How to make sure the column is upright? and in general how to install columns

[brandnewb]

Please imagine a 6m tall aluminum tube that will serve as the central column for the turbine.

How can we secure it tightly, while being able to spin, and.. this is the hard part I think. Make sure it is perfectly upright (sure there are tolerances because perfect is just not possible on micro levels)

I have huge scaffolding so I am thinking that when I get a aluminum tube i just hold it from the top on the scaffolding. And then when ever motion on the bottom stops then it is perfectly upright.

I really hope there are better ways of doing this so if someone has an idea then please shoot.

[brandnewb]

I just realized that there was little context.

This is regarding a rather large scale VAWT with the alternator close to the ground. Some of you might have seen my progress on this forum before.

[Mary B]

Most of the time a flat plate is welded to the bottom and holes in 4 corner that go to threaded rod that is bent at the bottom so it can't spin in the concrete. Nut, large flat washer, tube + plate, large flat washer, lock washer, nut... can then use a level on each side and adjust the nuts until level. Then pack in high compression grout under the plate to stabilize it.

Example, this held a 45 foot rotating tower with the rotator mounted on this. I used to own one. The base was 4'x4'x8' deep, the threaded rod was 3/4 inch and 5 feet long.

[brandnewb]

thanks Mary for the suggestion.

How is the base made "perfectly" level?

A bottom first approach requires extreme precision I am assuming? In both the installation of the base and the dimensional accuracy of the base it self?

[brandnewb]

I just remembered there are self levelling mortars we can use to make sure the base is level. I am just not sure if they have the compressive and shear strength it takes to hold up a big turbine.

[brandnewb]

could you please provide a manufacturer/model for the base?

I will then search if something similar or the model itself is available locally.

[Mary B]

thanks Mary for the suggestion.

How is the base made "perfectly" level?

A bottom first approach requires extreme precision I am assuming? In both the installation of the base and the dimensional accuracy of the base it self?

Use the nuts on the flat plate to adjust it up and down on each corner... until it reads level on the column. Time consuming but it works. Only then do you grout it with high compression grout. If it goes out of level the grout can be removed and the column re-leveled. With a nut and large flat washed on each side of the plate it is possible to get it perfect(+- whatever digital level inaccuracies, mine is .3 degrees).

[Mary B]

could you please provide a manufacturer/model for the base?

I will then search if something similar or the model itself is available locally.

That tower base is a US Tower MARB https://ustower.com/towerproducts/marb/ Any competent welder can make one, just add a flat plate to whatever tube you were planning on using for the 6m column. Make sure you do the math on tower bending moment. Figure out your square feet of wind loading at worse case wind speeds when your VAWT will look like a solid object to the wind. So if it is 6'tall and 3' wide then it is 18 square feet of wind loading. Aluminum has a yield strength around 43,000 pounds. Will whatever diameter you plan on handle that with 18 square feet of load at the end of a 6 meter lever?

Numbers I used are just examples, use your numbers to calculate things. Tower design is a serious business for safety reasons!