Tower anchors

[97fishmt]

The real work in getting my tower going was the dirt work

or rock work.  My site is solid granite and fragmented over

lying rock, softer magnetite or something, looks like purple quartz.

Little soil.

I drilled 16 inches into the rock for both the 3/4 inch threaded

rod and 1/2 inch rebar and epoxied them in.  I was working from the Bergey installation manual.



I used what I had around for good solid anchor plates, and threw in

what ever looked like it would help. Tie wired every thing together

and some welding where it looked like that would be better.







This hole was a problem. It was the softer rock and fragmented.  I kept

digging down to about 4 feet below the surface.  This is the other side of the hinge anchor and it had to be level with the base as did the other side and in line.





I got down to the nice solid rock and this is what I came up with to

keep a solid anchor into that rock.  The rebar is 5 feet epoxied into

the good rock and welded and tie wired to this old steam radiator.  

I was going to use it for a hydronic system but never got around to it.

It's 4 feet long and about 300 pounds I'd guess. I just needed something

strong and ridged to keep in contact with the bottom of the hole.

The results; the base is level with the two side anchors and they line through

the hinge so up and down movement does not affect the guy lengths.

[wpowokal]

You may know this(I think Bergey say it in their instructions) but just in case, it is only necessary to have a line of site from each side anchor through the base pivot point, the side anchors can be at different elevations.

allan down under

[97fishmt]

Hi Allen,

I guess you are right now that I think about it. The lengths would just be

different.  No wonder it was so much work.  I thought I read many times

from Hugh's books and Bergey, Home Power and others and of course this site

they should be level.  I did not try to think about doing it wrong again

I guess.  This installation is replacing my old kind of experimental one

witch worked but was way out of balance.  When the tower would go down it

would really stress some guys and others would go slack.

Thank you for being kind to my ignorance.  I was kind of over taken by dealing

with all the weights and lengths of steel by my self, and did not want any

pinching or extra stresses.  I am confident on trying to over build it though.

[97fishmt]

I guess my thinking was I wanted the gin pole to tilt also.

That means that it goes through 180 degrees of rotation from

horizontal to horizontal.  I spent a lot of time thinking about

it.  I'm sure it was worth it on my part to make sure extra forces

introduced in the up and down.  Again it is designed to fold against

the tower when down. I have to supply a small additional gin pole to

pull up the main gin pole and then it pulls up the tower.

I did not want to look at the gin pole up in the air if I had the

tower down.  In the past I only had the tower up while I was there,

it only took about 10 minutes to put up.  This may be different.  

Leave it up and rely on the breaking by shorting it out.  I don't

know about that.  I still want it to go up and down with out a hitch.

Lightning is going to be a real concern.

Thanks again, I am having a hard time sleeping trying to come up

with all the answers before I do something wrong.

[97fishmt]

I guess my thinking was I wanted the gin pole to tilt also.

That means that it goes through 180 degrees of rotation from

horizontal to horizontal.  I spent a lot of time thinking about

it.  I'm sure it was worth it to make sure extra forces introduced

in the up and down are not magnified .  Again it is designed to fold

against the tower when down. And then unfold to vertical and then pull

the tower up and it will end up horizontal on the opposite side. I have

to supply a small additional gin pole for the first pull to pull up the

main gin pole and then it pulls up the tower.

I did not want to look at the gin pole up in the air if I had the

tower down.  In the past I only had the tower up while I was there,

it only took about 10 minutes to put up.  This set up maybe different.  

Leave it up and rely on the breaking by shorting it out?  I don't

know about that.  I still want it to go up and down with out a hitch.

Lightning is going to be a real concern.

Thanks again, I am having a hard time sleeping trying to come up

with all the answers before I do something wrong.

[scoraigwind]

"You may know this(I think Bergey say it in their instructions) but just in case, it is only necessary to have a line of site from each side anchor through the base pivot point, the side anchors can be at different elevations."

This is a dangerous statement.  If the guy anchor is at a level above the hinge and the guys are tight, then the tower is hazardous to lower.  As you lower the tower, the guys will stretch and break.

If the guy anchors are below the hinge level then they will get slack as you lower it which is OK usually.  If one is high and one is low it will swing off the line sideways which is usually OK too.  But it may mean the gin pole ends up under a side loading of some kind.

another note:  If the ground is too low, and you wish to keep the guys tight during the lowering then you can attach a secondary (branch) guy to the main guy at the level of the hinge (above anchor level) and run this secondary guy away from the direction of fall to a small anchor, so as to hold it at this point.  This will create a pivot point at or close to the hinge level without having to build up the ground level to the hinge level.  Let me know if  you need a diagram of this.  Or is it clear?

It is terribly important to make sure that guys do not get tighter during lifting or lowering operations as this can lead to failure of the guys, the tower, and destruction of the machine.  Beware.

[97fishmt]

Thanks for stepping in Hugh!!

I have followed your advice for many years. This is why I tried to be as

accurate as I possible.  I'm clear on the elevations and site lines that

affect the motions. I only settled on making it level because of the problems

and experiences I've had with the last pole. It worked flawlessly for 10 years.

Aside from it being stressed in one way or another.

I can be assured of smooth motion by going the extra mile.  

I am going to leave everything exposed for a few sessions to see if there is

any movement.  I don't expect any, and then move earth around the bases.  

I'm sure it will add stability to the above ground anchor points.  

This also was considered in my design though.

I receive about 4 or 5 feet of snow in the winter and have the tower down.

I snowmobile in and put it up. Out of the ice and snow might help.

More mass around the anchors may be in order,  I will keep a good eye on it,

I was going for the perfect lift and lower.

I have already had experience with the secondary guy points and did have to

employ them before.  

I tried to avoid that this time, but my gin pole scheme was an after thought

and it will require attention for its lift but it is minor.

Thanks Hugh

Hope to meet you some day

Mike Lawson