Container Yard Design 1

[JoeH78]

Hi,

I've been asked to design a container yard, similar to those made on big ships harbours where containers are stacked one on top of the other, but mine is relatively on small scale. Analyse for piling of containers, I'm planning to perform linear static analysis of rigid beam/plate/shell resting on Winkler spring and this will be designed as RC concrete slab on grade.

It seems that governing case will be the maneuvering motions (twisting, torsional, warping of wheels) of stacker during loading and unloading containers, so slab on grade will be subjected most extreme loads during that case I believe. But I'm puzzled on how to perform that analysis (twisting, torsional, warping effects) of stacker during maneuvering, is there any standart analysis type that I need to perform?

Aside from all of this, client requires to apply the asphalt layer on top of the concrete, thickness of that asphalt needs to be determined and again I'm afraid of that stacker motions will play an important role in this scenario as well, too thin asphalt layer might be unbounded from Rc slab on grade, too thick asphalet may cause submerging effect etc..

I'll appreciate your guidance.

Regards,

 

[oldestguy]

Sounds like a foolish requirement. If temperatures get up in the 80's F, be aware of possible shoving. Takes a special design to minimize that.

 

[EngineeringEric]

This is why you use concrete and not asphalt.... Fire stations that have AC pavement will often have dips and wells from the trucks turning and parking on asphalt, that's why most of the time is always concrete. Also look at dumpster pads, the concrete extends out enough so the truck can place its front wheels on it and so forth (not a rule but common in my part)

I do know from a pavement design class that ship yards often have proprietary pavement designs which sometimes involve high grade asphalt running surface with highly designed/researched thickness on various subgrades/bases. But this isn't something we can talk about online in detail.

Voice the concerns to the client and your recommendations. If they don't back down ask for an example of a project that this was done and it performed well. Design concrete as if asphalt wasn't there for loads.

 

[oldestguy]

Here is something that may solve the question. Many residents in US have asphaltic concrete driveways. In time the asphalt wears off the surface aggregates nd the folks want their driveway to look newly done, black color. So they buy or contract to do what is called "sealing" with a painted black concoction. As a side note on those, I have noticed these "paints" cause more cracks than they prevent.

Since there is such an unrealistic requirement on concrete, about as useless as the driveway "sealing:, maybe they will accept painting the white concrete black with the stuff that home owners get for their newer looking asphalt pavements. Much less in the way of problems to deal with later.

 

[thaidavid40]

The Army often uses roller-compacted concrete for hardstands and tank turning pads. These may also have polymer concrete overlays, and contain steel fibers, for added durability. Check the UFC design criteria, as well as the UFGS specifications, which are related to Army training range design.
Dave

Thaidavid

 

[Ron]

Good points above.

Many container pavements are now done with roller compacted concrete as Dave noted. They are not reinforced and their durability for the turning/abrasion you noted is very good.

I would change the analysis approach you are using. It is a pavement. It can be designed as any other rigid pavement, just make sure that you get the material properties of roller compacted concrete and not conventional portland cement concrete. There are some excellent publications available on roller compacted concrete, and you can use downloadable software from the US Army Corps of Engineers for the analysis. It is a modified elastic layer analysis program. Google "PCASE" and get the latest version. While it is primarily geared to military equipment, there is also information in the database on container loading equipment as well.

If you want to do the entire analysis by hand, look at the Portland Cement Association's rigid pavement design methods (based on Westergaard). I am attaching a paper that might help you. It is directly related to roller compacted concrete design for container applications.

Also, if you want to know more about roller compacted concrete, one of the leading experts in the US is Dr. Shiraz Tayabji. Google him. He is located in the US, in Maryland.

 

[Ron]

Paper I mentioned didn't attach so I'll try again.....