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Forum Index : Windmills : Foundations
| Author | Message | ||||
| Jules Newbie  Joined: 08/05/2014 Location: AustraliaPosts: 9 |
I have a 1.5 kw turbine on a 6m guy wire tower. Some of the foundations have started to pull out of the ground due to the amount of wet weather we've had lately. The current foundations are about 700mm deep by 400mm circumference. Wondering how I should proceed option 1 remove the old foundation and start over or option 2 excavate around the existing foundation and dump another couple hundred kg of concrete around it. Either way I'm prevented from going deeper due to a layer of bed rock. Any suggestions? Julian |
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fillm Guru  Joined: 10/02/2007 Location: AustraliaPosts: 730 |
Do What they to with big tents , 2 smaller foundations Behind and at 60Deg, then tie these to the existing guy anchor point is one method. There are many ways but weight is not the answer , surface area is - even a sleeper trenched in behind with a small link trench to allow it to be tied to the existing with as little ground disturbance as possible. The more useful information would be the height of the top guy attachment points , how many ,and the distance out from the tower base to the anchor points then the Dia of the mill. PhillM ...Oz Wind Engineering..Wind Turbine Kits 500W - 5000W ~ F&P Dual Kits ~ GOE222Blades- Voltage Control Parts ------- Tower kits |
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
I have the same problem, my anchor points have moved about 6 inches in the last 2 years. How far from the tower footing to the guy wire anchor points? Would it be practical to dig a trench a few inches deep between each anchor and the tower, and drop in a length of galvanised pipe, with a blob of cement at each end to bond with the existing foundations. Sort of like spokes of a big wheel. It would stop the anchor foundations creeping towards the tower. Just an idea. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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Tinker Guru Joined: 07/11/2007 Location: AustraliaPosts: 1904 |
Glenn, The forces on the guy wire anchor decrease with the distance to mast base but there is obviously a practical limit. Often suggested is a 45 deg angle for the guy, so distance from mast base = attachment height on mast. I do not think your anti pulling pipe in a trench idea has anywhere near the benefit of the sub anchor points fillm suggests. I would go with the latter and use star pickets hammered in at an angle with the top of the picket further from the mast base than its pointy end. You might only need to do that in the direction of the strongest winds at your location. Klaus |
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| jkis Newbie Joined: 31/07/2014 Location: AustraliaPosts: 16 |
if your down to good rock, would it be worth it to put in some dyna bolts into it, then cover with concrete to ground level. cheers stuart |
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norcold Guru Joined: 06/02/2011 Location: AustraliaPosts: 670 |
From my tank stand building days, I built 450mm dia X 1m deep concrete foundations in decomposed granite "sand", 4 on each tower, 6m out from upright. Highest tower is 12m with 4 X 3 Guys anchored to foundations. Probably an overkill in my low wind site, biggest problem I have is the 5mm galv wire rope guys, although they are a Whites Wires product they have developed rust problems. I think they may have just passed closely by the galv process  Have replaced one set already with 3mm stainless multistrand wire, I luckily scored cheaply.
The suggestion to use dyna bolts on rock is probably the best way to go if you cannot get depth. We come from the land downunder. Vic |
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| Jules Newbie Joined: 08/05/2014 Location: AustraliaPosts: 9 |
Thanks for your advice ended up getting an excavator out and putting over a ton of concrete in each pier problem resolved for now. |
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