Building a multi story spiral parking ramp in Autodesk Architectural Desktop 2006.

After using Autodesk^® Revit^® Building 8 to construct a spiral-parking ramp by using ramp object, I decided to try my luck and push the spiral stair generator in Autodesk^® Architectural Desktop in the same direction. This time I have taken a slightly different approach and instead of using a profile definition for the railing object. I have used the ramp object in Autodesk Architectural Desktop in order to see how well the Spiral Ramp can be created.  These are the steps that need to be taken in order to create the resulting image above.

The first step is to define a spiral ramp style through the Stair Style Manager that can be invoked through the AecStairStyle command. Go ahead and create a new style and name it Spiral Ramp.

To define the geometry for a code compliant parking garage ramp the slope of 12% has been designated through the Design Rules section of the Stair Style dialogue.



The 1” riser is designated as a default one because it gives the best overall flexibility if the intention is to create a landing at the end of each run.

The next step is to determine which set of objects will represent the actual ramp slope and set of guard walls, and to do that the following adjustment has to be made to the set of stringers used within the style;



The first stringer named Structure is a Ramp Type stringer that spans the entire width of the ramp and its overall thickness is set to be 5”, except in the landing area to ensure for a smooth transition from the sloped ramp element into the level landing element. Both 8” wide guard walls are of the Housed Type and they extend 36” above the ramp surface.

At the landing portion of the ramp the Left Guard Wall has been lowered to accommodate for the transition from the ramp to the adjacent slab. These settings require some creative number tweaking in order for the ramp to show correctly and the only part of this puzzle that refused to cooperate was the inability of every consecutive flight to make a sloped transition between the first, what used to be, a riser and the landing surface.

From the attached file you will be able to see that this really did not have too much of an impact on the final model.

When specifying the dimension for the landing it was necessary to express this dimension in multiples of the tread’s length, and therefore if we had decided to use an 8” tread as the nominal value to define the ramp’s slope, a landing length of n x 8” has to be chosen.



After these main geometry factors have been defined, we can proceed to create the spiral stair object from the Spiral Ramp style, and the following property settings have to be defined in order to avoid the omnipotent “no smoking” sign.



According to the above settings we have created a spiral-shape Stair Object that is oriented clockwise and has a height of 60’. In order to accommodate 5 full turns of a ramp within the 60’ height we need to turn 5 x 360o and terminate the each flight with a landing. For the calculation rule the Tread and Riser have been set to 8” and 1” respectively. In order to assure that a new landing will occur at every 12’ we had to impose the maximum height limit of 12’. And there it is.

Although stairs can be easily regarded as the most complicated of all Autodesk Architectural Desktop objects, the final result for this exercise exceeded my expectation. Not only was I able to produce what Revit Building 8 can do, but pushing this another notch and producing this Stair Object as a fully parametric multi level spanning Spiral Ramp shows the power of both Architectural Desktop and one’s patience.

The following illustrations represent both section and elevation views for the 2 story spanning spiral ramp and the plan view where the display representation for the Stair object is modified in order to represent the ramp object in the way the most construction documents are created. Please notice that the 0” distance for the cut plane break mark is actually set to be 0.01” and the 0” value is a product of rounding.





If you think that this short tutorial will help you in creating your spiral ramp, feel free to download the following file that is available on Hagerman’s web site.

Click to download Spiral ADT-2006-Spiral Ramp.dwg.