Nonlinear member support for soil modeling

I am currently working on my thesis project concerning laterally loaded piles. As part of this work, I have developed a numerical model in RFEM 6 using the Python API. My question relates specifically to the implementation of nonlinear nodal supports.

I have an empirical load–displacement dataset representing the lateral soil response. In the RFEM model, the pile is discretized into a number of beam elements, and nonlinear nodal supports (defined through diagrams) are assigned to represent the soil resistance at each node.

In parallel, I have created a second model in CALFEM, where the soil stiffness is distributed continuously along the pile. In this model, I apply incremental load steps and determine the bed modulus using an iterative procedure based on a proposed formulation (Matlock curve). As a result, the two models differ conceptually: RFEM 6 uses discrete nonlinear springs at the nodes, whereas the CALFEM model employs a continuous nonlinear foundation.

I have explored the possibility of using the “member support” functionality in RFEM 6 to obtain a more continuous representation of the soil. However, this approach does not allow me to incorporate the empirical load–displacement data. My question is therefore whether it is possible to define a nonlinear member support in RFEM 6?

Thanks in advance

I have found that line support might solve the problem

Now I have tried to work with the line support, and I just realise that it only works for surfaces and solids.

Hello StudentInu11,

as a workaround for this problem, you can create a rigid link between your pile and a fixed member of type "rigid."

You can then define a line hinge for your rigid link, which has the same functionalitys as line supports. :blush:

For detailed information on rigid links, check out this page:
:backhand_index_pointing_right: Rigid Links - RFEM 6

And for more on line hinges, refer to this page:
:backhand_index_pointing_right: Line Hinges - RFEM 6

Hope this helps! Let me know if you need further assistance.

Best regards
Matthias

1 Like