Construction Stage Wizard for Building Structure

The wizard readily allows us to define the timing of elements created and loadings applied in the construction stages during the erection of a building. The time dependent material properties of concrete (concrete strength gain, creep and shrinkage) are reflected in the process. You may find it more convenient to first click the button to define the basic construction stages and modify them as necessary.

The construction stages created by the wizard are assembled and organized in Define Construction Stage for further refinement of stages such as loadings applied at different timing or change in geometries (element groups), etc.

From the Main Menu select Load > Construction Stage >  Construction Stage Data > Construction Stage Wizard for Building Structures.

  Construction Dead Load Case

Select the construction dead load case, which is typically a self weight static load case that includes the self weight of the members and the weight of slabs, which will be applied to the construction stage analysis. Provided that the self weight is defined as a load case, the self weight of the members are automatically generated and loaded to the previously erected structure at the time of generating the elements. That is, the self weight of the structure need not be included in the Construction Dead load Case if self weight load case is predefined.

Click the button to prompt the Static Load Cases dialog box to add or modify load cases.

When the button is clicked (The user may find this more convenient than the Normal Form.)

Erection Sequence List

Define the stories to be created and the timing of which the loads begin to act in individual construction stages.

Step

Enter the construction stage numbers (sequential numbers). In a composite construction, where both structural steel and concrete are used, a story can be used more than once for defining different erection timing. Similarly, a floor can be repeatedly specified for defining different framing in a given floor.  

Model Type
In a construction stage being defined, select a method to define the incremental structure portion pertaining to the stage (i.e, to create the elements). In practice, material types and names can be used in combination to represent not just different materials, but to differentiate columns and girders, etc.

Material Type: define by predefined material types

Material Name: define by predefined material names

Model Material
Specify the material representing the elements that will be erected on the corresponding story.

Model Story (To)
Specify the story that will be erected in the corresponding construction stage. If more than one story is erected in a single stage, specify the highest floor erected in the stage.

Starting Story for Dead Load

Assign the floor on which the Construction Dead Load Case applies in the corresponding construction stage.

The Start story represents the lowest floor among the floors that are newly constructed in the corresponding stage. The next higher story from the story specified in the End field of the immediately preceding construction stage is automatically defined.

End Story for Dead Load

Select the highest story on which the construction dead loads begin to act in the corresponding stage.

Stage Duration: Duration of the construction stage in days. All the stages are assigned the same duration, which can be modified in Define Construction Stage.

Member Age: Maturity of members in days. All the stages are assigned the same age, which can be modified in Define Construction Stage.

Note

The member age represents the number of days elapsed from the day of concrete casting to the removal of falsework and formwork, that is, until such time that the loads are actually imposed to the structure erected below. The start point of a construction stage does not necessarily begin at the time of concrete casting; in fact, the stage duration and member age are independent. A floor can be shored up for a prolonged duration exceeding the stage duration. The Stage Duration is accumulated in "real" time. The Member 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 Member Age is the maturity of the element groups at the start of the current stage being defined.

Note
midas Gen assumes floor diaphragms in Construction Stage Analysis as soon as the floor loads begin to act and activates the floor diaphragm groups defined by the user for each floor by the Story Diaphragm Group for Construction Stage function.

The floor load is applied by individual floors only. If partial floor areas are loaded at different timing, refine the data using the Define Construction Stage function.

Note

It is not necessary to assign the nodes, to which Diaphragm Disconnect has been applied, to Groups. Once the relevant nodes (story) are activated, Diaphragm Disconnect is automatically applied.

When the button is clicked

Erection Sequence List

Define the timing of applying construction dead loads in individual construction stages.

Step
Enter the construction stage numbers (sequential numbers).

Story for Dead Load
Define the story on which the Construction Dead Load is applied in the corresponding construction stage.

Stage Duration: Duration of the construction stage in days. All the stages are assigned the same duration, which can be modified in Define Construction Stage.

Member Age: Maturity of members in days. All the stages are assigned the same age, which can be modified in Define Construction Stage.

Note

The member age represents the number of days elapsed from the day of concrete casting to the removal of falsework and formwork, that is, until such time that the loads are actually imposed to the structure erected below. The start point of a construction stage does not necessarily begin at the time of concrete casting; in fact, the stage duration and member age are independent. A floor can be shored up for a prolonged duration exceeding the stage duration. The Stage Duration is accumulated in "real" time. The Member 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 Member Age is the maturity of the element groups at the start of the current stage being defined.

Model Selection for Each Step

Define the story being erected in each construction stage.

Type
In a construction stage being defined, select a method to define the incremental structure portion pertaining to the stage (ie, to create the elements).

Material Type: define by predefined material types

Material Name: define by predefined material names

Material
Specify the material representing the elements that will be erected on the corresponding story.

Story
Specify the story that will be erected in the corresponding construction stage. If more than one story is erected in a single stage, specify the highest floor in the stage.

Superimposed  Dead Load

Additional dead loads applied at specific timing and stories can be defined in addition to the main Construction Dead Loads. They may also be termed as a superimposed dead load such as floor finishes, mechanical items, ceilings, partitions, cladding, etc.

Load Case n
Define an additional dead load.

Starting Day: Time at which the additional load begins to act

Story: Story on which the additional load applies (specify the highest floor if more than one floor)

Delete all the contents entered in Construction Stage Wizard.

Invoke the dialog box of Automatic Generation to rapidly create the construction stages.

 Construction Stage
Enter the information necessary to automatically define the construction stages. Auto-generation may become handy when a regular pattern of erection is planned, or a preliminary study is required.

LoadCase: Construction Dead Load Case during erection

Story Incr: Number of stories erected in a construction stage

Stage Duration: Number of days for which the stage lasts

Member Age: Maturity of the members at the time of load application

Note
Please refer to the note above regarding Stage Duration and Member Age.

Superimposed Dead Load n
Additional dead loads applied at specific timing and stories can be defined in addition to the main Construction Dead Loads. They may also be termed as a superimposed dead load such as floor finishes, mechanical items, ceilings, partitions, cladding, etc.

LoadCase: Additional Construction Dead Load Case during erection

Story Incr.: Number of stories erected in a construction stage

Starting Day: Starting time (in "real Time") of applying the additional dead load

Day Incr.: Duration until which the additional load is applied to the subsequent story