composite deck with moving point load 4

[yt254]

Hello,

I am trying to design a one way slab deck with 3VL/3VLI composite deck. To give you an idea of what i am designing before asking the question:
the deck is 15'x29' and it's for a warehouse forklift (total load of the forklift and the pallet is 7000 lb -which is my worse case-). I know that the allowable load for 15'-0" composite deck with light weight concrete is 139(please see image). But since the load of the forklift+pallet transfers to the slab thru the wheels. so my question is how can I design my deck for 1750 lb point load? do I need to add reinforcement?

thank you!

 

[le99]

You should find out the contact area of a fully inflated wheel, then add the appropriate deck thickness to calculate the distribution width. Don't forget to include the impact in the calc though.

 

[KootK]

Composite steel deck does not do well with heavy, moving point loads. Those load create high, localized bond stresses between the concrete and deck that tend to neuter the bond. I recommend a concrete slab that can do the job in its own right. If you use steel deck, just make it as sacrificial formwork.

 

[KootK]

Here's some excellent, free guidance on how to attempt to design deck slabs for concentrated loads however: Link. Do keep in mind the source.

 

[yt254]

thank you so much!

 

[XR250]

Also, your point load is way over 1750 lbs. Consider that most of the load is on the front wheels - even more when braking and turning. There was a recent thread regarding this.

 

[dik]

Most steel floor deck suppliers do not recommend use of fork lift traffic. Best to check with them other than being used as a form.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Do you feel any better?

-Dik

 

[JLNJ]

As XR250 says, you can't just divide the total weight by 4 wheels if it's a fork truck. You need to get the equipment drawing from the forktruck manufacturer and determine the maximum rated (note that I wrote "rated" and not "what they say they are going to lift") front axle load. Divide by 2 if there are two front tires. Put the rated capacity on the drawings.

The front wheel load at truck capacity will be way more than 1750 pounds. (And the front and back wheel loads are nowhere near equal!) Fork trucks are the worst enemy of elevated slab design.

Don't forget to check the concrete shear capacity when a wheel is near the support. This often controls the slab thickness. Those tables with the uniform load capacity just don't cut it for point or moving loads.

 

[271828]

The article starting on Page 16 of MSC this month might be helpful.

https://www.aisc.org/globalassets/modern-steel/archives/2022/may2022.pdf