Concrete base size and force calculations.

[dmn44]

Hi All,

I am planning a project in the near future to erect a 5m high free standing metal pole with a concrete base. The pole will be used to house the following equipment:

2x Solar panels. 1m x 1.5m (Closer to the top of the pole on a 45 degree angle)
1x Aluminium bracket to mount the Solar panels on. (Guessing around 4kg)
4x Network Camera's
1x Car Battery
1x Wireless dish (Diameter x Depth: 70 x 45cm, Weight: 5.7kg)
and some other smaller electrical equipment.

My current thought is to make the concrete base 1.5m x 1.5m x 0.5m that should give me a 1.125 cubic meter volume and make the base weigh around 2.5 tons.

I am however wondering if this will enough to ensure that a strong wind will not blow it over and perhaps hurt someone.

So my question is, how do I calculate the force required to topple this setup while taking into account the dimensions and weight of the base versus the items I wish to mount.

Thank you in advance.

 

[Newboy]

You need to go significantly deeper - around 1.25m for the pole and foundation

I suspect that there is a higher risk of the pole distorting/snapping with that much strapped to it.

The base will be fine for the loads you're planning but you need to rethink the loads on the pole - guy wires or bracing struts would work

 

[dmn44]

Hi newboy,

Thank you for your response.

Due to the location of this I am unable to lay a foundation. The idea was just to make the pole "free standing" within the concrete block that in turn will be placed on the ground.

So if I understand correctly, you are saying I need to make the concrete block 1.25m high instead?

I can move the battery and the electronics to the base of the pole instead to reduce the load and look into strongest available steel pole option to prevent it snapping.

 

[freddiemercurystwin]

I'd pay a local one man band SE £100 or so for a quick sketch. You won't get anything but some guesses on here. Or maybe post in the Building section where the odd SE hangs out.

 

[PaulJR]

Looking at your location I assume this is some sort of remote camera set-up
Again assuming that it's not subject to the local equivalent of UK's building regulations then I would suggest the following;

make the base a little wider - 1.5m each way and say 1.0m thick. Normally column foundation are buried which gives them a much better resistance to overturning, sliding etc. Those solar panels are going to act like sails, the whole thing will vibrate like a tuning fork in wind and probably wander across the ground. If it is to be installed on the surface make sure that it is solid ground and as flat as possible. Put a bit of welded reinforcing mesh top and bottom in your block - it will stop it splitting from heat cycles or the post vibrating

If is at all possible - auger out a hole ~Ø300mm by say 1.0m deep and drop the pole into it, then pour 10mm (pea) gravel into the hole to fill it up and Robert will be your mothers brother, You can hire petrol driven augers for fencing posts, telegraph poles etc. You could even use 'post mix' premixed concrete in bags and just pour some water over it once its in place

You will need a decent sized pole, you can buy them from http://www.abacuslighting.com who make exactly what you need if your budget goes that far. If you are going to use a bit of, well lets call it pipe. I would recommend you go for 6"NB sch 40 which should give a decent resistance to fatigue failure at the base, if you buy a pukka column it will be a lot lighter as they are thick at the base then taper down etc.

If of course this is to watch lions or something and you simply want to drop it off the back of a truck with a hiab then go for the biggest block your system can lift.

Hope this helps - I am a Civil Engineering Technician
(HNC rather than a degree)