How to concrete posts/brackets into place?

[ptyltd]

Hi Folks,

Just thought I would see what the gurus had to say about how to concrete steel posts or brackets into place.

I have about 30 post holes dug (450dia and various depths) which will house mostly 75x75 steel posts as well as some saddle/stirrup brackets and I wanted to know the best way to set these in the concrete, at level and in line etc.? I was going to use a concrete pump for the pour (so time is a factor) and what I was planning to do was actually bolt the posts and brackets onto the bearers and posts and then brace these timbers into position so the posts/brackets are suspended in the hole which I am hoping will allow me to easily poor the concrete and ensure everything was in line and level (assuming they were braced well enough that the concrete won’t move anything ).

How do most people do this and what was the best way?

Another idea was to setup some profiles at respective levels and use intersecting string lines to show post/bracket positions and then just hold the post/bracket in place as the concrete is poured which I assume (maybe:confused: ) is how it is normally done.

I guess thinking about how I was going to do it there could be issues bracing the timbers into position as well as the bearers could restrict or hamper the concrete pump pouring (but then so would string lines everywhere).

Any advice appreciated.

[journeyman Mick]

I've hung the posts off the bearers and poured the concrete in, but it was a low set so it was just a matter of sitting the lot on a few blocks to get it to the right height. Otherwise set up your profiles and string lines and mark the height of the string line on the post. Hold post in place and plumb while pouring in concrete. Usually takes four people: pump operator; post holder/plumb checker; concrete tamper/post adjuster; concrete troweller/post adjuster. At least that's how I've usually done it, you could probably do it with less people but more stress.

Mick

[attie]

I've done it both ways ptyltd but prefer to assemble the frame, would it help to peg some timbers to the ground and clamp the bases of the posts in place.

[Off topic] If you need to plumb down from a string line, place a shallow dish of sump oil directly under the string line, straddle the line and when it's reflection lines up, sight along the trench/footing to give the plumb point. Good for starter bars etc.

[ptyltd]

Thanks for the replies folks.

Bearers were only going to be about 450mm of the ground so as you said Mick hopefully easy to set up the bearers on something (but was thinking still brace them to stop any movement).

As I understand it you can't hire concrete pumps per say but, rather it's a service so I am assuming they operate and pour the concrete (at least they were talking about breaking it down as you work back to the truck etc.) which just leaves me and whoever I can rope into helping which at this stage is probably 1 other (so I could be in for sum stress huh ). Something else to add to the list of things was vibrating the concrete as well.

Attie not quite sure what you mean about clamping the bases of the posts in place because these will be embedded into the concrete (thus if it was framed up they would be suspended in mid air in the hole).

[attie]

If your bearers are just 450 off the ground, you shouldn't have to bother. It's when you have a fair height I run a piece of scrap timber across the hole, peg it to the ground and clamp the post to it to stop the base of the post moving when you're pouring the concrete

[ptyltd]

Yeah Attie that's makes sense now that you have explained it.