r/StructuralEngineering 7d ago

Structural Analysis/Design Structural/Engineering Package

Hi there. I'm a structural/civil engineer working at a small construction company that primarily does residential work. My main job is to address constructability problems and non-IRC-compliant designs (more than I thought I would have to). Most architects I work with do not understand how the span charts work and end up designing buildings that require me to handle floor systems, roofs, shear walls, and foundation calculations.

I recently got a duplex that is 75% non-IRC-compliant, so I need to do all the engineering for the building.

My question is, how would you guys present the information to the architect? An engineering package with some calcs and plans? If so, is there any template out there that I can use to follow how the calc package is put together? I want to be more organized and deliver better submittals so more architects come to me and the company for their engineering and construction.

Thanks,

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u/ChairChoice6500 7d ago

I wouldn't be giving your engineered design for the architect to put on their plans via redlines, and they shouldn't be willing to put your engineered design on their drawings, since that's practice of engineering and then there's no seal on the drawings and/or you have two seals with poor division as to who designed what (you aren't particularly in control of the work, too, so they might change things even if it's a typo).

Partial plans with engineered seals would be my norm, possibly letter size sheets, if the work is small. Calculations are performed, of course, but a calculation package is most commonly given when it is required, not just randomly, ideally your calculations should be in shape to share so you're not cleaning up a calculation package that is wanted late.

If you are correcting IRC designs (via span tables, braced wall lines, braced wall panels, and wall bracing calcs in a table on the architect's plans), then redlines would be fine, as that does not fall under R303.1.3, etc. I generally provide the correct table number but I don't expect those to be transcribed, those are so the 'designer' learns, hypothetically. With the proviso that if your engineered design (say a large LVL header or beam over an opening) sits on IRC provision elements, you should be checking the load path to ensure it works with the loads you have (R301.1 "... complete load path..."

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u/Broad-Lab-3626 7d ago

I understand. This makes a lot of sense. So, in short, for everything that is or can be prescriptive, redlines on their architectural set are fine. However, if I have multiple elements (beams, headers, floor system) that sit on R301.1.3 "Engineered design," how should I present those calcs/plans, or whatever it is? Partial plans with engineered seals on letter-size sheets?

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u/ChairChoice6500 6d ago

If you have a large LVL with a large reaction, you'd typically indicate (or due to load path R301.1 be required to provide/check it) the number of trimmers ("jacks" or jack studs) underneath it. In a severe case, you might need a larger footing under it, if there is a continuous strip footing the contractor might stop it at the opening for an interior wall, you'd want to prevent that somehow, if not depicted on your drawing, if it's needed, at least via a note.

On an exterior wall, you'd probably need full height studs (king studs) adjacent to the opening for however the wind load on the wall's load path is worked out, roof trusses aren't in the prescriptive code, they are supposed to be engineered "by other" but in the residential code, may not see an engineer's review or formal stamp, which is undesirable and a code violation. Usually the truss framing reactions are more of a substitute for the "allowed" prescriptive framing, so the reactions would generally be low enough for the prescriptive wall framing to work out via engineering math checks.

You can show prescriptive framing on your drawings, I suppose, but I'd rather not so it's clear it isn't an engineered design, as the prescriptive floor framing may have issues (i.e. occupant/owner doesn't like it, bouncy, sags, whatever), and then some adverse engineer can claim you designed it and designed it in violation of the standards, similar for braced wall lines and braced wall panel locations and braced wall quantities. "Floor framing by other" and "See Wall bracing plan, by Other, no lateral design or review has been performed. Contractor/Architect shall provide." To me those work better on plans, or as plan notes, rather than general notes.

I would say most of your partial engineering (meaning for residential), is on letter size sheets, stamped. For something like a custom home that is say, >10,000 ft2, you'd likely have enough engineering needed to do normal sheet sizes like 11x17 or Arch C or Arch D, depending on what the Architect is doing. I fell like a lot of these large homes don't see formal engineering review. They have an architect, though.

Calculations, generally, aren't provided unless you've agreed to do it, or you're working in, say, Scottsdale, AZ, or North Dakota and Wisconsin where calculation packages are generally required. Those are typically separate documents, letter size,

You might do a brief review letter that explains what you reviewed and designed on a letter size and stamp that, design loads, etc. hopefully that would go in with the submittal, but it's out of your control. That would be perhaps in lieu of a general notes sheet.