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Crash Wall
- Thread starter AAAprince
- Start date
msquared48
Structural
A little more information about the possible scenario would be very helpful here.
Is this a runaway locomotive at 250 tons doing 60 mph (great movie!), or an unloaded boxcar or gondola in a switchuard doing 5 mph (not-so-great movie)?
Is the intent of the wall to deflect the energy or totally absorb it? Is the wall to be still serviceable after the impact or be expendable?
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
Is this a runaway locomotive at 250 tons doing 60 mph (great movie!), or an unloaded boxcar or gondola in a switchuard doing 5 mph (not-so-great movie)?
Is the intent of the wall to deflect the energy or totally absorb it? Is the wall to be still serviceable after the impact or be expendable?
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
Why not ask your client what their requirements are?
I've done a concrete block design a while back used for failure analysis (crash testing cars, airplane seats, etc). The client provided the specs that I needed to design the concrete block.
Your wall deflection is tied to how much energy it's supposed to absorb. Maybe your client has a set idea of the amount. With the project that I did, the number was given to me by the client.
I've done a concrete block design a while back used for failure analysis (crash testing cars, airplane seats, etc). The client provided the specs that I needed to design the concrete block.
Your wall deflection is tied to how much energy it's supposed to absorb. Maybe your client has a set idea of the amount. With the project that I did, the number was given to me by the client.
bridgebuster
Active member
Agree with the others, ask the client. I looked at AREMA (2002) and couldn't find any criteria on crashwalls. They did publish a survey of various transit agencies regarding deflection, and they varied from L/360 to L/1000.
paddingtongreen
Structural
I've designed turnpike toll plazas, but their deflectors are massive, compared to an automobile, but standard, so i don't know what went into them, probably experience more than calculation.
Your client must tell you what you are stopping/deflecting or you can do nothing.
Michael.
Timing has a lot to do with the outcome of a rain dance.
Your client must tell you what you are stopping/deflecting or you can do nothing.
Michael.
Timing has a lot to do with the outcome of a rain dance.
It's a little out of my league, but there doesn't appear to be much deflection on this baby:
I don't think deflection is a primary consideration. Strength is.
BA
I don't think deflection is a primary consideration. Strength is.
BA
paddingtongreen
Structural
BA, your link led me to this one
Train runs into nuclear container at 100mph. I liked a comment below it:
"Now drive it into? scientologists"
Michael.
Timing has a lot to do with the outcome of a rain dance.
Train runs into nuclear container at 100mph. I liked a comment below it:
"Now drive it into? scientologists"
Michael.
Timing has a lot to do with the outcome of a rain dance.
On the plane-vs-wall video, if you'll notice, that wall seems to move several feet. Also, it's not clear how much the wall moves or to what extent it stays together after the video ends.
In any case, a plane is made as light as possible, while a locomotive is intentionally made heavier, so there's not a good comparison between the two.
In any case, a plane is made as light as possible, while a locomotive is intentionally made heavier, so there's not a good comparison between the two.
Sorry can't give any advice deflection of a crash wall for trains.
I've recently specified a cantilevered car barrier that has been designed to have large deflections, the testing video showed it rotating till it almost hit the ground. The increased deflection reduced the equivalent static load to next to nothing and was still code compliant. Perhaps you could use and specify the deflection of the wall to reduce the load it is resisting. I assume an energy analysis of some sort would be in order wouldn't take much to do the calcs.
I've recently specified a cantilevered car barrier that has been designed to have large deflections, the testing video showed it rotating till it almost hit the ground. The increased deflection reduced the equivalent static load to next to nothing and was still code compliant. Perhaps you could use and specify the deflection of the wall to reduce the load it is resisting. I assume an energy analysis of some sort would be in order wouldn't take much to do the calcs.
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