For the design of noncomposite beams, and of the precomposite condition of composite beams, the default methodology reduces the stiffness of the bare beam section by 10%. The option to use the Virtual Work Method based on Design of Castellated Beams for use with BS5950 and BS 449, Appendix 2 may also be selected in the Criteria > Smarbeam menu. For more information on deflection calculations based on reduced stiffness, contact SteelFab, Inc. directly.

For the design of composite beams, the deflections based on the effective section I_eff are calculated, where I_eff is calculated based on the net section. The resulting deflections are then multiplied by 1.10 to account for shear effects.