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[SEAOC] Enercalc Wood Design CAUTION

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If you are using the Enercalc Wood design programs (part of the Enercalc
Library), please be aware of the following changes in version 4.4C1. The
following changes were made subsequent to the 4.4B3 version:

The program conforms completely to the 1994 UBC and multiplies the
Allowable stresses by a shape factor as well as the load duration factor.
You must enter the member stress from the '94 code. If you wish to analyse
a member based upon an earlier code, you will get incorrect results since
the shape factor is ommitted.

In a previous post I mentioned that I thought I was getting erroneous
results. The cause was from a recent upgrade to the 4.4C1 versions.
Previously, the releases did not consider the shape factor - which
increased my allowable stress by 30% for a 2x6 member.

Specifically, I was providing an analysis of an existing roof (30 years
old) where the owner wanted to add a new tile roof (lightweight) to
replace an existing Shake roof. Since it was an existing structure, I used
the repetitive bending stress from the 1991 code. Since the shape factor
was added to a stress that had already been increased in prior codes, my
results indicated a member that was grossly overstressed to be within
allowable values.

Be careful. The program is correct, but does not warn the user to
compensate his stresses when considering existing materials.

Mike Brooks considered my suggestion of placing the shape factor on a
toggle based upon the code being used. This will probably be added to the
Windows version of Enercalc.

Be cautious of programs written to comply with the '94 UBC when checking
members pre-dating the code.

Dennis S. Wish PE

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