Calcs for performance spec components

[legner]

Our firm often requires submittal of structural calculations for building components such as wood trusses, precast plank, etc. The calculations are specified to be prepared by a licensed structural engineer in the project's state.

What we get back varies widely. For example, we have had 20-page calculations on stone facing material and a 1-page summary sheets for wood trusses.

My question is three-fold:

1. How good (detailed) are the calculations you receive for preformance spec. items?

2. Have you tried to specify the level of detail you require?

3. If you have specified what you want for calculations, how did you do it and how well did it work?

Thanks,

Joe [sig][/sig]

 

[Ron]

Joe,
I have seen the same as you describe. It varies from little to too much, but the structural engineer of record maintains the responsibility for compliance with the design and intent, so can dictate how much or how little he wants to see. I don't know of any particular standardization; however, the State of Florida includes specific language in its Rules of Practice on delegated structural engineering functions (

http://www.fbpe.org).

These vary somewhat with the component, but the bottom line seems to always be that there needs to be enough info presented that will assure the Engineer or Record that the design intent was understood and that the submittal reflects compliance with the intent.

I have been on both sides of this fence, both in review of submittals as Engineer of Record and as a delegated engineer submitting calculations for review by the EOR. I have submitted copious calculations at times only to have them rejected because EACH load case was not expanded and calculated (never mind that those load cases were non-critical!). I suppose it boils down to individual preference, but as a minimum I want to be able to clearly follow the calculation methodology and for those calculations to clearly reflect comparable design requirements for other portions of the structure, i.e., all done under the same code (ASCE 7, SBC, UBC or others but not mixed up!) This particularly becomes a challenge when you have components that are being fabricated and shipped from all over the country to a single site, designed under local codes and standards.

Ron [sig][/sig]