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Kneebraced Post Design

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Tried sending this earlier, and it never made it.  I'm assuming the
list doesn't like attachments.  Instead, I've included a link to the
file on my web server.

--

A lot of our firm's work is residential, and of that, a moderate
percentage is small additions and remodels.

One thing that we see very often (and more frequently as jurisdictions
start getting tougher about requirements) is small covered patio
additions.

Engineering the lateral support for these is tricky.  The favored
solution for owners and contractors is to kneebrace the support posts.
We've done this in the past, and made it work for small patios, using
NDS combined lateral and pullout values for Lag Screws, and an R value
of 4.5 (UBC).

In the new code, we have to use R=1.5, which means that even for a
small patio, the seismic load is fairly high, and it is very difficult
to make this work.  However, in an effort to not have to specify steel
columms for every little patio we engineer, we've tried to look at
other options, such as 1/4" steel side plates with either lag screws
or through bolts.

I developed a spreadsheet, using the NDS equations, that gives options
based on what we put into it.  I've attached the spreadsheet to this
e-mail (actually, it's here:  examplecalcs.com/Kneebraced%20Post%20Design.xls)
and would appreciate it if any of you had time to review it and
offer feedback.  If you find it useful, please feel free to keep a
copy.

So the request for feedback is my first request.  But I also am
interested in what others are doing with regard to small patios and
knee braced posts.  I know that this type of thing falls way below the
radar of many on this list, but it is something we run into very often
in our practice.

Thanks,

Chris Slater

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