dump truck station design

[mesmelt21]

Design issue.

Problem: dump truck trailers tip over to the side when unloading material. The cause could be an uneven floor, material stuck in the dump platform,etc. These trucks weigh about 45k lbs (load included).

In order to prevent tip overs, I would like to design a dump station made of bollards( or some other type of material). There will be 2 rows of bollards and the dump truck will be in between, question is how much force can the bollard withstand at impact when truck tips over to the side. What type of bollards would I need? The bollards will have to be 10' tall or more, is this feasible? How deep the bollard would need to be to withstand a falling truck.

Of course, I could have an even floor and problem fixed. But where I work, trucks dump on a regular basis, and floor surface don't stay even for a long period of time. Trucks unload any kind of materials from engine blocks to concrete blocks; these materials damage the floor quickly.

I made some calculations, taking 0.5g sideways force (truck's cargo weight) and calculating the kinetic energy, based on bollard design for vehicle crash impact(linear motion). I assume a speed of 5mph, and bollard deflection of 3'. I can allow the bollards to have deflection on impact, maybe 3' or less. Structure engineering is out of my realm, so I figured I could get some tips from you guys.

Any suggestions or other design approaches will be appreciated!

Thanks,

 

[bridgebuster]

off the top of my head, it doesn't sound feasible. 3' is a LOT of deflection. You could try sizing a member assuming a cantilever beam fixed at the ground surface - just to give you an idea of the "bollard" size. To determine the embedment you would need a program such as LPile or you could go through the tedious calculations by hand.

 

[CBEngi]

IF your bollard is going to be 10' in length, I would think you would be looking more into some type of structural steel section instead of a conventional bollard. 3' of deflection over the 10' of height wouldn't be acceptable, the P-Delta effects of the load acting 3' off center of the bollard would make almost any section unlikely to work.

The foundations would likely be substantial to handle the overturning force. I think you should look at several bollard manufactures and see what standards they state their bollards are designed to. Find the standards and see what loading they should be expected to handle.

Likely this is a special request and you should consult a structural engineer for proper advice.

 

[bimr]

You would be opening yourself to additional liability should unintended happen with such a structure.

Look into prevention practices or alarms.

There are some anti-rollover alarms that are available.

http://www.3dx.com.au/terraintrakka/applications#app1

 

[cvg]

overloading the trucks seems to be the likely root cause of roll overs. restrict the load size. level up the floor and then protect it with steel plates.

 

[LittleInch]

Bollards will be of little use.

what you want / need instead is two high concrete walls with buttresses just wide enough apart for the truck to squezze in and then any out of balance forces will result in only a small movement before the truck hits the wall.


Anything which allows the truck to start falling over and then arresting the fall is difficult to design, ends up being very big and if its as common as you say, would need replacing on a regular basis.


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[mesmelt21]

I know it's a little late, but thanks for the replies, all of them were helpful. Just of curiosity, if I were to replace the bollards with a regular steel I beam (w12 x 45), 45kip load, 10 feet long, what would be the depth of the beam, or the slab thickness? I calculated the deflection and it's about 2.3", a cantilever beam fixed at the ground surface problem. I used the deflection equation, v= FL/3EI. Is there an equation where I need to calculate the depth of the beam underground? in other words, 10 ft above the ground, and x amount below ground; unless there are other methods.

Again, thank you guys for your help.

 

[LittleInch]

The ROT I've heard for what is basically a pile is that the buried part is twice as long as the exposed bit, in your case means 30ft long with 20ft in the ground.

Prevention is much better than cure though and preventing movement is much better than arresting it once it starts.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.