How much rise of a curved roof is natural pre-camber?
How much rise of a curved roof is natural pre-camber?
(OP)
Pals
You have a slightly curved roof. Line between supports may or may not be horizontal, but the roof has a rise and it is curved with a hump.
In deflection checks, without intended pre-camber, how should one evaluate deflection value?Is the hump to be considered a pre-camber? If yes, what would be the criterion for the amount of natural pre-camber, given unknown or nonhorizontal line between supports?
A reference to AISC or any other code will be appreciated.
respects
IJR
You have a slightly curved roof. Line between supports may or may not be horizontal, but the roof has a rise and it is curved with a hump.
In deflection checks, without intended pre-camber, how should one evaluate deflection value?Is the hump to be considered a pre-camber? If yes, what would be the criterion for the amount of natural pre-camber, given unknown or nonhorizontal line between supports?
A reference to AISC or any other code will be appreciated.
respects
IJR





RE: How much rise of a curved roof is natural pre-camber?
RE: How much rise of a curved roof is natural pre-camber?
You are basically telling me that there is nothing called "natural camber"?
respects
IJR
RE: How much rise of a curved roof is natural pre-camber?
RE: How much rise of a curved roof is natural pre-camber?
RE: How much rise of a curved roof is natural pre-camber?
Your message is like an entity in the planned European Constitution. Tough for me
respects
IJR
RE: How much rise of a curved roof is natural pre-camber?
How can you guarantee that the contractor wont mess up and put it the wrong way around with the camber downward.
It is also possible (although unlikely) for a beam to have no natural camber.
Anyway you said it was a roof beam and camber has no relevance for wind load. A cambered beam will move just as much under wind as a straight beam.
csd
RE: How much rise of a curved roof is natural pre-camber?
You are right with respect to wind. But the contractor has no chance of messing up the required curvature. It is architectural and will show up immediately during erection.
In my experience no mistake has ever been done with respect to curvature specified in drawings(within tolerances I mean)
My discussion is: Is unintended camber a camber?
respects
IJR
RE: How much rise of a curved roof is natural pre-camber?
RE: How much rise of a curved roof is natural pre-camber?
On our drawings, we always included a note to put the camber up instead of down. Whether they did it or not is unknown.
RE: How much rise of a curved roof is natural pre-camber?
Should share this with you. I am a structural engineer who rarely visits fabricators or site. Easy for me not to trust their work. However I made a quiet research and found out that fabricators do more than I can in most or all projects I am involved. Most are self trained guys who talk of their welding machines the way I talk ofe my excel spreadsheets.
Unexperienced erectors? Yes, they are often have little they talk about, and usually just want the job finished.
Bottom line: Guys got passion with their work
regs
IJR