Shotpins in Special Moment Frame Beam Protected Zone 1

[nampar]

Hi,
I am currently working on a project where the contractor has mistakenly punched about 6 shot-pins in the bottom flange of an existing SMF beam within the protected zone. It is a Wuf-w connection. This SMF must have been installed a few years back and we do not have calcs or dwgs for the same. Can anybody provide guidance on how to approach this?

 

[driftLimiter]

Yes. We have specced out 0.157" dia. PAF in protected zones and cited this reference: Eatherton, M., Toellner, B., Watkins, C., and Abbas, E., (2014). “The Effect of Powder Actuated Fasteners on the Seismic Performance of Protected Zones in Steel Moment Frames”, Virginia Tech SEM Report Series, Report No. CE/VPI-ST-13/05.

As note, I haven't read this myself, there are some limitations of course that you will want to understand.

 

[dold]

Seems sketchy to be honest. The protected zones really aren't that big so its not too hard to avoid fasteners in that area. I'm assuming DL is talking about shooting in a track or clip for metal studs to a beam flange or a brace?

Either way, the whole idea is that a defect in the protected zone may serve as an initiation point for a fracture in the beam (or brace or gusset or whatever), which would ruin the whole system since this is the location that plastic hinges form.

I could buy off on it if it's just a small building or some other "low risk" structure where the frame is already way stronger than it needs to be, and it probably won't ever go plastic. But I'd definitely have reservations if this were a large multi-story building.

**also haven't read DL's paper.**

 

[sandman21]

You are permitted to attach decking with shot pin in the protected zone up to a maximum of 0.18"Ø. AISC 341 I2.1d. The section prohibits the use for other applications such as tracks etc. The section also allows for the EOR to approve other attachments referencing D1.3. driftLimiter is pointing out the research behind the limits in Chapter I and a potential path for acceptance of the shot pins.

 

[nampar]

Thank you all for your inputs. I will use your suggestions as a means to try justify that the shot-pins penetrations do little impact/alter the structural intent i.e. hinging at the face of column.