which is the velocity factor given by NBC 1990 for Coquitlam and
accounts for the design earthquake magnitude. This indicates a
major earthquake zone,

which is the response factor depending on the period of the
building and is the maxitnum specified by the cade.

which is the foundation factor for normal soils.

which is the "importance factor" for post disaster buildings such as
fire stations which must remain in operation after an earthquake.
Normal buildings use a factor of 1.0.

which is the force reduction factor to account for "ductility" of the
seismic resisting elements. A modem building designed and
detailed to ensure ductile elements might have an R value of 3 or 4
We have chosen R = 1.5 which is specified for reinforced masonry
buildings by NBC 1990.

We have calculated the design base shear for a 1/475 year earthquake (10% probability
of exceedance in 50 years) to be .36W or 275 KIPS for this building.

On the basis of this force we have calculated the average shear stresses in the masonry
walls to be greatly in excess of the allowable stresses in the North South direction and
approximately 130% of the allowable stress in the East West direction.

The steel bracing in the upper storey provides approximately 50% of the required
capacity in the upper storey provided they are properly anchored into the lower wails.

The detail shown on the drawings for the roof deck diaphragm is very scanty with
respect to welding and connection requirements. However, we estimate the capacity
of the roof deck is approximately 50 to 60% of the present requirements.

The topping over the precast floor in the first floor does not have any reinforcement
specified. As well the connections between this floor diaphragm and the supporting
walls appear to be minimal and therefore the precast floor and the masonry walls

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