Joist Girders are not selected from a Joist Table. Instead, RAM Steel Beam Design determines the joist designation.

For example, a Joist Girder with a depth of 30 inches, having 4 panels, and a point load of 12.6 kip would have the designation: 30G4N12.6K.

If a uniform load with a magnitude not exceeding the value specified by the user in Joist Criteria for Maximum Uniform Load to Lump is loading a joist girder, the uniform load will be added to the concentrated loads, and the Joist Girder designation will be based on the modified concentrated loads.

If the concentrated loads are not all of equal magnitude, the program will investigate whether or not they are "close enough". This is done by calculating the moment and shear based on the actual loads. Then the maximum concentrated load is determined, and the moment and shear are calculated using this maximum concentrated load value at every concentrated load location. If the moment or shear based on the maximum load exceeds those of the actual loads by more than the percent specified in the Joist Criteria by the user as Tolerance for Variation of Point Loads, the loads will be deemed not close enough, and the joist will be given the Special Joist designation of xxGSP. Otherwise, the maximum load thus determined will be deemed close enough, and the designation of the joist girder label will be based on that maximum concentrated load. The user thus has control over what is considered close enough by specifying more or less stringent values of Tolerance for Variation of Point Loads. If a value of 0% is specified, only those joists with exactly equal concentrated loads will be considered "close enough".

If the concentrated loads are not all exactly equally spaced, the program will investigate whether or not they are "close enough". The tolerance for the spacing is specified in the Joist Criteria by the user as Tolerance for Spacing of Point Loads.

Joist Girder designations can be modified on a joist-by-joist basis using the Beam Design module's View/Update command. Enter a new label in the Joist Size edit box and issue the Update Database command. Remember that when this is done to a joist specified by the program as a Joist Girder, no capacity check is performed, even if the label entered is an actual Joist Girder label; the program is just treating it as a different label. Also, if the loads in the model are changed, the user-specified label will remain without any design check performed or warning given.

No joist weight will be included in the Takeoff for Joist Girders.