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Bollard Design for Elephant Enclosure 4

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Tuwair

Tuwair

Structural
Feb 5, 2021
1
I have an odd question for everyone. Has anyone designed an elephant enclosure? I am currently trying to design elephant containment bollards. These bollards are concrete filled steel posts.
The bollards need to be designed in a way that do not harm the elephant in case of impacting them. We prefer to partially damage the bollard but not the elephant.
I’ve used the car impact equation from the euro code to compute the kinetic force in case of impact but that calculated force was very huge (482 kips). Any other suggestions please.
Assumptions: The average weight of the elephant is 8000 lb and it’s average speed is 15 mph and point of impact is assumed at 7 ft. height. Thanks!
 
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Force = (mass/2) * (velocity^2)

There is however a reduction in this force available to account for barrier deflection. Your local code should have something on this for vehicle impact. In this case, your “vehicle” is an 8000lbs elephant!

Although usually you’ll find that such clients will have their own minimum requirements. No point designing for averages when big bertha comes in..
 
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On the deflection front, I'd imagine the elephant is also quite squishy to absorb the forces of an impact.

So more than anything I'd expect you're going to be guessing either way unless you can find some guidelines for zoo animal enclosures or similar.
 
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If you search this forum, I recall seeing a few of these threads in the past.
 
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Agent666 said:
On the deflection front, I'd imagine the elephant is also quite squishy to absorb the forces of an impact.
Click to expand...

This made me laugh out loud! I had images in my mind of the squishy elephant impacting the bollard with my dynamics professor lecturing on the coefficient of restitution.

MIStructE_IRE. Kinetic Energy.... not force is equal to (mass/2) * (velcity^2). The displacement component of the bollard (or squishy elephant fat) is a key unknown for solving for the force.

What strikes me as odd is that this same question (almost verbatim) was asked back in 2017 by a different poster. The first two sentences are the exact same.... Coincidence?

Link
 
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Perhaps the elephant has returned and the garden is now a write-off. I did come across a PDF for general elephant containment and one that stood out was that horizontal fence elements were subject to being climbed and to be avoided.
 
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I'm into high voltage enclosures, myself... sorta like a 50KV fencer...

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

-Dik
 
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Tuwair,

I would be careful using the equations in Eurocode intended for cars. They are based on certain assumptions regarding the deformation properties for the car and the barrier. I doubt that the elephant and your barrier will have the same properties.

I would instead go back to the dynamics of the impact. You know the kinetic energy from the elephant at impact. If it collides with a mountain it will possibly by killed, since there is no deformation in the barrier.
But how much must the barrier deform without hurting the elephant? And that you need a barrier that can deform that distance and also absorb the energy.

Good Luck
Thomas
 
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Problem solved... and no electric fencer... elephant's much happier.

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

-Dik
 
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South African here, I recently did a project for a rhino and buffalo enclosure for a veterinary school and
we have a code or recommended design loads for such animals. This is from SANS 1184-1:2004
Animal_Loadings_sialyx.png


This is for temporary housing though.
 
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steynvW... copied your posting... don't think I'll ever need it, but who know... thanks

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

-Dik
 
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I suggest asking the zoo what to design for. I designed an elephant enclosure many years ago and they provided all that information. Don't quote me but if I recall correctly (remember this was 7+ years ago) the force was something like 10 kips on a gate.
 
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for liability, it's good if they can provide the design loading...

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

-Dik
 
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and what is the destructive capacity of an elephant ?

... African or Indian ?

another day in paradise, or is paradise one day closer ?
 
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Is that a Monty Python elepant joke?

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

-Dik
 
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Is that an African elephant or an Indian elephant?

(missed it - thought it was part of the signature line which I skip for being nonsense.)
 
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Force = (mass/2) * (velocity^2)
Click to expand...

That's the formula for kinetic energy, right? Not force. You'd have to turn that into Strain energy on the column to determine the deflection. Then maybe convert that to an equivalent static load that could cause the same deflection.

Regardless, I think the solution to your problem is not entirely a structural one. You design the structure to withstand the load and deflection that are expected. Then you surround the column with something less rigid to protect the elephants from hurting themselves on your structure. Kind of like those water barrels that surround various columns or poles that you pass on the freeway.
 
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