Response Spectrum

In the Response Spectrum tab, you can assign response spectra to the individual directions of excitation that can be used to determine the seismic loads.

01 Specify Response Spectra for Directions

Assign Response Spectra

In this section it is to be determined in which global axis direction a response spectrum acts and which spectrum is relevant in each case. Different response spectra can be effective for the individual excitation directions.

At least one 'direction' must be activated. Then select one of the existing response spectra for this direction from the list. You can create a new spectrum with the button and edit the selected spectrum with the button.

You can specify a 'scaling factor' for each direction in order to increase or flatten the response spectrum. You can check the result of the scaling in the diagramResponseSpectra diagram and in the register Choosing the shapes in a table. There the values of the diagram are shown scaled.

Rotation of horizontal accelerations

The direction of excitation can be rotated by an angle in the XY plane. For example, if the response spectrum is to excite the model at an angle of 45 ° around the Z-axis, then only activate the X direction for the response spectrum and specify the angle α as 45 °.

Graph

The lower section shows the read-in response spectrum as a diagram. The default graph is the ' Acceleration - Period Chart '. You can use the X, Y and Z buttons to the right of the diagram to control which direction is displayed.

04 Selecting Direction for "Acceleration-Period Diagram"

If you move the mouse along the graph, the respective abscissas and ordinates appear. You can zoom with the mouse wheel, move the diagram with the left mouse button, and double-click the mouse wheel to restore the overall view of the diagram.

Abscissa: period or frequency

The diagram can be displayed as a 'acceleration - period diagram' or ' acceleration - frequency diagram '. Use the list button to specify which size is used for the abscissa axis.

05 Displaying "Acceleration-Frequency Diagram"

Representation: linear or logarithmic

A linear (lin) and logarithmic (log) division of the axes is possible for an optimal display. The following options are available via the list button:

• lin X / lin Y
• log X / lin Y
• lin X / log Y
• log X / log Y

06 Displaying Diagram with Logarithmic Division

Print function

The diagram can also be printed. You have the following options:

• Directly to a printer
• In the printout report
• Print Graphics to PDF
• Print Graphics to Clipboard
• Print Graphics to File

07 Printing Diagram

The printing of graphics is described in chapter Graphics of the RFEM manual.