Author Topic: New Tower (Read 22996 times)

ChrisOlson · « **on:** July 11, 2012, 11:47:56 PM »

I'm putting up a new design free-standing lattice tower that will replace one of my old angle iron towers. The angle iron towers have proven to be too flexible and exhibit natural frequency problems at certain rotor rpm ranges. This new tower is designed to address and rectify both of those issues.

The new tower is 71 feet to the top of the lattice with a 8 foot 8" diameter mast so it's 79 feet to the top of the tower and 80 feet from grade to the turbine hub. The columns are 2.5" x 1/4" wall 55Kpsi mechanical tubing on section #1, section #2 is 2.5" x 3/16" wall 55Kpsi, the top section is 2.5" x 1/8" wall 55Kpsi. The lattice is 1.25" x 3/16" angle. Base spread on the tower is 7 feet.

The tower and foundation is designed, certified and built to meet TIA/EIA-222 Revision G with 114 ft² flat plate loading, 90 mph survival, 3 second gust, Category B Exposure zone.

The foundation is 5 feet deep, 10 feet square x 1 foot thick at the base. The tower pier is 8 feet square. The foundation is basically an inverted "tee" poured in two lifts. I has ~1,600 lbs of rebar in it and 52,740 lbs of 5Kpsi concrete.

The gin is 30 feet and the gin attachment that bolts on the base of the tower has a provision for side guy cable braces on the gin to prevent it from buckling sideways when the tower is first started on its raise. But the side braces are not needed for just the base section so they are not pictured in the photos. In fact, the gin is so heavy I had to use a floor jack to start the tower on its tip in order to lay it down with just one section standing.

I got the base section of the tower standing on the pier, and leveled. I lowered the tower late this afternoon to put the next three sections on it. But I have to wait 3 weeks for the concrete to reach full strength before putting the turbine on it.

One of my 3.5 meter high voltage MPPT turbines is going on the tower.

Lots of turbine builds get posted, but not too many free-standing lattice tower builds. Thought folks might be interested in seeing how it's done. This tower is not cheap - about $12 Grand with excavator time, all the rebar work, concrete work and steel. But I hate guyed towers with a passion (plus guyed towers can't be erected in our township) so this is the way I do 'em.

--
Chris

GoVertical · « **Reply #1 on:** July 12, 2012, 10:14:35 AM »

Wow, great job! Did you notice any instability when you were sitting on top of tower?

madlabs · « **Reply #2 on:** July 12, 2012, 10:32:07 AM »

Chris,

I'm slowly working on restoring a 7' diameter pumper windmill and am going to need a tower for it. Did you fabricate the tower, and if so can you tell us more about the construction, like how did you keep it true and straight while building, how did you coat it, etc.

Nice looking tower!

Jonathan

ChrisOlson · « **Reply #3 on:** July 12, 2012, 10:32:30 AM »

Only instability I noticed was in me. My wife wondered what I was doing up there on top of that 31 foot base section, without climbing gear, when she snapped the photo. I told her it's a new tower. Therefore it's like a mountain. It has be climbed because it's there.
--
Chris

ChrisOlson · « **Reply #4 on:** July 12, 2012, 10:57:16 AM »

Quote from: madlabs on July 12, 2012, 10:32:07 AM

I'm slowly working on restoring a 7' diameter pumper windmill and am going to need a tower for it. Did you fabricate the tower, and if so can you tell us more about the construction, like how did you keep it true and straight while building, how did you coat it, etc.

Yes, I designed and built it. It's basically a copy of a Rohn SSV and the materials use are noted in the first post. Rohn's SSV are basically two designs - bolted together N or WN and welded together W. At some point in the past, they stopped producing all welded 5W and 4W sections and converted to manufacturing bolted sections for these sizes. I think they did this primarily because of shipping cost of welded towers, and bolted sections can be shipped broken down on a flat pallet.

I went with welded W, as if you've ever looked closely at a SSV, or assembled one and raised it, there's considerable warping in the columns from welding the truss member brackets to the columns causing a stress point in the steel. The columns on an SSV have to be "forced" into position to get the bolt holes to line up during assembly because they're shipped warped from the welding.

This tower is a 5W base section, section #'s 2 & 3 are 4WN sections.

The sections are just primed right now with a rust inhibiting red oxide primer. When the tower is fully assembled and laying on its stand I will paint it with aluminum paint with a pneumatic paint gun.
--
Chris

midwoud1 · « **Reply #5 on:** July 12, 2012, 12:21:40 PM »

Hi class tower .

I see a Tirfor to lift it ?
Pse a video when you set it up .
I made a Jacobs copy tower years ago 40 foot.
No place near my house so my neighbour Arie offered a place.
Because Arie made an extra building there , I gave the tower to a friend windmill maker.

This model tower can be a good idea for Madlabs windmill pump.

Chris goodluck.

- Frans -

ChrisOlson · « **Reply #6 on:** July 12, 2012, 01:06:07 PM »

Quote from: midwoud1 on July 12, 2012, 12:21:40 PM

I see a Tirfor to lift it ?

No, just a double reduction gear winch with a crank, hung on the side of an elm tree. It only takes about 650 lbs of pull to raise the tower with the turbine on it.
--
Chris

Steadfast · « **Reply #7 on:** July 12, 2012, 01:32:17 PM »

WOW...and I thought my tower was cool...

Dude...I am so unworthy!

Well done!

Mastiffman · « **Reply #8 on:** July 12, 2012, 02:22:38 PM »

Nice Tower Chris! Glad there are still those that love to climb.

ChrisOlson · « **Reply #9 on:** July 12, 2012, 02:27:20 PM »

Steadfast, your tower is cool because it's your first one, it's relatively economical, and sheer determination got it up. Big free-standing towers are expensive and probably not the thing for a beginner to try.

A free-standing tower is only as good as its foundation. The foundation alone for this tower will cost the average joe around $6,000. I takes heavy equipment to put up a free-standing tower this size. I happen to own an excavator and the heavy dirt moving equipment to do it. But it's still not the type of tower that most homebuilders are going to put up.

I posted it to show how it's done. More and more townships are passing ordinances prohibiting guyed towers anymore, whether it be for wind power or cell service. Revision G to the tower standards was passed because of tower collapses - one of the most notable being the 2,000 foot WEAU TV tower that collapsed a few miles south of here last year. When that tower came down the guy cables cut 24-30" hardwoods right down when they started whipping around like snakes, slicker than any feller-buncher I've ever seen. The total footprint of the destruction inside the guy radius when that tower came down may as well have been from a nuclear blast. Those cables cut big trees, power poles and powerlines right off, as well as putting a hole in a 500 gallon LP tank. And the winds weren't even that high when it failed - it came down because of ice load and a single failed guy wire. That tower stood as the tallest man-made structure east of the Mississippi for 45 years

http://www.weau.com/home/headlines/WEAU_13_tower_collapses_in_Fairchild.html

Free-standing towers don't take up as much real estate, and if one does fail the total footprint of the destruction zone is smaller. All it takes to bring a guyed tower down, just like the WEAU tower, is one failed guy cable.

I predict that it won't be long and guyed towers will be pretty much universally outlawed in the US.
--
Chris

Steadfast · « **Reply #10 on:** July 12, 2012, 03:06:50 PM »

well Chris, we are glad you are back with us...

just-doug · « **Reply #11 on:** July 12, 2012, 06:30:59 PM »

very nice. the tower hinge assembly appears to be approxamently 5/8 by 4 flat bar with a 1 inch hinge pin.am i even close.do you plan on having a jib crane of some sort on the top to give you the option of raising parts when heavy maintaince is needed?

ChrisOlson · « **Reply #12 on:** July 12, 2012, 11:11:03 PM »

Quote from: just-doug on July 12, 2012, 06:30:59 PM

very nice. the tower hinge assembly appears to be approxamently 5/8 by 4 flat bar with a 1 inch hinge pin.am i even close.do you plan on having a jib crane of some sort on the top to give you the option of raising parts when heavy maintaince is needed?

The hinge supports that come out of the foundation are 5" x 3/4" flat stock. There is no hinge pin - the tower legs are bolted to that flat stock with 1" diameter bolts. The third leg that tips up with the gin attachment on it is bolted to its pad with four 3/4" bolts. The tower hinges down on a single 1" bolt on each side. When it's raised and ready to go into service there's a leg brace that bolts on the two hinge legs and two more 1" bolts that bolt the leg brace to the foundation support on each side. The tower can't be tilted down with the leg brace on it.

I don't use hinge pins on my towers because they they can never be kept tight. I like a tower that's firmly bolted to its foundation, and that doesn't move. Towers that have loose parts sing in the wind and amplify noise from the generator, and are generally noisy. My towers have nothing that is loose or slip fit.

No crane on the tower. It has to be lowered to service the turbine. With the 8' mast, and the turbine on top of that, you're still 9 feet below the hub of the turbine if you climb to the top of the lattice and were standing on the top of the lattice. It would be impractical to try to service the turbine with the tower standing.
--
Chris

birdhouse · « **Reply #13 on:** July 13, 2012, 01:37:21 AM »

wait, i don't understand, you don't want to climb that tower and set up a 4' step ladder on top, to get to a comfortable working height to lube things up???

sounds simple and safe enough for me!

kidding!

adam

i do have a real question about the flexing ect, but i'll ask it once i'm more with it!

ChrisOlson · « **Reply #14 on:** July 13, 2012, 08:52:19 AM »

Quote from: birdhouse on July 13, 2012, 01:37:21 AM

i do have a real question about the flexing ect, but i'll ask it once i'm more with it!

Before you ask too many questions about flexing, be aware that lattice towers (or monopoles for that matter), bridges, tall buildings, etc. flex under extreme loading as part of their normal life in order to transfer the proper loads to the members that support the structure. Build it too rigid and you will find the weak point, and it will fail well before the design loading is reached.

FEA on a lattice tower is a bit beyond the scope of this forum.
--
Chris

birdhouse · « **Reply #15 on:** July 13, 2012, 11:19:30 AM »

Quote

I went with welded W, as if you've ever looked closely at a SSV, or assembled one and raised it, there's considerable warping in the columns from welding the truss member brackets to the columns causing a stress point in the steel. The columns on an SSV have to be "forced" into position to get the bolt holes to line up during assembly because they're shipped warped from the welding.

just curious as to when you constructed yours, did you preflex any steel to put it into tension or compression before you welded? or did the welding process alone put any forces on the tubes upon cooling?

i guess what i'm really asking, is if you sight down any one of the tower legs, is it dead straight or does it have a slight inward?? bend to it?

adam

ChrisOlson · « **Reply #16 on:** July 13, 2012, 01:09:17 PM »

The columns are pre-stressed on a jig I made to hold them in place while the lattice is welded on.

The loss of pre-stress along a structural member can be erratic, depending on the sequence of the tack welding. It's pretty much impossible to obtain a uniform pre-stress, when welding operations are involved, that will approach the theoretical values of the member. Even though a low pre-stress will not affect the ultimate strength of a beam or column, it can affect fatigue life and cause localized yield under excessively high static load.
--
Chris

Steadfast · « **Reply #17 on:** July 13, 2012, 03:06:54 PM »

more pictures....

RP · « **Reply #18 on:** July 13, 2012, 04:29:12 PM »

Chris,

A lot of the pipe towers I see run the cable down the center of the mast. Are you planning to use slip rings at the top and tie off to a leg or how will you route power down?

ChrisOlson · « **Reply #19 on:** July 13, 2012, 06:12:18 PM »

Quote from: RP on July 13, 2012, 04:29:12 PM

A lot of the pipe towers I see run the cable down the center of the mast. Are you planning to use slip rings at the top and tie off to a leg or how will you route power down?

I don't use slip rings. The turbine never runs much over 22 amps @ 130-145 volts, so it only requires 10/3 on the tower drop. I use Kellems grips at ~30 and ~60 feet to provide strain relief for the drop cable.

I've never yet had a problem with a turbine twisting up the drop cable. For folks that fly turbines on short towers in turbulent and variable wind, then it can be an issue.
--
Chris

RP · « **Reply #20 on:** July 13, 2012, 06:28:05 PM »

Cool!

Thanks

keithturtle · « **Reply #21 on:** July 13, 2012, 10:46:23 PM »

Nice tower, Chris. Thanks for sharing

Turtle

tanner0441 · « **Reply #22 on:** July 14, 2012, 10:23:46 AM »

Hi Chris

It looks like a very stable tower, if your first section is 31 ft will you have another two sections to the top or one long smaller profile. Someone commented on climbing it for maintainance, you could run a 3/16 nylon pipe up the tower to the yaw bearing and grease it from ground level, a bit like the old Tecalamit lube set ups on the old trucks, and talking of trucks could you get hold of a ram from a tipper to raise and lower it? I would imagine concrete base would more than handle the loading.

Brian

fabricator · « **Reply #23 on:** July 15, 2012, 09:32:39 AM »

He already stated it's a tilt up tower.

tanner0441 · « **Reply #24 on:** July 15, 2012, 12:45:07 PM »

Hi

I know it's a tilt up but I wondered as Chris has access to truck stuff if instead of using a gin pole and winch he could use the ram from a tipper truck, I have seen several monopoles that use that method.

Brian

fabricator · « **Reply #25 on:** July 15, 2012, 04:41:58 PM »

I'm not Chris and I don't play him on TV, but I do know he is a mechanical engineer and a farmer by trade and farms mot of two townships, he has more big equipment than some excavating companies.

ChrisOlson · « **Reply #26 on:** July 15, 2012, 11:46:53 PM »

Don't need any big equipment to raise this tower with a 300 lb turbine on it. A hand crank double gear reduction winch with a snatch block on the gin works just fine. I test raised it and it stands straight and true.

I prefer using the hand winch mounted on the elm tree to raise and lower it. That way I don't have to plow out in the winter time to get equipment in there to handle the tower if I want to lower it to de-ice the turbine or something. People tend to miss the big picture some times and get things way too complicated. I like to have my towers set up so I can lower the thing on a whim and have it back up inside of an hour. You start farting around with cranes and trucks and whatnot, and you're turning a tilting tower, which is a simple thing, into something more complicated than it has to be.
--
Chris

gww · « **Reply #27 on:** July 16, 2012, 02:10:37 AM »

Chris
It's probly been covered but I don't remember, how do you start you tower to tilt from a standing position?
Thanks
gww

ChrisOlson · « **Reply #28 on:** July 16, 2012, 08:22:31 AM »

Quote from: gww on July 16, 2012, 02:10:37 AM

It's probly been covered but I don't remember, how do you start you tower to tilt from a standing position?

A floor jack under the gin right near the base.
--
Chris

gww · « **Reply #29 on:** July 16, 2012, 05:50:47 PM »

Chris
Thank you
gww

ChrisOlson · « **Reply #30 on:** July 16, 2012, 11:01:30 PM »

Today's project was to get the new tower wired in to the power system in the utility room so there's a connection between the tower base junction box and the battery bank. Plus get turbine controls installed for it.

The voltage clipper is in the big box. There's an air intake screen on the bottom of the clipper box and an exhaust fan that exhausts hot air out the back (there's about a 1/2" between the back of the box and the wood that it's mounted on). The exhaust fan comes on whenever the clipper is activated. There's also an Omron two pole relay in there that I can activate with a toggle switch from inside the house to turn the clipper on manually and use it for a brake to stop the turbine without having to go outside and throw the brake switch.

A few more days to let the concrete get closer to full strength and I'll be ready to go live with this one.
--
Chris

ChrisOlson · « **Reply #31 on:** July 17, 2012, 11:25:19 PM »

Wind wasn't blowing that hard today - about 12 mph - so I put the thing up and turned 'er loose.

This is the turbine on its way to the top:

And putting out 300-400 watts in a nice 12 mph breeze:

--
Chris

fabricator · « **Reply #32 on:** July 18, 2012, 11:14:13 AM »

Beautiful.

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Author Topic: New Tower (Read 22996 times)