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IBC First Draft Comment

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I received a copy of the November 1997 first draft of the IBC. Inasmuch as I
have strong opinions regarding conventional framing - I immediately turned
to section 2308. I was pleased to find well written definitions for
conventional framing. Of these the most impressive were:

2308.2 (3)a. "Loads as determined in Chapter 16 shall not exceed the
following: a) Dead loads shall not exceed 15 psf for roofs and exterior
walls, nor 10 psf for floors and partitions."
This takes residences with heavy tile roofs out of the "Conventional Framing
Category". It has been my experience that medium sized, box shaped
structures will cross over from wind governing loads to seismic as the
weight of the roof approaches 20 psf - a condition common with the use of
Tile roofs.

2308.2 (5): "Roof trusses and rafters shall not span more than 35 feet
between points of vertical support."

Typical to small lots in areas such as mine (and those I remember in
Venice)generally do not exceed 50 feet wide with a 5 foot setback on each
side. Trusses traditionally span exterior to exterior wall or 40 feet. Once
again, this restricts the potential size of structures considered
"Conventional Framed".

2308.2 (7): " Conventional light-frame construction shall not be used in
irregular structures in Seismic Design Categories D and E, as specified in
Section 2308.12.6."

Again, this is a relief as it requires compliance of CLF (Conventional
Light-Frame) with lateral design specification in chapter 16. These are
currently not required of irregular structures defined in the 1994 UBC,
which allows multi-story, irregularly shaped structures to be designed
without consideration to interior shear transfer or discontinuities that
occur at reentrant corners or changes in either diaphragm levels or aspect

In short, it looks like SEAOC and the members of IBC committee have been
paying attentions to the feedback of members concerns regarding this.

Thanks for doing your homework - we are about to see fewer defaults and
bankruptcies and hopefully much less damage as a result improved design
enforcement and control of construction standards.

Dennis S. Wish PE

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