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RE: Cable Software

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Chrisopher,

Thanks for your response.

The mass of the cable does not play into it in this case because the applied
force is horizontal.

The 6 k load is from the UBC.  If the 6 k load is divided into three cables
then this is 1500# lateral per cable.  The estimated deflection by guessing
and working backwards through the geometry and stretch of the cable is 12"
for a cable that spans 18ft between supports with a backspan of three
additional 18ft spans.

The tension in each cable is about 8 k for 1/2" diameter strand (250ksi).

The cable stretches over the backspans in a linear manner but the V area of
the cable is non-linear since the cable tension depends on the geometry of
the deflection and the deflection depends on the tension in the cable.  In
addition, accounting for the pretension in the cable compounds the
difficulty (for me at least).

Brad Friederichs
CA S2780

(916) 505-0519 fax (916) 482-1173

 -----Original Message-----
From: 	Christopher Wright [mailto:chrisw(--nospam--at)skypoint.com]
Sent:	Monday, July 30, 2001 7:10 PM
To:	SEAOC Newsletter
Subject:	Re: Cable Software

>Do you have/use software for design of wire rope cable or strand with
>hanging loads?
>
>Project involves stringing cable to prevent cars from driving off of
parking
>decks.  6 kip point load at midspan on three cables.
If I read you correctly, the problem is statically determinant and
shouldn't require software. The cable mass is so small with respect to a
car that you can even do the dynamics. Where'd the 6 kip load come from?
Would I be too far off if I guessed a 3000 lb vehicle and 2g
deceleration? If I'm not too far off, you might want to verify
this--lateral loading puts a helluva tension on a cable.

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


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