Wind Loads on PV Structures, Ground Mounted

.......and?

I'll echo PW's statement:

"........and?".

heck, might as well make it three...

And????

"I have find Wind uplift force, Overturning moment, and Sliding force"

I think your question shall be clear if you rewrite that statement to be "I have to find Wind uplift force, Overturning moment, and Sliding force", which means you are not able to find or to calculate those figures. Is that true?

Good call, Abdel.

Exactly. Any help?

Same here, very diplomatic Abdel.

This very same issue on how to determine Design Wind Speed has come up and discussed at length (like beating a dead horse) several times during the past few years within the CR4 Forum.

I suggest that the OP conduct a search of the Forum blogs to get the right answer or a starting point, otherwise we're spinning our collective wheels (or reinventing the wheel all over again?) answering his questions; he appears to be like a wholly unprepared student walking into a final exam after not studying the night beforehand....

My sincere suggestion to him is to come back later after studying the issue, gathering the facts, and learning the basic principles....and being fully prepared. We cannot do the work for him.

As for determine Wind Uplift Force, Overturning Moment, and Sliding Force acting on the panes and supporting structure, you (the OP) need to have a solid knowledge of STATICS, following by a solid knowledge of Structural Engineering in order to design and analyze the framing elements. You forget to include determining the Wind Down Force in your OP list.

Where are you located and how did you determine the Design Wind Speed? Do you know how to calculate the Design Wind Forces from this value?

These are basic core questions that must be answered before proceeding with any valid design.

Hi,

Thanks for the suggestions. I am close to the answer now. I have a doubt.

While calculating sliding force, I consider the horizontal force as the sliding force acting on the structure. Will the vertical component acting downward add to the resisting force or not?

Dear Raam,

This is how I would approach the design:

#1. In regard to the horizontal component, use that force to calculate the necessary anchor bolt sizes at the top of your concrete piers, as well as design of the concrete pier itself to resist overturning and shear. Ditto with design of the pier footing. You also need to check the active soil bearing pressure acting against side of the pier to resist the applied force....UNLESS you elect to not use the soil resistance and therefore design a large enough pier and pier footing to resist the overturning moment + the effect of the vertical force component,

where,

the calculation of the design soil bearing pressure is then calculated as follows:

q (max./min.) = Pv/A +/- Mc/I; when you neglect the soil resistance component against the side of the pier this will result in a conservative design.

#2. In regard to the use of the vertical component. I wouldn't bother using it as part of a resisting force, where you'd be basically relying on the friction factor acting at the interface surface between the bottom of your base plate and the top of your concrete pier (or top of your non-metallic non-shrink grout)....that's why you rely on the anchor bolts to resist the horz. force via shear resistance. The main reason I wouldn't include the effects of the friction in the resistance is because there's a possibility that slippage may occur or that the bond between the steel baseplate and the grout may break.

The same cannot be said about the resistive fiction force acting at the bottom of the pier footing. You should calculate it's effects and use a minimum Factor of Safety against 2.0:1.0 against sliding, IF you elect to not include the passive resistance of the soil mass acting against the face of the concrete pier and that of the vertical face of the footing. I would use a minimum Soil Friction value of 0.3 for sand, but it really depends on the composition of the soil mass (and groundwater presence) where you're installing this gizmo.

I just want to know the basic calculation.

Let me take a metal plate of area say 5 sqm. It is tilted at an angle of 25 degree.

Weight of the metal block is say 500 Kg. that is approx 500*9.81 = 4.905 kN

Now let us take wind pressure acting is 35 kN.

I resolve this into vertical and horizontal components.

Hori.comp = 35kN * cos 25 and vertical is 35 kN * Sin 25

Now this structure is of steel and is placed in some type of soil. Coeff of friction is 0.3

Now,

Resisting force = 0.3* 4.905 = 1.4715 kN

Sliding force = 35 kN or 35 kN*Sin25 (here vertical component is the pushing force)

Is this approx calculations correct or am I wrong from the beginning?

The code is a good guide to show the steps.