Rigid Body in Plaxis 3D

Question

Can anyone explain this feature as I couldn't understand? Thanks in advance.

Vasileios Basas · Answer

Hi Nitharshan, In situations where deformations of structures and structural (internal) forces are not supposed to be relevant in output data, these structures may simply be modelled as 'stiff' structures, with an arbitrary stiffness that is sufficiently large compared to the stiffness of the soil. However, considering an arbitrarily large stiffness may deteriorate the condition of the global stiffness matrix, and should therefore be used with care. As an alternative to this, PLAXIS 3D provides the option to create so-called 'rigid body' objects based on predefined geometry components (surfaces and volumes). Rigid bodies may be used, for example, in rigid foundation plates (footing, mud mat), rigid walls, bucket foundations, spud cans (foundation for jack-up platform legs), etc. In short, a rigid body is an object without any change in shape. Each rigid body has a Reference point associated to it and it should be given a combination of forces / moments and/or displacements / rotations in x, y and z-direction, in order to apply external forces and to set its boundary conditions. 
 You can find more information in Chapter 5.8.8 (Rigid Bodies) of the PLAXIS 3D - Reference manual.