Spectra Comparison for Soil-Structure Interaction Effects Form

Access the Spectra Comparison for Soil-Structure Interaction Effects form as follows:

Define a nonlinear static analysis case whose Load Application type is Displacement Control and whose Results Saved type is Multiple States; run an analysis.
Choose Method a, b, or c to specify the display for a pushover curve, define parameters for it, or save the options as a Named Set, respectively:

Click the Display menu > Show Pushover Curve command to display the Pushover Curve form. Select FEMA 440 Displacement Modification or FEMA 440 Equivalent Linearization for the Plot Type, and click the Add New Parameters button, or select an existing curve and click the Add Copy of Parameters or Modify/Show Parameters button, to display the Parameters for FEMA 440 Displacement Modification form or the Parameters for FEMA 440 Equivalent Linearization form.
Click the Define menu > Pushover Parameter Sets > FEMA 440 Displacement Modification command or the Define menu > Pushover Parameter Sets > FEMA 440 Equivalent Linearization command to display the Define Pushover Parameters for FEMA 440 Displ Mod or the Define Pushover Parameters for FEMA 400 Eq Linear form; then click the Add New Parameters button, or select an existing parameter set definition and click the Add Copy of Parameters or Modify/Show Parameters button, to display the Parameters for FEMA 440 Displacement Modification form or the Parameters for FEMA 440 Equivalent Linearization form, respectively.
Click the Define menu > Named Sets > Pushover Named Sets command to display the Define Pushover Named Sets form. Then click the Add New Named Set button, or highlight a previously defined Named Set and click the Add Copy of Named Set or Modify/Show Named Set button, to display the Pushover Named Set Data form. On that form select FEMA 440 Displacement Modification or FEMA 440 Linearization for the Plot Type, and click the Add New Parameters button, or select an existing named set and click the Add Copy of Parameters or Modify/Show Parameters button, to display the Parameters for FEMA 440 Displacement Modification form or the Parameters for FEMA 440 Equivalent Linearization form.

Check the Include Soil-Structure Interaction Effects check box and then click the Modify/Show SSI button to display the FEMA 440 Soil-Structure Interaction form.
Click the Show Spectra Comparison For SSI Effects button.

Use the Spectra Comparison for Soil-Structure Interaction Effects form to generate demand spectrum plots of free field motion, free field motion reduced for soil-structure interaction kinematic effects, and free field motion reduced for soil-structure interaction kinematic effects and foundation damping. The demand spectrum curves can be plotted as spectral displacement vs. spectral acceleration, period vs. spectral acceleration, or period vs. spectral displacement.

Plot Type options. Choose the axes for the plot: Sa-Sd (spectral acceleration vs spectral displacement), Sa-T (spectral acceleration vs period) or Sd-T (spectral displacement vs period). Spectral acceleration vs spectral displacement is the default.
Items Visible On Plot area. Choose the items to be displayed on the plot. In some cases (e.g., when the items to be displayed occupy the same location on the plot), it may be necessary to deselect an option so that other options become visible.

Show Free Field Motion option and color box. The default color for the free field motion is red. Click the color box to display the Color form and select another color if desired.
Show Kinematic Effects option and color box. The default color for the kinematic effects only is green. Click the color box to display the Color form and select another color if desired.
Show Kinematic and Fnd Damping Effects option and color box. The default color for display kinematic effects and foundation damping is yellow. Click the color box to display the Color form and select another color if desired.

Display area. The display area will show the plot using the selected axes. The Horiz and Vert display boxes will show the mouse pointer location if the mouse is moved over the plot.
Units drop-down list. Use the units displayed or select another from the list; the units displayed will be used on the plot of the soil-structure interaction effects curve.
Reset Defaults button. Clicking this button will return all options on the form to program defaults.

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