Questions You Should Know about self support tower
Questions about assembling my 1st tower
I was looking at some self supporting towers and found one at a price I can handle. I've looked up videos on people throwing together similar towers, and i read the spec sheet on a few, but I still have a couple questions and I'm looking for any advise anyone might have on how to do this properly, safely, and effectively. I've never been involved with this type of tower before.
This is the tower I'm looking at: https://www.dxengineering.com/parts/tbx-thdbx48
I'm looking at the "Extra heavy duty" because we do get hurricanes and ice and ice hurricanes, and I figured why not go with the strongest thing I can afford. I will also also be ordering the 48" concrete anchors and the steps that are for this model tower. I will cement it to the ground as recommended in the tower catalog. I'm going to make my own climb sheilds as i really think theirs are overpriced considering I can take some decent sheet metal and bolt it on.
My questions are, is it safe to climb the tower (with safety equipment) the full 48ft without any sort of guy wires? I've seen a few videos of guys climbing these things without guy wires but I don't think those are this exact model, but they look like a "free standing" tower.
And would it be a good idea for me to put a set or two of guy wires on it anyway to avoid issues with wind or ice building up on one side? Or would ice building up on those just cause more of an issue or something?
mmckenna has it right on contacting the manufacturer. Their engineer will be able to explain how adding a guying system to a tower that is designed to be self-supporting will not add any safety factor. It will actually defeat the designed capabilities of the self-supporting tower. Please do not pursue this idea without a long talk with the engineers at the manufacturer. You are spending a pot of money to get the benefit of their design skills so don't be bashful about getting your money's worth.
With all this said, I have seen several self support towers guyed in my many travels around the country. The thing to remember here is that the tension of the guy wires does not need to be like a banjo string. This only adds load to the tower structure. All the guys are there to do is keep the self supporting tower from swaying back and forth in heavy winds.
What you put on the self support tower for antenna loading is what the limiting factor really is. I do agree that you should have a conversation with the tower company engineering to get their feedback.
The tower base foundation is the critical topic here. Your soil conditions are the steering factor. If you have sandy soil, your foundation will need to be much larger than if you have hard clay. If your soil is rocky or ledge, your in for some interesting foundation work. The engineering people typically use the term "average soil", but I in all my years working with public safety radio system around the country have never had one engineer ever define what this term really means. How deep the foundation needs to go into the soil will be steered by the soil conditions.
Here in southern Louisiana the soil generally is very soft. We normally use what is called pile cap foundations. The foundation is set on top of a bunch of driven piles. Then a concrete slab is poured on top of the piles. The piles keep the foundation from sinking and the concrete slab is the dead weight to keep the tower from tipping over. The piles have like U shaped steel straps that are bolted to the top of the piles to provide the up lift requirement to make sure the concrete is attached to the piles. The depth the piles are driven is determined by the soil conditions. It was not uncommon for the piles to go down to 30 or 40 feet in the New Orleans area.
The depth of the concrete slab can range from as little as 4 feet to as much as 8 feet. The dimensions of the slab are determined by the size of the tower and antenna loading. The self supporting towers used are on the larger size form what your talking. They ranged from 10 feet between each leg at their base to over 20 feet at their base. But they could go up 100 to 150 feet.
What I am trying to point out here is every tower installation is a different animal. It has to be engineered to the location and soil conditions of where it will be installed. In the case of the public safety towers, we always did a soil boring to make sure the foundation design engineer knew exactly what the soil conditions were to be able to design the foundation.
Good luck on your efforts.
In your case, you will be asked what the soil is like where the tower is going. You need to have a good answer when that question comes up. I would suggest that you have this knowledge down to at least 4 to 6 feet before even calling the tower company. You mentioned hurricanes and ice. So my guess is that your some where along the East coast. All the more reason to know your soil conditions.


