I am trying to define a custom section in Tekla Structural Designer and I do not recognise some of the properties. What are they?
Tekla Structural Designer
QuestionI am trying to define a custom section in Tekla Structural Designer. There are some properties which I am not familiar with such as AL, K1w, nw etc. (highlighted in the screenshot below). Could you please advise how these values can be calculated by the user?
AnswerThese are all Section Properties.
The K and n factors come about from the SCI P202 publication “Steelwork Design Guide to BS5950-1:2000 Volume 1 Section Properties Member Capacities”. Refer to Section 3.2.6 Plastic modulus (S) for the formulae used to calculate the values. They can also be found in the interactive Blue book here
The same approach to British Standards for combined bending and axial loads is used for Eurocode steel design, since this reduced plastic moduli approach is a generic method applicable to any design code. Hence the K and n factors are also listed in the European section properties database, since they are required if you add sections to the database. You can calculate these values using the formulas in SCI P202.
The AL and AG properties are Surface area properties per metre and per tonne respectively. These are listed in the Properties tables in the above document.
The Az and Ay references towards the bottom (below the K and n factors), are the shear areas of the section. These are required to deal with shear deformations in beams.