Design against Truck Impact
Design against Truck Impact
(OP)
Hi everyone,
I need to design a steel structure to resist the impact of a 7500kg truck running with a velocity of 80KPH.
please not the formula F.d= 1/2M.v2 will give extreme high forces .
can anyone know any practice/code for such design
regards
I need to design a steel structure to resist the impact of a 7500kg truck running with a velocity of 80KPH.
please not the formula F.d= 1/2M.v2 will give extreme high forces .
can anyone know any practice/code for such design
regards






RE: Design against Truck Impact
RE: Design against Truck Impact
RE: Design against Truck Impact
RE: Design against Truck Impact
See http://www.eng-tips.com/viewthread.cfm?qid=355042 which talks about similar things.
the key will be your requirement to "resist" the impact. what does this mean in reality? Be so solid that it doesn't bend or actually be a protective barrier - but able to deform - to the thing behind it that really matters? You'll get a different answer depending on which of those it is?
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: Design against Truck Impact
Other than those two onerous methods what will get get you in the game quickly is setting kinetic energy equal to work and solving for the force. But, to do that you have to know or decide over what distance it needs to be stopped, and the barrier has to have enough give and resistance to hold up over that distance. Once that's decided it's easy:
That is, set .5mv^ = Fd and solve for F. And watch your units, particularly if you're using the imperial system (i.e. divide pounds force by 32.2 ft/sec^2 to convert it into mass).
And as Excel noted, be prepared to see some large forces. Good luck.
RE: Design against Truck Impact
TLycan,
See the following thread for my reply for similar query.
It is applicable for your case for steel impact also.
http://eng-tips.com/viewthread.cfm?qid=355042
RE: Design against Truck Impact
RE: Design against Truck Impact
I don't think you've begun to give out sufficient information to even identify what tool to use.
TTFN

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RE: Design against Truck Impact
thank you all for this super-speedy response
to IRstuff,
for this current job , I am designing a steel-sliding gate 9.00meter opening , and 1.50 or 2.00meter height approx.
its for an oil-terminal, and the oil company required high safety issues against terrorist attacks, one issue is designing this gate.
the gate is to provide zero penetration and I think to still remain functionable afterward.
I don't know whether I should consider the impact as frontal or at corner.
the owner wants the gate as in the attached in file, the one in the photo is 6.00 meter the one required is 9.00 meters
RE: Design against Truck Impact
Might be a bit difficult to open the gate after though.... A 7 1/2 tonne truck at 50mph is going to take some stopping.
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: Design against Truck Impact
RE: Design against Truck Impact
Truck is travelling at 22m/sec. Truck stops in 2.2m (crumple zone/ destroyed cab - see the photo!) Therefore it takes about 0.1 sec. Therefore deceleration rate assuming constant deceleration is vel/time = 220m/sec/sec
Numbers seem to work out about right to me.
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: Design against Truck Impact
RE: Design against Truck Impact
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: Design against Truck Impact
Just some food for thought, no instant or profound solutions....
The variables needed to solve this problem are pretty tough to really put your finger on, so there may be a hundred numerical answers, non of them all right or wrong. The stopping or restraint devices designed for highways and the like have a large design component involved with stopping the vehicle without killing the occupants. That is absorbing a lot of energy, over some reasonably distance and period of time, so as to reduce high instantaneous impact forces. But, these aren’t your objectives, you want to stop the vehicle and don’t care about the damage to it or its driver. Notice in the picture you show, there is a good deal of cab damage above the elevation of the motor. You want to crumple a whole bunch of steel and sheet metal on the truck to absorb the energy, plus some on your gate. Start bustin up metal above and below the mass of the engine as quickly as possible, and then start stopping that concentrated mass too.
I think that having the gate be operational after the impact, may not be impossible, but is a pretty unreasonable design requirement. You can’t stop the gate from deforming and if so how can you pull it back into its slot, and will it operate properly after that. Why not work on a design which is fairly easily removable with available maintenance equipment, like fork lifts, front end loaders or a small truck crane. Use readily available components, like off-the-shelf WF beam shapes to span the 9m opening, so things can be replaced quickly, but not immediately. Heck, you’re going to spend a day gettin that busted up truck out of there. As your picture shows, two large conc. abutments and wing walls to take the impact. The gate slides through the one and locks into an 18" deep slot in the other, so it can deform quite a bit without disengaging. A track on the ground, may actually be a piece of RR rail, and chain drive pulling the gate either direction. This track system might be set in a 3'x5' deep reinforced conc. sill 9m long. In this sill you might also have some conc. filled pipes which could be pulled or pushed up 24-30" cantilevering out of sleeves in the conc. sill block, to start grabbing axles and underframe parts and bot. of the motor. Most of this stuff can be picked out in pieces and replaced, but straightening a bent gate may be quite a different matter.
RE: Design against Truck Impact
RE: Design against Truck Impact
RE: Design against Truck Impact
I really thank you for your quick and helpful response response, this discussion was really helpful for me
Regards
RE: Design against Truck Impact
The average velocity over the stopping distance is 11 m/s, so the stopping time is 0.2 s, and the deceleration is 110 m/s^2.
Doug Jenkins
Interactive Design Services
http://newtonexcelbach.wordpress.com/
RE: Design against Truck Impact
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: Design against Truck Impact
The design requirement is not realistic - you should be considering 2 x gates and possibly an additional barrier which can be raised out of the ground between them. A single gate is always a risk. What happens when the gate is opened for one vehicle and the terrorists waiting behind then drive through the open gate?
RE: Design against Truck Impact
The difference is probably the stopping distance. Presumably you do not resolve the ship impact over 1 meter or less. Run the numbers. In the same way that it requires infinite force to reduce a centenary sag to zero, even a gnat would generate infinite force it it had to stop instantly without deformation. It becomes an issue of dividing by zero. That said, each engineer has to come to terms with what is realistic...up to a point. On issues such as this it depends who's setting the parameters and approving the design. And certain governmental authorities do indeed use the exact criteria described above for their design parameters. In short, the customers' requirements must be taken into account.
RE: Design against Truck Impact
I was reading some of the post, and I wonder if any one provide a complete design for gated crash barrier
and show the detail design computations
thanks
RE: Design against Truck Impact
Bolt some cyclone fence to the side of a big ol' locomotive,
and park that in the gate opening.
Mike Halloran
Pembroke Pines, FL, USA