how can I replicate an ipe section in plaxis?

Question

Hi, i must model Steel pile which have Ipe200 section. I used this way , but the equivalent section is more or less the Ipe 200.
There is other way?
Any tips for this model about embedded beam and steel piles?

Vasileios Basas · Answer

Although we accommodate certain predefined sections (solid circular, solid rectangular, hollow circular), the input parameters of a beam are its section area, A, Young's modulus, E, and moment of inertia (I) for elastic materials. With those mechanical properties in mind, it is possible to calculate the structural forces based on Eq. [358] of the Material Models manual. 
 The equivalent properties are relevant only when plasticity is considered (elastoplastic behaviour) and the yield strength, &sigma;, also becomes a required parameter. As discussed in the Material models and Reference manuals (also here: RE: Equivalent properties in Beam & Plate max. Axial force in Plaxis 3D ), the convention in PLAXIS is that calculations of elastoplastic beam (and embedded beam) elements are made based on a rectangular shape. Converting any shape of a section to a rectangular one follows a specific process, such that the maximum axial force and bending moment of the two sections remain the same. 
 Although there is little reason not to use a beam or embedded beam element to model the IPE 200 section in your model, you could, in theory, also use a plate element to represent the section of the beam.

Vasileios Basas · Answer

Hi Vincenzo, 
 Are you referring to the Bauschinger effect of steel? PLAXIS does not offer a way to account for the change of the material's stress/strain characteristics when the stresses are applied in the reverse direction. 
 Regarding your second question, if you don't have information on the skin friction from in-situ tests or conventional theories of pile design, I would suggest using the "Layer-dependent option". In this option, the local skin resistance is related to the strength (cohesion, c and friction angle, &phi;) and the interface strength factor, Rinter, as defined in the material data set of the corresponding soil or rock layers in which the pile is located. This means that the interface will have the following strength parameters: 
 c i = R inter * c soil and tan &phi; i = R inter * tan &phi; soil 
 where &phi; i and c i are the friction angle and the cohesion of the interface, &phi; soil and c soil are the friction angle and cohesion of the correspondent soil layer, and R inter is the strength reduction factor associated with the soil layer. If the soil fails with this axial skin resistance option, you need to inspect your Output and try to understand what causes this failure. 
 The base resistance, F max , which is the maximum allowable force at the foot of the pile, is considered an input parameter and not a result of the FEM calculation. Usually, this value can be defined using the bearing capacity theory (see Meyerhof's equation). It is generally advised for the ultimate shaft (T max ) and base resistance (F max ) of the embedded piles to be calibrated against the capacity of the single pile as derived from pile load test data. For more information on the theory behind the embedded beams, I would suggest that you also refer to Chapter 6.7 of the PLAXIS 3D &ndash; Reference Manual. Some very useful information on pile design can also be found in the classic book of Poulos & Davis (Pile Foundation Analysis and Design).