Change Section
The default "Change Section Properties" operation essentially involves removing a stressed object and replacing it with unstressed object. This is documented in CSI Analysis Reference Manual, chapter "Nonlinear Static Analysis", section "Staged Construction > Changing Section Properties".
To model staged construction for the composite section, you could use one of the following approaches:
(1) Use "Change Modifiers" staged construction operation:
Please note that you would need to first create frame property modifiers via "Define > Named Property Sets > Frame Modifiers" menu command.
(2) Explicitly model the individual components (such as the girder and the slab) of the composite section.
Change Supports
While it is not possible to directly change the support or restraint type in the staged construction in the current version (as of V14.1.0) of the program, this can be accomplished by using frame releases and a dummy frame element:
- Define short and stiff frame element to represent the bearing.
- Use "Define > Named Property Sets > Frame Releases" menu command to define frame releases representing the final bearing condition for the frame element defined in step 1.
- Define "Change Releases" operation in the staged construction load case to change the frame releases.
Alternatively, you could also use link elements at the supports and then remove the link element(s) simulating the old support condition and replace it by a link element(s) simulating the new support condition.
Change Frame Releases
- Use "Define > Named Property Sets > Frame Releases" menu command to define the frame end releases.
- Define "Change Releases" operation in the staged construction load case to apply the frame releases.