[TowerTalk] How do bldg inspectors handle screw in earth anchors?

[Brian Amos]

As for the utilities usually the municipality doesn't inspect their
installations as they are self regulating.  The "screw anchors" ie
"helical piers" are installed to a certain torque which the software
tells the installation contractor he must meet.  As a soil engineer I
have many times had to "inspect" the installation where I watch the
pressure gauge and make sure they make it to the required pressure
(which they tell me) for each pier and then I have to send a document
to the owner stating that it complies with the design and put my stamp
on it.  I'm not a big fan of that setup as I don't do the engineering
but I have to certify that it will hold up.  It drives me nuts
actually.  For a residential purpose I would guess that you just tell
the building official when you will be installing it and they can come
and watch. That is the only way to really inspect them.

BTW: Is this for supporting the tower? Or is it for the guys?  If it's
for the tower I suspect you will need at least one per leg and it must
be a large tower to keep them at least 3 screw diameters apart to
prevent interaction.  This type of support provides virtually no
lateral resistance (especially the square chance bars that have no
soil contact anywhere but the helix, they are all tension and
compression, so for guy supports they work great, but not so well for
a foundation.  I suspect that the building official won't care about
inspecting screws for a guying system.  They usually only care about
the foundation itself.

Brian
KF7OVD

On Thu, Jul 10, 2014 at 2:21 PM, Jim Lux <jimlux at earthlink.net> wrote:
> On 7/10/14, 10:29 AM, Richard (Rick) Karlquist wrote:
>>
>> Has anyone had experience getting a building permit
>> for a tower with screw in earth anchors?  How does
>> it get "inspected".  There is no empty hole for
>> the inspector to look at.  Do you show him the anchor
>> before insertion?  If you have an authorized AB
>> Chance installing contractor put in the anchor,
>> do they issue a certificate that you can show the
>> inspector?  In a sense, this contractor is also
>> the engineer and building inspector all in one.
>>
>
> could it be more like a material and process inspection?
> You have the paperwork showing you have the anchor and the mfr's paperwork
> showing what its properties are.
> Then you have paperwork showing you did the installation appropriately (e.g.
> if you used a truck mounted drive, it gives a reading of the torque as it
> drove it)
>
>
> The only time I've had an "official" inspection of a structure using screw
> in anchors it was for a temporary installation, and the guy came out, looked
> at the plans, looked at the erected contraption, verified that what we had
> built matched the plans, and said "go for it".
>
> Granted it was in an area and application where failure would hurt nobody
> but ourselves.
>
> What do utilities do when installing poles with these anchors?  I find it
> hard to believe that the city sends out an inspector to watch them plant
> every pole and its guys.
>
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