How to secure anchor bolts in concrete?

[BotusBuild]

The simple question is how to hold the four bolts in place while the concrete is poured? I'm guessing someone has had to deal with something like this before, so be interested in seeing your solutions. Wax paper cones and polystyrene cones are two things I have found in my searches

 

Here is the proposed connection - a steel column that will sit on a 250mm insulated raft that will have two layers of A393 mesh reinforcement. The column is sited flush with an edge of the raft.

 

[markc]

Plywood drilled to match the bolt pattern. If you are not sure of getting it placed correctly then foam cones should be added to the bolts to give wiggle room for lining up later. the pockets are filled with grout later when the steel is fully fitted.

[Dudda]

The plywood works well. Just make sure the bolts are tight in the plywood or use two layers of plywood to keep them vertical otherwise they can be in the right place but at an angle and not vertical.

[BotusBuild]

1 hour ago, Dudda said:

to keep them vertical

An alternative might be a nut and washer either side of the plywood to hold the bolt vertical?

[Dudda]

1 hour ago, BotusBuild said:

An alternative might be a nut and washer either side of the plywood to hold the bolt vertical?

Oh that's a given. That's why I'm saying the bolts are tight to hold them vertical but even then I'd consider two sheets of ply particularly if using only 12mm or 15mm ply. You've very little tolerance so need them exact.

[markc]

As above, you use nuts to secure the ply in pl;ace to mimic the base plate of the column. If you are still worried, put a piece of pipe insulation around each bolt between the ply and the bottom washer, when the concrete has gone off a bit take off the ply and dig out the insulation, then wiggle the bolts around a bit while the concrete is still green. This will give the necessary movement. This is how steel building are put up.