When RSTAB has finished the calculation of the structure, you can open the LTB add-on module. First, you create at least one design case in the module for which you define the members and sets of members that you want to design. In addition, you determine the load cases or load combinations that are required for the design. 

Take advantage of the RSTAB graphic tools to select the members and sets of members easily. The materials and cross-sections used in RSTAB are already preset in the module but can always be modified and completed. Furthermore, LTB provides comprehensive libraries for the selection of materials and cross-sections. 

Moreover, LTB allows you to optimize cross-sections.

The specifications for the lateral torsional buckling design are defined separately for members and sets of members. The following parameters can be set:

Generally, LTB performs the analysis according to the equivalent member method described in DIN 18800, part 2. A separate dialog box allows you to define detailed settings for the design:

You can apply this method to determine the

This plastic-plastic method of calculation is only applicable for pinned supports with uniaxial bending together with a load introduction on the upper flange. If the requirements are not fulfilled, for example in case of biaxial bending, LTB displays an error message. Furthermore, it is possible to set the reduction factor k_M for the bending moments M_y to 1.0 by conservative assumption if a rotational restraint is available. 

It is possible to neglect non-designable internal forces to exclude them from the analysis if the quotient of design force and plastic capacity falls below a certain value. In this way, you can ignore for example a low moment about the minor axis to avoid applying the method for biaxial bending.

If you want to determine the factor used for the determination of the ideal elastic critical moment M_cr automatically, you can select one of the following options:

When comparing the moment distribution diagrams, you can take advantage of the library with more than 600 diagrams listed in tables.   

Subsequent to the design, LTB displays the results sorted by cross-sections, members, sets of members or x-locations in clearly arranged results tables. The result values in the tables are shown always together with the corresponding cross-section graphic. In the RSTAB analysis model, the values are highlighted by different colors. In this way, you can easily detect difficult or oversized structural components. The colors and values assigned can be modified.

Diagrams showing the result distribution on the member or set of members allow for a specific evaluation. It is also possible to represent every intermediate value.

The masses determined during the design are displayed by member as well as by set of member in the form of parts lists.

Finally, you can export all tables to MS Excel or OpenOffice.org Calc or in a CSV file without any problems. All specifications required for the export are defined in a special transfer menu.