Tuesday, January 19, 2010


Happy New Year! Gosh, I missed giving you all the traditional Holiday wishes and now we’re already halfway through the first month of the year. By now we’ve all made our resolutions and some have already committed to losing weight and getting in shape (yeah rrrright!). So I’ll try redeeming myself by posting about stairs and discuss how I used them recently on a project, and what issues I encountered.

As many others I am now working on billable projects. I love working on projects by the way, but it’s hard to juggle both roles of giving Revit support and being responsible for project delivery, deadlines, etc., especially on projects with tight schedules and low manpower. It’s becoming more common to be asked to do more with less, right? So now a little bit about the project: it was an addition & renovation of a High School stadium which included a new Press Box and ticket booth; an expansion of the Visitor grand stand, toilet facilities and ticket booth; upgrading the existing field-house and building another one; a new 2 story AD’s office and staff development facility; and plenty of site-work, miscellaneous projects and fencing upgrades. Over the next series of posts I plan on posting some tips & tricks learned with regards to sweeps in walls and share the techniques used to do phased site work (existing, demo and new construction). Today I’ll be concentrating on the grandstand structure.

Section When I got started in August, I needed to model the existing concrete structure and decided to try the stair tool for the precast bleachers. I wanted to push the tool to see if I could get the required representation. Here’s a snippet of a structural section drawing. Do you think it’s possible to model this with stairs?

I didn’t think it was, but after playing around a little bit with the Nosing Profile, I was able to get the desired result.

Bleacher section composite

One of the positives of this approach is that now you have a host for your railings, which makes adding intermediate rails and guardrails quick and easy. Using railings, it is also very easy to add steps between the bleacher rows. How? Make steps as balusters and create a railing definition with balusters only, at the correct spacing. You can also extend this idea to the seating but I decided to stick with line-based families in my case (not shown below).

Step railings

Openings One of the problems I ran into is when having to insert openings, such as Vomitory exits (I hate that term!). I was forced to split the grandstands into multiple stair sections. It would be great if the shaft tool was able to cut through stairs.

You probably want to see the stand as a continuous structure in plan, but dividing into multiple stairs results in lines between these segments which you probably don’t want to see. You have to use the linework tool to set these lines to <invisible> in multiple plan views, which can get a bit tedious.

Missing Steps Plan representations work quite well. You have subcategory control of steps above the cut line, making them easy to turn off. The only issue I noticed with the step railing mentioned above is that depending on where the cutplane was set, the step before the cut line disappeared even though it should have been visible.

Fine-tuning the view’s cutplane made this issue less evident. The other problem I ran into was when setting up a reflected ceiling plan of the underside of the press-box. By default, Revit does not represent steps in RCP views and the user cannot control this. My workaround was to overlay a correctly oriented 3D view with only stairs showing over an RCP view in a sheet. Use the section box to crop out elements so your view matches the view range of the RCP.


Note that the raker beams that support the bleachers were built with a custom Structural Framing family to obtain the required representation. Overall, stairs have worked quite well for this particular condition and I wouldn’t hesitate to use them again in the future. Do you have other tips and suggestions? Did you find better ways to solve similar conditions? Feel free to comment on this post!



Greg said...

How did you deal with the parabolic nature of seating bowls? With the riser constantly changing every couple of rows you'd have to have a series of stair objects right?

Dave Baldacchino said...

Greg, this approach is only valid for a simple stand with a single slope. For what you're describing, you have to create custom families.

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