Redundancy Factors

Q: How do I include the redundancy factor(s) ρ in the ASCE 7 load combinations?

1)Open the ''Load Cases & Combinations'' dialog box. Under the ''Base'' tab, select the ''Edit Parameters of Edition'' option. The default values are set to 1.0 (Image 01)#image@034340#Case A: To apply the same factor in the X and Y directions, use the generic (no direction) redundancy factor, ρ.Case B: To apply different factors in each direction, use the redundancy factors, ρx and ρy. The generic factor ρ in the first row is not used.2) Under the ''Load Cases'' tab, create a seismic load case with Qe as the ''Action Category''. Next, select the ''Additional Settings'' tab and pick the direction (Image 02)#image@033443#3) Under the ''Design Situations'' tab, select the applicable seismic Design Situation Type. Both LRFD and ASD methods are available (Image 03)#image@034342#'''Note:''' When neither or both directions are activated under the '''same''' load case, the generic redundancy factor ρ is used. Create a '''separate''' load case to apply the individual factors, ρx and ρy. 4) In the ''Load Combinations'' tab, verify that the correct factor(s) have been applied. Factors are also shown in the ''Result Combinations'' tab, if applicable. Click OK to exit (Image 04)#image@034343#

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FAQ 005319 | How do I include the redundancy factor(s), ρ in the ASCE 7 load combinations?

FAQ Explanatory Video

01
Redundancy Factors

02
Seismic Design Situations

03
Load Combination Including Redundancy Factor

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09/26/2022

005319

Cisca Tjoa

Modeling | Loading

RFEM 6

Steel Design for RFEM 6

Steel Structures

Buildings

Structural Analysis

Dynamic and Seismic Analysis

ANSI/AISC 360

ASCE 7

How do I include the redundancy factor(s) ρ in the ASCE 7 load combinations?

Answer

1) Open the Load Cases & Combinations dialog box. Under the Base tab, select the Edit Parameters of Edition option. The default values are set to 1.0 (Image 01)

Redundancy Factors

Case A: To apply the same factor in the X and Y directions, use the generic (no direction) redundancy factor, ρ.

Case B: To apply different factors in each direction, use the redundancy factors, ρ_x and ρ_y. The generic factor ρ in the first row is not used.

2) Under the Load Cases tab, create a seismic load case with Qe as the Action Category. Next, select the Additional Settings tab and pick the direction (Image 02)

Create Seismic Load Case

3) Under the Design Situations tab, select the applicable seismic Design Situation Type. Both LRFD and ASD methods are available (Image 03)

Seismic Design Situations

Note: When neither or both directions are activated under the same load case, the generic redundancy factor ρ is used. Create a separate load case to apply the individual factors, ρ_x and ρ_y.

4) In the Load Combinations tab, verify that the correct factor(s) have been applied. Factors are also shown in the Result Combinations tab, if applicable. Click OK to exit (Image 04)