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8.2 Cross-Section Optimization

As mentioned in Chapter 3.3, RF-CONCRETE Members provides a means of optimizing cross-sections. In column C of Window 1.3 Cross-Sections (see Figure 3.17), specify the relevant cross-section by selecting the check box. The following dialog box appears.

Figure 8.5 Optimization Parameters dialog box of a T-beam

Select check boxes in the Optimize column to specify the parameter(s) you want to modify. This enables the Minimum and Maximum columns where you can define the parameter's upper and lower limits. The Increment column controls the interval in which the parameter's magnitude varies during the optimization process.

The optimization criterion specifies that a Targeted percentage of reinforcement either must not be exceeded at any location or is an available as average value over the entire member or set of members. The desired reinforcement ratio can be defined in the input field.

During the optimization process, RF-CONCRETE Members examines which dimensions should be used in order to still fulfill the design. Please note that the internal forces are not automatically recalculated with the changed cross-sections (the internal forces may vary significantly due to the changed stiffnesses in the structural system). In fact, it is up to you to decide when the optimized cross-sections are transferred to RFEM for recalculation. It is therefore recommended to recalculate the internal forces with the modified cross-sections after the first optimization and subsequently optimize the cross-sections once again.

It is also possible to export the modified cross-sections to RFEM: Go to Window 1.3 Cross-Sections and select the menu item

    • Edit → Export Cross-Section to RFEM.

You can also use the shortcut menu of the table row in Window 1.3 to export the modified cross-section.

Before a cross-section is transferred, a query appears that asks if the results from RFEM should be deleted.

After starting the [Calculation] in RF-CONCRETE Members, the internal forces and designs are determined in one calculation procedure.

If the cross-section has not yet been exported to RFEM, you can reimport the original Cross-Section from RFEM by using the corresponding option in the shortcut menu.

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