Piece marks.

[SteelPE]

I visited a job recently where the fabricator etched the piece marks into the steel members. I didnt really think too much of it until I realized that they etched into the bracing members. Now, I would say the etch was 1/16 of an in of less, and the machine they use is very popular. Is it normal for a fabricator to mark the steel in this manner? Seems like they could run into a problem real fast.

 

[jayrod12]

Around here, it's a paint stick.

 

[Lomarandil]

We get a mix of paint/marker and etching or laser patterning depending on the shop.

Unless you're talking about very thin members, very high strength steel or fatigue/fracture concerns, I wouldn't worry about it.

 

[BUGGAR]

In ASTM A6 or somewhere like that, there is an allowance for a manufacturer to roll or otherwise mark their trade names in rolled steel products. Old engineers usually have a chunk of S-beam on their desk with "Carnegie" rolled in the web. Whether intended or not, fabricators use fancy machines now to mark their products for erection.
Good point though. Time to study field damage relative to notch toughness in seismic elements.

 

[SteelPE]

Attached is a picture I took of the mark while onsite:

 

[KootK]

This is surely not an example of it but I wonder how such a piece mark would play with the "protected zone" seismic provisions.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[andriver]

We have some sort of stamper that is used by hand. The result is the same though, a slight decrease in wall thickness. I am in the OG industry so our members tend to be oversized and quite thick. Still though, it's not as if its along the entire length of the member, and if 1/16th wall thickness is a concern,\ you are designing to essentially a 1.0 unity.

 

[SteelPE]

I know it wouldn't be allowed in the protected zone. This is a single story building designed using R=3 so I am not concerned. However, this is a client who received a new machine recently and I would like to make sure (for myself and for the client) they are doing it right. Also, how it he fabricator to know if a member is designed to unity or not..... or should they really care, they are just there to fabricate the steel.

 

[BUGGAR]

AISC has a fabricator certification program. What do they say?

 

[MikeHalloran]

That mark seems quite large, and looks like it's about half as deep as the corner radius of the HSS, which implies a significant reduction in wall thickness. It also appears to have sharp-ish corners at the bottom of the impression, where the cavity is not filled with melted steel or goobers.

It seems like overkill to me, especially given that a nearby crayon mark, presumably carrying the same information, is still visible.

I.e., if they let the laser travel a little more slowly, or bumped up the power, the marking would pierce the wall, which is probably not a good idea. ... and you should not mention the capability to an architect, or all your future members will look like swiss cheese and you will have to deal with liberally slotted members in your analysis.





Mike Halloran
Pembroke Pines, FL, USA