Problems with the installation of shims for static equipment
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Everyone, please help. I have several vertical compressed air storage tanks here, with leg-type bases； A few more horizontal storage tanks. The design calls for welding to the base embedments. I would like to ask: in a situation like this, where there are no foot bolts, is it necessary to use both flat washers and shims together, or can flat washers alone be used as long as the horizontal and vertical requirements are met?
No, if there are no foot bolts, you can use flat shims as well, but from a construction perspective, it’s more convenient to use wedge shims for alignment; flat shims are generally used for aligning pumps
On one of our recent construction projects, there was a slight issue with the position of the anchor bolts when the equipment was placed in place; after the equipment was installed, it tilted a bit (upon inspection, it became clear that the orientation of its entrances and exits was slightly off). This is a bit strange; it was after the first molding and the installation of the foundation bolts that someone raised questions, and later it was modified based on the actual measurements taken of the equipment upon its arrival. Looking at the equipment itself, the bolt holes in the flanges at the inlet and outlet areas are not aligned (the upper two bolt holes are not horizontal); such a poor standard of manufacturing is truly shameful. In the end, as a last resort and to accommodate the piping, the floors under the three legs had to be cut away; after aligning everything vertically in all directions, the legs were reattached. That was just a digression; let’s get back to the serious topic: The height of inclined beams can be adjusted by varying the insertion depth, but this is not possible with horizontal beams. Similar to the alignment of mechanical pumps, there are also shims under their bases; when aligning the motor, shims made of metal or copper with a thickness of just a few millimeters are used. In this case, it’s not a matter of flat or inclined shims – it’s simply a piece of metal (or copper).
The functions of shims are, first, to transfer loads, and second, to align components. For equipment with low precision requirements, if there are pre-installed elements that can ensure levelness, shims may not be necessary
This post was last edited by Jinbei Zhisou on 2016-7-14 09:12. May I ask, can wooden planks be used as substitutes for shims for the foundation of horizontal storage tanks? Since this phenomenon has been observed, are there any relevant regulations? Thank you!
Surely you can’t use wooden planks as shims; they’ll get damaged after a while
Generally, a combination of flat and inclined beams is used, with the flat beams at the top and bottom and the inclined beams in the middle. Flat shims ensure proper contact between the equipment floor, the foundation surface, and the shims, while inclined shims are used to adjust the height. There are still differences in the installation of shims for moving and stationary equipment.