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Since LRFD combinations are intended for strength design and there is no guidance in the NDS, ASCE or IBC as to the combinations to be used for serviceability design, i.e. deflections, ASD load combinations are used to calculate deflections even if LRFD is chosen as the design procedure in the Design Settings.
The LRFD KF, j, and λ factors are not applicable to the modulus of elasticity E or stiffness EI used for deflection, nor is the CD factor that is used for ASD only, so there is no other effect of the ASD vs. LRFD choice affecting deflection calculations. Deflections in Sizer are identical for ASD and LRFD.
When LRFD is selected, Sizer lists both sets of load combinations, LRFD for strength design and ASD for deflection, in the Analysis results.
In the deflection Analysis diagram, Sizer shows deflections from the ASD load combination with the same set of loads as the LRFD combination selected in the drop down list. It shows the ASD combination used in the text on the left had side of the diagram.