One of the great difficulties we encounter with “classic” plan delineation methodologies are ramp and stair projections. It has always been difficult to avoid calculating the ramp’s slope, as well as the dimensions of the footprint and riser of the communication staircase between two floors of a building. Do they comply with current regulations in my country? Do they adapt to the project standards? Will they be accurately calculated?
Thanks to great advances in project modeling using BIM methodology and Revit software, these calculations can be made with greater ease. However, these elements will probably be an aspect of modeling that will bring us the most difficulties in the project phase.
In the particular case of ramps, there are two clear ways to model them: by sections and by contour.
The first of the two options –by section– turns out to be the simplest and most standard method. This process joins two levels by means of a curved or straight ramp, simply marking its route. The big difference between this ramp and contour-modeled ramps is that the route of the non-contour ramps will always have the same section, and in the second option, we can vary the section during its route.
When it comes to modeling ramps, we will only have to place two parameters: the width of the ramp and the height of the levels that we will have to join. As in so many other elements in Revit, we can duplicate a type of ramp and create as many as needed for our project. The only drawback is that the ramps can’t have more than one material, so to create ramps with several materials, we will have to create sloping floors or superimpose several ramps on top of each other with as many materials as our ramps have.
In the case of stairs, as we have mentioned previously, we have to bear in mind that stairs are the most complex elements of Revit. As in the ramps, we can model them by sections and/or contour, the difference being exactly the same as that described in the previous section.
However, Revit offers us three types of predefined stairs: "spiral through center and endpoints", "L-offset" and "U-offset" stair. The first one is commonly known as a spiral staircase, that is, a curved staircase in which we will have to indicate the radius of the staircase, as well as the entry and exit points of the staircase. The second, offset "L" step in an L-shaped stair; but with a different angle, offset steps are applied diagonally instead of placing the classic landing. Finally, we could define the stair with a U-offset rung as a stair exactly the same as the previous one, but with more than two sections, so the rung compensation will occur in all section changes.
When we model a stair in Revit, apart from parameterizing the levels that will have to be joined by the stair, we will also have to detail parameters such as: maximum tread height, riser depth, minimum section width, type of landing, type span, support, etc. In conclusion, we need to have a fairly close idea of the stair we want to create before modeling it in Revit; it needs to be pre-designed.
Pay attention to the stairs and separating them from the landings; this distinction is one of the most advanced parts since, in the case of stairs modeled by section, the separations are made automatically.
Finally, in both the case of stairs and ramps, Revit models the railings automatically at the moment our element in question is validated. We can also duplicate and modify these railings, but we will address that idea in a future article.
Check out a 6 minute tutorial for creating ramps and stairs in Autodesk Revit:
If you want to delve deeper into stairs, ramps, and other Revit tools, enroll in the GoPillar Academy complete course of Revit BIM.