Netting Wind Loads 2

I did something similar recently, and assumed an essentially solid surface on the chain-link fences, as though signs were attached, or something blows onto the fence. As for netting--I don't really know. Maybe you can calculate a net (so to speak) surface area.

If ASCE 7-02 is of any value to you, see 6.5.2.2. Basically it says you have to assume it's solid unless you have approved test data or recognized literature proving that a lower load can be used. As to assuming a net surface area, that may not be accurate as the design wind load applied to an area assumes a solid surface and in doing some work with electric poles and other things I've learned that wind on a circular element works quite a bit differently than on a solid flat surface.

akastud

ASCE 7-02 6.5.2.2 states you have to use section 6.5 "Method 2 - Analytical Procedure" or a test procedure, not that you have to assume the net is solid. I would use 6.5.13 and Figure 6-21 with an epsilon value, and see if the results seem reasonable.

The Chain Link Fence Manufacturers Institute addresses wind loading for their products. Although I have not looked into it, the approach MAY be similar for netting.
Here is a link

I agree with SlideRuleEra. I recently checked a backstop and used the Chain Link Fence Manufacturer's "A Guide for the Selection of Line Post Spacings for Chain Link Fence" They say that in order to get the wind force, you have to establish the net surface area minus the void spaces.

If you can get a hold of an ASHRAE design handbook, there's formulas for losses through screens of different sizes. You can then run the fluid mechanics formula using air at 90 mph (or whatever you wind speed is), density times losses times v^2/2g, using the density of air and get the pressure directly.
I did this once for a wrought iron fence and the end pressure was believable (between zero and the ASCE 7 solid sign pressure).

Some years back we did a third party review for netting supports at a driving range. As I remember it, we haggled with the designer over the loading as there was no governing code, and arrived at the following Design Loads:

• Case I = 80 mph (Code Basic) Wind Load on 12% net solid area + Dead Load
• Case 2 = 40 mph Wind Load on 90% net solid area + Ice Load + Dead Load