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Basement wall restraint by wood

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I can agree that designing the walls as cantilevered is not incorrect;
nor is assuming it is a tank (with special considerations for long
walls).  I am shocked that there is even a discussion about the
preferred way (not always the best) to design basement walls.  First of
all, wood diaphrams are not designed to support the walls.  The floor
joists and blocking are (and in some situations, sub-diaphrams).  There
was a very good article in SEA a few years ago about such a design.
First of all, if setting your joists/trusses on top of the sill plate,
special attention should be given the attachment to the sill plate in
order to provide the proper restraining force.  If the joists or trusses
are hung off of the sill plate, the shear connection to the sill plate
can be neglected.  

The code requires a continuous connection of attachment of
joists/girders/blocking from one wall to another when designing wood
diaphrams supporting CMU walls.  This is to assure the support of the
walls and to not rely upon the diaphram in tension or compression for
wall support.  

It is a much simpler problem with basement walls in that they only see
inward forces.  With continuous floor joist/trusses/blocking properly
called out, one need not worry about "loading" the diaphram.  I'm sure
one could argue "what about creep and deformation in the wood
joists/blocking".  First of all, with manufactured wood products, creep
is not an issue.  Secondly, calculate the amount of compressive load in
a joist/truss at 16" o/c. or blocking at 48" o/c. These loads tend to be
very minor resulting in negligible movement.  Besides, the tile would
continually expand and contract with the house temperatures which would
be more of a concern than wood creep.

Bottom line :  design the basement walls as pinned, give some extra
attention to sill plate connections and continuos joist/blocking from
wall to wall and save the home owner some money.  Any contractor that I
required to build the basement walls as cantilevered would soon find
another engineer to due their design.  Why chase away business when a
little detail in the right place solves the problem?