My old 80 ft tower had this problem, cracks in all three legs from water
freezing, splitting the legs. The cracks were about a foot up from the
bottom of the tower. I welded a "dot" at the upper and lower end of each
crack (the cracks were about 5 inches long) to prevent them from cracking
any further, then drilled a large hole at the bottom of each leg. I never
had a problem after that. The tower stood there for 20 years after I did
the repair. It was eventually taken down and replaced by a rotatable crank
up tower.
73/Peter SM2CEW
At 20:18 2002-10-06 , you wrote:
>I like Tom's suggestions for THOSE towers. The base problems with those
>towers was either rust or shearing. The tower in question had standing
>water in the leg and it froze, splitting the leg. The only real solution to
>making sure this will not happen again is to make sure there is NO standing
>water in the legs. I don't know how to do that without replacing the base
>section completely. It is probably plugged at the bottom, far underground.
>
>You COULD actually loosen the guys wires a little, unbolt the tower from the
>base, jack up the tower a few inches, and remove the base entirely. With
>the tower supported by a framework, you could jackhammer out the concrete
>and totally install a new base, this time with proper attention paid to
>drainage of water from the legs. In this instance, the other solutions I
>have heard just sound like the same trouble all over again the next time it
>freezes . . .
>
>Stan
>w7ni@easystreet.com
>
>----- Original Message -----
>From: <n4kg@juno.com>
>To: <TOWERTALK@contesting.com>
>Sent: Friday, October 04, 2002 6:27 AM
>Subject: Re: [Towertalk] Cracked Leg on Rohn 45G
>
>
>> Basically, Stan's approach is to TAKE DOWN the tower and
>> reinstall it. Here are two alternative approaches:
>>
>> N4AR discovered his 200 ft R45 tower with a 4 high stack of 4L20's
>> had rotated at the base following a near pass by a tornado, sheering
>> the R45 legs at the top of the concrete. He made a form and poured
>> a block of concrete around the base.
>>
>> N4KG discovered two legs of a TV tower (similar dimensions to
>> R25 but no diagonal bracing) RUSTED through at ground level.
>> Three 3 ft lengths of 2" angle iron were pounded halfway into the
>> ground to prevent the legs from moving out. H braces made of
>> 2X6 pressure treated lumber were placed inside the tower legs
>> at right angles to each other to prevent the legs from moving in.
>> These wooden braces extended up to the next steps which will
>> support the vertical load in case the tower sinks. This tower is
>> still standing 2 years after discovery of the rusted through legs,
>> supporting 3 tribanders at 40, 60, and 80 ft. with guys every 20 ft.
>>
>> Note that both of these 'solutions' are probably violations of
>> 'the Prime Directive', but the towers are still standing.
>>
>> Remember, for a GUYED Tower, nearly all of the forces at the
>> base are VERTICAL. Horizontal forces are primarily handled
>> by the GUY Wires. Remember to ALWAYS install temporary
>> low guys when removing ANY guyed tower.
>>
>> Tom N4KG
>
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