Partially Enclosed Criteria Compliance - New/Existing Config. 2

[JJMEI]

Does anyone know how to apply the Partially Enclosed Criteria to an addition? Should the entire complex (see attached)

be included in the determination of the classification or should the criteria only apply to the new construction? The given the dimensions of the addition and proposed 20'x7' opening the new construction fits the definition of "partially enclosed." As a structural system that is designed not to rely on the existing structure (to an extent) for lateral support I'd say this is correct. However, I think that the procedure to make the determination for the classification is intended to consider the entire inseparable structure (new + existing) in terms of wind loading.

Any guidance is appreciated, thanks.

 

[JAE]

I've always considered that the wind doesn't "know" whether part of a building is an addition or simply part of the building. Even if the addition is structurally separate the wind doesn't "know" it and will behave the same regardless.

That said, with a large opening (20' x 7') like that I'd be a bit wary if the determination suggested an enclosed condition. When in doubt make it stout and all that.

 

[phamENG]

If the existing and new use independent lateral systems, I would look at each one separately.

If you think it's reasonable that the existing would be exposed to a higher internal pressure than it would if it were simply enclosed, I would check it for the higher loading. This could come from adding openings between the spaces, replacing exterior doors with flimsy interior ones, etc.