Resistance Factor (LRFD Only)

 

resistance factor Φ or strength reduction factor

 

Strength ↓ as Uncertainty, Assumptions, Danger, Brittle Failure, Etc ↑

 

NDS Appendix N table N2

Bending Fb	Φb	0.85
Tension Ft	Φt	0.80
Shear Fv	Φv	0.75
Compression Fc, Fc⊥	Φc	0.90
Stability Emin	Φs	0.85

shear strength is highly variable and may produce sudden, brittle failures
compression is very ductile