The gravity load data is shown in the Gravity Loads dialog, which is invoked with the Loads – Gravity for Notional command. These values are based on the applied gravity loads (defined in the Modeler), including self-weight of members and slabs\decks if those options (for member dead loads) have been specified. For each diaphragm, RAM Frame automatically calculates the total Dead Load, Live Load (Imposed Load) and either Roof Load or Snow Load as applicable, and the location of the centroid of those loads.

Calculated or user defined gravity loads are used in the calculation of Notional Loads. In addition, they are used for P-Delta analysis of Rigid diaphragms if Use Gravity Loads option is chosen in General – Criteria dialog.

Note that while the gravity load data was derived from the loads applied to the members, modifying the values listed in this command has no impact on the gravity loads applied to the members, it only has an impact on the magnitude of the generated Notional Loads as well as calculated P-Delta effects.

Where Live Loads are reducible, the program determines and applies the appropriate Live Load Reduction factor. Generally, because of the large area involved, the reduction factor is usually the maximum allowed by the specified Code (as specified by the user in the Criteria – Member Loads command in RAM Manager). The user can override the reduction values used by specifying the desired values.

The Diaphragm Gravity Loads dialog tabulates story/diaphragm loads according to their diaphragm numbers. It should be noted that any loads associated with diaphragms are shown with respect to the story name and diaphragm number. If there is any load that is not associated with any diaphragm (such as a point or line loads placed outside of any diaphragm), it is listed separately, with the Diaphragm Number specified as None ; it is part of no diaphragm.

The column Combine To is used to combine (lump) gravity loads from one diaphragm to another diaphragm (for the purpose of calculating Notional Loads only – this does not affect the gravity loads applied to the members). The user can select a diaphragm number and a story (diaphragm – story name) from the drop-down list to indicate the diaphragm to which the load is to be combined. Similarly, the None load component of a story (if applicable) can be combined to any diaphragm at either the same story or another story. Note that a None load component of a story cannot be combined to a None load component of another story.

Occasionally there are small partial levels that do not contribute significantly to the lateral force resisting system or to which it is not desirable to have a generated Notional Load assigned. In such a situation the loads of that level can be combined to another diaphragm by using the Combine To command. The same command can also be used to lump loads from levels with no diaphragm to levels with a diaphragm.

Notional Loads will not be generated for any gravity loads not associated with a diaphragm.

When the self-weight options have been selected in Criteria – Self-Weight in RAM Manager, all of the self-weights of columns and walls are included with the gravity loads of the level above; there are no options to have half of those self-weights included with the level above and half of those self-weights included with the level below.

Snow drift loads are defined in the Modeler by specifying the magnitude of the snow load at three points. When calculating member loads the program considers the variable load along the member, but when calculating the gravity loads due to snow drift loads for the computation of the notional loads, the program only considers a flat load based on the smallest of the three magnitudes (i.e., it is ignoring the drift effects). This approach is taken due to the fact that it is unlikely that all of the drifts modeled at the roof would actually occur simultaneously; to consider all of them simultaneously in the load used to generate the snow notional load would be overly conservative. Generally only considering the flat snow load would likely be sufficient, but if this is determined to be unconservative the user can specify greater values of snow load in the Loads – Gravity for Notional command.

RAM Frame checks whether Combine-To assignments are valid or not and gives a warning if an invalid Combine-To assignment is detected. For example, if the loads in Diaphragm A are combined to Diaphragm B, and if Diaphragm B is later deleted in the RAM Modeler, RAM Frame gives a warning for Diaphragm A and clears the Combine-To assignment. It is the user's responsibility to re-assign the Combine-To for Diaphragm A again, if desired.