jacking on concrete base

[elibintner]

hello,
what should i be considering in order to jack (lift) 190,000lb of equipment. the base is structural concrete with a lift of grout. the grout is not yet in place.
i have thought that the compressive strength of the grout should equal or better the concrete and that a metal base plate should be placed between the back and the grout. this is in response to concerns over compression and pressure?
Also what would the minimum time for the grout to reach adequate strength be?
I look forward to responses.
eli

 

[PEinc]

Assuming the equipment weighs 190 kips, how is it currently distributed on the concrete base? If you jack 190 kips, there will be a 190 kips concentrated load on the concrete base. Can the concrete base support this now concentrated load? Is the base of the jack large enough to sufficiently distribute the 190 kip load onto the concrete? Will you need a larger base plate under the jack? Check the grout manufacturer's spec sheets for the estimated time to reach the required strength before jacking. You may need to be conservative with the grout strength or use test cubes to determine when the grout reaches sufficient compressive strength.

Make sure the jack has enough excess lifting capacity and sufficient ram travel to lift the equipment without having to keep shimming the equipment and then resetting the jack.

With the little information you have given, I don't think there is much else to add.