Solar Pergola Project - how big on the posts and how many needed?

[capvent]

Hoping some experts can chime in with their opinions here. I am looking to have a solar pergola built and the size will be 20’ 8” x 17’ 5”. It will fit roughly 15 panels on it. At 50lbs a panel, that will put the weight on it at 750lbs. Just for the panels. Looking to use either 6” or 8” cedar or redwood wood posts. Can anyone recommend which would be best and how many posts I need to get this to pass Fort Worth city review? Would appreciate any and all help here! Thanks.

[Mike 134]

What has Fort Worth said you'll need to get a permit?

[J.P.M.]

As Mike write, check with the city building dept. You may be in for an education.

Also, other loads (such as wind) often/usually control the design and need to be considered along with deadloads.

What will the array orientation be ?
Horizontal (or mostly horizontal) panels will require frequent cleaning. Reason: they tend to turn into shallow sandboxes from windblown dust.
Then, rain mixed with the accumulated dust leaves a layer of caked mud that doesn't blow away and the buildup will easily reduce the array output substantially.

Also, and in any orientation and for a lot of reasons leave the array open enough so that all the panels can be accessed for service, repair and mostly cleaning.

PV design/install involves a lot more than simply putting panels in the sun and connecting some wires.

Welcome to the forum of few(er) illusions.

[Rade]

I concur with J.P.M. - check with your local building department.

We live on the bay here in RI and spent most of January and February with the consistent wind gusts that rocked our house. A pergola, even in Fort Worth, will certainly be subjected to wind sheer more often than you think. Those cedar posts will be no match to the wind if you essentially have an airfoil attached to the top of the structure. You may need to consider something like lolly columns with a cement footer for the structure support.

But I am not an engineer, nor did I play one on television nor stayed at a Holiday Inn Express. I just built enough decks and yard structures over the years to understand that nature can be a bitch when it wants to be. Plan accordingly.