Design of Base Plate and Concrete Thickness

[keen_mentee]

Hi,

I need to design a base plate for attachment of a 2700# equipment to a concrete slab. I also have the operating loads(force and moment) which is greater than the lateral seismic force as it is a SDC B. I wanted to know how we can proceed with the design and have the questions as below:
1. What load would the operational load be categorized as (DL/EL/others) and what do you suggest the load factor in the combination of lateral load with vertical load?
2. How can we determine the thickness of the base plate? So far I am checking the plate in flexure using distance between two extreme anchor points. Is there any check you would recommend?
3. How can we calculate the thickness of the concrete slab under the equipment? I am working with a old template that has the formula as follows and I do not think it it right. The units on the left hand side and right hand side are different too. What do you suggest?
Slab thickness= Load/(0.75*2*sqrt(fc')*Bearing Area of the Plate)
Thank you,

Thank you,
Ruchin Khadka

 

[Agent666]

1 - I'd tend to treat it as dead load if it was ground supported on a specifically designed footing. As for the load combination, your local code should cover this. If some part of the operating load is a dynamic load then I'd tend to consider that a little differently maybe, with that portion as live load. I guess there's a bit of judgement involved.

2 - posting picture of the baseplate arrangement and actual loading is likely to get some specific feedback. Otherwise your query is probably too general to provide specific advice.

3 - that looks purely like a bearing stress on concrete type of formula, often the sqrt(f'c) part has implied units of MPa, not MPa^0.5. This should make the units work out? But there is more to designing footings than just working out that the bearing works. Again maybe posting an idea of what your were envisaging for the footings would get more targeted advice to your situation. Any good text book should run through the basics of foundation design.

 

[MegaStructures]

Is this on a footing, or a flat concrete slab? If it's a slab how thick is it? Also do you expect any lateral loads on the equipment leading to uplift on your bolts, or just pure compression?

“Any idiot can build a bridge that stands, but it takes an engineer to build a bridge that barely stands.”