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Retrofit existing flat slab

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I have a project to retrofit a three story mezzanine
concrete floor building that was built in 1954. Metal
roof deck and walls. Lateral resisting elements are
angle cross bracing at perimeter. Building located in
Zone 4 and close to fault line. The square area is
21,600 square. ft each floor (60' x 360').Second floor
elevation at 20'-10" and 32'-10" for third floor.
These 5" thick concrete two-way slabs were supported
by 14WF beams spaced at 10' o/c across 60' span and
24WF girders at 20' o/c. Two ends and one intermediate
columns at every 20' bay carry the loads down to the
footing.
>From the existing drawing, there is no welded stud on
any top flange of the beams/girders nor metal deck for
diaphragm shear transfer. The top of beam/girder
flange was embedded 1/2" into the 5" thick concrete
slab below. My main concern areas are as follow:

A. Shear transfer from these flat slabs to the steel
beam and column bracing without any shear transfer
elements. Any suggestion?

B. 40 feet high, 6" CMU min. reinforced in-filled wall
between 24WF steel columns spaced at 20' o/c. Any
suggestion for out-of plane anchorage?

I would appreciate if someone can share with me
similar experience on this retrofit project or point
me to the proper source of information that I can be
enlighten on.


Stevenson Lim, P.E.
 

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