Used to input the prestress load. For truss/beam elements, the initial load for axial direction force and moment can be applied. For plane strain elements, axis symmetric elements and solid elements, the initial stress can be defined.

For truss/beam elements, the [Pretension Type] option can be applied. Checking this option maintains the input pretension regardless of the stress state changes that occur in the construction stage. If this option is unchecked, the prestress changes with the input stress state. If a prestress of 50 is input as shown in the figure below, checking [Pretension Type] retains the prestress as the axial force, regardless of the stress change due to excavation. If the pretension is not checked, the axial force is affected by the stress change of 10 due excavation and so, the output axial force is 40. Pretension can only be applied if the prestress is input for a truss element type.

[Element Type]

The applicable element types are as follows and the input load component is different for each type. The target shape can be selected by directly selecting the element or geometry shape (edge, face, solid). For shapes, the selected shape must have been used for element creation and the input load is applied to all element nodes within the shape.

[Components]

Define the load or stress for each axial direction and use a function to simulate the linear increment/decrement of the load size with reference to the global coordinate system(GCS). The load components for different element types are as follows:

• Nxx : Initial axial force acting on 1D element

• Mx, My, Mz : Bending force (moment load) with reference to each element coordinate system

• Sxx, Syy, Szz : Axial stress in each axial direction

• Sxy, Syz, Szx : Shear stress in each plane direction

The load application direction for the initial stress of Plane/Axis Symmetric/Solid elements can be set with reference to the GCS or element coordinate system.