In Tekla Structures 2024, we have completely renewed the way how rebar set bars are generated for non-linear geometries. With the new method, the bars follow the underlying concrete geometry much better and bars that are not valid are less likely to occur.

The previous bar generation method did not always work with complex geometries and it might produce invalid bars or incorrect bar geometries.

To address these issues, we now also introduce a user control for the generation accuracy, to ensure valid bar geometry generation. The new Smoothing factor user-defined attribute (UDA) is available for rebar sets on the Rebar set UDA tab. This setting is useful when leg surfaces in complex geometry parts do not produce the desired bar geometry. There might be too short consecutive, zigzagging bar segments, or in some cases bars might not follow the concrete surface closely enough.

Smoothing factor is a percentage of the overall leg length, so a value between 0 and 100. If a leg segment is shorter than this percentage of the overall leg length, it is eliminated. The default value is 0.1. To eliminate the leg segments causing a zigzag effect, increase the value. To make the bars follow the concrete surface more closely, decrease the value.

The Extra point shortening attribute, on the Shape recognition tab of the rebar UDA dialog box, is now also used in rebar set bar generation to determine whether two bar legs are sufficiently collinear, for a given Extra point shortening tolerance, that they can be considered as one. If no Extra point shortening value is specified, the value is given by the advanced option XS_REBAR_RECOGNITION_EXTRA_POINT_SHORTENING, which has a default value of 0.3. Typical Extra point shortening values are between 0.3 and 2.56.

The advanced option XS_REBAR_GEOMETRY_TYPE_IN_NUMBERING was introduced in Tekla Structures 2023 SP1. You can use it to specify how the geometry of reinforcing bars is taken into account in numbering and which type of bar geometry is used when bars are compared with each other. Now, in Tekla Structures 2024, the default value of this advanced option has been changed from POLYLINE to FABRICATION.

Using the FABRICATION option means that, in addition to converting segmented arcs in reinforcing bars to true arcs (= the RATIONALIZED option), Tekla Structures uses Maximum curve radius requiring bending to treat certain arcs as straight legs in numbering. Also bars that have the Recognize as straight bar UDA set to Yes are treated as straight bars in numbering.

For example, top face bars of a sloping drainage slab are often small diameter bars that can be treated and delivered as straight bars.

The selected geometry type, for example FABRICATION, is also used when cast units are numbered and their reinforcing bars are compared.

The algorithm for calculating the parent part of bars in a rebar set has been modified because previously in certain cases the wrong part was chosen. The change is in the definition of a vertical bar.

A bar is now considered horizontal if its overall horizontal extent H is longer than or equal to its overall vertical extent V multiplied by the default factor of 2. Otherwise the bar is considered vertical.

(1) = horizontal bar, (2) = vertical bar

In general, a bar in a rebar set is considered horizontal if:

H ≥ XS_REBAR_VERTICAL_FACTOR * V

For more information about adjusting the default factor, see XS_REBAR_VERTICAL_FACTOR in Tekla User Assistance and in Changes in advanced options.

The reinforcing bar end specific UDAs, which are used with couplers and end anchors, are now controlled with the new advanced option XS_REBAR_END_SPECIFIC_UDA_METHOD. If you use the default value START_AND_END, start leg and end leg UDAs are created, for example, METHOD_START. If you set the advanced option to SHORT_AND_LONG, short leg and long leg UDAs are created, for example, THREADED_LENGTH_L.

See also Changes in advanced options and Administrator's release notes: Reinforcement improvements.

• The length of spiral bars is now calculated and reported correctly.

• The number of rounds and the length of spiral bars are now displayed correctly in the Inquire object dialog box.

• The rounding of Number of rounds is done accurately for spiral bars.

• The new Number of rounds box is now displayed for spiral bars in the property pane instead of the Number of reinforcing bars box.

  With Number of rounds, the Exclude options are no longer available for spiral bars.

• The new template attribute ROUNDS can be used to show the number of rounds for a spiral bar wherever the number of rounds is needed, for example, in report templates and in reinforcement marks in drawings. The ROUNDS attribute shows a decimal value, since the number of rounds is not always a whole number. The same value is also shown in the Inquire object dialog box.

• The maximum number of bars in a reinforcing bar group or in a reinforcement mesh has been increased from 1000 to 10000.

• Previously, in some cases, a rebar set splitter might change the side of lapping or cranking in the middle of a splice.

  

  This happened, for example, if the splitter was at the edge of a round hole in a vertical face. This has now been improved, and the lapping or cranking side is consistent.

• Rebar shape manager now uses the new bar geometry type FABRICATION. Previously it used the non-simplified polyline bar geometry, which might have led to inconsistencies between Rebar shape manager and reporting.

• The RebarShapeRules.xml file has been updated, and the rebar shapes with arcs in them, such as shapes 34 and 49, are now excluded from the rebar shape catalog and rebar shape placing tool.

• Rebar shape recognition was improved in Tekla Structures 2023 SP4.

  Rebar shape recognition now also finds arcs from reinforcing bars that have irregular point geometry. Previously, rebar shape recognition only tried to find arc geometry if the bar geometry points were at a regular distance from each other with a regular angle between them.

• Spacing properties are now available for circular and curved rebar groups in the Custom component browser, and they can be linked with parametric variables.

  

  This improvement was already introduced in Tekla Structures 2023 SP6.