A new installation (the drawings and footprints are available) coming up soon calls for two separate large concrete pedestals: the driven machine on ground level and the motor - on a pier.

I am looking for a source on a procedure and instrumentation required to pour the conctrete pedestals ( in particular the one for the motor ) in a most accurate way, so that precision alignment will be feasable to perform afterward.

I hope this info will be useful for many of us.

I'll appreciate any feedback.

David

The concrete structure itself is not the crutial factor. It must be of required strength and slump and etc..... But, dealing down to mils will mean that your sole plate and its grouting is where is it and what it's all about. You can set you elevation from the benchmark (army corp of engrs) via water level and 98. Bring in the sole plate via 98 or 200 master level depending on your specs. Set the sole plate ~125 mils low to driven so you will have adequate shimming room for future subsidence. I generally like the 100+mils for the driven machine as well to compensate for future settling. This should keep you from getting bottom bound in the future. Critical machines - find my tolerance charts posted on my site or write for a copy.