Correspondence ' - 7 / `ts S w I Ja& k. (�° c1 Eo 5 1 C1 P.Zo I o -0 o /5 5
Ridge Engineering LLC
P: 503.702.9169
Structural Engineering • Evaluations • Planning F: 503.647.5152
15475 NW Pumpkin Ridge Road • North Plains • OR 97133 ridgeengineering @coho.net
Cathy Jean
Ceiling and Framed Wall Support
December 9, 2010
Pleger I Henry Architecture
C/O Tim Pleger
15640 North 7th Street - Suite B9
-
Phoenix, Arizona 85022
Re: Cathy Jean - Ceiling and Framed Wall Support
Dear Tim:
At your request Ridge Engineering LLC (RE) has reviewed the ceiling and framed wall supports for
the Cathy Jean Tenant Improvement (TI) at the Washington Square Mall located in Tigard, Oregon.
RE understands the TI Is approximately 1500 square feet. RE further understands that the front
sails area will have a gyp board ceiling and the back stock room will have a drop /lay In ceiling.
• In discussions regarding this TI RE understands there are three concerns from the City of Tigard.
The first concern is the vertical support of the two ceiling systems. The second concern is the
seismic support of the two ceiling systems. The third concern is the support of the new framed
walls. The concerns will are addressed as follows:
1. The existing mall structure is capable of supporting the vertical load of either the gyp board
ceiling or the drop /lay in ceiling. See detail '1' for the required support for the drop in
ceiling. At the gypsum board ceiling an Armstrong or USG gypsum board ceiling system will
be used thus only the vertical wire supports In detail '1' will be required.
2. The horizontal seismic support of the drop /lay in ceiling will have splay wires placed per
detail '1'. For the vertical strut requirements the contractor is requesting to use a box beam
at 12' o.c, The box beam will be located within a couple feet of the ceiling and a strut
placed at 12' o.c. from the ceiling to the box beam. See detail '2'.
The seismic support of the gyp board ceiling is not as involved. Per the Ceiling and Interior
Systems Construction Association (CISCA) the seismic requirements of ASCE 7 -05 section
. 13.5.6.1 are not required.
3. The new framed walls will be supported by the gyp board ceiling as the gyp board ceiling
creates a. diaphragm. This allows the wall(s) to span from the slab on grade to the ceiling
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Rim CAODt AWING\2010%210061- (k) Cathy 3aanWeililnp and framed Well Support Review Letter.doc. Pape 1 of 2
Printed: December 09, ZO 10
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Cathy Sean
Ceiling and Framed Wall Support
system. Per detail '3' the connection of the walls to the ceiling shall use a 2" x 2" x 18 gage angle."
See detail '3'.
If you have any questions, please call. I z- -aq oc)
•
Sincerely, ! , % IkFF
Ridge Engineering LLC 57/ •
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Richard M. Boyer, P.E. M.
President 4.
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Enclosure: Structural Calculations and Details
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File: C: \ODRAWING\20101.210061 - (R) Cathy lean Welling and Framed Wall Support Review Letter.doc Page 2 of 2
Printed: December 09, 2010