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Conventional Framing Provisions Inadequate?

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In a recent post, Mark Deardorff said, "I disagree, however, with the option 
of eliminating conventional framing provisions as such.  I agree that they 
are inadequate and should be strengthened."

I'm not convinced that the conventional framing provisions are even 
"inadequate" if applied consistently.  I think that strict interpretation of 
the "not of unusual size or shape" provisions is the principal need. 

I've looked at many homes built using the conventional framing provisions of 
the past.  They survive earthquake shaking with damage consisting of cracked 
plaster (occasionally extensively cracked) and little else.  Exceptions, of 
course include the need, in the case of older houses, for underfloor bracing 
on cripple walls to keep them from "parallelograming", and bolting of 
mudsills to keep the framing from sliding on the foundation during an 

Provided a conventionally framed house is maintained to repair termite and 
rot damaged framing and to keep water leaks and deteriorating drainage 
systems under control, and provided a knowledgeable carpenter follows the 
plumber and HVAC guys with their chain saws through the house to correct 
their damage, it seems to be capable of remaining quite serviceable in 
earthquake country. 

I believe that strict interpretation of the "unusual size, or shape" 
provisions is important.  Masonry chimneys are a serious problem.  But they 
are not included in the Conventional Framing Provisions and should not be 
allowed as part of a house built by the Provisions in earthquake country.

Can anyone cite seismic damage, beyond cracked-up plaster, to a house without 
a masonry chimney built by the Conventional Construction Provisions of the 
UBC, not of unusual size, or shape, cripple walls braced and mudsills bolted 
that is not due to failure to follow the Provisions, or due to damage done 
post-construction by plumbers, termites, fungi, or others who have no concern 
for the structural significance of their intrusions?  

Any such cited damage may provide a pattern that could appropriately become a 
basis for modifications to the Provisions.  The fact that we "can't make them 
figure" shouldn't be considered an appropriate basis for modifications to the 
Provisions, if they actually work in real earthquakes. 

Nels Roselund
Structural Engineer