Notional loads are required to be applied. They are generated using the Loads – Load Cases command in RAM Frame Analysis mode. If the ratio of 2^nd order drift to 1^st order drift (i.e., B₂) is greater than 1.5, the notional loads must be applied in addition to the other lateral loads (wind and seismic); if the ratio is less than 1.5, it is permissible to apply the notional loads to the gravity-only combinations (note that the value 1.5 is based on a model with nominal member properties. otherwise, it is 1.7 for models with reduced member stiffness properties). This is specified when the load combinations are generated using the Combinations – Generate command in RAM Frame Steel Standard Provisions mode.

The notional loads are defined as:

Ni = 0.002Yi

where Yi is the gravity load. The values used for the gravity loads at each diaphragm are automatically calculated, but can be modified using the Loads – Gravity for Notional command in the RAM Frame Analysis mode.

If τ_b used in the reduced stiffness is set to 1.0, it may be necessary to increase the notional load by an additional 0.001Yi.

Note that for LRFD the notional loads are unfactored for analysis; they are factored in the Load Combinations. For ASD the notional loads are factored by 1.6 for analysis as required by the Specification.

Options for these various requirements are available at the time the notional loads are generated.