Regenerate staged construction

With PLAXIS 2D and PLAXIS 3D it is possible to regenerate any Staged construction setting to the definition of the previous phase. This feature is available for any item that is part of the Model explorer and to be set per phase. This includes e.g. the active state of soil and structures, the assigned materials and load values. Items that are not included in this feature are:

• the phase settings, e.g. calculation type, solver type, pore pressure calculation type and general phreatic surface;
• the material parameter values since these are defined globally (for all phases);
• the (dynamic) multiplier values since these are defined globally (for all phases)

Regenerate all staged construction settings

In order to regenerate all Staged construction settings, go to the model tree for the desired phase. In the model tree, right click Geometry. A pop-up menu will appear. Here, choose the option called Regenerate.

This will regenerate all items to the Staged construction definition of the phase this phase starts from. Also, all Staged construction settings in all phases following the current phase will be regenerated if the setting is not different from the current phase’s setting for the selected items.

Example A: regenerate a model

In this PLAXIS 3D example, we will take a very simple model with two soil layers and two surface loads, see the image below.

For the initial phase, Soillayer A will be assigned material A and Soillayer B will be assigned material B. In phase 1, we will activate the two surface loads: the left will be set to σ_z = -50 kPa and the right surface load to σ_z = -50 kPa.
Now we will add a new phase, Phase_2, in which we will keep the left surface load σ_z = -50 kPa, the right surface load will be changed to σ_z = -100 kPa, and the material for Soillayer B will be set to material C:

If we would now regenerate Phase_2’s model, by using the right mouse button on Geometry in the Model Explorer, we can regenerate the settings for Phase_2 to the setting of Phase_1:

Regenerate specific staged construction settings

The regenerate option is available for all staged construction settings. These are Model explorer items that are phase specific and that are on any level in the Model explorer. These settings are also in available the Selection explorer when selecting items.

You can easily regenerate the following items by right-clicking any of these model explorer items:

• all properties for a geometric object, like Lines by right clicking Geometry > Lines
• all properties of a structure type, e.g. all Plates by right clicking Plates
• all load values for surface loads by right-clicking Surface Loads
• all properties of a group, when groups are selected by just right clicking Groups > [Group x]
• a single soil layer by right-clicking Geometry > Soil volumes > [soil layer]
• a single structural element, e.g. Beam_4,  by right-clicking Beams > Beam_4

To continue the example above, we will do some different actions, all starting after the original definition of phase 2.

a) Only regenerate loads
Now we will only regenerate the values for the surface loads to the values of phase 1, without changing the soils in phase 2. To do so, we use the right mouse button on the Surface loads item in the Model Tree, and choose Regenerate. As a result, the material assignments will not be changed, but both the surface loads are now set to σ_z = 50 kPa:

b) Regenerate second soil layer in model view
For this, we will use the right mouse button to click on the second soil layer in the 3D model view. From here we can also choose to Regenerate. As a result, phase 2 will now again have material B assigned to the second soil layer, while the loads are not changed.

c) Regenerate first soil layer in selection explorer
In this case, we will select the first soil layer with material A assigned by clicking on it. It will turn red and in the selection explorer you can see the selected soil material. The regeneration option will also work here. To do so, just go to the selection explorer and right-click on the soil object, and choose Regenerate. Of course, no change will be made in the model since both in Phase 1 and Phase 2 material A was already assigned to the first soil layer:

Regenerate water conditions

Regenerating water conditions is less straightforward and involves first a selection of the desired part of the model.
To regenerate a single volume’s water condition, these steps should be taken:

• Select the volume to let it appear in the selection explorer, or expand the Model explorer tree until you reach the desired Volume:
  
• Now right click the Water Conditions item to Regenerate the water conditions to the previous phase’s Water Conditions.

When water conditions for multiple volumes need to be regenerated, a multi-select is required in order to perform this action in the selection explorer.
If the entire phase’s water conditions need to be regenerated, the following steps are needed:

• First, make sure that all desired soil volumes are selected:
  • for all soils, click with the left mouse button on the Soils item in the Model Explorer to select all Soils
  • Alternatively, you may select all soils in the visualization:
    • first, make sure the desired soils are visible (also the deactivated ones)
    • Use the multi-selection tool to select all Soils:
    • While the entire model is visible on screen, drag the multi-selection square from bottom-right to top-left. All soils should now turn red.
• Then in the Selection explorer, you should see something like this:
  
• Now right click the Water Conditions item to Regenerate the water conditions to the previous phase’s Water Conditions.

Please do not forget to check if the global water level needs to be regenerated in the Phases window as well.

This same approach to regenerate only specific parts can be used for e.g.

• Soils: VolumeStrain
• All point loads: force in x-direction, but when you do not want to change the active state of the point loads.

Influence on succeeding phases

One of the features of the regeneration process is that it will regenerate all changes into the succeeding phases. This regeneration process will continue per individual property until it reaches the last phase, or when the property is not equal to the property value as it was defined as in the phase we are now regenerating.

As an example, we will use the same model as described above, and add a phase that has the same settings as in phase 2. After regeneration of the entire Geometry of phase 2, both phase 2 and phase 3 will have the same staged construction settings as phase 1:

If we now would have defined different load values in phase 3 compared to phase 2, then the result of regenerating the entire geometry in phase 2 will look like this:

The loads in phase 2 are regenerated to the load values as in phase 1, as well as the material assignments. In phase 3, we see that the material is also regenerated to the one as defined in phase 1, since it was the same for phase 2 and phase 3 prior to regeneration. The load values however were not the same as in phase 2, so these will not be changed in phase 3.

In the next example, we will take phase 1 as in the original case, but for this case in phase 2 we will change a load, and all material assignments. Then in phase 3, we will change another load, and change the material for the second layer again. We will regenerate the entire geometry in phase 2:

The following items will NOT be regenerated in Phase_3:

• Phase 3: the second soil layer’s material will not be regenerated to material B, since the material assignment was not the same as in phase 2 prior to the regeneration
• Phase 3: the left load since the load was not the same as in phase 2 prior to the regeneration

These items will be changed:

• Phase 2: material for the top layer to the material of phase 1 for this soil layer
• Phase 2: material for the second layer to the material of phase 1 for this soil layer
• Phase 2: the load value of the right load
• Phase 3: top soil layer. This soil layer was assigned the same material as it was in phase 2 prior to the regeneration.
• Phase 3: the load value of the right load. This was the same load value as it was in phase 2 prior to the regeneration

Conclusion

The regeneration option is a powerful tool to reset and regenerate features in phases to the values in the previous phase. It can also apply these changes into the following phases, as long as the values were the same as in the phase you are regenerating.