CA for PEMB
CA for PEMB
(OP)
Our firm is designing the foundation for a new PEMB. The Architect has asked us to provide CA phase services including reviewing shop drawings and observing steel erection for the PEMB. Is this typical? Or would an Engineer from the PEMB shop perform those tasks?






RE: CA for PEMB
RE: CA for PEMB
Most buildings did not have any engineering oversight. Maybe about 20% had a structural engineer visit the site a few times during construction.
These buildings go up so quick that there aren't many site visits.
On one project, we had the wrong bolts (not enough exposed thread past the nut) delivered and the engineer caught it immediately when very few had been used. It saved us a lot of time on the construction side and it may never have been caught if the engineer wasn't there.
I think a couple of site visits by an engineer is a good thing for the contractor and the owner. You just have to be careful with the liability issue and be specific with the scope.
RE: CA for PEMB
I'd say, in general, if you're the Engineer of Record on a project you should be glad to be paid for as much construction involvement as possible, Review the language with your lawyer and keep an eye on things.
RE: CA for PEMB
I have never seen a PEMB supplier do anything at the site.
RE: CA for PEMB
RE: CA for PEMB
One of the beauties of the PEMB world is that they are intended to go together without any field welding requirements. Yes, I know there is the occasional weld to be made, but the basic structure is 100% field bolted. The manufacturers typically specify turn-of-the-nut method for pretensioned bolts. Keep in mind that the erector is not normally directly associated with the manufacturer so what they do or don't do in terms of inspections of bolt tensioning in the field is not the fault of the manufacturer. For shop welding, all members of the MBMA (Metal Building Manufacturers Association) have IAS AC472 accreditation. Just like the various AISC fabricator programs, this accreditation replaces per project special inspections in the plant per IBC 1704.2.5.2 (2012 ref).
The manufacturer is typically a vendor to either the GC or the structural steel subcontractor. The way the codes read, special inspections are usually intended to be performed by the owner's representative. This is not the manufacturer, and would present a conflict of interest if the manufacturer did it given who their contract is with. That said, the major manufacturers have erection consultants available for larger structures to insure that the erector understands how the parts need to go together and answer nuances about the particular part arrangements. It is in the manufacturer's best interest that the buildings are erected properly and competently and that they are structurally sound upon completion. An unhappy owner is going to look elsewhere the next time they need a building.
RE: CA for PEMB
It would be nice for the PEMB providers, as an industry, to acknowledge that Special Inspection and other code mandated requirements, do exist even for them. If they would indicate, as part of their design, that someone needs to witness bolt tightening, welding, etc. so that it's not a mystery during assembly, that would be a start.
RE: CA for PEMB
As for turn-of-nut method, those should be clearly marked. If not, I assume they have not been done. I prefer to have bolt tensioning observed by me or by an independent testing lab.
Keep in mind that many erectors use the electrical conductivity method of quality control...if it touches, it is properly connected.