- Define (create, modify & delete) boundary group names to which specific nodes and elements specified with particular boundary conditions are later assigned.
- In a relatively complicated model for a complex structure, grouping specific nodes and elements assigned with particular boundary conditions becomes handy when the groups of the boundary conditions are to be repeatedly selected. Using the boundary group names, can we then select (Select Identity) or activate (Active Identity) frequently used boundary groups. Boundary groups are especially dedicated to Construction Stage analysis (of a sequential bridge construction) where each part of the total structure erected in each stage may retain different boundary conditions from those of other stages.
- 경Boundary groups can be defined in Define Boundary Group first. Next, the desired nodes and elements assigned with particular boundary conditions can be selected in the Group tab of the Tree Menu and assigned to the groups by Drag & Drop. Or, the boundary groups can be directly assigned at the time of defining the boundary conditions.
From the main menu, select [Project] tab > [Group] group > [Group] > [Boundary Group]
Fig. Define Boundary Group dialog box
Enter the name of a boundary group to be created, modified, or deleted.
When a PSC box bridge is modeled by the use of Bridge Wizard of midas Civil, the names of the auto-generated Boundary Groups are as follows:
ILM Bridge Model Wizard
Final: Support condition of Permanent System at the final stage
Temporary: Support conditions of temporary piers and prefabrication plant
CSn-Dfmm: Support condition for Construction Stage, n th segment, m th step (assigned to the deformed locations), ie. supports provided after deflections have occurred
CSn-Orgm: Support condition for Construction Stage, n th segment, m th step (assigned to the undeformed locations), ie. supports provided at the original undeflected geometric locations including the effects of forced displacements
CSn-OrgmP: This represents the boundary condition immediately prior to a pier supports the front end of the launching nose. The construction stage CSn-mP (the capital P denotes Pier) is activated for the condition immediately prior to the launching nose becoming supported by a pier and deactivated at the next stage.
- In Construction Stage CSn-m, "m" signifies the steps (sub-stages) created by the launching distances within the n th segment.
- The construction stage CSn-mP depicts the condition when the launching nose retains the longest cantilever immediately prior to becoming supported by a pier.
FCM Bridge Wizard
Support: Support condition of piers and buttresses (activated at Construction Stage CS1)
Elastic Link: Elastic link connecting the PSC box girder and pier (activated at Construction Stage CS1)
MSS/FSM Bridge Wizard
Start_Roller: Roller support condition at the starting buttress (activated at Construction Stage CS01)
Piern_Roller: Roller support condition at the n th pier (activated at Construction Stage CSn)
Pierm_Fix: Fixed support condition at the m th pier designated in Wizard (activated at Construction Stage CSm)
Pier1_Fix: Temporary fixed support condition assigned to the first pier until the construction stage progresses to the pier with the permanent fixed support condition (CSm) (activated at Construction Stage CS1 and deactivated at CSm)
Pier1_Roller: Roller support condition will be reassigned to the first pier, which was assigned a temporary fixed support condition, after the construction stage progressed to the pier with the permanent fixed support condition (activated at Construction Stage CSm)
Endn_Roller: Roller support condition of the End buttress (activated at the stage immediately prior to the final stage)
The Suffix entry field is provided for the convenience of creating a number of related group names simultaneously. This is mainly used to generate changing boundary conditions pertaining to multiple construction stages.
The construction stages defined by using Construction Stage Wizard for Building automatically create the Boundary Groups of "#CS Construction Stage No."and"#DP-Story Name".
, : Sort in ascending/descending alphanumeric order
, : The selected group moves up/down one position in the list. The use of [Ctrl] or [Shift] key permits multi-selection.
The entered boundary group is created. The boundary groups as many as defined in the Suffix entry field are simultaneously created.
The designated boundary group name is modified.
Selected boundary group names are deleted. The use of [Ctrl] key permits multi-selection.
All the boundary groups on the list are deleted except for the selected groups. The use of [Ctrl] key permits multi-selection.
Close the Define boundary Group dialog box.
Fig. Boundary Group
Use the Group tab of the Tree Menu to assign nodes and elements specified with particular boundary conditions to the defined Boundary Groups.
First, select the nodes and elements specified with particular boundary conditions to be assigned to a group using the Selection functions. Next, drag and drop the boundary group name to which the selected nodes and elements will be assigned from the Tree Menu to the Model Window.
Fig. Select Boundary Type dialog box
Select the boundary conditions that will be assigned to the boundary group in the Select Boundary Type dialog box. Upon clicking OK. the selected boundary conditions will be assigned to the selected nodes and elements, which will in turn be assigned to the boundary group.
When a number of boundary conditions are defined by different boundary groups and assigned to a node or an element in a given construction stage, the accumulated effect is considered in that construction stage.