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RE: loader surcharge at top of retaining wall

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>Your first statement is a valid statement - but I'm not sure why you say it 
>doesn't account for any kinetic energy. Isn't kinetic energy accounted for 
>in the formula F=Ma?
Nope. There has to be an energy balance and momentum conservation. One 
comes from thermodynamics, the other from Newton.

>F = Mass x acceleration = (weight/32.2 ft/sec^2) x (14.7/0.25 sec) = 1.83 W
>But I must admit that if the deceleration rate is, for example, 0.10
>seconds, the force increases to F = 4.6 W.
Exactly. The impact force du jour requires only that you guess the 
corresponding acceleration.

>the best one can do is get an "estimate" of the magnitude of load. 
If it were easy they'd let anyone do it. ;-> 

Christopher Wright P.E.    |"They couldn't hit an elephant from
chrisw(--nospam--at)        | this distance"   (last words of Gen.
___________________________| John Sedgwick, Spotsylvania 1864)