How can I reduce the deflection of 18' high 4" diameter steel post? It is schedule 40 Pipe so around .5" wall

Question

The post is well concreted in, but bends to and fro, because of the climing wall attached to it. Will filling it with concrete reduce deflection? Should I use High strength concrete, small aggregate or Large. Does any of that make a difference? It is not going to be easy dumping concrete down a Pipe 18' in the air.

Answer 1

'DoitRight'  was pretty good and I would like to add to it.  It will be very important to keep this post perfectly plumb until the concrete has cured.  Otherwise you have a bigger problem.  There will be alot of weight in this column, do you have adequate support underneath?

Answer 2

if you have the room, you could attach stranded steel cables as 'guy wires'. i.e. like a telephone pole is supported to prevent sway. I-bolts could be used as attachment to pole, and as an anchor into the ground or the structure itself.

Hope that helps.

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Dan V: i can guarantee you that a 4" tube of un-reiforced concrete will crack\crumble into gravel as the tube even sways in the wind. the concrete will not bond to the pipe. the pipe needs to be stabilized from the outside. i think you are gonna be disappointed.

Good luck buddy...

Answer 3

It's hard to picture how this is installed, as the top is open?

Well anyway, if you have access to the top, and their is plenty of room, you could add another pipe, that fits tight inside, or outside.   Or, as you mentioned, fill it with cement, get a wide-mouth plastic container.   One in which the top fits inside the post, like the ones that health powders, or pool chemicals are sold in.  Cut off the bottom of it to make a big funnel.

Use a strong 3000lb, 4000lb, concrete with small aggregate to reduce air pockets.   Have someone vibrate the pipe to help the concrete settle as you're pouring.

One other way- get three 1 1/2" x1 1/2" x 18' galvanized angle irons.  Place each 1/3 way around the pipe, and secure every 2-3' with long stainless steel hose clamps.

(you might have to double some up).

I hope this helps, Good Luck.