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# [SEAOC] L.A. Building Code -Reply

• To: seaoc(--nospam--at)seaoc.org
• Subject: [SEAOC] L.A. Building Code -Reply
• From: Dave Schnitger <DSCHNITG(--nospam--at)BAS.CI.LA.CA.US>
• Date: Tue, 05 Mar 1996 14:21:19 -0800
• Cc: skh(--nospam--at)eqe.com

```>>> Stephen K. Harris  <skh(--nospam--at)eqe.com> asked on 02/21/96 10:05am
Does anyone know what year the City of L.A. changed the seismic
portions of its building code to the equivalent of the 1976 UBC?  I'm
particularly interested in the change of Cp for tilt-up wall anchorage
from 0.2g to 0.3g and the increase in the maximum base shear from
0.133W to 0.186W.

Stephen K. Harris
EQE International
44 Montgomery St, Suite 3200
San Francisco, CA 94131
...
Steve:
According to George Potter, Structural Engineering Associate with the
Department of Buiding & Safety Training and Emergency Management
Division (213) 580-1150, the code formulas with common values are:

1) 1972 Los Angeles Building Code (LABC)
V = KCW = (1.33)(0.1)(W) = 0.133W                  Cp = 0.20

2) 1976 LABC
V = IKCSW = (1)(1.33)(0.14)(W) = 0.186W        Cp = 0.20

3) 1980 LABC
V = IKCSW = (1)(1.33)(0.14)(W) = 0.186W         Cp = 0.20

4) 1985 LABC, based on 1985 UBC, and adopted 5/27/87
V = ZIKCSW                                                          Cp = 0.30
CS = 0.14, Z=1.0, I=1.0, K=1.33 for bldgs with a box system
except K=1.0 for plywood shear walls less than or equal to 3 stories.

V= ZIKCSW = 0.186W for bldgs with masonry shear walls
V = ZIKCSW = (1)(1)(1.0)(0.14)W = 0.14 for wood bldgs w plywood
shear walls.