Structural analysis of communications tower

[cedarbluffranch]

I'm considering doing communications tower structural analysis for part-time consulting work. My client base would be amateur radio operators installing towers in their backyard.

What kind of analysis techniques might be appropriate for laods on radio towers? I did quite a bit of research and found several software FEA packages designed for communication towers but they are more in-depth than would likely be applicable for an amateur radio tower. (The tower manufacturers already have done the load design and analysis for amateur radio towers. All I would need to do is create an installation drawing for the specific location.)

I'm thinking something along the lines of designing an appropriate concete foundation and some rather basic structural calculations to show that the tower will be safely installed.

Anyone have any experience with this?

(Yes, I am a professional engineer).

 

[JAE]

You might first check with some various local authorities to determine what sort of restrictions/requirements there might be for this. I would think the following would be my initial concerns:

1. Even though you are a PE, are you experienced in structural design? Practicing outside your area of expertise might expose you to issues with your engineering board....just asking.

2. Radio towers in some neighborhoods might be disallowed due to zoning, code, or covenant restrictions - this would vary from place to place.

3. Lightning protection an issue? Would you be responsible for it?

4. In some areas of the country, seismic demain is an issue that would have to be addressed. Do you have experience in this area?

 

[cedarbluffranch]

I'm well aware of the requirement to only practice in areas that a person is skilled. That goes without saying, with or without a PE stamp.

But there's nothing wrong with asking questions about how to design things that are outside my field, and that's what I'm doing here.

 

[JAE]

I was just responding to your "mechanical" tag on your handle. no offense intended.

Asking here is fine, but I think local building departments might shed better light on each area. The local areas might all be different depending on local laws.

 

[DonPhillips]

Assuming the zoning will be handled by the homeowner, I would start with the building code. These would be covered in Section 3108, which refers to Chapter 16 and ASCE 7 for determining seismic and wind loads. It would also be designed to TIA/EIA-222. Those referenced standards would be a good place to start your research.

For the tower design, you would have either Chapter 20 or Chapter 22, depending if you are proposing aluminum or steel. Chapters 18 and 19 will guide you on the foundation and concrete requirements. These four chapters have their own set of referenced standards.

Don Phillips

http://worthingtonengineering.com

 

[am]

I had successfully used Microstran - MSTOWER program and Weisman - Guymast program in the recent past. I was associated with analysis and engineering of telecommunication structures for ten years.

 

[LobstaEata]

Hi Cedarbluffranch

JAE has made several good points to consider, especially if this is the first project of this type for you. You also might want to take a look through ANSI/EIA/TIA-222, Structural Standards for Steel Antenna Towers for further guidance.

Hope this is helpful.

 

[EddyC]

I spent some time in telecommunications. Whenever we had a project that required a tower, we would produce site specific drawings along with a performance spec for the tower (height, code, antenna size & quantity). The manufacturer of the tower would do the structural design themselves using in-house engineers or sub the design out to a consultant.

 

[LobstaEata]

EddyC

I can't help thinking that regardless of whether the manufacturer provides the tower design, the engineer in charge takes ultimate responsibility. I've reviewed manufacturer designs for truss type structures in the past and detected issues that required modification under current design loading.

On the other hand, we engineers may be paranoid on the issue of professional liability, however it doesn't mean that lawyers aren't out to get us. )

 

[1mitchsklar1]

You may want to check out a new software solution from Bentley...STAAD (X).Tower for your next Monopole, Self-supporting, or Guyed Tower Structure.

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

http://communities.bentley.com/blog...d-x-tower-v8i-releasing-on-december-15th.aspx

I have been a structural engineer for over 19 years and have worked in the cellular antenna market for a number of those. This new software is wizard driven, contains the two most recent TIA codes, a significant library of antenna appurtenances, and is built upon the new STAAD (X) platform.