Activity Feed › Discussion Forums › Strictly Surveying › TBM — in a utility pole?
TBM — in a utility pole?
Posted by dmyhill on August 30, 2021 at 9:06 pmJust had a request for a TBM in a utility pole. It struck me as strange because I haven’t been asked for a TBM in a pole for a very long time. Then I realized that it had been a long time since we used TBM’s in utility poles around here, which also seems a bit weird as it used to be so common.
My interpretation of RCW 70.54.090 is that to place a nail much less an RR Spike into a utility pole is against the law, so I suppose that is why it is no longer common!
dmyhill replied 2 years, 6 months ago 21 Members · 42 Replies- 42 Replies
I agree with your interpretation.
Some fun could be had if you got permission, then set a TBM 12 above the ground.
It was practice for years around here. And from what I’ve seen, some folks are still at it.
I don’t know if the OK legislature has gone so far as to address the practice as a misdemeanor. But none the less it’s really not a good idea from a surveying standpoint, let alone any damage to the pole (which btw is someone’s private property).
Utility poles settle over a period of time. Poles can also be subject to tension (uplift) and shear (twist) from the cable attachment dynamics and render an assigned elevation inaccurate. Nails in poles for horizontal references are also a poor choice due to these same dynamics. They move. Some of them move a lot.
More than once I’ve been asked to place an elevation on a utility pole for a TBM. If there’s no other choice, my practice now is to blow a 12″ square of white paint on the pole and draw a horizontal line with a good black marker over the white with the elevation info. Of course the paint and marks will eventually fade. I let the end user know the maintenance is their duty. 😉
I’ve set some over the last few years in Oregon, but I’ve put them no more than a foot or 2 above ground and sticking out maybe an inch or less. The beef seems to be interference with guys climbing the poles so I figured stuff below knee level shouldn’t be a problem.
Around here no one climbs poles anymore. They use bucket trucks. Heck on construction sites no one uses ladders. They have dozens of scissor lifts.
I’ve gone back to a TBM to find the Utility company replaced the pole, and they kindly “reset” the nail in the new pole.
Gosh, it’s been over a decade since I set a rr spike in a utility pole. It was common practice back in the Midwest but it would hardly occur to me to set one out here in California. If you can find a wooden pole, it’s usually pretty much dried to splinters… you may as well chop it down if you’re going to attempt to drive in a rr spike. I would expect an angry phone call from whoever owns the pole too, that is if it’s not getting replaced in the immediate future already.
I’m still a fan of shooting the “arrow bolt” on hydrants. That’s always been a stealthy TBM for those in the know.
When spirit running levels on roads we’d pop a RR spike into a telephone/power pole a few tenths above ground level in difficult terrain where turtles didn’t work well for TBMS but once the level loop closed pop them out. The pole companies frowned on any iron in their poles but we were in and gone before they could complain. One incident that bolloxed me was we had a summer intern (Musicology Major) rodman who set the rod on the ground against the RR spike so all our loops were a few tenths off, but his minor error made some loops close. Took some head scratching but releveling through the RR spikes fixed it. Mr. intern’s logic was we’re levelling the ground and the RR spikes were only locative, logical if you don’t know surveying.
- Posted by: @drew-r
I’m still a fan of shooting the “arrow bolt” on hydrants.
Nope, never establish a BM on a hydrant, the FD endlessly fiddles with standpipe height, replacement hydrants, upgrades etc. Not reliable in the long term.
When unable to complete a section it was.common to set a TEMPORARY Bench Mark. It would be occupied the next day and was not intended for subsequent use.
For all the reasons stated I would not expect a TBM to remain valid.
Spikes in poles, hydrant spindles, corners of stone or concrete steps, all common around here.
I prefer the front bonnet bolt instead of spindles, but otherwise, they all work for a specific construction project, as long as you have a few to check between.
If you’re after longevity or building particle accelerator, then you might want to consider using something else more stable
@norman-oklahoma When we “used to” set TBMs in power poles we used a 60d nail driven in so only about an inch was protruding. This was set about an inch above grade. That way it was not in the way of anyone climbing the pole. Years ago we would also nail a couple of stakes to the pole so that the outer stake could be rotated and write the elevation on the inner stake.
Andy
I used a specific corner of the stone base of Birdy Bone’s tombstone on a six-mile route survey. Bet it is still good.
@mike-marks yeah, I knew someone would say that. The earth moves too, no bm is safe 🙂 I used to use hydrants all the time when I did subdivision work and they were pretty safe, but yeah, they are susceptible to movement.
ymmv
Exactly. The lath trick is one I’ve used, many times. The TBM’s I set were either at an even foot or at an integer number of feet above or below finished floor.
We were running a level loop for vertical control one day and were passing a partially built street for a new subdivision at lunch time. There was an old “Sheeps foot” roller there at the entrance that hadn’t moved in months, it had been there long enough that all the feet were rusty. I shot the top of one of the feet to use as a TBM while we ate. You KNOW what happened!!! When we got back the Sheeps foot was gone. @&(*&%( it.
Andy
- Posted by: @holy-cow
I used a specific corner of the stone base of Birdy Bone’s tombstone on a six-mile route survey. Bet it is still good.
Purcell is a town a little south of me. The local cemetery is located at the intersection of the interstate and a state highway just east of town. It’s high on a hill, the road is good and always dry. You can almost see the horizon for a full 360 degrees.
I work down there a lot. Over the years I’ve placed control points that keep me from having to recover section corners and the like over and over. It also keeps my butt out of traffic. My CP down there in the cemetery is the NW corner of a marble headstone base for ol’ John Sloan. John has done me right for years.
Not too long ago we were down there and I needed to set up on that CP. Danged if there wasn’t a plantin’ going on about 20′ away from Sloan’s headstone. Rather than interrupt family and friends we decided to take an early lunch. I’ve never set up with folks whimperin’ and prayin’ close by…and I’d like to keep it that way. 😉
We were working an ODOT job near Oilton, OK. We had recovered a 1/4 corner a half mile from the highway and were referencing it out for the CCR. The property adjoining to the SW was a cemetery, and the headstone nearest the corner read “Infant Boy” with a 1916 date. It was a very sad thing.
I instructed one of my helpers to tie the corner of the headstone for a reference. He went over there and stood over it for some time, while I did other things, not paying much attention to him. After some minutes he came back to me and asked, very plaintively, “did you want me to drill a mag nail into that stone?”
“Oh! God! NO!” says I. Naturally he was very relieved, and so was I that he had asked!
Most of the smaller builders I work for ask me to set a TBM of mark a finish floor elevation when we are staking foundations. I typically do not set them in telephone poles because I got yelled at for setting a spike in a pole when I was a green party chief. If there is a tree near the foundation location, I have me guys paint the face of the tree facing the foundation and make a horizontal marker line at FF, then write the location. It doesn’t damage the tree, it fades away and will likely not move before the foundation is poured.
In the end though, what do we really ever set that is not prone to some type of movement through freeze and thaw cycles, ground surface disturbance and other things. Even a 36″ monument is subject to movement when the frost line gets deep enough.
Since Hurricane Irma in 2017, most of the poles here are composite (fiberglass). You won’t get a spike in them. They’re about 2.3′ Diameter, so they’re often on line, and ugly as H. The local power co. can’t drill a hole big enough to plant them. One that was hit by a truck a year ago broke at ground level so the base has moved about 3 feet and the power lines are holding it up. I think someone realized they’re a good idea that doesn’t work, so they sent them here.
Now, that’s hilarious.
Log in to reply.