Wind Load on Slat Canopy

[vmirat]

I have a wood canopy over a large patio that is composed of 2x2 slats at 3 inches on center supported on 2x8's at 2' o.c. The intent is to create some shade over the patio. The horizontal projected area of the structure is essentially the 2x8 and 2x2 (about 10" nominally). However, since wind doesn't actually blow perfectly straight horizontally, I believe the actually lateral loading on the structure is a result of some wind pressure against each of the 2x8 rafters at some shallow angle, perhaps 10 degrees or so. I can't find anything in the codes that addresses this kind of situation. Any suggestions?

 

[ishvaaag]

In the standing code for loads in Spain effectively the wind is required to be considered not ony acting horizontally, but also 10 sexagesimal degrees upwards or downwards. This code is NBE AE-88. This same code has some provisions for forces on surfaces in the shadow of others, but more than anything targeted to building elements. Anyway something could be done from this.

However it is in the standing code for loads on bridges that the wind forces on elements in the wind shadow of others is better defined. This code is

http://www.carreteros.org/estructuras/iap98/indice.htm

and the shadow thing in wind of course

http://www.carreteros.org/estructuras/iap98/apartados/3_2_3_2_1.htm

 

[vmirat]

ishvaaag,
Thanks for the response. Unfortunately, I don't speak spanish so the web sites aren't of much use. Also, would you mind explaining what "10 sexagesimal degrees" means? I looked up sexagesimal in the dictionary and it means 60.

vmirat

 

[ishvaaag]

Sexagesimal (in spite of the name) means the usual division in ninety degrees per quadrant. Have not the lesser idea (other than degrees abd minutes being in 60 divisions) the system keeps such name. It is opposed here to the surveyors' system called centesimal that use 100 degrees per quadrant. Surely not exactly english words, sorry.

 

[ishvaaag]

Respect translation Google can do it for you (to what quality who knows). Any search result page in Google has a up a link for a tool for translation. Both pages by its URL and texts can be thrown at it, and spanish to english is surely an option.