Wind load on a sloped Solar Panel?

[structure567]

I am having trouble finding the right method in calculating the wind load and the net effective area on a solar panel that has a 45 degree slope. This will be attached a to a cantilever column. If I were to use ASCE 7-10, should I calculate the wind load as a solid sign or a sloped roof? Or is there an alternative method that will give me a more precise wind load.
Thank you.

 

[Ceinostuv]

Somewhat relevant question - How large is it and is it at-grade or is it a rooftop array?

Since it's attached to a cantilevered column, I'd probably design it as a solid freestanding sign if I were using ASCE 7-10.

ASCE 7-16 added several methods for calculating wind loads on Rooftop Solar Panels, so if I were asked to do one today I'd look into (and probably use) section 29.4.3 with h=0.

Judgement-In-Training

 

[ACtrafficengr]

Don't forget there will be uplift when the wind is northerly! (or southerly in the southern hemisphere)

My glass has a v/c ratio of 0.5

Maybe the tyranny of Murphy is the penalty for hubris. -

http://xkcd.com/319/

 

[structSU10]

There is a SEAOC documents PV2 for wind design of solar panels that was published in 2012.

 

[Aesur]

ASCE 7-16 closely adopted PV2 from SEAOC. Depending on the size, what you described could be considered an open building and designed per Figure 30.8-1 (C&C) and Figure 27.4-4 (MWFRS) in ASCE7-10. Depending on where the structure is mounted you may have other considerations as well, ie. a solar carport mounted on top of a parking garage should consider Kzt as if the building is a cliff face. This is because Open Buildings provisions don't include for structure on top of other structures.

 

[structure567]

Thank you for the replies.
So this solar array is directly mounted on a steel column that is on grade. It is not on top of a roof structure. I did read the SEAOC document and that seems like it describes design loads on top of roofs and with angles less than 35 degrees.

 

[r13]

So, how we usually design a flat roof, like roof over open shack?

 

[structure567]

I don't know if I should treat this as a open structure since its only a 7'x7' solar array with one steel column attached to it. The open structure method has many limitations which does not allow me to go that route. The h/l ratio is over the required range (0.5~1) and the slope is over 35 degrees.

 

[r13]

I don't know the new code. But at the past, we usually take the worst case scenario - 0° with full wind.

 

[Aesur]

This is why many solar companies do wind tunnel studies of their systems, historically the code wasn't great at providing wind loading on solar panels. Additionally with a wind tunnel study they would be able to give you insight on the gust factors required as solar structures are typically flexible with a natural frequency less than 1 Hz. Being that h/L is greater than 1, I am not sure the code adequately provides any information to design the wind on this structure. This is where engineering judgement comes into play and it would be best to get the input of the EOR before moving forward.