Slope for Concrete Hardstand for stacking empty crates

[SHOOTZ]

Am designing a concrete hardstand for stacking empty crates up to 3m high, the existing ground slope is about 3%, to minimize earthworks Am planning to design a floor with a maximum gradient of 2%. I read somewhere that allowable slope for hardstand is 1% which is costly to adopt. Is this safe to adopt 2% grade, Any suggestion is appreciated.

 

[racookpe1978]

"Empty crates" like irregularly-stacked pallets thrown on top of each other?

 

[SHOOTZ]

empty crates well arranged on pallets ready to be carried by forklift

 

[racookpe1978]

Frankly, you've got yourself a problem not easily "analyzed" by engineering, because I see carelessness (in stacking the cartons on the pallets, and (possibly) stacking loaded and unloaded pallets on top of each other) being the MUCH more severe problem causing likely collapse than a slightly uneven concrete surface.

I'd leave the slight slope "as-is" and require separators between pallet loading zones (make a series of slots for the loaded pallets to go into) so one collapsing pallet load by illegals or untrained or incompetent/overzealous workers (both potentially dangerous!) won't cause the whole row to fall over when the load on the pallet in the middle slides sideways..

3 meters is 10 feet - certainly high enough to be dangerous if the pile collapses. Another safer "fall direction" is to make each slot sloped away from the open front. Then, when the pile falls, it falls away from the loading zone (the open front) and the collapsing load is trapped by the rear wall and both side walls. More expensive though. CME walls?

 

[racookpe1978]

Now, understand mentally I'm thinking of a pallet with empty cardboard boxes on it: If you've got rigid fairly sturdy plastic or steel "boxes" that CAN be stacked accurately and safely that high - rather than a loose pile of cardboard or something that is not sturdy and can be stacked by nesting together (like plastic milk boxes) rigidly, then a 10 foot stack of empties is much more likely to be re-stacked by hourly employees back into a safe configuration.

You got a photo of the load ?

 

[SHOOTZ]

Thanks for replies here is the photo

 

[LittleInch]

I think a lot of this goes on which way the slope is compared to your photo - is it left to right as you look at it or front to back or back to front?

None are particularly good to me as 3% in 10m is 300mm. Also if the weight of one of these things is say 2 tonnes, your force is 60kg trying to move it. Might not sound a lot, but none of this type of stacking system or indeed the forklift, is really designed for it and if it gets a bit wet or is stacked a little incorrectly, down it comes.

Just my thoughts anyway.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[civilman72]

Are you sure the 1% is a requirement related to the safe stacking of the pallets, or is it actually a requirement for the forklift to operate safely?

 

[SHOOTZ]

Am told by the client that is their standard related to safety but we are extending the storage area which is currently not paved with average slope of 3% so adopting 1% will results into cut of more than 1m hence difficulty accessing existing facilities, I have seen forklift working on 2.5% grade without any problem.

 

[oldestguy]

Can you do a series of terraces?

 

[racookpe1978]

Yes, terraces seem attractive, but then you have to fight the forklift adjusting from terrace to terrace across an even steeper (and short) "ramp" with a loose load on its vibrating jerky tongues that exaggerate the movement as the rigid forklift wheels hit each ramp.

Seems like cutting out the high side, using that to fill in the low side is as good as you can do. Loose loads on forklift tongues stacked next to each other so close to the next stack, driven by today's typical workers?

 

[ameyerrenke]

I agree doing multiple terraces is your best option. As someone who has operated a forklift, my biggest concern at that point would be carrying a loose load down the 3% grade and hitting a bump or trying to stop. The load will want to keep moving forward. Usually you would resist this by leaning the forks back, most forks will only tilt back 5 degrees (and they deflect a good portion of that so you don't actually get the full 5), some tilt back up to 10 degrees, you'd want one that would tilt back 10 degrees to be used in this area. A decent warehouse forklift wouldn't have an issue navigating this terrain otherwise.

 

[racookpe1978]

The warehouse forklift would require an almost absolutely smooth floor too. They don't like gravel, dirt. Do "ok" on rough concrete, but not if there are breaks in elevation - the little bitty very, very small very-stiff tires are not very forgiving.