cement post inside metal post

soups05

Hi guys,odd sort of question for you. I have a set of metal gates which a local dipstick hit with his daddys car.(16 years old and out for a joyride) after waiting months for an apology and getting nothing i decided that i would need to fix it myself.
I purchased a welder, cheap adli job but all i could afford, and after a lot of practise i done what i think is a pretty fair job at welding.
when we lifted the gate back on,allowing a couple of hours for the welds to cool and set while i had a lunch break and done some other little jobs, the post cracked at the weld straight away.
I have reached the limit of my welding abilties so have come up with another apporach. and need some advice.
at the moment i have rewelded the post. it seems secure but will not bear the weight of the heavy gate. so i am thinking i can cut the top off of the post,insert a 12 inch long bolt to act as rebar,and fill the post with cement.

would this have the effect of strenghting the post or will it be a waste of time. i have never worked with cement so don't know what sort of mix or quantity i would need for a post about 3 inches wide by about 3.5 foot tall.
suggestions would be helpful.

slimjimmc

Cement is great in compression but has feck all tensile strength so I don't think it'll be much good are resisting the bending forces which a heavy gate would put on it, imo.

You could try inserting another steel pipe to act as a sleeve. Tack it inside to the base with a few welds then slide the rest of the post over it and weld the joint. You need to chamfer both parts of the post so that you have a V-groove to weld into. Alternatively you could put the sleeve on the outside and weld the ends.

If you're not confident about welding you could bolt the either sleeve in place or ask a decent welder to have a go at it.

soups05

thanks slimjimmc, guess i will have to re-think my plan then. i just figured cement+rebar =strengh. have already re-welded the post in a vertical postion so may look at fixing some sort of metal sheath around it for extra support.