Sooo...am I on the right track?
V = 85 mph
Exp = B
Kd = 0.85 (Table 6-4)
Kz = 0.57 (MWFRS, Exp. B, Case 2)
qh = 0.00256(85)2(1.00)
= 8.96 PSF
G = 0.85
Cp = 0.90
Cpi = 0.00 (open structure)
p = (8.96)(0.85)(0.90)
= 6.9 PSF
Dead Load of Fabric = 5 PSF
Net uplift = 6.9 – 0.6(5) = 3.9 PSF
I might have a hard time selling Exp. B, but other than that, how many errors did I make here?
T. William (Bill) Allen, S.E.
Consulting Structural Engineers
V (949) 248-8588 •
> -----Original Message-----
> From: Drew Morris [mailto:dmorris@bbfm.com]
> Sent: Friday, May 02, 2008 4:14 PM
> To: seaint@seaint.org
> Subject: Re: Wind Uplift on Awning
>
> Bill Allen wrote:
> >
> > I have a client who is creating a shade area by attaching a canvas
> > awning between two exterior trellises. The canvas panels are 22’-0” x
> > 16’-6” and there is a gap of about 1’-8” between them. There area a
> > total of three canvas panels to form a shaded area of about 22’-0” x
> > 38’-0”.
> >
> > I’m a noobie when it comes to the ASCE 7 wind load provisions and I’m
> > not really sure on what to use to calculate the wind uplift. My
> > interest is in the design of the cables and particularly the
> > attachment of the cables to the trellises. In my mind, I don’t think
> > these items are C&C, but I could be wrong.
> >
> > What should I use, Method 2, MFRS or C&C?
> >
> > From what table should I obtain the gust coefficients?
> >
> > TIA,
> >
> > T. William (Bill) Allen, S.E.
> >
> > ALLEN DESIGNS <http://www.AllenDesigns.com>
> >
> > Consulting Structural Engineers
> > V (949) 248-8588 • F(949) 209-2509
> >
> I would use MWFRS. The load on the cables is analogous to the load in a
> holdown, it is based on MWFRS, not C&C.
>
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