# Re: canvas awnings tension on dowel supports

• To: seaint(--nospam--at)seaint.org
• Subject: Re: canvas awnings tension on dowel supports
• From: h.d.richardson(--nospam--at)home.com
• Date: Thu, 05 Jul 2001 23:20:10 -0600
```Tom,

You might try the equation

W*L^2/8 = P*Delta

Where	W = 60 psf

L = Span of canvas between rods

P = Canvas tension under load (per foot of width of canvas).  This
value is limited by the strength of the canvas

Delta = Sag of the canvas under load.  This value will allow you to
calculate the "stretch" of the canvas under load and hence the maximum
permissible value of the pretensioning force given the elastic
properties of the canvas.

60 psf seems to me to be a fairly high snow load so you might have to
make some radical assumptions like ignoring deflection of the support
rods to get a practical solution from the above.

Good luck.

Regards,

H. Daryl Richardson

Tom Hammond wrote:
>
> How does one calculate the horizontal tension force for steel or fiberglass
> rods supporting a horizontal canvas awning having 60 PSF snow load on it?
> The canvas is to be wrapped around the rods each end.  The canvas is
> "pretensioned" to make it taut when it is installed.  Thus the rods must
> support the vertical and horizontal forces from the snow LL and the
> pretension.  Help!
>
> Tom Hammond
>
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