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So, what is on the tower now and what will be on the tower? That is a very important factor. This is why structure owners require the structural analysis be done whenever anything is added to the tower. If you go with a structural engineer that has already done the original, then they should know everything that is on the tower. They know what you have on it because they mapped the tower.

What is mapping a tower, well, let me tell you. Mapping a tower is when the structural engineer lays out a plan for the climbers to go out and look at everything on the tower. If it’s done for the first time, then they measure everything with a tape measure, or a measuring device. Measure anything mounted on the tower to include the width, length, and thickness of all steel as well as the height from the ground. Don’t stop there! They also measure the tower steel, the diameter of the pipes, the size of each cross member, the size of each leg, the thickness of all the angle iron on the tower, and anything they can measure. If the tower legs are round then they need to understand whether they are solid or hollow. A good engineer will measure anything that is on the tower as well as research the tower plans and design. Measure everything! Bolts, yes, measure and inspect and document every nut and bolt. Holes, yes, any holes in the tower should be documented. Mounts holding hardware are logged. Remote Radio Heads on tower are all logged. Everything is logged if it is being done for the first time. Inspect, measure, record, log, and document everything on the tower, and the tower, and attached to the tower. Get it all! Document everything! Save it all for when it will need to be done the next time.

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Hey, what about the foundation? They do one of 2 things. If they need to they will dig down one leg, which I think is very dangerous, and look at the depth and size of the concrete base. Then they will assume that all of them are the same. If it is a guyed tower then they will look at one of the guy lines and the guy foundations. The foundation is very important. Guy lines need a serious foundation as well. They need to be solid, deep, and well designed. Guy foundations will have pressure on them and could move. I have seen guy foundations replaced for this reason. It the engineer isn’t allowed to dig then they will have to assume it is built per the design. Take a look at these, http://www.precisiondrill.com/Cell%20Tower/celltower.htmhttp://drennerconcrete.com/tower-foundations/jessup-cell-tower-foundation/ to see some examples.

Results of the structural can be a report. In the report, like the ones I point to above, they can have what the tower is rated for, what it is expected to handle, and if something new is being added then it should have that hardware added to it. It should review the tower as a whole and also as sections. The report should identify the tower ratings, the wind load, and the ice expectation. Remember that an engineer has to put his stamp on it and wants to be sure it will hold what he says it does. If there is one thing added after the structural is done, then he has no liability whatsoever because something changed. Oh yes, it matters. Again, go to http://web.mscsoftware.com/support/library/conf/wuc93/p03393.pdf to see what is on the report.

Evolution is the reason for the change. Towers need to be upgraded to hold the Remote Radio Heads (RRH) that are being added to towers like there is no tomorrow. In my book I mention these because the landscape of the tower has changed. Evolution of the wireless system has changed the tower. We need to put the radio, and soon the entire cell site, up on the tower. You heard me; the industry is going to add more hardware to the tower. It’s going to be the heavy radios, RRHs, up on the tower, on the platform just behind the new antennas with more steel. They will have power and fiber run to them. They will be on the tower and live radios. This will add hundreds of pounds to the tower. This will mean that towers will need to be strengthened. To beef up the tower they will need to change something. It will have to have steel added to it. In some cases concrete will have to be added to the foundation. The steel will either be welded or they will need to beef up the cross members. This will call for a plan of action. You can’t just remove cross members and hope for the best, you need to have a plan to strengthen the tower so you can make changes. The tower crew will need to work with the structural engineer to put an upgrade plan in place. Remember to plan, plan, and then plan. Then take action. Work with the engineer, review the plan, and point out any potential problems you see. Talk about it before you go on the site! Do a proper survey to make sure the drawings match what is really there. Experience really pays dividend. An experienced climber that has done structural upgrades will have a good idea of what will need to be done and how it should be done.

I hear that because of that West Virginia accident there will be major changes coming down through the industry. The carriers know that something bad may happen giving them a black eye. Now that OSHA can review the contracts they are being extra careful, (finally). This is a good thing but it will add money to the contract and it will delay the project. We probably can’t take a crane to every site, although that is a possible solution. A crane with a man basket is something that may become more and more common. If you are in a man basket you still need your PPE and PFAS. I think you still need people on the tower or you need several cranes on one site, talk about expensive. Someone really needs to think this through before they go crazy. If the proper planning is done, and experienced people think through the process then the construction should be done properly. We need to make sure we approach the problem from beginning to end. These additions are adding a lot of weight to the tower. Think about the extra weight after you add the RRH and all the extra steel and the antennas. They should all be mounted properly.

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Something has been mentioned is that the equipment may be mounted on the ground prior to the installation on the tower. This will work if the details are taken care of. Remember that it still have to mount the assembly to the tower, so all of the hardware must match. The clamps must fit, the brackets must line up, and you may need to make changes in the air. I think the less work in the air the better if you can manage it. As most of you know when you get to the site things sometimes change because there is a knuckle in the way of where you need to put the bracket or there is another obstruction. You need to plan, then adapt, then improvise, then overcome any problem on the site. The site design may not be accurate, so be prepared.

Some links about towers and structural:

http://www.ce.ncsu.edu/srizkal/linked_files/Study_in_the_Improvement_in_Strength_and_Stiffness.pdf

http://www.ehresmannengineering.com/engineering-services/structural-analysis/

http://www.bentley.com/en-US/Products/STAAD.Tower/

http://www.wirelessestimator.com/t_content.cfm?pagename=Tower%20Design%20Checklist

http://www.varcon.ca/structuralanalysis.php

http://www.wirelessestimator.com/community/threads/what-is-the-useful-life-of-a-tower.1183/

http://www.wirelessestimator.com/t_content.cfm?pagename=Tower-Design-Construction-News-2

Let me know what you think by leaving a comment or hitting me up on Facebook! Feel free to post tower pictures on Facebook! I am also looking to hear what you may want me to write about. I am going to put together a series on small cells and industry growth as well as a comparison between climbing regulations in other countries compared to  the USA. We have a horrible track record for casualties in the US and I am trying to figure out how to make it better. I think the policy now of asking people to be more careful just isn’t working. We have to protect each other the best we can.

I am working on a new book, an aid for the field worker and I plan to have a new website ready soon. I have been very busy on other projects but I think that it should happen soon.

My current book is available at the links on this page. I also have an Amazon link to buy books and other things if you’re interested. Look at the menus on this page, one at the top and one on the right side.

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2 thoughts on “Where’s the Beef? Part 2 of Tower Structural overview.

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