You have at least two options for repairing the problem
without demolition and rebuilding the foundation.
First you could break out the concrete out around the failed
AB down say 9" to 12". Trim the broked AB and tread the end
of the AB and use a treaded coupler to attach a new section
of 1" all thread and then replace the removed concrete with
Second you could drill and grout new AB's in lieu of the
existing but rotated 45 degrees from the original. Then cut
off the original and reset the tower on the new bolts.
Either way will work. Talk to some industrial type concrete
contractors or mechanical contractors in your area who do
equipment setting. You may be able to get a lead on someone
who works for them who would do a small moonlite job.
Lonberg Design Group, Ltd.
Hank Lonberg, P.E.,S.E / KR7X
[mailto:firstname.lastname@example.org] On Behalf Of K6XN
Sent: Friday, January 13, 2006 2:48 PM
Cc: email@example.com; 'Sunnyvale VEC'
Subject: [TowerTalk] NEED ADVICE RE SNAPPED TOWER ANCHOR
In the last storm one of the four one inch diameter 27 inch
bolts holding my MARB base for my self supporting (unguyed)
US Tower MA 550
snapped just below the leveling nut. I have lowered the
tower and braced it
with a 6 x 6 and a hydraulic jack opposite the snapped bolt.
leveling nuts can not currently be turned. The tower has
been in place for
approximately 12 years. The concrete base is approximately 3
feet by 3 feet
by 6 feet deep and steel reinforced in accordance with US
recommendations for the MARB 550 base and the MA-550 self
Does anyone know of any contractors I can contact in
in the bay area) for advice and help who specialize in tower
Can I simply take the tower and antennas down, remove the
MARB support base,
cut off the remaining three anchor bolts, have four new 27
drilled in the concrete and then have four new 1 inch
diameter by 27 inch
long new anchor bolts epoxied in........or do I need to hire
a couple of
guys with jack hammers to take out the 2 ½ cubic yards +/-
reinforced concrete and start over?????? ARRGGHHH!
Thanks in advance for your advice and recommendations.
Please don't hesitate
to respond to me directly at firstname.lastname@example.org
Thanks, Ted, K6XN
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