Function
- This function allows us to define necessary construction stages to analyze a bridge structure reflecting the effects of evolving structure configurations and elastic and time dependent (creep and shrinkage) displacements.
- Each construction stage is identified with activated (or deactivated) element, boundary and load groups. Each stage retains a unique element group, a boundary group and a load group, forming an interim independent structure. The stage information that was difficult to define in Wizard can now be added or modified using this function. Refer to the Wizards "ILM Bridge Stage", "FCM Bridge" and "MSS/FSM Bridge".
Call
From the main menu, select [Load] tab > [Type : Construction Stage] > [Construction Stage Data] group > [Define C.S]
Input
Name : Displays the name of the construction stage.
Duration : Displays the duration of the corresponding construction stage.
Date : Displays the accumulative time for the corresponding construction stage.
Step : Displays the additional step that was inputted.
Result : Displays the criterion for saving the construction stage. If the user wants to display the results by Stage, then this will display the last step of the corresponding construction stage. If the user wants to display as Stage & Step, then the spreadsheet will display all the results for each and every step.
Add : Define and add a new Construction Stage to the stage list. The new stage is added to the end of the list.
Insert Prev : Add a new construction stage immediately preceding the selected stage in the list.
Insert Next : Add a new construction stage immediately after the selected stage in the list.
Generate : A number of construction stages are generated at once.
Modify/Show : Modify or check the data for the stage selected in the list.
Delete : Delete the construction stage selected in the list.
Close : Close the Construction Stage dialog box.
Compose construction stage dialog box
1. When a new construction stage is defined
Depending on the timing of the new construction stage, click Add, Insert Prev or Insert Next to invoke the dialog box for Compose Construction Stage and provide the following information:
2. When modifying or checking the construction stage.
Select the construction stage to modify. Invoke Compose Construction Stage dialog box by Clicking on Modify/Show tab and modify or check the information assigned. The user can also check another construction stage by clicking on the stage box and scroll, or can use the up and down arrow.
Stage
Name
Enter the name of construction stage to be defined. The selected name appears if the Modify/Show button is clicked.
Duration
Specify the duration of the construction stage being defined.
Save Result
Specify a method of saving the analysis results. Both Stage and Steps can be selected.
Stage
Analysis results are saved by construction stages.
Additional Step
Analysis results are saved by construction stages.
Current Stage Information...
Upon clicking the button, the nodes, elements, boundary groups and load groups applicable to the current stage being defined are displayed in the Current Stage Information box.
Additional Step
Define the analysis steps within the construction stage. Within a construction stage, where the model and boundary condition remain unchanged, changes in load application timing or additional loads may be incorporated through additional steps.
Day
Sub-durations corresponding to each step within the construction stage are defined. These are reflected in the Active Day and Inactive Day under the Load tab.
Add : In the current construction stage being defined, select a day subsequent to the entered Day and add the step to the bottom of the Step list.
Modify : Modify the time (day) of the selected step in the Step list.
Delete : Delete the selected steps from the Step list.
Clear : Clear all the steps listed in the Step to revert to the initial state.
Auto Generation
Multi-steps can be automatically generated. Specify the number of steps in the Step Number field and click Generate Steps. The total Duration is equally divided by the number of steps in logarithmic scale.
Element tab
Activate or deactivate relevant element (structure) groups to define the elements applicable to the current stage being defined.
Group List
The list of all the predefined element groups is displayed. Click the ... button to the right to prompt the Define Structure Group dialog box to add or modify groups.
Activation
Select relevant element groups in the Group List, and click Add to activate the selected groups. Click Modify to change the Age of the selected element groups. Click Delete to expel the selected element groups from the active group list to the main Group List. Multiple selections are permitted while pressing the control key. Note that the self weight of members are automatically accounted for at the time of element generation as long as the Self Weight Load case is defined.
Age
Specify the maturity of the concrete elements to be added or modified. This is to reflect the effects of creep and shrinkage on the elements. The Age represents the time elapsed from the time of concrete casting prior to the start of the current construction stage being defined. That is, the Age is the maturity of the element groups at the start of the current stage being defined. The Age typically represents the time span from the time of concrete casting to the time of removal of falsework/formwork for horizontal members such as slabs.
Deactivation
In the cases of temporary structures, where certain element groups created (activated) in the previous construction stages no longer exist in the current stage being defined, the element groups must be deactivated. Once activated element groups remain active unless they are specifically deactivated. In the Group List, select relevant element groups, and click Add to deactivate the selected groups. Click Modify to change the percentage of Element Force Redistribution for the selected inactive element groups. Click Delete to expel the selected element groups from the inactive group list to the main Group List. Multiple selections are permitted while pressing the control key.
Element Force Reduction
When certain elements become inactive, we need to specify as to what percentage of the forces resisted by the elements is to be distributed to the remaining contiguous active elements. In general, this would be 100%.
The results of all prior construction stages are accumulated and applied to the current stage. Once activated elements, boundary conditions and loads remain active until they are deactivated. When an element is removed, the internal forces are internally imposed to the contiguous remaining elements in the opposite directions.
3. When modifying or checking the construction stage
Select the construction stage to modify. Invoke Compose Construction Stage dialog box by Clicking on Modify/Show tab and modify or check the information assigned. The user can also check another construction stage by clicking on the stage box and scroll, or can use the up and down arrow.
Boundary tab
Activate or deactivate relevant boundary groups to define the boundary conditions applicable to the current stage being defined.
Group List
The list of all the predefined boundary groups is displayed. Click the ... button to the right to prompt the Define Boundary Group dialog box to add or modify groups.
Activation
Select relevant boundary groups in the Group List, and click Add to activate the selected groups. Click Modify to change the supports /spring supports or their relative positions for which the boundary conditions are imposed. Click Delete to expel the selected boundary groups from the active group list to the main Group List. Multiple selections are permitted while pressing the control key.
Support/Spring Position
Define the positions of the selected active groups when constraints or spring supports are included in the boundary groups.
Original : Apply the boundary condition to the undeformed position. This is equivalent to imposing forced displacements to the original position prior to providing the supports.
Deformed : Apply the boundary condition to the deformed position.
The Support/Spring Position is considered when there is a need to reflect changes in boundary conditions during the construction stages of structures such as ILM bridges. For example, in the case of a launching nose that is extruded up to the position of a pier, deflections occur due to self-weight. In the "Deformed" method, boundary conditions are applied at the deformed position, while in the "Original" method, the deformed state is forcibly restored up to the position of the pier, and then boundary conditions are applied.
When using the ILM Bridge Stage Wizard, all boundary conditions except the hinge point's translational direction (DX) are considered as "Original".
Deactivation
To deactivate specific groups during the construction stage, you can select the desired groups from the Group List and click the Add button to add them to the Deactivation Group List. You can use the Modify button to modify the support/spring position options for the groups registered in the Deactivation Group List or remove them from the list using the Delete button.
Boundary condition groups are activated or deactivated at the beginning of the corresponding construction stage.
Load tab
Activate or deactivate relevant load groups applicable to the current construction stage being defined. The status of activation can be identified in the stage as well as at the steps. To activate/deactivate at the steps the Additional Steps must be predefined.
Group List
The list of all the predefined load groups is displayed. Click the ... button to the right to prompt the Define Load Group dialog box to add or modify groups.
Activation
Select relevant load groups in the Group List, and click Add to activate the selected groups. Click Modify to change the Active Day of the selected load groups. Click Delete to expel the selected load groups from the activation group list to the main Group List. Multiple selections are permitted while pressing the control key.
Active Day
Define the time span from the start of the corresponding construction stage to the point of activating the selected load groups. Either the start or the last (end) of the construction stage can be specified. The Day selection list includes additional steps if defined.
Deactivation
Select relevant load groups in the Group List, and click Add to deactivate the selected groups. Click Modify to change the Inactive Day of the selected load groups. Click Delete to expel the selected load groups from the deactivation group list to the main Group List. Multiple selections are permitted while pressing the control key.
Plane Load and Floor Load cannot be removed once they have been applied, so Load Groups that include these types of loads cannot be added to the Deactivation List.
Only the general static analysis can be carried out for construction stages. Moving load analysis, time history analysis, response spectrum analysis, etc. can be performed on the completed structure at the Final Stage. When a force is removed, the force is internally applied to the structure in the opposite direction for the previous stages. However, the self weight is an exception. When the self weight is removed, self weight of activated elements remain, but self weight of newly activated elements after removing Self Weight will not be considered.
4. When defining multiple construction stages simultaneously:
Click Generate in the Construction Stage dialog box to prompt the Define Construction Stage dialog box to enter the following: Click Modify/Show to modify the generated construction stages.
Stage
Name : The name of the construction stage you want to define.
Suffix : The suffix appended to the construction stage name.
For example, entering 'CS' in the Name field and '1 to 4' in the Suffix field will generate four construction stages named 'CS1' to 'CS4'.
Duration : The duration of the construction stage.
Additional Step
Create steps to reflect changes in loads for each construction stage.
Day
Enter the elapsed time to set as a step within the construction stage duration. This is used when modifying the composition of the construction stage in the Compose Construction Stage dialog box, specifically for the activation or deactivation days of loads in the Load tab.
Add : Sets the entered time (Day) as a step and adds it to the list of steps for the respective construction stage.
Modify : Modifies the elapsed time of the specified step in the list of steps.
Delete : Deletes the specified step from the list of steps.
Clear : Deletes all steps, resetting the list of steps.
Auto Generate
Multi-steps can be automatically generated. Specify the number of steps in the Step Number field and click Generate Steps. The total Duration is equally divided by the number of steps in logarithmic scale.
Save Result
Specify a method of saving the analysis results. Both Stage and Steps can be selected.
Stage
Specify a method of saving the analysis results. Both Stage and Steps can be selected.
Additional Step
Analysis results are saved by steps within the construction stage.
Upon clicking the Apply or OK button, the last generated construction stages are added to the end of the construction stage list in the Construction Stage dialog box.