Tekla Open API, Rebar Numbers

Many concrete design firms will provide a rebar bending schedule along with their detailing plans, similar to the one below:

As you can see columns L and F display the bar number. The bar number is a unique number assigned to a set of rebars with the following properties:

  • The same length
  • Start and end hooks are the same
  • The same size

The bending schedule is then used to determine how many rebars of each type (same size, endhooks, length, …) is needed, and will greatly assist the onsite engineers.

The bar numbers are also displayed on the detailing plans. Often inside a square or circle:
Although some may argue that you can create bending schedules using the tekla report generator, but I would have to disagree, due to the fact that the template editor does not give you the CLL (Center Line Length):
LENGTH-Length, LENGTH-GROSS, LENGTH-MAX and LENGTH-MIN as not the CLL (center line length) of the rebar. and therefore without knowing the length there is no way the report tool would know how to group the similar rebars.

Also using the report generator will not provide us with any tools to add the rebar number to the drawings.

In order to overcome these problem a program was written using the Tekla Open API in VB.Net. The main interface of the program can bee seen below:
The user specifies 2 elevations (Top and Bottom), and a series of classes. The program loops through all the rebars in the model. If the rebar centroid is located between the 2 elevations specified by the Top and Bottom parameters and the class matches one of those specified by the list of classes it will be numbered.

The rebar number is then stored inside the “Rebar Sequence Number” attribute of the rebar. The advantage of having the rebar number inside one of its attributes is:

  • It can later be used in the report generator to create a bending schedule report.
  • It can be used by another program.
  • It can be used in the drawing layout to automatically display the rebar numbers in the drawing (without any further input by the user)


If you need assistance with your Tekla model, or you are looking for a Tekla Open API programmer to hire feel free to contact me. Also please visit my home page  www.software-solutions-online.com

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