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Dipl.-Ing. (FH) Paul Kieloch
2015-04-14

Consideration of the Effects of the Second-Order Theory

In RFEM and RSTAB, the internal forces of individual load combinations are determined according to the second-order analysis by default. If you use the RF‑CONCRETE add‑on module for stability analysis of reinforced concrete columns, you can change the calculation method of LCs to the linear static analysis, since the effects of the second‑order analysis are already considered in the calculation according to the model column method in RF‑CONCRETE Columns (nominal curvature method).

When you use the results of such load combinations for design in RF‑FOUNDATION Pro, the effect of the second‑order analysis is missing in the foundation design. The reason is that the RF‑FOUNDATION Pro module uses the support reactions of individual LCs for the design.

In order to consider the support moments according to the second‑order analysis anyway, RF‑FOUNDATION Pro provides the option to affect the support moments according to the linear static analysis by a user‑defined factor. You can enter these increment factors separately for both design directions in the "Details" dialog box of the RF‑FOUNDATION Pro add‑on module. Please note that this entry applies to the entire design case.

If there is a moment applied with a certain factor, it will be recorded in the design details and in the result tables of the printout report by entering the multiplication factor.

Author

Mr. Kieloch provides technical support to our customers and is responsible for development in the area of reinforced concrete structures.

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