Before we get started with this exercise, let’s be clear. You should consult a professional and do thorough research about your floor and foundation. This blog post is meant to be a basic overview on this topic.
When implementing an industrial equipment platform (mezzanine) be sure you are not overloading your building floor. Too much weight will cause the floor to crack. Worse than that, it can be disastrous if the floor isn’t properly built to take the weight of both the platform and its load.
Our modular mezzanines are structurally engineered to support 125 pounds per square foot. The typical factory and warehouse floor in many regions is made of 6″ thick concrete and has a capacity of 25,000 pounds. On its face, this looks like a “no brainer.” However, keep in mind that this is the typical capacity, not a standard. When you start adding tons of equipment and material to a floor, you need to know the actual capacity.
Floor Capacity and Column (Post) Spacing
While the thickness of the concrete is an important consideration, it’s not all you need to know. After all, your concrete slab is sitting on top of soil or earth. Additional weight onto the slab will cause the soil underneath to compress. How significant is this? In some situations, where a 6 inch slab was in place, the load capacity of the floor was only rated at 10,000 pounds per square foot due to the very high water table.
It is important to perform a stress test on the floor itself which will determine the PSI rating of your warehouse or factory floor.
The next thing you need to know is how much load the mezzanine itself is placing on the floor and foundation. And here’s where the modular design of CIP’s mezzanine system can actually minimize the load being placed on your floor.
WARNING: Math ahead.
So, let’s look at a few key data points. Our mezzanine structures are rated at 125 pounds per square foot LL (Live Load). And, they are made of 10 foot X 10 foot square modular units. That means a single unit, with a total load capacity of 12,500 pounds is supported by four posts, no further apart than 10 feet.
In this scenario, we are perfectly fine with a single unit that does not have a center post as the distance being spanned is only 10 feet.
Let’s look at another configuration, using four modular units. Now, we are spanning 20 feet X 20 feet. Using our modular units, this would have a minimum of 9 posts, with eight running outside every 10 feet, and one center post that all four units straddle.
How much load is that center post placing upon the floor and foundation at full capacity?
The rule of thumb is that the center post supports half of the load across the spansion. This would be the equation for determining the load placed on floor at post “D” in drawing below. Let’s do the math.
Width of structure: 20 feet
Length of structure: 20 feet
Total square feet: 400
Weight rating: 125 feet per square foot
Total capacity: 50,000 pounds
Center post load equation: ((w/2) * (l/2)) * weight rating
Center post load = 12,500 pounds
Notice what has happened in the equation. Since the distance between posts remains at 10 feet, the load is capped at 12,500 for even the post bearing the most weight.
If you think this is a trick, let’s look at how much additional load you could be placing on your floor if you try to custom design a mezzanine with as little a change as a 28 foot X 28 foot structure with posts every 14 feet.
In that equation, the load being placed on the center post with a structure rated at 125 pounds per square foot could place up to 24,500 pounds on the center post if the mezzanine is loaded to its capacity.
In other words, your floor would have to be almost twice as strong.
If you have the space to accommodate, and you needed that much additional square feet, our system would have a 30 foot X 30 foot modular unit that now would have 16 posts. It would increase usable space by 900 square feet, allow you to store up to 112,500 pounds of material, and place no more than 12,500 pounds per foot of load onto the floor at each post.
Why You Need to Consult With Experts
It should be noted that it is the purchaser’s responsibility to verify that their facility will support any loads placed on it by equipment purchased from CIP.