Embedded beam row_ Plaxis 2D reference maual 2020_Page 107

Dear Nitha,

I will comment on each part in the same order.

• That is for the case that you include an embedded beam element inside a polygon with a linear elastic material. Typically a linear elastic material is used to model concrete and if an embedded beam is inside the concrete we consider the connection to be rigid and therefore, for instance, the shaft resistance is ignored.
  Extra note: when an embedded beam is snapped to the edge of a polygon cluster the connection point is singular and it sometimes causes numerical problems. For that reason, we advise either extending the embedded beam inside the polygon or adding a dummy plate element to ensure proper connection between the embedded beam and the polygon you want to have a rigid connection with.
  
  
• The default behaviour is to have a rigid connection between the embedded beam and the surrounding objects. If that object is a structural element then both rotation and translations are transferred. If that object is soil, then no rotations are transferred but only the translations.
  Therefore, when an embedded beam simply lies inside the soil, the connection type can be set to rigid (fixed), which is what is shown by the square visualisation, but it actually behaves as hinged as the soil cannot take any rotation from structures.
  
  
• If there is no structural element in the location where the interface is added, then the embedded beam is connected to a soil node and thus behave as a hinged connection, as explained before.
  
  
• You can check the following article: communities.bentley.com/.../connect-a-node-to-node-anchor-with-an-embedded-beam-row-halfway

Dear Mr. Stefanos, 

Thanks for the explanations and why if we provided the embedded beam row in soil polygon without any plate, the shaft resistance is ignored?

With that i'm eager in stiffness factor clarification. 

01. Please tell how this factor comes?

02. For axial and base stiffness resistance, Gsoil is used as shear failure can occur but what is the reason for using Gsoil in the lateral stiffness calculation ?

Thanks.

Any help please

Dear Nitha,

If the embedded beam is extended inside the volume (modelled as linear elastic) the purpose is achieved in making it rigidly connected. The extension is not based on reality but rather a "trick" to achieve a proper connection with the concrete. 
If you add the plate, then the connection is also ensured so either way will work fine.

The factors that you mention are the Interface Stiffness Factors of the embedded beam row elements in PLAXIS 2D. Note that the default values are for bored piles which are loaded statically in the axial direction and the surrounding soil is modelled with Hardening Soil with small-strain stiffness. You may need to calibrate these parameters to fit your case. 

The Gsoil is considered in every case just like in the typical application of the interfaces on a plate element. For more information, you may need to check our Materials Models manual.

Noted with thanks.