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Re: Transmission Line Tower Foundations

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ARW

I meant to reply yesterday, but had some pressing issues to attend 
to.

>From the information that you are getting regarding the project, I 
would have some reservations about this project.132kV... I assume 
that this transmission line is not in the states?If I remember, 138kV 
is the equivalent voltage here. 132kV is used in Australia, and I 
assume, other ex-british commonwealths. Anyway, to help your 
bid process, you may need the following

1)Do you have the line profiles that show the location of each 
structure? Structures may be located in varying terran, including 
swamps, rock ledges etc. 
2) It is recommended that a soil analysis should be conducted at 
each tower location.Shear strength parameters will govern; bearing 
capacity will be of secondary importance.
3)Caisson type foundations are the most popular type used for 
heavy loads.

If all your load data is Ultimate, then conduct your footing analysis 
with a factor of 1(Ultimate concrete design) ensure that your soil 
data is ulitmate, not allowable.

Try and contact "Power Line Systems Inc."(they have a web site, 
but I dont know the http) They have a program called "Cassion" 
which was developed for transmission line structure foundations. 

Also, contact a Dr. Tarum R Naik. He was a presenter at a 
continuing education course I attend offered by the University of 
Wisconsin. I think he is also one of the developers of "Caisson". 
His contact details are:
ph:414 229 6996
fax:414 229 6958
email:tarum(--nospam--at)c.sd.uwm.edu

I am not 100% sure if he is still there, but he has alot of knowledge 
on the subject.

I hope this helps.

Peter McCormack

From:           	ARW <arw(--nospam--at)lhr.paknet.com.pk>
To:             	"'seaint(--nospam--at)seaint.org'" <seaint(--nospam--at)seaint.org>
Subject:        	Re: Transmission Line Tower Foundations
Date sent:      	Mon, 28 Feb 2000 05:29:16 +-500
Send reply to:  	seaint(--nospam--at)seaint.org
Organization:   	http://www.seaint.org

> In reply to clarification sought by Peter McComack, who wrote:
> 
> "Before I jump in with any suggestions, what type/types of towers
> are you dealing with? is it a single circuit structure, a dead end,
> deviation etc. . . . . "
> 
> Dear Peter McComack:
> 
> I am extremely grateful for your prompt reply.
> 
> My line is 132 KV Double Circuit Overhead Transmission Line. The towers 
> include: suspension, 10 deg, 30 deg, 60 deg and terminal. I am making 
> bid-stage foundation designs.
> 
> The tower reactions have been provided by the tower manufacturer. The data 
> says that the reactions are "ultimate" reactions using the same overload 
> factors, as have been used in the tower design. I requested the breakup of 
> loads and the values of the overload factors, but the manufacturer has 
> shown its inability to provide any breakup. All I have been given, for each 
> tower type, are: Compression, Uplift, Transverse Shear and Longitudinal 
> Shear. I also requested separate reactions for each pair of foundations, 
> for the case of angle towers, but even that information does not seem to be 
> available.
> 
> But I think we can safely assume that broken wire condition must have been 
> considered, but how many wires, I can not say.
> 
> The employer has provided a design criterion which is rather ambiguous.
> 
> Sincerely,
> 
> Rizwan Mirza
> --------------------
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