defining automatic seismic static load cases in etabs and sap2000

Last Update Tir AP1387, July AD2008 

Copyright © 2005–2008 Caevandish All rights reserved. 

    Defining Automatic Seismic Static Load Cases in ETABS and SAP2000     for Iran’s Code of Practices (AP1384‐AD2005 Edition) 

UBC 94 Seismic Auto­Lateral Load Parameters Prepared for ISEA™, by V. Sarmast, Dey AP1384, December AD2005 

   Use “User Coefficient” for “Auto Lateral Load” in “Define Static Load Case Names” dialog box. Use these parameters:

• Base Shear Coefficient, (from Code)

• Building Height Exp., 1

 Use UBC 94 for Auto Lateral Load in Define Static Load Case Names dialog box. Use these parameters:

• Time Period: User Defined, (from Code)

• Factors: Numerical Coefficient, from Code

• Seismic Coefficients: Seismic Zone Factor, , User Defined, (from Code)

• Seismic Coefficients: Site Coefficient ( ) and Importance Factor ( ): Use following table based on “Soil Type”, “Seismic Zone ( )”, and “Importance Factor ( )” from Code:

Parameters from Code ETABS Parameters Soil Type Seismic Zone ( ) Time Period ( ) (in seconds)

I All Zones 0.10 0.40 2.0 0.9090 0.40 1.0 1.0858

II All Zones 0.10 0.50 2.0 0.9090 0.50 1.2 1.0499

III All Zones 0.15 0.70 2.0 1.0000 0.70 1.5 1.1563

IV

1 and 2 ( 0.35, 0.30)

0.15 0.8668 2.0 1.0000 0.8668 1.00 2.0 1.1000 1.00 2.0 1.1000

3 and 4 ( 0.25, 0.20)

0.15 0.8668 2.0 1.1818 0.8668 1.00 2.0 1.3000 1.00 2.0 1.3000

Note: For 1.85, must control that 0.1 . If it’s not satisfied, the multiplier value of may be increased.

UBC 94   Factors for Approximate and Program Calculated Methods Prepared for ISEA™, by V. Sarmast, Tir AP1385, July AD2006 

Structural System (in metres) (in feet) Empirical Method (Method A)* Program Calculated Method** Not Increased 25% Increased Zone 4 Zone 1, 2, or 3

Steel Moment Resisting Frames 0.08  0.0328 0.0410 0.0316  0.0293Concrete Moment Resisting Frames 0.07  0.0287 0.0359 0.0276  0.0256Other Structural Systems 0.05  0.0205 0.0256 0.0197  0.0183

*

** min  ,

Where  

and 1.3, 0.35 Zone 41.4, 0.30 Zone 1, 2, or 3