Announcement

Collapse
No announcement yet.

Rail Spans for ground mount

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Rail Spans for ground mount

    I am designing my own ground rack because after 3 months of trying to buy a pre-made rack I couldn't find anything reasonable actually for sale. I was all set on a Schletter but then the price tripled at the last minute, I found I could get a Patriot rack for my 20 Solarworld 295 panels but shipping would add 800. OpSun makes a nice rack in Ottawa but again the shipping would add 1000 to the cost. The "locally sourced Sch-40" racks don't mention the pipe will add 1500 to the price plus 500 for concrete (min truck charge). I went thru 25 racks / manufacturers and most of what is advertised is discontinued, available only to utility sized projects, dealers don't have, OEMs won't return email or phone calls or the price ends up in the 4000-5000 range. So I decided to design it myself. Fortunately I have 20 years Architectural/Engineering background, Autocad, and a no-inspection required county permit.

    I am doing a 2x10 portrait, 30 degree, 4-post in ballast block with 4 additional front edge support posts. I am using 6061 Structural Aluminum. My main posts are 7'x 5"x3" T-sections sticking out of the concrete 4', the front posts are 30"x 3x 3" Angle about 12" high supporting the leading edge. The table support beams are 10'x3"x3" aluminum angle and I have 5'x2"x2" angle braces for support from the main Post to the rear of the table beams. So far everything is going together well. I am ready to pour the ballast block concrete (they are 8'x2'x18" each)

    I am about to order the rails and am trying to decide on using UniRac or IronRidge XR1000.
    I am in the ASCE 7-05 90 mph-no snow zone and both of these rails should handle at least a 9' span under my conditions. My posts are spaced 8'-9" and I will be using (4) E-W Rows of 11'-14'-11' rails spliced together. I will cut the 14' rail to about 12 1/4' so the splice is only 1-1/2' from a post. My cantilever is within 25% of my span...

    I am leaning toward using the XR1000 rail because it's splice kit is internal and adds some structural support while the UniRac will save me $200+ it has a non-structural external splice plate. I thought of making the splice right over the posts but then I would have to make custom L feet wide enough to span the splice and secure both rails...and I don't know if the plate will be in the way..

    What do Y'all think of the above? If not the XR1000 then what would the strongest rail would be?

    thanks
    sd
    Last edited by Syberdog; 09-28-2017, 09:41 PM.

  • #2
    I don't follow it too closely, but XR1000 is the strongest rail I know of. I was ready to use it on my roof to minimize penetrations until I found that the roof attachment hardware wasn't strong enough to take full advantage and my city requires 6 ft max spans for fast permitting in any case (so I went with XR100).
    CS6P-260P/SE3000 - http://tiny.cc/ed5ozx

    Comment

    Working...
    X