# Can I use custom section properties in Tedds Library Steel Design calculations?

## Question

**I have calculated some steel custom section properties using the Compound Sections or Sections Properties calculator, can I import these into a Tedds library steel design calculation?**

## Answer

In general the answer is that this is not possible. Tedds library calculations do not have a section properties import option. In addition, the Section Properties tool does not calculate some properties required for steel design, such as torsional constant or warping constant. However there is some limited support for using custom section properties in some calculations as detailed below.

### 2D/Member Analysis & Design Calculation

The 2D/Member Analysis & Design Calculations have an option to directly edit the section properties via the "**Custom...**" button when assigning/ editing a section as shown in the picture below. However users should carefully note the warning giving in the properties dialog when doing this (highlighted in the picture below) and also note that this does not change the assumptions of the calculation regarding the section shape. E.g. if you edit the properties of a square hollow section, the calculation still assumes the section is this shape.

### Other Calculations

In general, all steel design calculations are based on the design rules (from design guides and codes) for specific section shapes (e.g. I, H, RHS, T) that have certain inherent assumptions, for example equal flanges and fixed classification formulae.

It is not possible to directly edit the Tedds automated design calculations to change such fundamental assumptions.

However, for some calculations you can access the "**Components**" set***** from the Library index (in Tedds for Word only). You can execute to a document the checks that you wish to make for your section, then customise these to suit your section shape and engineering assumptions. You will need to ensure you have all the required section properties for your section such as warping constant if required by the checks.

This is not an exercise we would recommend if you are not already fairly familiar with writing Tedds calculations. For more on this see the article Is there a way to edit or enhance a Tedds Library calculation?

Note that this is approach of editing components is not possible with more recent and sophisticated calculations such as the Steel Member Design calculation.

*****If you do not see the "Components" option in the Library Index, click the View menu option in the Library Access System and select "Advanced Menus" if this is listed (if "Simple Menus") is listed this means the Advanced Menus are active. With Advanced Menus active, turn on the "Show calculation components" button (third button from right).