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RE: Wood - Lateral columns and knee braces (kickers)

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I don't consider the diaphragm since none exists. For this reason, I take
the base shear as 30% of the weight of the structure and design the columns
to resist this force for increased stiffness. Inasmuch as the resulting load
is rather small, this is not a problem and I don't expect much problem with
movment within the casing. I doubt that it will be much more than a bolted
connection and since the capacity of a 6x6 in bending is much greater than
that induced by a 1400 ft-lb moment at the base, there should be less chance
for failure.

I guess you might be correct - I'm over analyzing the thing, but it is a
point of contention with the local building officials.

Regards
Dennis

-----Original Message-----
From: Parkerres(--nospam--at)aol.com [mailto:Parkerres(--nospam--at)aol.com]
Sent: Thursday, September 03, 1998 7:21 AM
To: seaint(--nospam--at)seaint.org
Subject: Re: Wood - Lateral columns and knee braces (kickers)


Dennis -

We have used this approach before for lightly loaded trellises such as
yours,
and have found the performance to be pretty good.  We use kickers from the
columns to the beams, sometimes inplane with both ends lagged in, and then
CB
bases for the columns.  We design the system as a pinned base frame.  I
don't
like to use freestanding wood columns with a "moment connection" at the base
like your TS
approach.  I find that you get too much play in the column, particularly at
8'
tall.

If your trellis is small and lightly loaded as you describe, this should
work
fine.  But how do you justify the diaphragm???  Don't worry about it, it's
just a trellis.

Bruce Resnick, S.E.
Parker Resnick Str. Eng.