Building on a Good Foundation – Skyneedle Base

Radio towers need a good base to survive.

This is particularly important with a free-standing tower.

I tend to over-specify the tower bases put in for my towers, and the TM-370HD base follows form.

Skyneedle base – The chain is a positioning chain that will come off after a few rains. The team has it spot on level and worried about upsetting that level if it rained before everything was cured.

The drawings provided for a base that would weigh 12,879 Lbs and have 98 square feet of lateral bearing surface.

My upsized base uses 19,238 Lbs of concrete (+49%) and increased the total lateral bear surface to 128 square feet (+31%).

My thoughts are both the counterbalance/inertia is aided by the added weight and the increased surface area reduces the per square foot forces laterally transferred to to the surrounding soils by spreading the overall force over more area.

The oversize additions served me well in prior installations, and at this small scale of concrete work the extra for the added concrete is kind of free, as the basic 3.2 cubic yard delivery would have incurred a minimum charge for rural delivery that basically offset the added 1.6 cubic yards needed for the supersized base. There is of course more incremental time to do the larger pour, so it isn’t exactly all for free, but isn’t a huge upcharge either.

It is hard to be patient as the cure time will put off erecting the actual tower for another 2-3 weeks. I think we are all so ready to put it up now, but that wouldn’t be wise.

The flagpole can go up after Labor Day though.

73

Steve
K9ZW

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.

%d bloggers like this: