Draw Special Joint
Dynamic Analysis
Mode Shapes
Response Spectrum Analysis
Click the File menu > New Model command to access the New Model form.
Verify that the units shown in the status bar are 
.
Click on the Grid Only button 
to access the Quick Grid Lines form. In that form:
Select the Cartesian Tab.
In the Number of Grid Lines area:
Type 1 in the X direction edit box.
Type 1 in the Y direction edit box.
Type 1 in the Z direction edit box.
Click the OK button.
Click the “X” in the upper right-hand corner of the window labeled 3-D View to close it.
Click the Draw Special Joint button 
or the Draw menu > Draw Special Joint command to access the Properties of Object form.
Click on the axes intersection at the origin to enter a joint.
Click the Set Select Mode button 
to exit Draw mode and enter Select mode.
Select the joint by clicking on it.
Click the Assign menu > Joint > Springs command to access the Joint Springs form. In that form:
Type 64 in the Translation 1 edit box.
Click the OK button.
Select the joint by clicking on it.
Click the Assign menu > Joint > Masses command to access the Joint Masses form. In that form:
In the Masses in Local Directions area type 1 in the Direction 1 edit box.
Click the OK button.
Click the Define menu > Functions > Response Spectrum command to access the Define Response Spectrum Functions form. In that form:
In the Choose Function Type to Add area, select the UBC94 Spectrum from the drop-down list.
Click the Add New Function button to access the Response Spectrum UBC 94 Function Definition form. In that form:
Type SPEC1 in the Function Name edit box.
In the Parameters area type 1 in the Seismic Zone Factor, Z edit box. This variable is being scaled up in excess of the required code value to give a peak ground acceleration of 1g.
Select 1 from the Soil Type drop-down list.
Click the OK buttons on the Response Spectrum UBC 94 Function Definition and Define Response Spectrum Functions forms to exit all forms.
Click the Define menu > Load Cases command to access the Define Load Cases form. In that form:
Click the Add New Load Case button to access the Load Case Data form. In that form:
Type RS in the Load Case Name edit box.
In the Analysis Case Type area, select Response Spectrum from the drop-down list.
Accept the default Modal Combination option, CQC.
Accept the default Directional Combination option, SRSS. Note that this option is irrelevant in this example since the response spectrum is run in only one direction.
In the Loads Applied area:
Verify that U1 is shown in the Load Name drop-down list.
Verify that SPEC1 is shown in the Function drop-down list.
Type 386.4 in the Scale Factor edit box.
Click the Add button.
Verify that Modal Damping is set to Constant at 0.05.
Click the OK button.
Click on MODAL in the Load Case Name list to highlight it.
Click the Modify/Show Load Case button to access the Load Case Data - Modal form. In that form:
Verify that the Eigen Vectors option is selected in the Type of Modes area.
In the Number of Modes area, type 1 in the Maximum Number of Modes edit box.
Click the OK buttons on the Load Case Data - Modal and Define Load Cases forms to exit all forms.
Click the Analyze menu > Set Analysis Options command to access the Analysis Options form.
Uncheck all of the Available DOFs check boxes except for UX.
Click the OK button.
Click the Run Analysis button
to access the Set Load Cases to Run form. In that form:
Click the Run Now button.
When the analysis is complete, check the messages in the SAP Analysis Monitor window (there should be no warnings or errors) and then click the OK button to close the window.
Click the Display menu > Show Forces/Stresses > Joints command to access the Joint Reaction Forces form. Click the OK button. If the axes make it difficult to read the spring force, click the View menu > Show Axes command to toggle the axes display off.