FAGUS allows the introduction of shear-torsion models (V-T) on the sections that are being analysed. Three different types of V-T models are defined: TYPE A, TYPE B and AUTOMATIC
- TYPE A MODEL
In this TYPE A model, FAGUS will distribute the shear and the torsion proportionally to the inertias of the shear walls that have been defined and it allows to indicate a weighing (s), equivalent to the stiffness of the spring in every one of the walls.
TYPE A model is the one suggested for box sections.
- TYPE B MODEL
In a TYPE B model the stress components acting on each wall and its weighing can be indicated. The torsion values will be a sum of rectangles. Distributions that are proportional to the shear wall areas.
In a TYPE B model, for each shear wall that is also under torsion, the program will create a small, internal torsion circuit.
On the numerical results output, the sum of all the Ak and the tef of each shear wall will be displayed, showing what part of the torsion and the shear it takes.
TYPE B model is the one suggested for T and double T section.
- AUTOMATIC MODEL
There are certain simplified sections for which an AUTOMATIC model can be implemented. With this model, the calculated values for the torsion will be the real ones, taken from the geometry of the section.
The AUTOMATIC model is especially suggested for circular and elliptical sections because the values of Ak, u and tef, necessary for the calculation of the torsion reinforcement and its efficiencies, are calculated exactly.
NOTE: If an analysis using the tangential shear flow is desired, the program will require the AUTOMATIC model to be selected.
In the special case of having one only shear wall, FAGUS will use it for every stress and it will generate an internal torsion mechanism.
Lastly, and to facilitate the understanding of the efficiencies that FAGUS obtains, it is briefly explained what the efficiencies on the results tables mean. In them the following will be shown: a efficiency (effc) of the compressed concrete rod (associated to the calculation of the value Vu1), a efficiency of the placed reinforcement (associated to the calculation of Vu2, , which will be 1.00 if we have dimensioned) and the maximum of both of these, on the eff column (V,T). Note that if we see the values of eff (V,T) in the table of FAGUS, we might think there is a mistake, because 0.79+0.25 is not equal to 1.00. In reality, as it is shown further down, the maximum shear and torsion efficiencies are being displayed, but in this case, the efficiency of 0.79 on the shear refers to steel, while the 0.25 on the torsion refers to concrete.