Alternative Basic Load Combinations
Alternative Basic Load Combinations
(OP)
I am working with the Florida Building Code [FBC 07]. And I had a uplift situation (for some anchor bolts) I am trying to address with the Alternative Basic Load Combinations [sect. 1605.3.2]. One thing that I don't get here is the absence of a load combination that has just dead load and wind. Granted, the introductory paragraph tells you to have a 0.66 factor times the dead load (where it counteracts the wind) and the load factor on the wind is 1.3......but this still seems to me that it could possibly underestimate the uplift. Anyone know the reason this combination isn't included?






RE: Alternative Basic Load Combinations
Structural Design Engineer
New York, NY
RE: Alternative Basic Load Combinations
RE: Alternative Basic Load Combinations
Since my original post, I found this [on this topic]:
So it appears you can use those combinations even though they are much less conservative than the afore mentioned "basic" combos. As a sanity check: I also checked with a realistic minimum dead load and full wind load......not necessarily as part of my official calcs but just so I could get that warm fuzzy feeling about it.
RE: Alternative Basic Load Combinations
Structural Design Engineer
New York, NY
RE: Alternative Basic Load Combinations
That was the whole point of doing the "sanity check" I mentioned. [I.e. the likely Dead load + the full wind load.] If the Alternative combos were giving me something outrageous I wouldn't use them.....but it doesn't seem so in this case.
And that sort of prompted my question as to the mentality of having no combination without live load [other than the seismic case]. It doesn't let you completely off the hook: you do have to use a factor of 1.3 on the wind and 0.66 times the dead.....but with all that, I didn't follow including the live load.
RE: Alternative Basic Load Combinations
Structural Design Engineer
New York, NY