Hollow Core Definitions
To be able to draw Hollow Cores, one need to create definitions to use.
Preparation
Before starting to create the definition in IMPACT, one needs to prepare the section, cores, and strands. This is usually done by using the Hollow Core sections provided by the manufacturer of the production lines.
Start with copy the section to an empty IMPACT Drawing. Before doing anything, it is good to use AutoCAD command Explode on the section. This prevents different problems when defining the section.
The next step is to join the lines into polylines. This can be done with AutoCAD command Boundary, as can be seen in Figure 1 below. The command will create one polyline for each set of lines that are somehow "closed". For a Hollow Core, the section and cores will convert to polylines.
Figure 1: Converting the section into polylines with AutoCAD command Boundary
The next step is to make sure that there are no lines hidden under the newly created polylines.
Figure 2: make sure that there are no lines hidden under the newly created polylines
The last step in the preparation is to change the symbols for the strands into blocks used by IMPACT. This is because IMPACT will read the name of the blocks for the strands. The blocks that will be used can be found in the Standard folder \Standard\1100\1100\templates_drawings. The name of the blocks is _uStrandSymbol.
Figure 3: _uStrandSymbol
Figure 4: Replace strand symbols
Define Hollow Core
Start with launching the command Hollow Core Definitions.
Figure 5: Hollow Core Definitions
Create a new definition at any level.
Figure 6: Create a new Hollow Core definition
The next step is to use the prepared section to create the definition. To get the information, use the functionality Select Objects.
Figure 7: Getting the geometry, cores and strand positions with Select objects
When using this functionality, one will get two questions:
- Get cores from the section?
- Get strand positions from the section?
If answering "Yes" to these questions, one will get all the required information for the definition. If answering "No", one needs to specify this information manually in the Cores and Strands tabs.
Fígure 8: Hollow Core Definition General tab
- Section preview
- Height
- Width (incl. tol.) - actual element width plus the tolerance
- Tolerance - the distance between the actual element and the element boundary
- Diff. bottom top
- Endcap - default endcap for the definition
- Material
- Production line
- Section geometry - geometry of the hollow core section
Under the Cores tab, one can add information about the cores. Since answering "Yes" when selection the objects above, this information is already specified.
Fígure 9: Hollow Core Definition Cores tab
Under Cutting tab, one can specify preferred zones for cutting the section. If the user will specify the width of an element manually so that the cut will be placed outside the preferred zones for cutting, IMPACT will warn the user that the cut will be outside the cutting zone.
To define the zones, one can either draw some rectangles over the section and use those as help for defining the zones "Select Cut Zones" (see Figure 10), or specify the positions in the dialog (see Figure 11 point 13).
Figure 10: Select cut zones
Fígure 11: Hollow Core Definition Cutting tab
- Section preview - the green rectangles show the preferred cutting zones
- Cutting method -
- Use nearest cut zone when cutting elements -
- Preferred zones for cutting section
Fígure 12: Hollow Core Definition Strands tab
- Strand groups - different groups for different strands
- Strand positions - added manually or automatically by using Select Strands in the section preview area
Fígure 13: Hollow Core Definition Strandpatterns tab
- Strandpatterns - one definition can have several strand patterns. Here the user adds a new strand pattern and specifies which strands that should be included by thickening the boxes in Strand positions (18 in Figure 13). Here one can also specify which strandpattern that should be the default one
- Strand group properties - diameter, steel quality and prestress value for the different Strand groups
- Strand Positions - select which strands that should be included in a strand group by thickening the boxes for each strand. The strands that are selected will be shown as green in the section preview
Fígure 14: Hollow Core Definition Lifting tab
- Add lift - if the lifts should be added always or manually
- Rotation - if the lifts should be rotated
- Min width four lift points
- Default type - which default lift type should be used. Lift type is basically a category of lift. In this example Lift type is different lifting angles
- Number of lifting points
- Lift set up - here, one will specify all the possible lifts for the definition depending on mass and lift type
- Placing long side
- Placing short side
- Visibility - if and on what drawings the core fillings should be visible on
- Dimension
- Length - the length of the core filling
- Cores - which cores the filling should be added to
Fígure 15: Hollow Core Definition Drawing tab
- Presentation - either geometry or symbol
- Scale - of the section on the shop drawing
- Dimension strand groups
- Text strand group properties
Fígure 16: Hollow Core Definition Naming tab
- Group - possibility to subcategorize elements of one element type
- Product
- Prefix designation
- Prefix element mark
- Prefix drawing name
- Drawing type
- Drawing template - default template that should be used
The Calculations tab is used for calculating slabs in floor plans.
Fígure 17: Hollow Core Definition Calculations tab
For Hollow Cores, there are two types of connections that can be predefined for the Hollow Core definition. The first one is Connection Recess and the other one is Connection Recess Edge.
Connection Recess will go through the whole element.
Fígure 18: Hollow Core Definition Recess tab
Connection Recess edge will be placed on one edge only.
Fígure 19: Hollow Core Definition Recess edge tab
Recess edge can have two different types
- Rectangular and circular
- Rectangular - the circular hole on the top will not be added
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