slag. Riveting practices of the time were mechanically based and hydraulic in some shipbuilding. The later provided a punched and reamed hole for the rivet to be placed. The rate of upsetting of the rivet head, combined with the temperature of the rivet at the time of upsetting can have a significant effect of the performance. I actually obtained large-scale samples and video of the demolition of a large gas storage tank that was undergoing demolition. The variation in upset shank head size, as viewed as a repeating pattern along the section being joined can be clearly seen. This seems to be the result of the heating practices employed at the time. The heater and bucker would work together to feed hot rivets in batches. Naturally the rivets formed easier when they were hotter, (flow stress vs Temperature); however, higher temperatures and incipient melting of the nonmetallic inclusions (sometimes referred to as constitutional liquation) can result in slag inclusions being oriented 90 degrees to the axis of the rivet. This significantly reduces the preload stress of the rivet, and makes it more subject to transient loading (impacts) and temperature effects because of stress concentration effects. Feel free to contact me at gerd@beckmann.com if I can be of further assistance. Also see

http://www.beckmann.com

for some photos of fasteners from a case I was involved in several years ago.