993x
003212
2019-06-24

Question

Is there a way to easily prevent RF‑SOILIN from recalculating the foundation every time the load in the governing load case is changed?


Answer:

No, that is not possible. The calculation of the foundation parameters in RF‑SOILIN is performed iteratively. The first iteration step requires that the start values for the foundation parameters are selected internally by the program. These start values can be used to perform a finite element analysis of the FE model in RFEM.

The result is soil contact stress distribution. The soil contact stress of the first iteration step is included in the RF‑SOILIN calculation as the initial value. Together with the stiffness modulus of the soil layers entered, it is possible to calculate the settlement for each finite element. The settlement and the soil contact stress are then used to calculate the foundation parameters.

In the next iteration step, the new foundation parameters replace the old ones, and a new finite element analysis is started, which results in a new distribution of soil contact stress. As a convergence criterion, the new distribution of soil contact stress is compared to the old one.

As long as the deviation exceeds a certain convergence limit, the new distribution of soil contact stress in RF‑SOILIN is considered in the calculation of the new foundation parameters. If the deviation of the soil contact stress distribution of two consecutive iteration steps is not reached the first time, the iteration is ended and the foundation parameters of the last iteration step are given as a result in RF‑SOILIN.