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Re: Seismic Lateral Load

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Dear Christopher,

As some one who gets to tutor in mechanics first and second year.  Teaching
about the FBD is absolute best idea.  Never ever trust code always do a hand
check.

A kid the other week got a reaction wrong becasue he told me 3 * 12 was 38.
Swore blind.

It would be funny but he carries his calculator on his hip.  I almost said
to him I might use a calculator once or twice a week.

such is life.

John Nichols


At 11:58 1/05/98 -0500, you wrote:
>>Do I have to apply
>>the Fx (determined node load)to all joints at the same level or divide
>>the Fx by the number of joints on that same level.
>This is a good rule for any finite element software when you're not 
>absolutely certain how it will apply loads--
>Make a simple model with loads applied the way you suppose they should 
>go. Check the reaction forces and moments (all six equilibrium equations) 
>against what you think the input loads should be. If the reactions 
>equilibrate the applied loads within 5 significant figures, you got it 
>right. Checking within three significant figures is usually ok, but might 
>want further checking (like the effect of arcs modelled as chords) to 
>make sure it's not an input error. Less than three figures means bad 
>software or input problems.
>
>I've found hundreds of my own (and other people's) mistakes, program bugs 
>and documentation errors this way. And, 30 years after my last mechanics 
>class, boy, can I draw free-body diagrams. ;-> 
>
>Christopher Wright P.E.    |"They couldn't hit an elephant from
>chrisw(--nospam--at)skypoint.com        | this distance"   (last words of Gen.
>___________________________| John Sedgwick, Spotsylvania 1864)
>http://www.skypoint.com/~chrisw
>