Machine Anchor Bolt Loads

[dilbert318]

I am trying to come up with the loads on the anchor bolts of an existing machine. There are several bolts, some are 2" and some are 3" dia., with an irregular layout. The base of the machine is "L" shaped in plan. What methods are there for comming up with the loads are machine anchor bolts and are there any good references out there?

 

[twinnell]

Is there an information plate on the machine that you can get the manufacturer and model number. Call them and ask for the base reactions. They might even have a drawing with the loads on each bolt.

 

[dilbert318]

I wish I could. The equipment is for a strip mill and has been modified to handle significantly larger coils than originally intended (167% of original design). Even if I could find information about the original design It wont reflect the current state of the equipment.

 

[mickeymouse]

I may be wrong, but I assume this is rotating equipment of some sort? Do you have a little more description of the operating conditions, weight, shaft centers in relation to base, etc? The "L" shaped base plan was for a reason and the use of 2" and 3" size nchors also points to heavy loading by rotating equipment. To figure loads on anchor bolts shaft centerlines to base, loadings in relation to base, etc.

I would recommend the following:
1. Blodgett, "Design of Welded Structures"
2. Blodgett "Design of Weldments"
The James F. Lincoln Arc Welding Foundation
Cleveland, Ohio.

 

[JStephen]

For symmetrical structures, the anchor bolt loads are usually derived by assuming a stress distribution similar to that in beams, and finding Mc/I - P/A for the whole bolt pattern. This assumes you know all loads acting on the item, including weight of it. This is an approximation. WIth odd-shaped machinery, if the machine itself is more or less a rigid block, I'd treat it the same way. If it's fairly flexible, then you'd have to start looking at internal forces to really get a good idea.

 

[JStephen]

Also refer to ACI-318, newer editions, App. D, for useful info on design of bolts in concrete.

 

[dilbert318]

Thank you both for your input.

 

[zcp]

Wild idea here. Any chance you could load cell or strain gage them? That way you would get a loading pattern for operation for max loads and fatigue.

ZCP

http://www.phoenix-engineer.com

 

[dilbert318]

I don't know, never thought about doing it that way.