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Rw for dual systems

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I'd like to get some opinions on the upgrade of a historic seven story
building built around 1920's in Oakland.  The building is 100 ft. by 50 ft.
in plan.

The building's frame system consists of  H columns infilled within 3 to 4
ft. wide  unreinforced masonry piers on the outside and concrete fireproofed
interior H columns and I beams. The diaphragm is 3.5 inch concrete slab. The
building back wall (not a bearing wall) is 8 to 13 inch thick brick.
The building also has both horizontal and vertical irregularities ( tall
first story with partial mezzanine and reentrant "rectangular" corner in the
middle of the building 14.5 ft. by 25 feet deep).

The building was red tagged after 1989 earthquake. The preliminary
retrofitting design scheme includes shotcreting of the back wall and
addition of either braced or portal frames on the other three sides.

I am reviewing the work of another engineer, and I am concerned about some
of the choices and assumptions that he made.  He uses Rw=8,  shotcrete the
back wall only with to the third floor, and  steel moment resisting frames.

My questions are:
1. Should we use Rw=6 with this kind of combination lateral force resisting
2. What should we limit the deflection to minimize cracking to the slender
masonry piers at the front and on the sides of the building? Is 0.005*h
3. Should we disregard these slender piers encasing steel columns in
modeling of the building?

Any other comments?


Sasha Itsekson, PE