Factor for Seismic Design

Enter factors for special seismic loads and vertical seismic forces, which will be applied to specific members selected by the user in design.

 

ΆΖ Description

< Factor for Seismic Design Dialog >

< Modification Factor Calculation Dialog >

Scale up for Response Spectrums Load Cases

RC Load Combination : ACI 318-05 , ACI 318-08, ACI 318-11, KBC–USD05, KBC-USD09,

KBC-USD12

 

STEEL Load Combination : KBC-USD09, KBC-USD12

If seismic load is inputted by response spectrum analysis, base shear of static seismic load(original base shear) and base shear of modal analysis(modal base shear) are compared with each other to define modification factors. Select Load Set to apply Modification Factor after the analysis an click Calc. to access dialog for Modification Factor calculation.

If Response Spectrum Load and Static Seismic Load are included in Analysis Case, Modification Factor can be automatically calculated if the analysis is already performed.

 

Modification Factor For Calculation

Original Base Shear (V) : Original Base Shear is automatically calculated if Static Seismic Load Set is selected to compare with Response Spectrum Set.

Modification Base Shear (0.85V) : 85% of Original Base Shear of Static Seismic Load.

Modal Base Shear (Vt) : Base Shear due to modal combination.   

Modification Factor (Cm) : Modification Base Shear / Modal Base Shear.   

 

Calculated Modification Factor is multiplied to Response Spectrum Load Set as a factor and applied to Load Combinations.

Parameters for Special Load Combination

Enter the factors which is multiplied to Seismic Load Set when Special Load Combination is generated.

Factor : Over Strength Factor

 Check to activate Factor in corresponding Load Set and Over Strength Factor which is suitable for Seismic-Force-Resisting System.

Sds :  Short period spectrum acceleration.

Sds values defined in Design Spectrum dialog is automatically updated.

Vertical Load Factor : Enter a factor which will be used to consider Vertical Seismic Force in Special Seismic Load.

 

Refer to "KBC 2005 0306.2.3" for Special Seismic Loads information.

Parameters for Special Load Combination

Vertical Load Factor : Enter a factor which will be used to consider Vertical Seismic Force in Special Seismic Load.

 

Refer to "KBC 2005 0306.8.4.3" for Vertical Load which considers Vertical Seismic Forces.