Slab design and analysis can be a complicated task for designers and engineers, specially if the slab needs to have openings and cuts so they need to use simplified methods to address these kinds of projects. Nevertheless, the more complicated the models the less effective are these methods, especially for the slabs with large opening or cuts. Clause 13.10.10 of A23.3-19 provides instructions to design slabs with these constraints, although this may be time consuming and less economized compared to a FEM calculation.
Therefore, FEM solutions are used to remedy the situation. In this article we will discuss and provide the best solutions for engineers to design and generate reinforcement specially for slabs with openings.
With the help of Graitec software Advance Design and Power Pack for Revit, we will model the following project:
The figure above illustrates a slab element with multiple columns and one opening, position and size of the opening are randomly assigned. We have used refined mesh to generate more accurate results specially in stress concentration points. Figure bellow shows the displacement of the model:
Advance Design then calculates the required reinforcement area to assure the resistance of the element under all governing forces, the user can define the design standard, in this model CSA A23.3-19 is used:
We have then the possibility to generate rebars using the concrete design module. Reinforcing bars are generated automatically based on the FEM results and openings are considered in the process, figure bellow illustrates the result obtained:
Using the BIM export tool of Advance Design, we export the model including the results to REVIT. Then we open the same model in Revit and generate reinforcement details for the slab in REVIT using the Graitec Power Pack for REVIT and analytical rebar areas imported from Advance Design.
FEM results are imported and along with required reinforcements additional rebars can be generated using the power pack detailing:
Diagonal and Edge rebars are created for both top and bottom layers. Using a simplified and user-friendly interface detailed drawings are obtained in few steps.
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