How deep to make gate post for heavy gate

[bcraigie]

I'm helping a friend of mine. She has a 5-bar large gate she asked me to hang and I have concreted-in a big round post (about 8 inches diameter) to about 3 feet down. I packed the hole (about 18 inches dia) with big stones at the bottom and concreted in with 1 part cement to 2 parts sand/gravel (two wheelbarrows full) to about 18 inches deep. Left overnight to set then packed soil on the top.

I hung the gate next day. Top hanger was one you drill a hole and tighten a nut to pull it through. No problem. Bottom one was a hammer-in job. Friend insisted it was just hammered in. I wanted to drill a hole to make it easier (thing is about 1 inch square, 8 inches long with a pointed end). To make matters worse, post had a knot right where I wanted to put the hanger. So I drilled it a bit. Needless to say, I couldn't get the hanger hammered in far enough AND the hammering loosened the post. :-(

My question is, with that type of hanger, I think a hole should have been drilled to make it easier to bang in and reduce the chance of loosening the post. In fact it looks like it should have been pressed in with a huge vice. Am I right or wrong? What is "normal" ?

Now that the post is loosened, the gate is dropping and needs lifted at the "open" end. If I strain the post at the top with wire fixed to a huge concrete boulder buried down-hill (to make a cantilever) would it help?

Should I rip it up and start again (as someone else she knows has suggested)?

Thanks for any advice. :)

Brian

[thedoctor]

Rip it up Brian, the post should be in the ground at leasy 600mm and concreted all the way down with the mix shown in our mixing concrete project.

[bcraigie]

[quote="thedoctor"]Rip it up Brian, the post should be in the ground at leasy 600mm and concreted all the way down with the mix shown in our mixing concrete project.[/quote]

Thank you Doctor,

I don't understand though. My mix was correct according to the Mixing Concrete page.

600mm is only 2 feet (or 24 inches). Doesn't seem deep enough to me.

The post was sunk 3 feet down, with concrete on the bottom 18 inches (measured up from the bottom of the post). So surely if I had just added another 6 inches of concrete, it would be the same as you describe, only a foot deeper. :?

Thanks for the reply though Doctor. Makes me feel I was at least on the right track. Guess I just hung the gate too low initially as I didn't account for the post bedding in.

Brian