How does the structural model work?
The model we build inside SCIA Engineer and use for calculation is called an analytical model. This is a simplified representation of the reality, where beams are approximated by 1D lines. Local details, like for example how the beams get cut off at the height of the column, get neglected in this calculation model. For some purposes however, for example the modelling of steel connections, it is necessary to know these details. This is why a second type of model exists inside SCIA Engineer: the structural model. In this model, beams are 3D elements and their connections are displayed as they would be in reality:
The structural model has three main functions:
- Needed for the modelling of connections
- IFC files will export the structural model and not the analytical model
- Proper display for realistic 3D images
To display the structural model, the functionality needs to be activated in the project data. It will also be automatically activated when steel connections are selected. Next go to View > Set view parameters > Generate structural model:
Once the structural model is generated, you can switch between both models through View > Set view parameters or in the ‘Set view parameters for all’ menu under the structure tab:
The decision off which member should be continued and which member should be cut is made based on the priorities of the elements. The element with the lowest priority gets cut. If elements have the same priority they both get cut at the point where they cross.
By default the priority of an element is the value displayed between brackets after the element type (see red rectangle). This can be overwritten under Structural model by choosing ‘defined manually’ for the priority definition (green rectangle).
In the purple rectangle eccentricities can be entered specifically for the structural model. The eccentricities for the structural model and for the analytical model are defined separately and are not linked. This allows to display an eccentricity in your structural model, that is not accounted for in the calculation.