...As from the inside of a concrete wall to the other inside of another concrete wall, or between the flanges of two steel beams or purlins. As in "clear" of the supports.
Appreciate the responses. However, I am wondering, why construction clear span; why not just clear span? Is there a reason to say construction clear span? Is this a term only for metal deck construction?
The Canam catalog lists Span for various deck types. Tables include single, double and triple span. I did not find the term construction clear span anywhere. It does seem a bit redundant.
I think it means the maximum span when concrete is poured before you need to shore the deck. i.e. the max span to support the wet weight of concrete and meet strength and deflection criteria.
In the dry and cured state, decks with concrete can span much longer distances. i.e. if you shored the deck when the concrete was poured, you would be able to achieve much longer spans when the concrete has cured.
See the verco catalog they have additional explanations.
Oh, and also note when looking at the catalogs there is single,double, and triple span conditions. Usually you want to stick with the single condition, because you never know how the contractor will layout his deck.
This term is in the Vulcraft deck catalog for non-composite floor deck. I agree that it applies to the strength of the deck during concrete placement. Does it also have to do with SDI recommendations for workers walking on the deck during construction?
For composite deck P-3615, the Canam tables list "Maximum Unshored Span" for various slab thicknesses, deck thickness and single, double or triple spans.
No such listings are given for P-3615 steel deck (non-composite).
Sorry, I missed this one earlier. It's been a while since I worked for a steel fabricator but if my memory serves me well:
The Steel Deck Institute requires the design loads during construction to be the weight of the deck and wet concrete PLUS the greater effect of either 20 psf uniform over the span, or a 150 pound load on a 12" section. It also has some deflection limit requirements which is limited to, if I remember correctly, L/180. I don't think it's allowed to deflect more than 3/4" under the deck and wet concrete loading condition.
Basically, it is what StructuralEIT said but most engineers don't know that the "unshored spans" are based on this requirement. I wouldn't know it if I hadn't worked for a fabricator. Vulcraft calls it what it is, but most of us know it as StructuralEIT said.
Stazz:
Centerline to centerline for most apllications. Flange tip to flange tip if I need it.
