How do I specify elastic member foundations in RFEM?
This is necessary for a bore pile orientated in the global Z-direction and with different foundations in the global X- and Y-direction.
The parameters for defining the elastic foundations depend on the constants of the surface supports.
The constants always refer to the local member axes (x,y,z). The constants C1,x, C1,y, and C1,z describe the translational spring constants in the direction of the local member axes (x,y,z).
The value Cφ expresses the restraint of the member rotation about its longitudinal axis.
The values C2,x, C2,y, and C2,z allow you to take into account the shear resistance of the soil in the direction of the local member axes (x,y,z).
The definition is always relative to 1m width. If the member has a smaller width, you must consider this in the constants, for example for a 30 wide member C1,z = 10,000 kN/m³ x 0.3m = 3,000 kN/m².
To specify different horizontal elastic foundations in the global X- and Y-direction, you thus need to look at the local axes of the member. Then you can specify the spring constants in accordance with the directions.