In the material data base of Plates in PLAXIS 2D and 3D there is the option to select ‘End bearing’. Selecting this option may be appropriate to provide some sort of vertical end bearing (tip resistance) in the case the plate is used as a wall.

In reality, vertical loads on walls, for example as a result of vertical components of anchor forces or point loads on the wall, are sustained by the shaft friction and the tip resistance. A certain amount of resistance is offered by the soil under the tip, depending on the thickness or the cross section area of the tip. Slender walls are often modelled as plates. Due to the zero thickness of the plate elements, vertical plates (walls) have no end bearing. The effects of end bearing can still be considered in the calculation when the corresponding option is selected in the material data set. In order to consider end bearing at the bottom (tip) of plates, a zone in the soil volume elements surrounding the tip of the plate is identified where any kind of soil plasticity is excluded (elastic zone). The size of this elastic zone is determined as D_eq = √(12 EI / EA).

Notes

• In contrast to embedded beam elements, it is NOT the idea that this end bearing represents the true end bearing capacity of the wall. It just prevents unrealistic vertical movement or penetration of the wall into deeper layers. The value of end bearing cannot be prescribed by the user, and it is neither theoretically determined by PLAXIS.
• Note that sheet pile walls have very little end bearing, considering that the thickness of the steel is much less than D_eq, when modelling them as plates. Hence, the end bearing option shall NOT be used for sheet pile walls.

For more background on the End bearing option, please refer to the PLAXIS 2D and 3D Reference Manual and Material Models manuals.