Architecture - analysis of calculations

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student2
08-12-07, 11:30 AM
Shamelessly looking for free analysis of my calculations.

My homework:

Deck size = 16' x 8'
Dead load = 10psf
Live load = 100psf
Total loading = 14,080lbs
Number of columns = 6, evenly spaced @ 8'
Max Span of beams = 96"
Beams = C4x5.4, A36 steel channel
Permitted Deflection L/360


C4x5.4 Data:

Area = 1.59
Depth = 4"
Web thickness = 0.184
Flange width = 1.584
Loading = Uniform
Support = simple
Moment of Inertia [in(4)] = 3.83
Section Modulus [in(3)] = 1.915
Modulus of Elasticity = 30,000,000psi

Deflection @ center = 0.235 = 96/408 =< L/360

Is this correct?

Thank you
Student2


lefty
08-15-07, 09:42 PM
student2,

I build decks for a living. I don't go through all that!! I simply figure out what spans the building dept. in question will let me use and go from there!! They have handouts that tell you what the inspector is going to be looking for. GO WITH THEM!!

student2
08-16-07, 05:04 AM
Thanks, Lefty. I did. The chief building official said if it (C-Channels for beams) is not Code listed, then he wants proof (calculations or engineering approval [$$$]) of equivalent compliance (in this case, with the limiting factor of L/360 deflection).


fredmorrison
08-26-07, 11:18 AM
Deflection for a simple beam uniformly loaded is:

5/384 x WLLL/EI =
0.013 x 3520 x 96 x 96 x 96 / EI =
0.3523 inches or L/272

You need a stiffer beam.