Purpose of Partial Factors
Partial factors account for:- Material variability — Scatter in material properties
- Model uncertainty — Differences between theory and reality
- Geometric tolerances — Installation and manufacturing variations
- Consequence of failure — Reliability requirements
Resistance Partial Factors (γM)
Steel Failure Modes
Product ETAs may specify different γMs values. Always check the ETA for the specific product being used.
Concrete Failure Modes
Other Failure Modes
Complete Factor Table
Reference table for all modes:Reduction Factors (ψ)
In addition to γ factors, various ψ factors reduce characteristic resistances:Tension ψ Factors
Shear ψ Factors
National Annex Variations
National Annexes can modify recommended γM values:Typical Variations
Product-Specific Factors
ETAs may specify different factors based on testing:When ETA Values Differ
Clariti automatically uses product-specific factors when available in the database.
Consequence Classes
EN 1990 defines consequence classes affecting reliability:
Most building applications use CC2. Modification factors KFI apply to actions, not resistances.
Durability Factors
For corrosion and environmental exposure:
Durability is typically addressed through material selection rather than factor modification.
Fire Design
For fire design situations:
Fire design follows EN 1992-1-2. Clariti focuses on ambient temperature design.
In Clariti
Factor Display
Clariti shows all factors in calculations:- Summary view: Shows resulting design resistance
- Expanded view: Shows Rk, γM, and Rd = Rk/γM
- ψ factors: Each factor listed with value and source
Factor Source
For each factor, Clariti indicates:- EN 1992-4 reference (recommended values)
- ETA reference (product-specific values)
- Which value was used and why