Stockpile level control 1

[sdz]

I am designing a retaining wall around a stockpile fed from an overhead conveyor. The client says they will install a sensor to limit the height of the stockpile and hence the height (and cost) of the retaining wall. How reliable is this? I would prefer to design for a stockpile up to the underside of the conveyor to allow for control system failure/lack of maintenance/de-activation.

What is my liability if the control system does not work and the stockpile overfills and caused structural problems?

 

[IDS]

What is my liability if the control system does not work and the stockpile overfills and caused structural problems?

That depends on the extent of the structural problems. If it is greater than expected deflection, or wider than specified cracks, then it would be pretty hard to blame the designer (assuming you have a clear statement of the lower design stockpile height from the client). If it is collapse then you could have a problem even if you followed the clients specification exactly.

I'd suggest designing for the lower stockpile height following the normal code requirements, then check what happens if you use the maximum possible fill height as an ultimate load case, with a lower load factor on the stockpile weight and accepting some movement or overstress (above SLS levels) in the wall.

A similar approach to earthquake design.

Not sure why this is specifically an AS/NZS code issue by the way?

Doug Jenkins
Interactive Design Services

http://newtonexcelbach.wordpress.com/

 

[sdz]

Thanks, Doug. That's along my line of thought.
No it's not specifically AS/NZS but the project is in Oz & I couldn't find a better place for it.

 

[hokie66]

These type retention walls are typically designed for loading to the top, with the retained material sloping up and away. If the wall is overtopped, the material should spill over. So that's your control system. Am I misunderstanding?

 

[sdz]

hokie66, in this case the material above the wall will be retained by cladding attached to a separate structure.

 

[sunlightpower]

Agree with the suggestion from Hokie 66, That's the best thing the designer can do.

 

[PersonalProfile]

It is difficult to say without understanding the situation in detail, though if the design is not suitable for the foreseeable reasonable abnormal condition you would probably have a problem.
Hence the over height detection (device (s), control system etc) needs to have suitable integrity (alternative detection methods, redundancy, SIL / category rating AS4024 etc) to maintain the design assumptions.

Regards,
Lyle