Concrete Slab Properties : Strength Reduction Factors

Design codes have one of two methods for introducing a factor of safety: either applying a factor to the material properties or a reduction to the calculated strength

Strength Reduction Factors

For codes (ACI and Australian codes) which implement a strength reduction factors there is a $φ$ factor for in-plane compression and a $φ$ factor for in-plane tension & bending. Depending on the forces/moment on the section the $φ$ value will vary between the limits for compression and tension. The actual reduction value used will depend on the actual strain plane across the slab.

Note

Typical compression and axial tension & bending reduction values are 0.65 and 0.9 respectively.