The AM Forum

I just noticed damage to one of the guy anchors of the tower.  Apparently, it was run over by a vehicle, since there are rubber tire marks on the equaliser plate (see photo below).  I suspect the person who last mowed the field, which has been taken care of by the farmer who leases the crop land for over 30 years, and never before caused any  damage.  He says he wasn't aware that he hit the anchor, but someone  would really have had to be careless not to see it, since I keep a strip around the guy anchors clear with the lawn mower just to avoid such a mishap.  I am not aware of any trespassers driving vehicles into the antenna field.

The farmer said he would take care of repairing any damage, but I doubt he is aware of what the cost would be. Replacing the bent guy anchor would involve digging up the concrete anchor and pouring a new one.  The original is probably 2 ½ ft. square and 2 ft thick, buried to a depth of 3' below grade.  I used considerable overkill at the outset and then had extra concrete poured into the holes after they had finished, to dispose of what was left over. The cost of having one anchor totally re-done by a professional would likely add up to more than what I paid for the entire tower in 1980 even after adjusting for the dwindling buying power of the dollarette. If the farmer or his insurance company are indeed willing to foot the bill, I'm not sure I want to go through all the hassle, plus I'm sure they would do considerable damage to the radial system driving tractors and back-hoe all over the field.

The alternative would be to take a long crow bar and attempt to re-twist the anchor rod back to its original shape, but I am concerned that metal fatigue from the initial twist and then the repair would weaken the rod, so perhaps the best thing to do would be to just leave it alone.  But the guy wires would still be thrown out of alignment, even if the bent turnbuckles (I have spares) were replaced.  This could be a problem, particularly if I ever decide to re-guy the tower.

Another problem with  replacing the whole thing would be how to hold the tower in place while the old anchor was being removed and a  new one installed.  I would assume professional tower installers would know how to do this.

For some time I had been planning to dig out one or more of the anchors down to the concrete to check for rusting, so I'll likely do this one to check for underground damage.  Removing the dirt away from the rod all the way down to the concrete should allow the bend to correct itself to some extent, but I am not sure about trying to force the twist out of the rod, which appears to be a little less than 45°.

Needless to say, I am extremely pissed off.  One more example of why I try to do as much of the work as I can around the homestead myself.

Don
A tower crew would probably want around $1500.
Was is really bad damage like bent the tower? Can you retension the tower and  make sure it is plum? Maybe you should call a tower company to inspect and give a thumbs up.

The pics are very nice BTW,,,,looks like the turnbuckle screws are bent at the end of travel. Weakened?? dunno Can you replace and tie the two guys to a vehicle, or loosening any guy wire is a no-no??


Fred

The steel that the guy anchor and the turnbuckles are made from is mild steel...It should bend without breaking and probably won't fail unless it is bent back and forth a few times...Check any bent areas for fractures..If there are no visible stress cracks, it is probably as strong as the day you put it in...No worries...See Standard disclaimer .....

Awww, sh@@ happens, OM... ;)

Yes, I'd say you could leave it as-is and not worry about failure. That steel can take quite a beating. I would not try to bend it back due to needless additional fatigue generated.

If you are really concerned, you could  clamp on a STRONG bracket using u-bolts onto the rod behind the turnbuckles - where the rod enters the ground. Use for "safety lines" -  guy wire jumpers that would hold each guy wire in case of a failure at the turnbuckle plate.  U-bolt each safety line to each of the individual guy wires.


Another alternative is to put in a minimum-sized  hole anchor point behind the exisiting anchor point. Use the same safey line technique as back up. You could dig the hole by hand and mix your own concrete - and use a $10 I-beam from the scrap yard as the anchor rod.  Put the new hole right behind the existing concrete as a barrier/buffer for more pull strength.

Either way, it will be easy to replace the two or so bent turnbuckles that now exist. Use a steel loop through each plate hole to give the new turnbuckle flexiblity to handle the "new" angle that now exists.


You probably already do this, but by using a come-along and those twist-on guy grips, you can release a guy wire to work on the turnbuckles quite easily. If you are not familiar, I can go into more details, but if you put up the tower, you know... ;).

T

That's what I'm  thinking.  But I still plan to excavate around the steel rod down to the concrete, probably in the spring while the ground is still wet and soft.  I had been planning to do that all along to check for rust damage, and the recent article in QST nudged me along to go ahead with the project even before I had discovered this damage.  The end of the rod should shift position slightly, with some resolution of the bend due to the straight pull from the guys without any lateral force from the soil.

I might go ahead and replace the bent turnbuckles since I have spares on hand, so that everything will reach equilibrium with the guys in straight lines all the way to the plate. I'm glad I picked up those extra turnbuckles at whatever forgotten place it was that I found them.

Wow Don, this really stinks.  yeah, I once investigated having a yard service here and nixed the idea after thinking about it for 10 seconds because I didn't want some yahoo out there cutting through feedlines, hitting ground rods etc.  

Sometimes when you get a professional to take a look, the solution can be a pleasant surprise--you might find out there is a quick effective (and cheap) fix.  If the ground is dry and hard (late fall/winter conditions) this might be a good time to have the fix done if one is needed and involves heavy equipment.  I have no idea off-hand how they do a temp anchor of the guys but there must be a way to do it.   If you wind up needed concrete, you'll probably have to have it trucked in.  That's some weight right there.   This might be the best time of year to do it.

Well now I know another reason why broadcast stations put chain link fence around their guy anchors.  I used to think it was about preventing vandalism and kids playing around on the guys; I guess it's also keeping kids with their stupid texting habit with bush-hogs away.

I'm just extremely glad one of the guys didn't snap.

Rob

The only problem with the chain link fence is that without  some way to  get a mower in, weeds will grow 10 ft. tall and before you know it trees will be growing in the spot.  I think the farmer may have been letting his kid who is still in high school do the mowing. Figures.

I have a guy come in with a tractor and brush hog every year to take out the high grass. I told him if he hits a guy wire, he will most likely take down the tower and might get killed. If not, he will have a big bill to pay. That sobered him up and I see him drive around those guy anchors like they're holding nitro-glycerine.. ;D

But what works well -  before he shows up I take out my roll of florescent day-glo orange plasdick tape and hang tape from all the guys and anchor points. That may be a good idea for your installation all the time, Don.


I suppose since the guy offered to pay you could get an official estimate from a tower company and submit the bill. Then do the job yourself, however way you intend. Or wouldn't the home owner's insurance pay? As much as you probably hate to even get them involved... I know.

All in all, you got away pretty unscathed. It will have no effect whatsoever on your operation. Good thing you have virtually no load on the tower too. A 2x2x2 40M stack wud be a different situation.

Though, when you climb it, looking down and seeing that bent rod may be unnerving. I wud probably add in some kind of safety back-up as I described above just to calm the nerves... ;)

T

Time to put in some stout bollards around the guy points.   

They can bend up a tractor in no time... ;)

BTW, that's a manly 1" diameter anchor rod, right? Not one of those thin homo 1/2" types I hope.  

Why are you concerned about rust? Is this in concerete or does the rod go through a layer of dirt first?

My oldest 150'er put up in 1986 goes through a few feet of dirt. I inspected them a few years ago and see the rod galvanizing is gone, but the steel rod is fine. My dirt must be accepatable.

Since then, I put in my newer anchors so that the rod is surrounded by concrete all the way to the surface. Rods will not rust through in concrete - at least the rebar I see in some work that is 100 years old still looks good.
 

T

I'm not sure if it's a full 1".  It is the one Rohn recommended in their tower book for the 25G, for heights well above mine, had their part number and I bought it from them. I know it is more than a measly 1/2". I'll measure it next time I am out there.

What made me want to check the rod for corrosion after almost 30 years is the same thing that got me my base insulator.  A BC station in Alabama had the top half of their tower fall.  It just barely missed their transmitter building.  When they decided to replace the entire tower instead of just repairing the old one, they didn't want to put a brand new tower on top of a 40-YO base insulator, so they bought a new one to go with the tower.  I inherited the old one, courtesy of Hoisy, W4CJL of SPAM fame.  When I went to pick up the base insulator, they showed me what happened.  The guy anchor rod had rusted and pulled in two right at ground level where it entered the concrete dead-man, and that rod was a substantially larger than mine, since the tower was about 250' tall, solid instead of hollow, and about twice the cross section of 25G. The straw that broke the camel's back was the article in a recent issue of QST.  The author mentioned that often the rod corrodes just where it exits the  concrete, due to electrolysis.  That is exactly what happened at the station in AL.

I seem to remember that the QST article, which appeared just a month or two ago, generated a thread on this board.

Ouch!

He knew he hit it.

I'd have some pipes in concrete sticking up in order to prevent just this sort of thing from happening...

                  _-_-bear

That's what I had to do at the guy anchors for the poles on my property line next to the road.  Guy anchors at both the beverage pole and the wooden utility pole terminating the Philystran that holds up the end of the dipole, got hit by the dingbats who mow the right-of-way.

Since I kept a broad strip mowed all around the tower guy anchors to keep them clearly visible, and they had mowed the field almost 30 years without damage, I stopped worrying about it.  Initially, I installed some of those bright yellow fibreglass shields the power co. uses over the guy wires to their utility poles, but the UV eventually destroyed them and I didn't replace them, thinking there was no need to.

Don,

Do you think the electrolysis was a result of power being dumped into the BC tower?  I wonder if this effect would take place with a cold tower... 

Yes, we beat that thread here to death once. The worst case I've seen is a 300' Rohn 45 tower coming down cuz a farmer had previously dumped his old batteries in the same place as the rods where placed.


Rohn made both a small and big anchor rod. The big one is MUCH more strapping. Maybe it's for Rohn 55 tower, I dunno. I used them until I discovered that a scrap yard I-beam with a "T" bolted to the dead end was far superior and about 1/20th the price.

T

On some commercial towers I've seen some sort of epoxy grout poured around tower anchor bolts into concrete to prevent the rusting you're describing. I've also seen tar used for the same purpose. Both seem to work well.

If you did put a fence around it. Cut the grass really close. Then put a heavy sheet of plastic on top of the grass, then cover it with about 4-5 inches of crushed rock. I think that would solve the grass cutting problem

The reason I keep goats!  No mowing....anything that sprouts up, they get it.

This morning I had another look at the guy anchor.  The diameter is a little more than 5/8", 0.64" to be exact.

Although I had said I would leave the twisted rod alone, I decided to try and see how much "give" it had.  Using nothing more than a long screwdriver about 18" in length, inserted between the equaliser plates that sandwich the eye of the anchor, I twisted it, and was able to return the rod almost exactly to its original shape, taking the offset out of the guys so that the guys no longer tend to cause the turnbuckles to bend.

Actually, this is a little disconcerting, that the rod twisted back and re-formed so easily, making me wonder if its strength has been compromised.  The tops of those anchor rods appear identical to the "screw-in" type that Rohn also sold at the time.  I helped a friend erect a 25G tilt-over using those screw-in anchors, and they were very stiff and wouldn't deform even with all the torque both of us could muster with all our might, using a 3' or 4' lever inserted into the eyelet.  But I was able to return mine back nearly to original form, single-handedly with an 18" lever using my 68-YO arms that were never that strong to begin with.

If the rod hasn't been compromised, they either used much harder steel for screw-ins, or else my rod had conserved a "memory effect" that allowed it to be returned to its original form with little torque.  I definitely will dig down to the concrete to inspect the condition of the rod before I climb the tower again.

if it bent back as easily as you say, i think I'd definitely want to dig down to the concrete and see how that anchor looks below grade.  I sure wish I lived within an hour or two of ur qth don; i'd come over and help you dig.

Yeah, I think you should look into that the sooner the better Don and be careful not to get in the way of that equalizer while digging. It dose sound like the rod is rotted and, it could be when it got rolled over, it gave so easy it wasn't noticed.

It might be best to follow Tom's advice and sink and install a  second, temporary anchor before digging. Three temporary screw in anchors might get you through the winter without worry if, as you say, you want to wait until spring to do a more permanent job. Good luck. Looks like this accident might have saved you from a tower fall. Be safe.

There's one way to find out, Don.

Take the same screwdriver to one of the other good anchor rods and see it you can twist it even a fraction of an inch.  It may have spring, but will probably settle back to its original form. 

That does seem suspiciously easy to turn. Can you imagine if it fatigued and the plate twisted off? That would have made for a shocking day... :o  I would proceed cautiously with that anchor until you proof it out with the other samples.


And, yes, those 5/8" anchors are the lighter rods, though still speced out OK by Rohn for Rohn 45 use.  The 1" diameter ones are much stronger and may have survived the tractor-mash.

T

Figure's, huh? Just get your new doghouse done, and now you get to mess with this. From the looks of it, it looks like it was pressed right down to the soil by a tire, and then sprung back up to that 45° position. If you were able to twist it that easily, it sounds like the rod may be cracked below the soil.

Might not be a bad idea to hurry up and get diggin before any strong winds come though your area. You wouldn't happen to have (or borrow) something heavy you could park near it and tie off the equalizer plate to just in case?

.

Par for the course at this place. I don't even have the tuners fully re-assembled and installed in the dawg house yet.  If it isn't one thing, it's fifteen.

This had to have happened about a month or 6-weeks ago, last time they mowed. It has been so dry that nothing has grown for over a month.  First time ever that I remember not having to mow the lawn in all of October and do a final mowing about the first of November. I understand we had some pretty high winds Thursday night, but I was in Memphis at the time.  We returned to see the remnants of about 1" of snow and sleet that accumulated as the storm blew through.

I started the exploratory dig this afternoon.  Dug down about 18-20" below grade, and think I hit  the concrete slab, but had to quit because I ran out of daylight. Slow, a lot like an archaeology dig, because I didn't want to ding up the rod with shovel and spade.  So far, the rod appears sound. The bright zinc plating is gone and there is some evidence of surface rust, but no visible cracks, deep pitting or etching away of the metal.

I did notice a visible kink in the rod.  Perhaps I should have gone ahead with the exploratory dig before disturbing anything to see what really happened upon impact, but it appears that the twist in the plate position may have actually been due to a bend in the rod as the tractor pushed the equaliser plate against the compacted earth and then the rod sprang back up.  Once I got down about 8" below grade, there was absolutely no give to the rod. The clay might just as well  have been concrete, except I could chip away at it with the spade. I believe forcing the plate back into position merely straightened out most of the bend, and I would consider a simple bend to be less cause for worry than evidence that the rod was actually that easy to twist and then re-form back approximately to the original.

Here are some photos I took when I quit work.  They look more like B&W because I took them at dusk using flash.  The kink is clearly visible, but so far I see no irregularities at the surface of the rod that would resemble a stress fracture or severe twist. To-morrow I plan to finish the dig all the way to the concrete slab, and then carefully clean the rod with water to wash away the dirt to get a better look at the surface over the entire exposed length.

I dunno, Don.    Who knows what's inside that bent rod kinked area? The metal could be beat up internally.   If the rod was twisted as much as it was, there was nothing holding it in that position. It had to take the fatigue when straightening it out.

Anyway, here's what I wud do. Looking at the rod I see only one obvious bad spot. I would get another steel rod and u-bolt it across the bad spot. Use (4) 3/8"  U-bolts per side. Make the new 5/8" rod overlap by at least 12"  + -  the bend. (or as far as possible)  Use stainless steel U-bolts with galvanized 1/4" thick steel brackets to clamp onto the good areas.  Then bury it and forget about it.  

If your inspection shows the rest of the rod to look flawless, then this patch should be all that's needed for peace of mind.

T

That's exactly what I was thinking of doing, except running the parallel rod the full length of the exposed rod, and using a U-bolt every couple of inches.

If they make such a thing as hot-dipped 5/8" wire rope clamps, I thought about using those, since the grooves designed to accommodate the cable strands would bite down into the metal like the teeth on a vise-grip and make slippage less likely, and the zinc would add protection to both rods.

One thing that may have made it so easy to reverse the distortion, since the displacement was causing the guy wires to pull at an angle against the bend, would be that the straightening action was assisted by the guy wire tension, kind of like power assisted brakes that run off the engine vacuum.

Good point about the power brakes analogy.

A good thang is the 45 degree twist was absorbed by a long shaft. If it was real short, the internal damage would be more focused.

Yes, wire cable would work, though I think a steel rod would hold well too.  Bolting either one the full length is a good idea.

So looks like it will be a relatively painless repair. Now flag it like Times Square and it won't happen again... ;)

T

Actually, I was thinking more along the line of a solid piece of hot-dipped 5/8" rod, but clamping the two rods together with the cable clamps. The bracket that goes with the clamps is formed to grip a round object, plus the indentations on the bracket for the cable strands would act like teeth to bite into the solid metal.  The problem with stranded cable as a reinforcement bar is that it would rust through long before a solid rod would, since so much more of the steel in a cable is surface area that would be directly exposed to minerals in the soil.

my experience with this kind of hardware and forces is zero but intuitively I would be very uncomfortable using any compression friction method fail-safe.  I would investigate having a reinforcing rod added on by welding.  I do not know it this kind of steel can withstand that but I would certainly find out as to me that would be far better than any nut and bolt clamp method and the whole shooting match rides on that one 8 or 9/16 inch rod.

Don,

Is it possible that the rod is rotating in the concrete ?  I've not seen a real-deal Rohn anchor rod,  perhaps it has deformations as does ReBar,  which should help keep it put,  but had to ask.

Sorry to hear about the  issue.  Know that that tower  has been up for a long time -- a testiment to you having done it well to start with.  Too bad that now you need to worry about it.

73  GL  Vic

I'd also do what Tom I think recommended which was to take the screw driver and put a little rotational force on the other two eq. plates just enough to get some sense of how easily they would twist.

The fix is 4 legged and simple.

1 to many goats.

--Shane
KD6VXI

The anchor rod has a couple of 90° bends right at the end, so it couldn't rotate in the concrete unless it is corroded in two.  In that case, it probably would have pulled free of the concrete long ago.

The problem I see with welding is that from my experience, welded steel seems to rust easily, and this thing will be buried underground in direct contact with the soil. The heat most likely burns away some of the carbon or alters the crystalline structure of the steel. It would certainly burn away any remnants of the galvanising on either rod.

The clamped rod couldn't hurt anything, but I don't trust it as a 100% effective backup. OTOH, there is no guarantee that the original rod has, nor that it has not, been significantly compromised.

They do make 5/8" clamps, and HD galvanised ground rods are listed as 5/8" diameter. The appropriate length could be sawed from the bottom end, and the sawed through part allowed to extend above grade where it wouldn't be in direct contact with the soil.

Ground clamps installed below grade seem to work loose over time.  Not sure if steel-on-steel U-bolt clamps would do the same or not.

Clamps below grade in the freeze thaw cycles will probably work loose.  you could try lock washers.

Well, I don't want to tell you what to do Don, since you've been at this a long time.  It might not hurt to step back and consider out of the box options.  Example:  You can easily solve any burial problem by simply pouring concrete right up to ground surface to cover a weld after you spray it with cold galv. spray.  Since you seem uncertain on how to proceed, I'd weigh the cost of consulting a professional with the cost and labor involved with replacing the tower, insulator (I know you have a spare fortunately) and possibly the dog house (if a guy cable slices through it).  R25 is over $100 / section now.  Not sure if you want to climb and hoist with a gin pole or not.  Next to that a few hundred bucks to have someone who services commercial towers look at it might be a bargain.  He might say it's fine leave it alone and charge you an hour minimum.  He might have a method you and everyone else here never even thought of.  Expert eyes and hands on the scene can be valuable.

I finished the dig this morning, and cleaned mud off the rod and concrete entry point.  No sign of cracks or surface damage, and the rod looks sound all the way to the concrete, but the zinc appears to be all gone below grade. I scraped on the rod, and it looks more like I exposed bright steel than zinc.

The rod clearly has some bend down to where the dirt was hard and compacted.  It looks like the impact and subsequent straightening of the plate cause more of a spiral bend than a twist in the rod, probably negligible weakening.

Using a crow bar about the same length as the screw driver, I tried twisting on one of the undamaged anchors and then the damaged one. They both had the same feel and give, although I was careful not to apply enough torque to permanently bend anything.

I plan to show the farmer the damage, and if I can find a professional tower installer to look at it (this should be at the farmer's expense), follow his advice, maybe loosely filling the hole in the meantime if I can't find anyone right away. After closely inspecting the rod, I am not so worried that it on the verge of pulling apart with the slightest breeze.

Here are  some shots I took this morning.

This is great; bet you are relieved--I sure would be  ;D   Also, this means at least one anchor hasn't been cathodically eaten away like in that QST article.  Bet when all is said and done, you have four or more fat concrete filled pipes sticking up out of the ground around each of those anchors hi hi.