Ghosh Seismic Code Presentation, FEB 2013

IBC Structural Provisions
with Particular of Reinforced Reference Concrete to Guam
S. K. Ghosh
S. K. Ghosh Associates Inc.
Palatine, IL and Aliso Viejo, CA
www.skghoshassociates.com
- 1 -

WIND SPEED MAPS
- 2 -

Wind Loads
Load factor on W is now 1.0 in Strength Design and
1/1.6 or 0.6 in ASD.
Thus, the design wind speed maps in ASCE 7-10
produce strength-level design wind forces. The
mapped design wind speeds are, therefore, higher
than in ASCE 7-05.
W SD
0.6W ASD
- 3 -

Wind Loads
No Importance Factor is used in wind design any
more.
I
- 4 -

Wind Loads
The Standard includes three design wind speed maps:
A 300-year return period wind speed map for
design of Risk Category I structures
A 700-year return period wind speed map for
design of Risk Category II structures
A 1700-year return period wind speed map for
design of Risk Category III, IV structures
- 5 -

Wind Loads - Guam
V of
ASCE 7-
05
V 05 √1.6√I V of
ASCE 7-
10
- 6 -
V 10/V 05
p 10/p 05
OC/RC II 170 215 195 -10.7% -25.4%
OC/RC III,
IV (I = 1.15)
OC/RC I
(I = 0.77)
170 230 210 -8.7% -16.6%
170 189 180 -4.7% -9.3%

SEISMIC GROUND MOTION MAPS
SSEISMIC
- 7 -

ASCE 7-05 Figure 22-14
Maximum Considered Earthquake Ground Motion for
Guam And Tutilla
0.2-sec Spectral Response Acceleration (5% of Critical Damping), Site Class B
- 8 -

ASCE 7-05 Figure 22-14
Maximum Considered Earthquake Ground Motion for
Guam And Tutilla
1.0-sec Spectral Response Acceleration (5% of Critical Damping), Site Class B
- 9 -

Seismic Design Map Updates
CHANGE 1
Updated source zone models and
attenuation relationships
CHANGE 2 Switch to risk-targeted ground motion
CHANGE 3
Switch to maximum-direction ground
motion
CHANGE 4 Change in deterministic ground motion
- 10 -

ASCE 7-10 (2012 IBC)
Maps of the MCE R ground motion parameters, S S and
S 1, for Guam and American Samoa are not provided
because parameters have not yet been developed for
those islands. Therefore, as in the 2005 edition of this
standard, the parameters S S and S 1 shall be,
respectively, 1.5 and 0.6 for Guam and 1.0 and 0.4 for
American Samoa. Maps of the mapped risk
coefficients, C RS and C R1, are also not provided.
- 11 -

ASCE 7-10 Figure 22-11
Maximum Considered Earthquake Geometric Mean
(MCE G) PGA, for Guam and American Samoa
- 12 -
PGA, % g, Site Class B

2015 IBC Figure 1613.3.1(7): Originally Proposed Maps
Risk-targeted Maximum Considered Earthquake (MCE R)
Ground Motion for Guam and American Samoa
0.2-sec Spectral Response Acceleration (5% of Critical Damping), Site Class B
- 13 -

2015 IBC Figure 1613.3.1(7): Originally Proposed Maps
Risk-targeted Maximum Considered Earthquake (MCE R)
Ground Motion for Guam and American Samoa
1.0-sec Spectral Response Acceleration (5% of Critical Damping), Site Class B
- 14 -

2015 IBC Figure 1613.3.1(7): Final Approved Maps
Risk-targeted Maximum Considered Earthquake (MCE R)
Ground Motion for Guam and the Northern Mariana Islands
0.2- and 1.0-sec Spectral Response Acceleration (5% of Critical Damping), Site Class B
- 15 -

2015 IBC Figure 1613.3.1(8): Final Approved Maps
Risk-targeted Maximum Considered Earthquake (MCE R)
Ground Motion for American Samoa
0.2- and 1.0-sec Spectral Response Acceleration (5% of Critical Damping), Site Class B
- 16 -

Chicago Main Office
334 East Colfax Street, Unit E
Palatine, IL 60067
Phone: (847) 991-2700
Fax: (847) 991-2702
Email: skghoshinc@gmail.com
Thank You!!
For more information…
www.skghoshassociates.com
Follow us on:
- 17 -
Southern California Office
43 Vantis Drive
Aliso Viejo, CA 92656
Phone: (949) 215-6560
Fax: (847) 991-2702
Email: susandowty@gmail.com