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Hollow Core Middle Recess

Last updated October 6, 2016 by Area Finland Service tekla.support.fi@trimble.com

Software version: 

Hollow Core Middle Recess


This extension allows the user to create recesses in hollow core slabs by adding cuts and extra beams to the hollow core slabplate that represents a concrete structure

In Tekla Structures, a slab is created by picking three or more points.

Slab may be part of a floor, for example.


1. Purpose and description
2. Using Hollow Core Middle Recess
3. Additional information

1. Purpose and description

The extension is designed to work with hollow core slabs created out of Tekla Structures ‘beams’ or hollow core slabs created with Tekla ‘components’. This extension will create auxiliary beams, cuts, and fittings in order to create the recesses and cross beams.

2. Using Hollow Core Middle Recess

The extension can be created from the Component catalogcatalog that contains all system components and custom components, and the macros and applications

The term component catalog is used in Tekla Structures until version 21.1.

. The extension name is “Hollow Core Middle Recess”.

After starting the extension:
    1. Select a hollow core slab part or component.
    2. Pick a point in the beginning of the recess
    3. Pick a point in the end of the recess

If 1st or 2nd picked point distance to the slab end is smaller than 400mm the cross beam will not be created and the recess is created until the edge of the slab.
In the figure above, on the left, the distance from the recess start to the slab end is bigger than 400mm. On the right, the cross beam is omitted and the recess is inserted until the end of the slab because the distance from the recess end to the slab end is smaller than 400mm.

In the figure above on the left one can see how a hollow core slab with half width recess is created when the hollow core slab has an odd number of hollows. On the right is the method used when the hollow core slab has an even number of holes.

When user picks the dimension type to be automatic the tool will automatically choose the “Recess Depth”, “Offset from Recess to Slab Bottom”, and “Cross Beam Width” based on the picked hollow core slab height. See default values in the table shown below.
Note that the “Recess Depth” is different than the “Groove Depth” in the electric/sewer groove components.

Height [mm] Recess Depth [mm] Offset from Recess to Slab Bottom [mm] Cross Beam Width [mm]
265 90 15 250
320 120 15 300
370 170 15 350

3. Additional information

The parts created by this extension have the same assembly prefix/start numberfirst number of a numbering series

, cast unit typeproperty of a concrete part in a cast unit that defines if the structure type of the part is precast or cast in place

, material, and part prefix/start number as the picked hollow core slab. Classpart property that groups parts according to identifiers given by the user

The identifiers of classes are usually numbers. Classes can be used for defining the color of parts in the model, for example. Class does not influence the numbering of model objects.

is the same as the picked hollow core slab class if user leaves the class fields empty in the user interface.

Recess length is always bigger or equal to 400mm. If user choses a smaller length the tool uses sets the recess length to 400mm.

Note that existing part cuts, line cuts and fittings attached to the selected hollow core slab will affect the extension modelled parts. E.g. If there is an existing part cutcut that is defined by a cutting part

in the location where the recess is to be created that same part cut will be used to cut the recess.

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