I would avoid any drilling if at all possible. That is a good point for a
stress riser/crack to form.
Roger Halstead (K8RI and ARRL 40 year Life Member)
N833R - World's oldest Debonair CD-2
www.rogerhalstead.com
> Welding may work - it would be much better if the tower were down to
> repair
> it. However, I would try to brace the legs together with some sort of
> stout
> brace, then pin them. Weld them too. Once that is complete, then you
> could
> weld the legs. Pray for no wind.
>
> -----Original Message-----
> From: towertalk-bounces@contesting.com
> [mailto:towertalk-bounces@contesting.com]On Behalf Of K4SAV
> Sent: Sunday, November 13, 2005 10:30 PM
> To: towertalk@contesting.com
> Subject: Re: [TowerTalk] A near imminent TX-455 failure
>
>
> Man, that is a scarry looking situation. Looks like one little twist of
> the tower, and down it comes, and there seems to be a house close by.
> Does someone have any suggestions as how to stabilize this thing before
> it all comes down?
>
> It looks like two legs have broken all the way through, just above the
> weld point. KB0FPH said he thought the welds had failed. I know this is
> somewhat difficult to see, but it appears to not be the weld that has
> failed, but the main support legs just above the welds. I had to save
> the web page, recover the jpg files, then blow them up with a viewer to
> get a closer look. Scott, would welding still be appropriate if the
> welds have not have failed?
>
> Wish I could offer some good suggestions, but I don't have enought
> experience in this kind of problem. I would probably be trying to drop
> some steel rods down the tower legs, and then guy the thing to keep it
> from falling, but what do I know? Maybe someone else can help. He
> really needs it, guys.
>
> Jerry, K4SAV
>
>
> D. Scott MacKenzie wrote:
>
>>>From the photographs, it appears that failure originated from the edge of
>>the weld beads. Usually this indicates lack of fusion on the weldments.
>>Failure should occur in the base metal. It also appears that the tower is
>>either painted or galvanized (I can't tell because I can't see well enough
>>at the fracture. Since the welds appear to have failed at the weld bead,
>>grinding the weld bead off, then rewelding would be appropriate. I would
>>also suggest some sort of backing plate to reduce the loads on the weld
>>may
>>be utilized to reduce the stresses on the weldment. The hard part will be
>>getting the joints lined up for welding.
>>
>>In my former life doing failure analysis on structures and components,
>>unfortunately, this is a common mode of failure, most often associated
>>with
>>inadequate penetration of the weld.
>>
>>IMHO
>>
>>Scott aka KBOFHP
>>
>>
>>-----Original Message-----
>>From: towertalk-bounces@contesting.com
>>[mailto:towertalk-bounces@contesting.com]On Behalf Of Nick - VE3EY
>>Sent: Sunday, November 13, 2005 8:26 PM
>>To: towertalk@contesting.com
>>Subject: [TowerTalk] A near iminent TX-455 failure
>>
>>
>>I am posting this note on behalf of a friend of mine.
>>
>>His 55 foot TX-455 US Tower is on the verge of collapsing down. The
>>owner just noticed that two out of three legs of his tower just broke
>>down. The legs snapped just above the mounting ears where the tower is
>>fastened to the "T" mounting plate. We suspect that some 90 km/h wind
>>gusts we have had here in Toronto last week may have been a contributing
>>factor.
>>
>>The tower is currently nested and the antennas are still on top of it.
>>It is basically holding on only one of the remaining legs and a few
>>cross braces. It was installed brand new in 1990 and it had a 2 el GEM
>>Qubical Quad installed ever since. In 2003, owner replaced the short
>>mast with a 22" cromoly nested about 3" inside the tower and added a
>>home made rotary dipole for 30/40 m at about 10 feet above the Gem
>>Quad. The dipole is a modified Cushcraft D3W warc dipole.
>>
>>The pictures of the damage can be seen here.
> http://dx.fireroute.com/TX455
>>
>>We are looking for some advice how to remedy this problem. Would there
>>be any way to fix this tower short of buying a new one?
>>
>>
>>73, Nick
>>ve3ey
>>
>>
>>_______________________________________________
>>
>>See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
>>Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with
>>any
>>questions and ask for Sherman, W2FLA.
>>
>>_______________________________________________
>>TowerTalk mailing list
>>TowerTalk@contesting.com
>>http://lists.contesting.com/mailman/listinfo/towertalk
>>
>>_______________________________________________
>>
>>See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
> Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with
> any
> questions and ask for Sherman, W2FLA.
>>
>>_______________________________________________
>>TowerTalk mailing list
>>TowerTalk@contesting.com
>>http://lists.contesting.com/mailman/listinfo/towertalk
>>
>>
>>
> _______________________________________________
>
> See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
> Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with
> any
> questions and ask for Sherman, W2FLA.
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
> _______________________________________________
>
> See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
> Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with
> any questions and ask for Sherman, W2FLA.
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|