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perimeter. There is a 2 storey reinforced masonry enclosed stairwell at the east side of
the one storey section. The wood roof is attached to the perimeter masonry walls by
means of wood ledgers and nailers bolted to the masonry wall.

3.0 CODE PHILOSOPHY FOR SEISMIC DESIGN

The earthquake resistant design requirements of the National Building Code of Canada Fe Se
1990, are based on designing the structure to prevent major failure and loss of life. eas
Modern structures ,designed in accordance with this code, should meet two criteria:

1) In moderate more frequent earthquakes, the structure or equipment should not have
significant damage.

2) In strong earthquakes which may occur only once in the life of the building, the
structure, or equipment could be severely damaged but should not collapse.

Based on the above criteria, the earthquake forces specified by the code for the design
of buildings are generally much lower than the forces that would occur in a large
earthquake if the building were to remain "elastic" (i.e. no damage criterion). This is
made possible by ensuring that the seismic load resisting elements are "ductile". This
means that these elements must be designed to have relatively large movements beyond
the elastic range, without failure, but structural damage may be sustained. As well, in
general, good seismic design not only tries to keep the overall probability of failure
below a given level but it also provides a system so that less desirable modes of failure
are less likely to happen than others. This increases the reliability of the desiga by
decreasing the potential for damage and increasing overall safety. The less desirable

modes of failure are:

1) Those resulting in total collapse of the structure (failure of vertical load carrying
members such as building walls or failure of connections tying the building

together such as between supporting walls and floors).
2) Those involving sudden failure (e.g. non-ductile failure in brittle or buckling

modes).

The above concepts will be addressed with respect to this structure in the seismic
review section.

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