When performing the fire resistance design in the RF-CONCRETE Members, acting internal forces, e.g. My,Ed,fi, are applied that do not correspond to the internal forces of the underlying determination of internal forces. What is the background?


In the fire resistance design, the acting internal forces are determined again if the thermal expansion of the concrete and the reinforcing steel and the precamber due to the temperature difference is taken into account (Figure 01).

If the thermal expansions and the precamber are not taken into account, the acting internal forces should correspond to the internal forces of the calculation from RFEM or RSTAB (Figure 02).

To what extent it is allowed to deactivate the thermal expansions and precambers has to be checked in connection with the underlying standard.


Fire resistance Internal forces Precamber Thermal expansion


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