Industrial Floor Loads

[corvette63]

Can someone provide a good design reference for evaluating the capacity of an elevated two way slab for its ability to support a crane or forklift.
This question has come up in our office and we have referred the question to a civil engineer. Before sending the solution to the engineer we were trying to determine over what area the load from the tires will act and how to evaluate this.
If there are some simplifying assumptions that can be used in the analysis that would be good. Also is there a good design reference that I could aquire for similar problems. Thank you.

 

[Ussuri]

Leave it up to the Engineer to decide???

 

[jike]

I am really confused! Why are you refering this question to a civil engineer? This problem is more in the realm of a structural engineer's expertise.

If you are using a consulting engineer for the answer then why are you interested in coming up with a solution before you ask him?

If you are looking for one simple answer to this problem, there is not one. It is quite a complicated problem and must be analyzed in detail.

 

[corvette63]

This problem can't be that difficult. There must be simplifying conservative assumptions that can be used to solve this problem. If the conservative assumptions prove to be a problem then a more detailed analysis is required.

Any positive comments are appreciated.

 

[whyun]

I am used to designing to the code minimum or known crane/forklift loads whichever governs the design, unless the owner (typically transit authorities in my experience) specifically requests the whole floor to be designed for a heavier uniform live load.

Code live loads may not be descriptive enough for your application. Find out the NEED of your client before going too far with the design.

 

[jike]

If the concentrated loads are small, you may be able to include them as part of the uniform load. If they are relatively large concentrated loads, you may have to analyze your 2 way slab by equivalent frame method or finite element method. You will have to use your judgement as to what is considered small or large.

I know of no simplified methods for two way slabs, however, there are a number of simplified methods for one way slabs.

 

[JLNJ]

The difficulty of the problem depends on the design of the existing slab and the size of the forktruck.

If your slab was properly designed as a two-way slab for 250 psf or more then a small lift will likely be OK.

A 15,000# axel load from a 2 ton forktruck on a skimpy slab likely won't be OK.

A good structural engineer should be able to do a couple of back-of-the-napkin sketches and tell you in 30 minutes how great your concern out to be.