Sizing concrete base small wind turbine

[dedeleco]

Here, it's strange, Dedeleco, confuses the weight of a light bulb VS a wind turbine

and Obamot superbly ignores the shrouds, I don't know why ???

The weight of the pole is greater than that of the wind turbine, but remains low and the force of the wind on the pole is much greater than the weight of the wind turbine.

Obamot does not know how to see and appreciate an assembly, simple, easy, light, more inexpensive and therefore very remarkable !! compared to others who embark on complicated, difficult, heavy, and unnecessarily expensive !!

The base could have been a simple stump of a dead tree or a post or stake driven into the ground with blows from the ground.

They would do well to do this on stakes or tubes for the heavy Chinese house that disappears in the soft rice field.

[Obamot]

And does Dedelco knowingly ignore:

- the answers already given?
- the force of the wind ... multiplied by the weight of the wind turbine and the mast according to its height?
- the fact that I only answered the freezing problem?
- the opinions of others about it?
https://www.econologie.com/forums/que-faut-i ... 11652.html

Is Dedeleco as immature as Quartz?

[dedeleco]

wind strength ... multiplied by the weight of the wind turbine and the mast depending on its height?

This is wrong, on the guy lines attached, at the top the force is not multiplied at all, unlike the financial leverage of 39 on Deutsche Bank and 29 on Credit Suisse, which risks ruining everything by evaporating our savings and putting us without the money !!!

Once again, Obamot is angry with elementary physics !!

[chatelot16]

of course with guy wires we make the same solidity with a total weight of materials much lower

but the shrouds are not my preferred solution: it only takes a small accident of nothing at all to cut one and everything falls to the ground

the unique and solid mat is not bad

it takes concrete weight to hold it, but not necessarily buried: a small square masonry hut does not cost more than buried concrete! and with the same price of materials the small cabin will easily contain various inverter and electronic batteries

therefore reinforced concrete slab, chipboard wall and reinforced concrete ceiling slab, with concrete iron in the aglo holes at the 4 corner of the hut

for the mast, the round or octagonal scrap tube is not the right solution: the high angle pylon angle iron braces are much more economical, and easy to build

[Obamot]

It is also a Chatelot possibility. There can therefore also be an arch in the roof, which will reinforce the hold of the mast compared to its lever effect. Only it will not prevent the temperature from falling. So you have to close it with a door. It still requires resources and time ... And other foundations ,. But I'm for the idea.

The problem as I understand by reviewing the photos, is that apparently the mast would be intended to tilt and bring the wind turbine down to the ground to possibly do maintenance ...

As Dedeleco noted, it's simple and ingenious ...! It therefore requires an intermediate solution, or provide an opening in the house, to allow the tilting of the mast (which will also be much easier to remember in its descent, thus guided)

[dedeleco]

For crosses like the Eiffel Tower or wind pump support from the 1930s, absolutely agree.

But the price of the swallowtail solution is unbeatable because pure recovery of reformed lighting pole, ultra simple, light and removable with the shrouds.

We can do the same function, with huge price differences !!!

Against their breakage of these shrouds, it suffices to double them with basic ropes which have stood with me for more than 12 years on trees of several tons uprooted at the end of 1999 by the storm of the century and straightened with ropes by pulling these few tons with a 20 ton winch at 2 €, trees thus saved, pines and beech, which have a lot more wind resistance than this wind turbine !!

Also the steel cable shrouds, lined with elastic cords, which absorb oscillations, are a very good very solid solution.

What makes steel cables fart is that they relax a little, and then the oscillations hit by strong inertia on the rigid cable, brutally pulled at the end of its travel, and then fart, by this inertia, which multiplies the forces per 100 and more, like a hammer on a nail, in the report, force of the wind by amplitude of the oscillation on the amplitude of stretching of the cable under this force, (less of the mm) while a cord much more elastic resists well, not seeing excessive strain.
Otherwise, on the shrouds you need a correct shock absorbing tension spring.
Well known mountaineers who unscrew and do not get the wrong rope to ensure !!

In my opinion the concrete base was almost useless, except to go up and down.
But the shrouds must be well attached, with stakes well set deep, and sometimes stretched.

With guy lines and stakes, well put, we can hold a garden shed 6 to 10m2, without making any cement base and cinder blocks, as I have in my garden, ultralight, just placed on the ground, and attached with stakes invisible, (but well laid), for 20 years and which has withstood the storm of late 1999, with 180km / h at the top of my roof and at Orly too, and also other gusts of wind! !!!

[Ruthenian]

The weight of the base is greater than the post. This type of lighting pole, I have already seen it well inclined on the road, with the ground having moved under the trucks next to it and with the wind, this without shrouds !!!

All so-called freestanding pylons are designed for and are very resistant. (Eiffel Tower, candelabra, large wind turbines ...)
It takes a good foundation and weight to stabilize everything.
My base has a mass of more than 8.5 Tons dug into the rock.

It's a shame because you obviously had it really easy.

If a guy breaks, you will have everything on the ground.

[dedeleco]

The weight of the base is greater than the post. This type of lighting pole, I have already seen it well inclined on the road, with the ground having moved under the trucks next to it and with the wind, this without shrouds !!!

All so-called freestanding pylons are designed for and are very resistant. (Eiffel Tower, candelabra, large wind turbines ...)
It takes a good foundation and weight to stabilize everything.
My base has a mass of more than 8.5 Tons dug into the rock.

It's a shame because you obviously had it really easy.

If a guy breaks, you will have everything on the ground.

carved into the rock

indicates that a concrete base is useless, the unchanged mass of rock, easily a thousand tonnes, is enough by drilling a few holes in it with a drill or perforator.
It all depends on the rock quality but in my opinion it is enough, with a little concrete in the cracks and stems in the rock.
.

If a guy breaks, you'll have everything on the ground

.
Well designed, they do not break more than the mat, so doubled and with shock absorbers, as I explained above, even doubled with cords !!

I thus have a beech tree of a lot of tons (80cm in diameter) felled by the wind, then straightened (hard hard, and tricks, with 40 € of material) and maintained by a rope for 12 years !!
It has picked up well since, full of branches !!
With this nothing material, I straightened a lot of heavy trees 20m high, like pine trees !!

The small swallowtail candelabra, with guy lines and a wind turbine at the top of 20 Kilos, which in a wind of 180km / h or 300Kgp / m2, will not undergo a force of more than 100kilos, will hold perfectly with guy lines resistant to 2 tonnes. (or even cheap big strings for this strength).

Forhorse had his wind turbine, held by fence wires, overturned, mainly because the wires, not elastic at all, relaxed, then suffered impacts at the end of the stroke, which break, because they multiply forces like a hammer on a nail !!
He would have put 3 more taut strings, which cushion, nothing would have broken.
Having the mechanical and scientific sense of the resistance of materials, neither not enough, nor too much, we avoid accidents and also we avoid emptying our wallet unnecessarily.

swallowtail has made good choices and if its shrouds are well lined with shock absorbers, it will have no problem.


The base is almost useless for the light swallowtail candelabra, with the double shrouds !!!
Simple 2m stakes driven into the ground to hold are enough to raise and lower, only.
Once vertical, almost no base is necessary.

Watch the circuses go up, with almost nothing on the ground, ropes and cables, stakes well put, and huge canvases over 1000m2, with such huge catches in the wind, which resist, except tornado at 200km / h.

Same for the light antennas, very high, held only by guy wires.

[swallowtail]

good evening everyone,
that controversy for not much ....
All the opinions are interesting to listen to.

some details about my wind turbine:
1 ° --- at each end of the cross 10 concrete bars 900mm x14mm are inserted at 70 ° / vertical and crossing the sills, forming "hedgehogs" increasing the shear resistance ...

2 ° --- the shrouds are made up of 4mm galvanized steel cables (7x7torons) given for approximately 1200kgrr rupture and mounted in double copper crimps + 8mm turnbuckle

3 ° --- the total nacelle weight (rotor + generator + tail) is 18kg

here for the technical data.
To answer you :

Dedeleco: Turbulence question: not everyone can live by the sea with a laminar flow wind. For my part, the flow is good over a sector of 180 °, medium over 90 °, and turbulent over the last 90 °.
The important thing is the prevailing winds (meteorological winds, valley breezes, etc.) and there it is not so bad and very complementary with my photovoltaic.

Obamot: - " the force of the wind ... multiplied by the weight of the wind turbine and the mast depending on its height? " "But I would love to see the mouths of these after a storm after a 50t surge, ....."
50 Tons ??? Where do you get this number from? 3,5 ???? x12 m
The weight of the nacelle has practically no importance on the flight of the foundations and works only in compression on the mast and the foundations (as long as the mast is vertical). What matters is the LATERAL force [b (] drag) [/ b] exerted by the flow of the wind on the mast and wind which tends to cause them to tip over. It increases by the square of the wind speed (Fx = 1 / 2ro.S.Cx.V2)
This is none other than the sum of the "drag" of the mast added to the drag of the rotor disc surface of the wind turbine.

Indeed, in the case of a guyed mast [/there is no leverage on the base of the mast (we are not in the case of a simple installation) because the shrouds take up in pure traction the majority of the forces due to the overall drag x sin angle of the shrouds (45 °).
In addition, the antenna masts in guyed lattice beams (more than 150m high) or certain mast of the sailboat, are mounted on an articulated ball joint base and the very light foundations only work on compression (epontilles on a simple A4 stainless steel bolt 12MM, for sailboats).
Only the shrouds take up the lateral forces, and the mast the compression.
This is also the case for the majority of self-built wind turbines by the association Tieole (mast 18m triplehaubannage)
The volume and surface area of ​​the base are only important in the case of a single NON-guyed mast.

When frost, nothing indicates that this wind turbine is not in the tropics or in frost-free area ...... and the foundations are covered since by vegetalized earth
In addition, the expansion coefficients of steel and concrete are certainly different, but it is also the case for many "classic or aerial foundations", prestressed beams, chaining, etc ... which constantly undergo freezing and thawing with in addition a changing hydrometry ... without short-term cission.
Your remark on this problem seems interesting and well founded in the self-supporting matt case, but not essential in my case ...

Châtelot:
certainly the self-supporting mast is simpler and more aesthetic, but requires clearly + voluminous foundations, a pylon of greater inertia (section, thickness) to resume bending, a mast base capable this time of absorbing the overall drag x lever arm (see photo obamot), a hydraulic cylinder or minimum a shroud + lifting mast + winch ........ etc
That's a lot of very honorable things.

My goal was to make a max by myself (blades, hub not variable, pivot, tail, welding, crimping, excavations, concrete, anemometer ... etc) to reduce the overall cost to the minimum.
Goal achieved!

To conclude I will say that:

for once, dedeleco criticizes little !!! see even congratulations !!! (it's quite rare to note it)

I am astonished, considering the profession and the studies of obamot, that it has "shifted" applications of the principles of static meca and other?
and if he could share with us his calculation method for his concrete base ... we could learn!

and for chatelot, tell him that by my experience of + 30 years in aeronautical construction, delta and ulm flight among others, where our lives are "tied" to 2,3mm stainless steel cables and that this leads us by obligation to have some confidence in the material ...

truly

[Obamot]

Swallowtail should read again, my comments focused exclusively on the issue of freezing:

When frost, nothing indicates that this wind turbine is not in the tropics or in frost-free areas ...

But nothing indicated to the contrary.
Since it was the thing that was catching my eyes, I allowed myself to say it. I should not have?

les foundations are then covered with topsoil [e]

This is exactly what had to be done (if it is not done yet, but I trust you ...).

In addition, the expansion coefficients of steel and concrete are certainly different, but it is also the case for many "classic or aerial foundations", prestressed beams, chaining, etc ... which constantly undergo freezing and thawing with in addition a changing hydrometry ... without short-term cission.
Your remark on this problem seems interesting and well founded in the self-supporting matt case, but not essential in my case ...

Mouarf, we have at home "SIA Standards" that other countries envy us (our dean was French ...). This is normal, we have a place where the temperature can drop to -40 ° C (la Brévine). So a good "pro" applies what he has learned, without spreading it in the media: period! But as we are in a forum, I'll say the most I can say ...

To solve these problems, it is possible to proceed (from memory, I no longer practice) by different means:

1) first, the photos are misleading, no one knows what the reality of the field is without having gone there myself! (See saturated conditions but exposed or unexposed etc ...)

2) the posters in the forums In spite of telling everything they want, the first instinct is caution / mistrust. I don't know you and neither do you, even if a priori, we should not consider anyone as a storyteller (but we see so many, since we even have a specimen on this forum, who claims to be a physicist, but does not know the law of mass, confuses acoustic insulation and acoustic correction, and does not even flush out the enormities that I knowingly wrote above! While he allows himself to have an opinion on "the question" by having missing data to the problems lol ... as an example we do better) ...

3) this remark is therefore justified, but first there are “exposure classes” of concrete! Then there is NOT ONLY concrete that comes into play in freeze / thaw issues: but above all the immediate environment (which must be controlled by drainage for buried concrete) such as runoff , which accumulate in the ground and can cause a rupture, because the gel can also "take" on and in the concrete, by phenomenon of capillarity! (Which is not or hardly the case for the examples you cite). However from what I saw in the photos, I did not see any drainage. Since I don't know everything about the site, I can only repeat it. Although indeed, I confirm that these foundations also work and especially in compression with regard to the precision of the weight of the nacelle (when I had read the weight of 3,8t, but I presume that this included the weight of the mast included ...). But this is not a scoop, since it is specific to concrete that withstand compression forces, without even the need to put reinforcement! So you say that there is no torsional or shearing forces, but you put reinforcements ... Hmm! I don't know if you see the contradiction in the reasoning. So yes indeed, it was necessary to put reinforcements, because at 2 meters in height (if we admit a force of 300 kg at the top under the pressure of the wind, or a wind return, and the weight of 3,8, 2t in total) you will have at a height of 3,5 meters a moment of ~ XNUMXt (without shrouds I do a little like these electronic journals which put big errors in the circuits, so that novices cannot take ownership of the data and do the editing, so always be careful with what I write ...).

4) this remark is justified, but first we need a mixture of concrete at the top, and for that we use a pervibrator: nothing indicates that this was the case! And then there is the monitoring of the site, the confidence of the company and the guy who did the work, etc ...

5) not knowing your particular case, apart from some data - and even if you told us everything I would not want to know and would not take a stand - so I could not go ahead.

6) there are several ways to resolve questions of frost resistance in concrete: except BPE delivered by rotary tipper truck (which avoids the selection of aggregates up to the site ... and therefore the mixture is "studied for ”), We add concrete admixtures and additives such as bubbling agents (introduced into mixing water up to ~ 1%) creating billions of microscopic air bubbles, with the cheapest insulation on the market. ..

7) Physico-mechanics of cementitious materials subjected to freeze-thaw, is the subject of very extensive studies which cannot be summarized in a single forum. Our chemist knows something! Like the phenomena of segregation, capilarity (which the adjuvants make it possible to avoid while giving better "workability".)

structures subjected to the air are only rarely subjected to the constraints of the foundations (accumulation of water, in a first stage, then freezing ...), it is hardly that the freezing rains which do not cause such accumulations, therefore, have only a superficial action. But we still take precautions whenever there is the possibility of accumulation of runoff water or other source, such as for dams, dikes and reservoirs, airport runways and road concrete, concrete placed in the mountains, civil engineering works and mass concrete structures ...

So I repeat it again:

I already said that I did not go into structural calculations in detail (I never did and never will in a forum

Besides I do not believe that any engineer does that on the canvas ...! If following his advice a work should fall, responsibility is criminal!

So don't count on me too much to validate your approach. But at least now I am a little more reassured, since everyone can deduce from your comments, that you seem to have studied the question! ;)

" the force of the wind ... multiplied by the weight of the wind turbine and the mast depending on its height? " "But I would love to see the mouths of these after a storm after a 50t surge, ....."

50 Tons ??? Where do you get this number from? 3,5 ???? x12 m

I have not released ANY usable figure so far (for the reasons mentioned, you must read me again ).

The weight of the nacelle has practically no importance on the flight of the foundations and works only in compression on the mast and the foundations (as long as the mast is vertical). What matters is the LATERAL force [b (] drag) [/ b] exerted by the flow of the wind on the mast and wind which tends to cause them to tip over. It increases by the square of the wind speed (Fx = 1 / 2ro.S.Cx.V2)
This is none other than the sum of the "drag" of the mast added to the drag of the rotor disc surface wind turbine

No detail, already seen above, but indeed, there is reasoning.

Indeed ,in the case of a guyed mast [/there is no leverage on the base of the mast (we are not in the case of a simple installation) because the shrouds take up in pure traction the majority of the forces due to the overall drag x sin angle of the shrouds (45 °).
In addition, the antenna masts in guyed lattice beams (more than 150m high) or certain mast of the sailboat, are mounted on an articulated ball joint base and the very light foundations only work on compression (epontilles on a simple A4 stainless steel bolt 12MM, for sailboats).
Only the shrouds take up the lateral forces, and the mast the compression.
This is also the case for the majority of self-built wind turbines by the association Tieole (mast 18m triplehaubannage)
The volume and surface area of ​​the base are only important in the case of a single NON-guyed mast.

1) I would not have concluded thus, even if there is the idea. Already for lack of data.
2) I had already given the formula (force "x" lever arm, without taking into account the shrouds, I admit). I had applied the intentionally wrong formula of 3,8t X 12m = 45,6t (ie 50t). It goes without saying that this was purely illustrative, since I did not have the elements in hand.

So sorry and without any hard feelings!

I am astonished, considering the profession and the studies of obamot, that it has "shifted" applications of the principles of static meca and other?
and if he could share with us his calculation method for his concrete base ... we could learn!

And now, is it seen?

for once, dedeleco criticizes little !!! see even congratulations !!! (it's quite rare to note it)

I don't believe anyone who has barely twenty posts in this forum, can afford to give a "relevant opinion" on what is really going on there ... And besides, he did not read well. It's fine to be petted in the direction of the hair, but give an opinion when you have missing data and pretend to be a physicist, shows how much Dedeleco is a public danger!

PS: it is no longer possible in this forum to say anything without being censored by Dedeleco. I had decided not to answer, but it will hardly be possible all the time!