Author Topic: A Question For Tower Guru's  (Read 3801 times)

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freejuice

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A Question For Tower Guru's
« on: March 14, 2010, 06:24:17 PM »
Hi Folks,

 First, these 60 foot towers are a lot of work!

Hopefully the tower will be up by this time next week...if I dont vapor lock first! Here's the stats:

 4 inch diameter pipe , three sections @ 60 feet...the last three feet being a 2 inch diameter pipe for a tower stub

I have 4 guy locations at 19 ft, 38 ft and 51 feet.

 The gin pole is a little short at 20 feet in regards to my tower length....it has a piece of 2 of two inch pipe as a gusset wleded between the tower and gin pole...the gusst length is roughly about 6 feet long close to a 45 degree angle between the gin pole and tower. At the top of the 20 ft gin pole I have three guy to help support the tower while lifting....thes guys attach at the locations I listed above ( 19ft, 38 ft and 51 ft)...my question is two parts:


I have a midsize pickup....ford ranger 2wd and I'm wondering if it could lift it?

 Lastly, any idea how much force will be exerted on the cable and connection points when the tower is in its most heaviest point?......I'm guesstimating at 30 degree angle or less.

 The reason I would like to know is because I'm wondering if my shackle at the top of the gin pole is strong enough to be the critical point for the tower lift.


 As a side note I discovered while raising the gin pole I realized that cables being  "straight line tight" is probably not a good thing especailly during temprature changes. When getting my gin pole plum I disciverd a cable with some slck in it could easily move the vertical postion gin pole when I adjusted the turnbuckles....thus I left a littel slack or slight droop in my three cables which go from the top of the gin pole to the tower connections.

 Thanks for any and all comments!

 Gavin

« Last Edit: March 14, 2010, 06:24:17 PM by (unknown) »

youmanskids

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Re: A Question For Tower Guru's
« Reply #1 on: March 14, 2010, 07:29:12 PM »
hey feejuice,  as you know I just raised my 60 footer a few weeks ago,  my gin pole is a bit longer than yours at 30 feet, and I had only the 2 sets of guys.  I left a bit of slack in all the guys during raising and then adjusted it once up.

mine went up super smooth with my Dodge Caravan minivan, not even a strain, almost at a rolling idle.  I used two pulleys, one on the tip of the gin and one on the anchor point to double my force and double the length of pull. the guys were attatched to the gin as you are doing. like i said, it went up under good control and smooth. the video from youtube if you want to see it--http://www.youtube.com/watch?v=N8Co2hpR_hA


the force on yours with the shorter gin will be a bit more but I dont think youll have any trouble with off the shelf hardware and your truck.  good luck, and get some video of the lift. Roger

« Last Edit: March 14, 2010, 07:29:12 PM by youmanskids »
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freejuice

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Re: A Question For Tower Guru's
« Reply #2 on: March 15, 2010, 02:32:43 AM »
Hi Roger,

 Thanks for the information! Yes I love that video!

All together, I think my tower weighs in (roughly) about 1300 lbs.

I like the pulley idea you used and I'm seeing few other folks around here are using a pulley too. So I'm convinced I will probably go that route too!

 The gin pole connection for the 3 tower guy support cables is a 1/2 inch ( 1/2 inch being the pin that passes through the shackle)rated at 2 ton (4000) lbs.

 All three of the tower lifting guys are on this shackle...I'm wondering if this point has enough "Butt" to handle it throughout the most part of the strain, say from the ground of 0 degrees to a 30 degree tilt.


I would like to make things a bit bigger but going up a ladder 20 feet off the ground is a bit touch and go...I have the extension ladder tied off at various points up the gin pole and just used this method to get the three cables pulled tight at the connection point....but getting up there to enlarge the hole through the plate I welded to the gin pole to accomodate a bigger shackle, is a bit risky with a hand drill at 20 feet off the ground...we all know how a hand drill will twist and bite while trying to enlarge a hole with a 5/8 bit.

 I'm sure I could weld something up ther to accomodate a bigger shackle but the less I have to get 20 feet off the ground the better I feel. :o)...just hoping that 4000lb rated shackle will do.


 Since my gin pole is a bit short, I will have to transfer the gin pole wires... groan...thats the least of my worries at this point.

 what do you folks think about this shackle/anchor point?

 thanks!

 Gavin

« Last Edit: March 15, 2010, 02:32:43 AM by freejuice »

Volvo farmer

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Re: A Question For Tower Guru's
« Reply #3 on: March 15, 2010, 05:21:11 AM »
You're going to test-raise it first aren't you? If you really want a bigger shackle, couldn't you could do that once you have the gin pole on the ground? 4000 lbs is about what your whole pick-up truck weighs, I think it would be sufficient for a test-raise.


I feel your anxiety. I felt it tipping only 40' of steel in the air. I think it's good to be scared because it makes you more careful. I lowered my tower once, then looked up at the top of the gin pole and realized there was only one wire clamp on the cable I attach to the tractor. So I had to take the turbine off and re-raise it so that I could put extra clamps on the cable. I think the forces are not all that huge on an empty tower, even at 60' tall.

« Last Edit: March 15, 2010, 05:21:11 AM by Volvo farmer »
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SparWeb

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Re: A Question For Tower Guru's
« Reply #4 on: March 15, 2010, 12:10:51 PM »
freejuiceIf you say to yourself you're pushing it - then you probably are.  I don't think a 20' gin pole is enough to operate safely, and since you don't know heavy everything is, you don't know how much load is required.  Have you tried to figure it out?


I believe it was a Ford pickup involved in one tower-raising incident that went badly when the weight of the tower drew the truck, with the brakes on, right up to the anchor base.  Well, it could have been any truck, but it's the traction not the engine torque that gets the tower raised.


Youmanskids:  I saw your video for the first time.  Did you really have two guys standing at the back guy anchor?  Do you know how many milliseconds they have to get out of the way if your tow cable lets go?


A sufficiently long gin pole, some freedom of motion in the gin stay wires, adequate safety margins on cables and connections, all (and much more) are necessary if you're going to do this safely.  


PS, take that ladder down.  When the gin pole for the tower gets long enough that it's hard to access, use a secondary gin pole to lower the main gin pole.  Then you can make the connections on it at your leisure, raise it back up, remove the secondary gin pole, and re-attach the tower to raise it.

« Last Edit: March 15, 2010, 12:10:51 PM by SparWeb »
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freejuice

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Re: A Question For Tower Guru's
« Reply #5 on: March 15, 2010, 12:29:10 PM »
 Hi Volvo,

  I'm probably going to do a few short test raises first as I adjust the cables.... then probably a slow working test raise completley up as I get the guy wires further adjusted....I just dont want to drop the tower and bend up the works with a shackle shearing off.... I might try to lace another cable through the guy wires loops at the top of the gin pole and around the gin pole itself.....as a safety...maybe I can squeeze two laps through the cable loops....and cable clamp the "beegeebers" out of it!


 I wish I could lower the gin pole but everything is welded and into position; gin pole is up and the tower is on the ground, any work now requires the ol' ladder routine. I was going to ahve the gim pole removable, but I thought " what the heck, that extra weight wont hurt, it will help hold the tower in the unpright position just a bit more.


concerns/comments?

 All the best

 Gavin

« Last Edit: March 15, 2010, 12:29:10 PM by freejuice »

freejuice

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Re: A Question For Tower Guru's
« Reply #6 on: March 15, 2010, 12:45:44 PM »
Hi Steven,

 Thanks for the info, but I have welded everything into position so its the ladder or nothing at all. I did lash that ladder down tight as I went up it. Too fully access the top of the gin pole I had the ladder in the back of the truck with the ropes pulling it tightly up against the bed side wall and the ropes tying it down ...it was actually failry secure...it wasn't a secenario of an extension ladder toggling around a 4 inch diamater piece of pipe...I just dont like working with one hand free at twenty feet off the ground.


 I'm with you on the truck traction.


The tower weighs in at about 1300-1400 lbs and the gin pole is around 200 lbs...if I can get this thing up..I bet you one thing this tower will not be lowered until I can get that ginpole out another 10 feet and a shackle with at least a one inch pin through it!


 All the best,

 Gavin

« Last Edit: March 15, 2010, 12:45:44 PM by freejuice »

fabricator

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Re: A Question For Tower Guru's
« Reply #7 on: March 15, 2010, 04:06:45 PM »
You never said how big the shackle bolt is, shackle bolts are grade eight or better, just by memory here, but the stretch failure strength of a 1/2 inch grade eight would be around eight thousand pounds, the tension failure would be around ten thousand pounds, if your welds will hold the shackle is the last thing you need to worry about.
« Last Edit: March 15, 2010, 04:06:45 PM by fabricator »
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freejuice

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Re: A Question For Tower Guru's
« Reply #8 on: March 15, 2010, 05:38:33 PM »
Hi Fabricator,

 The shackle pin or bolt is a 1/2 inch diameter.  The welds are good, I dont think they will let go. With the numbers you have, it looks like I might be good to go....hopefully I can give an update this weekend.

 Thanks again,

 Gavin
« Last Edit: March 15, 2010, 05:38:33 PM by freejuice »

Ungrounded Lightning Rod

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Re: A Question For Tower Guru's
« Reply #9 on: March 15, 2010, 06:16:42 PM »
I believe it was a Ford pickup involved in one tower-raising incident that went badly when the weight of the tower drew the truck, with the brakes on, right up to the anchor base.


It's things like that which make me glad I got an F-150.  And if I use it to raise a mast I'll fill the bed with a half-ton of SOMETHING before starting.  B-)

« Last Edit: March 15, 2010, 06:16:42 PM by Ungrounded Lightning Rod »

freejuice

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Re: A Question For Tower Guru's
« Reply #10 on: March 15, 2010, 06:28:20 PM »


 Good point,

 I will put some weight on those back tires.....if I only had a grip hoist, the stress level would probably drop a few points....the truck probably weighs in at 3500 lbs empty, I have a tractor but it only goes about 2000 lbs...but is has a  verrrrrrry, very slow creeping gear range, to bad its too light.


Thanks for the info,

 Gavin

« Last Edit: March 15, 2010, 06:28:20 PM by freejuice »

Ungrounded Lightning Rod

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Re: A Question For Tower Guru's
« Reply #11 on: March 16, 2010, 02:16:36 PM »
(My F150 is a 4X4 with 4-low.)
« Last Edit: March 16, 2010, 02:16:36 PM by Ungrounded Lightning Rod »