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Questions for structural steel fabricators building miscellaneous steel:
What is the commonly seen weld for doglegs on the common channel stringers used for miscellaneous steel stairs in buildings?
Do you commonly see CJP welds?
Or PJP welds?
Do you UT the splice?
AISC and AWS D1.1 would be governing codes.
thcqci
On our last set the detail showed Prequalified CJP Figure 3.4 B-U4b-GF with a grind notation on the outside faces of the channel. But I have them PJP most of the time depends on engineer and service I guess. And never have had to have them UT'd just visual.
Good Luck
Marshal
Doing mostly schools in Mexifornia. The detailer's mostly use the same lazy squire-butt weld symbol without size as thy see on the design prints. D1.1 used to call this symbol a CJP. Now I believe D1.1 says with this symbol the weld must be equal to or stronger than the strength of the base metal. So, it almost always boils down to a full penetration welds with UT.
The co. i weld for have us cjp on all splices and doglegs for stair-stringers, and we ut all cjp welds. All are prints come from a third party,so I don't know if this is a company guideline or customers either way i get paid the same low low low.
We inspect lots of C doglegs, usually CP, and UT if over 5/16" web. (California)
As a structural engineer, I typically specify PJP's because we don't (generally) need the full strength of a CJP in the dogleg portions of the stringers. This is usually not the highest stressed part of a stair stringer so if the calcs work with a PJP, that's what gets called out. I am careful to specify the effective throat required and we typically specify special (full-time) inspection so that is our quality control. Testing is visual unless something is suspect, then we have made small cuts or borings to verify effective throat and penetration. We specify welding on both sides of the joint but don't grind unless the stairs are architectural. I like to leave joint prep up to the fabricator. And we always get the WPS's for these welds (for all welds, actually) and weldors certs. This is in California also.
Strictly speaking, in AISC, stairs are considered miscellaneous metals and are not covered by the AISC Code of Standard Practice. You have to cover them in a miscellaneous metals specification. Frequently, we just specify that stairs shall be considered structural steel and subject to the Code of Standard Practice so all steel is covered in one place.
Bob G.
I just thought I would add this:
I can specify a CJP weld for a stair stringer in a couple of minutes. It takes me about 30 minutes to do the structural analysis for a PJP. So the owner pays for an "extra" half hour for me to design a PJP.
How much time (money) am I saving on the welding by going PJP - less critical joint prep, less demanding testing, less weld metal/time? I'm curious about that.
Thank you for responses.
Good questions Mr. Garner. I will ask our people for some numbers and respond.
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