Transmission Lattice Tower 1

[civeng15]

Hi all,
[URL unfurl="true"]https://res.cloudinary.com/engineering-com/image/upload/v1568838187/tips/TWR_36_ekza4g.pdf[/url]Any idea why redundant are failing and legs are bent (see attached pdf)?
We analysed the suspension tower using PLS Tower and maximum legs usage is below 70%. Initially received maintenance report asking to replace the bottom cross bracing witch we though were damaged then received the attached photos where bent redundant are connected to damaged/failing legs. Are legs and redundant failing? Any thoughts?
Thank you

 

[KootK]

1) Vandalism / climbing?

2) If the legs are buckling, this could be an outcome for the redundants.

HELP! I'd like your help with a thread that I was forced to move to the business issues section where it will surely be seen by next to nobody that matters to me:

http://www.eng-tips.com/viewthread.cfm?qid=456235

 

[civeng15]

Thank you KootK,
I have the same understanding, but when I noticed that only redundant connected to bent legs I was confused.

 

[KootK]

Bears!!

HELP! I'd like your help with a thread that I was forced to move to the business issues section where it will surely be seen by next to nobody that matters to me:

http://www.eng-tips.com/viewthread.cfm?qid=456235

 

[SlideRuleEra]

Likely all the damage is from impact by heavy-equipment used for transmission line right-of-way maintenance (removing undergrowth). Those towers appear to be decades old. Right-of-way maintenance does not have to be performed often (every few years), but pretty sizeable equipment is used to do it.

http://www.SlideRuleEra.net

 

[atrizzy]

Are you in a location where heavy ice/snow rime buildup occurs?

 

[msquared48]

From the tire marks and wood chips seen on the ground that close to the tower, I would have to agree with sliderule...

Mike McCann, PE, SE (WA, HI)

 

[human909]

That would be a skilled operator to get both sides in the same manner.

It seems to me that an event has put too much load on the tower in the direction towards the camera. The main legs buckled and the intermediate braces buckled along with. This buckling didn't continue as load distributed to other members. ... my 2cents.


In this context what are the 'redundants'?

 

[12345abc6ttyui67]

I'm with human909, although it's hard to tell with only one photo from one angle.

 

[civeng15]

Thank you everyone for the input.
Well, I probably don't agree with the last few comments who are saying it is due to structural failure. I don't think that the shown leg failure (assumed) will lead to severe buckling of bracings. Therefore, I lean toward damaged leg/bracing than structural failure from loads or event that put too much load on tower on these legs.

 

[KootK]

I don't think that the shown leg failure (assumed) will lead to severe buckling of bracings.

1) I agree with your ultimate conclusion but only because I feel that many of the other explanations are more probable than primary leg buckling is.

2) I disagree with your assessment that primary leg buckling / deflection couldn't lead to such severe buckling of the braces. If you run the numbers on it, it takes very, very little forced axial motion to effect a significant lateral displacement. Check this thread out for a salient example: Link