Make a beam with several different cross sections

In contrast to other beam types (e.g. SIB, STT, RBX) the CUSTOM beam type is defined by a dynamic number of segments. Each segment has a name, a length, a section definition, and a section alignment definition. Just like other beam types the CUSTOM beam is available in the selector for 'Beam type'.

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To define the specifics for the CUSTOM beam press the Configure button. A new beam has no segments defined and the configurations window is thus empty to start with.

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Below the first list frame ("Segments") buttons for working with the list is placed. The "Add" button opens the "Segment properties" window with some default values preselected.

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Here the name, length and section definition is entered. The CUSTOM beam supports several cross section types as seen here. Different amounts of section parameters needs to be entered depending on type of section. As an alternative to manual input of section parameters, the internal section database in PRE-Stress is available via the "Import from database" button. Once the OK button is pressed the segment is added to the list in the main configuration window.

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With segments defined, visual feedback in 3D is shown in the bottom frame of the configure window. 

The "Remove" button below the segment list will remove the selected segment.

The beam segments are defined from start of the CUSTOM beam towards its end, meaning the segment at the top of the list is the first segment of the beam and the segment at the bottom of list is the last segment of the beam. The "Move up" and "Move down" buttons moves the selected segment up and down the list (i.e. towards the start of the beam or towards the end of the beam). The total length of the CUSTOM beam is the sum of all segment lengths.

In the "Segment properties" frame there are two buttons; "Edit segment" and "Edit alignment".

The "Edit segment" opens the same window as the "Add" button but shows (and allows editing of) the selected segment.

All sections are defined as having their bottom side on the same level along all segments.

However, each segment can be moved sideways as to define where each segments section interconnect, this is defined in the "Segment alignment" window.

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The section corners and "mid side points" are highlighted as possible alignment references. When a possible reference point is selected a red dotted line is drawn. Imagine the global center for the CUSTOM beam across all segments, the red dotted line represents where that center will connect to the current segment. Each segment will be translated sideways in such a way that their red dotted line aligns along the entire beam.

Should the predetermined reference points not be enough to adequately describe the local reference point, additional translation for the red dotted line can be defined just below the figure. The additional translation can be defined directly in the text box or by the "<<", "<", ">", ">>" buttons. The effects of the individual alignment settings can best be checked in the bottom frame of the main configuration window.

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NOTE: Should you open the CUSTOM configuration window for changing some detail, the OK button does not save the changes to the PRE-Stress input until you press the "Change" button for the entire element.

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J
Joakim is the author of this solution article.

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