best tower analysis software 1

[sean40]

What software would you recommend for telecommunication tower analysis/design projects?

TSTower, MSTower, TnxTower, GUYMASTER
What are using and what are their advantages?



Guymast also has INSPECTOWER program that looks like a very good tool for tower inspectors. Did somebody use it?

 

[msquared48]

When, if ever, Peter at TnxTower is able to integrate a seismic analysis into the program, I would recommend that one. Very versatile and links with RISA 3D too for special applications.

Under the current TIA, you have to do seismic design on each tower, and the IBC no longer blankedly defers to TIA either.

Mike McCann, PE, SE (WA)

 

[JoshPlumSE]

Mike -

That's not entirely true. You merely have to demonstrate the seismic forces are less than 50% of the wind forces. And, that's usually the case... even in high seismic zones. It just usually takes some extra effort to demonstrate that.

I built an example (back when TnxTower was still RISATower) of an SST in the highest seismic zone in the US (Sds - 1.69 and Sd1 = 1.17) located in a reasonable wind zone (80mph) and I found the following:

Method 1 (equivalent static) force = 85% of wind shear
Method 2 (equivalent modal) force = 65% of wind shear
Method 3 (modal response spectra analysis) = 43% of wind shear

This was put together originally as TnxTower / RISATower training materials. All told, it took me 14 pages of increasing complexity to eventually demonstrate that none of my work was really required.

 

[msquared48]

Ok, but now you have to check. Prior to the new TIA code, it was not specifically required. You could just make a statement that wind controlled hased on your previous experience, and that was that, in most jurisdictions anyway.

Mike McCann, PE, SE (WA)

 

[transmissiontowers]

I don't analyze them very often but PLS-CADD has their Tower Module which can be bought as a stand alone program and it has the ability to analyze (and probably design too) free standing lattice towers and guyed lattice towers and masts. They have a load module that will generate EIA loads if you specify the wind speed.

Their main focus is my T-Line world but they can handle telecom type towers also. I'm sure that they do not do seismic but if you have a guyed mast with all the sections having the same geometry and member sizes, you can quickly copy and paste sections on top of one another to build very tall masts. You can also specify linear appurtenances of waveguides and equipment areas.

_____________________________________
I have been called "A storehouse of worthless information" many times.

 

[Gumpmaster]

I had an interview with one of the largest cell phone tower owners in the country to see if we could do some work for them. They required TnxTower. We didn't have any experience with it and didn't get the job. It would have been a huge contract. So, maybe your clients or potential clients require a certain software. Something to think about.

 

[BrentB1776]

Sean -
We use tnxTower. It can be cumbersome to use at times, especially with towers that have complicated geometries. As msquared48 indicated, tnxTower does export to RISA-3D which is versatile and useful for special applications. I cannot speak for the other programs, but would be interested in what others think about them.

I am not sure if you have to do seismic design on each tower. As per ANSI-TIA-222-G-2 (Addendum 2):

2.7 Earthquake Loads
2.7.3 General
"Earthquake effects may be ignored for structures assigned to structure Class I in accordance with Table 2-1 or for any structure located in a region where the earthquake spectral response acceleration at short periods(Ss) from 2.7.5 is less than or equal to 1.00. Further, for structures without irregularities as described in Table 2-9, earthquake effects may be ignored when the total seismic shear is less than 50% of the total horizontal wind load without ice."

2.7.5 references Ss periods given in Annex B and Appendix 1 except as provided by 2.7.5.1.
Annex B references ASCE7-05

Here in the Midwest we rarely encounter a site that has a Ss greater than 1.00, save Southern Illinois/Missouri. However, I imagine if you are in area with high seismicity this would be a concern.

ANSI-TIA-222-H is supposed to come out in Spring 2016, however it seems that the revised TIA code would address topography, mounts, potential fatique, exposure and load factors.

http://www.wirelessestimator.com/windgeneral.cfm

 

[msquared48]

I would have to check, but if it is a category 1 structure, you do not have to consider ice, so you may not need to consider seismic. I am no longer working on towers after three years doing so, so I no longer have access to TIA 222-G.

The program automatically defaults to no ice with cat 1.

Mike McCann, PE, SE (WA)

 

[MidnightClyde]

The 2012 IBC actually will not allow a seismic base shear vs. wind base shear comparison as permitted in TIA-222-G. Section 3108 of 2012 IBC (and elaborated in the commentary) states all towers must meet ASCE7 seismic provisions, that seismic design exceptions listed in TIA-222 shall not apply, and that TIA-222 is not a referenced standard for seismic design by the ICC.

Full seismic analysis for towers is not widely enforced amongst areas where the 2012 IBC has been adopted, but technically it is required.

 

[ElliottJames]

Bah, tower software is for wimps. Real engineers model their towers with a generic FEA program from scratch. ;-) I have done this. The disadvantage is that it can get tedious to post-process the FEA output vs. factored material strengths. The advantage is you really get to know TIA-222-G and how your tower behaves, compared to pushing the Start button in a "black box" program.

 

[theonlynamenottaken]

@ ElliottJames: Same thoughts here. I haven't done much in the telecommunications and power transmission tower world, but an acquaintance of mine down the road owns a firm that specializes and only does just that. He told me that they finally dumped all the purpose-built, boutique tower software a few years ago and only use GTStrudl now. Since GTStrudl can use text input they wrote pre-processing and post-processing spreadsheets themselves and can model entire towers in minutes, including non-linear cable guys, member eccentricities, ice, wind, seismic loads...

 

[transmissiontowers]

I've used GTStrudl to model T-Line towers (many years ago) before PLS-CADD's Tower program came out. GTS has a tower module based on Manual 52 which was the manual before ASCE 10 came out. I'm not sure if GTS has kept up with the changes (ASCE 10 will be out in a few weeks and can be pre-ordered now, IIRC) in ASCE 10. You are correct that GTS can model the eccentricities and moment in the legs but the vast majority of T-Line practitioners use PLS TOWER to analyze and design T-Line towers. Many towers are tested to destruction in full scale load tests to verify the design assumptions and the results compare pretty favorably to the software.

The single angle compression equations take into account the normal framing eccentricities as specified in ASCE 10 which are based on many full scale tests.

The nice aspect of PLS Tower is the load generation from PLS-CADD where the wire loads and wind loads are automatically calculated and applied. If you use GTStrudl, you will have to correctly calculate the wire tension for all the different load cases with the wind on the wires. If you only analyze tangent towers with 0 line angle, the tension does not matter, but when an angle is involved you have wind normal to one span and at an angle to the other side which changes the wire tension and introduces a longitudinal load. We routinely run 100 load cases on our towers and have a library of hundreds of tower models.

_____________________________________
I have been called "A storehouse of worthless information" many times.