This article explains the way FAGUS determines the lever arm (z) of a shear wall included inside a shear-torsion model (V-T) which must be introduced in FAGUS.
The lever arm of a shear wall z is defined as, in the case of a vertical shear wall, the distance between the compression and the tension chord in a section.
In the usual case of a section under simple bending, the Eurocode indicates that z can be considered 0.9d as shown in the following:
When a shear wall is created using FAGUS interface, the program determines the value of z from the its geometry, that is, from the defined drawing. It is not possible to ask the program to manually adjust the value of z, making the inverse process, that is, introducing a value of z so that the figure is redrawn.
This is due to the complexity of manually defining the value of z in a generic section where there would be many shear walls, which can take part in the shear Vy, Vz and torsion mechanisms. Also every one of those shear walls, depending on their z, will have a compressed rod efficiency (effc).
All in all, the way FAGUS work facilitates the work involved in defining the shear walls on an shear-torsion calculation model (V-T).