Function
- Different load (analysis) cases can retain separate boundary conditions within a model.
- Even in the case where static analysis and dynamic analysis are associated with different boundary conditions, the two analyses can be carried out within a same model without having to make two different model files.
- Analysis procedure for assigning different boundary conditions to Load Cases/Analyses is as follows:
1. Define Boundary Condition Groups:
Define boundary condition groups for the permanent structure conditions and those that change due to seismic or external loads.
2. Define Boundary Conditions and Associated Load Cases:
Define the boundary conditions for each group, considering the different conditions for permanent and seismic states. Associate these boundary conditions with corresponding load cases.
3. Apply Loads Based on Boundary Conditions:
Apply loads to the structure according to the defined boundary conditions.
4. Define Boundary Condition Changes for Each Load Case:
Create boundary condition groups that will be applied as changes based on the load cases.
5. Perform Analysis for Each Load Case and Boundary Condition:
6. Verify Results Based on Analysis Type:
Check the results based on the selected analysis type in this functionality.
Call
From the main menu, select [Analysis] tab > [Analysis Control] group > [Boundary Change Assignment]
Input
Boundary Change Assignment to LoadCase/Analysis dialog box
Data Selection
The types of defined boundary conditions, which can be applied to different load cases, are listed.
Boundary Group Combination
Boundary Group List
Boundary condition groups selected in Data Selection to the left are listed.
If Filter Boundary Group at the bottom is not checked, all the boundary condition groups are listed.
Name
Name a Boundary group combination, which will be applied to a load case. Having named a Boundary group combination, select desired boundary groups from Boundary Group List, and click Add/Replace to create a Boundary group combination. Multiple Boundary group combinations are thus created, each of which is assigned to each load case. A separate analysis can be then performed for each load case with its own Boundary group combination.
Load Cases & Analysis
Load combinations of static analysis and analysis types are listed. In the case of static analysis, click + to expand the table and list the static load cases defined by the user.
Boundary Group Combination
Select a Boundary group combination (by clicking in the right end of the entry field) to be applied to the static load case or analysis type to the left. If Unchanged is selected in a construction stage analysis, the boundary condition corresponding to the final construction stage is used. If Unchanged is selected in an analysis without construction stages, all the entered boundary conditions are used.
Constrain DOF associated with Specified Displacement/Settlements by Boundary Group Combinations
In a Specified Displacements or Settlements analysis, the degrees of freedom at the corresponding nodes are internally constrained and treated as supports, and forced displacements are assigned. If this option is selected (checked on), the internal DOF constraints are included in only the boundary group combination corresponding to the Specified Displacements/Settlements.
Click Remove Boundary Change Assignment to Load Cases/Analyses to remove all the data.
The Boundary Change Assignment, as the name suggest only changes specific boundaries as required by the user. By default, all the boundaries which are assigned/active in Post CS are applicable for the structure. The workflow for this feature is as below:
1. Under “Data Selection”, select the boundary type which needs to be changed.
2. Under “Boundary Group List”, select the boundary groups which are to stay active.
3. Type the Boundary Group Combination Name and click Add/Replace.
4. Now select the “Boundary Group Combination” for relevant static load case or analysis type.
If certain boundary type is not selected under “Data Selection”, then all the boundary of that type are applied to the structure by default.