The RAM Frame program provides the option of analyzing the model with a rigid diaphragm or with no diaphragm. If the "Rigid Diaphragm" option is selected, lateral loads are defined as story forces in the RAM Frame program or as Nodal Loads in the Modeler. If the "No Diaphragm" option is selected, lateral loads must be defined as Nodal Loads, in Nodal Load Cases, from within the Elevation Mode Modeler.
Nodal Load Cases are used to group Nodal Loads that will be applied to the structure. For example, the Wind forces in the X direction might comprise one Nodal Load Case and may consist of several Nodal Loads, while the Seismic forces in the X direction might comprise another. Each Nodal Load Case is given a unique descriptive label. There is no limit to the number of Nodal Load Cases that can be defined. In the RAM Frame program, the user selects which load cases will be analyzed.
Nodal Loads and Nodal Load Cases are defined and assigned only in Elevation Mode.
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Nodal Load Cases are defined using the PropTable - Nodal Load Cases command. When the command is issued, the Nodal Load Cases dialog box appears. A unique descriptive label for each Nodal Load Case and the Type of force (Wind, Seismic, Virtual or Other) is entered. The Type is used in the merging of story and nodal loads and generation of load combinations in RAM Frame. The Virtual Nodal Load Case is used for the RAM Frame Drift Control module; it is used to determine the contribution of each member in the structure to the overall drift in the direction of the virtual nodal load. |
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Nodal Loads are defined using the PropTable - Nodal Loads command. When the command is issued, the Nodal Load Properties dialog box appears. A unique descriptive label for each Nodal Load and the magnitude of the force acting in the global X, Y, and Z directions is entered. Refer to the RAM Frame manual for information on the sign convention of forces. |
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Nodal Loads are assigned to the model using the Layout - Nodal Loads command. When this command is issued, the Nodal Load Layout Mode dialog box appears. From this dialog box, the Nodal Load Case that contains the loads to be assigned is selected from a drop down list box. The Nodal Load to be graphically assigned is selected from the list box located at the bottom of the dialog box. |
When the Add button is selected, the dialog box closes and the target cursor appears. Nodal Loads are applied to the structure by clicking the target cursor at the intersections of the columns, beams, braces and walls. When a nodal load is assigned to the frame, it is shown graphically.
