No announcement yet.

Rebar Modeling

  • Filter
  • Time
  • Show
Clear All
new posts

    Rebar Modeling

    What kind of benifits could one expect modeling all the rebar in a project?

    What negative would one expect when modeling all the rebar in a project?
    -Alex Cunningham

    From My experience,

    Generally Sections are dead easy to cut if the Reo is already in, and you have tags to call it out where needed.
    You can schedule the reinforcement (however that is not done in house so it is not required)
    You can do 3D details to respond to RFI's quickly.

    File Size becomes very large, very fast.
    Working with some of the tools is (was) painful.
    Major changes to the project tend to hurt alot more if there is alot of reinf. (thou REX has helped in that regard a little)

    I'll Caveat this post by saying I fully reinforced 1 project early on (RST2009) and whilst the Pros were good, the whole experience was spoiled by major alterations to the project that ment a section of the building was in effect just cut off. this resulted in shifting of slab edges, beams, and columns and the reinforcement tended not to follow the changes as I expected. I do have a very small project comming up that I may Reinforce fully to see how things go as 2D detailing is a PITA in this office due to users attitudes towards Revit. More recent experience on 10/11/12 may well be different.

    Being able to have families that contain reinforcement would be of an advantange and I really need to get up to speed with current opinions on nesting families in this regard.



      I totally agree that not having rebar nest in families is a major pain and could result in un-bim models. For instance, let's assume you have 30 24"x24" columns I'm a project. There are 4 different reinforcement patterns in those columns. To document that, you add text parameters to the column family and create 4 geometrically identical types with different reinforcement text. You could even go so far as to nest a 2d component for showing the rebar. But the second you model the rebar, you will realize there is no association between the column type parameters and the rebar hosted inside the column. You could easily document one rebar condition and model another.

      I don't know that nested rebar is the answer, though it would make life easy. But there needs to be a way to associate rebar to parameters in it's host and tie the two together in such a way as to allow scheduling and consistency between the model and the documentation.


        I don't think the ablity to place rebar in families will come any time soon since you can never bring systems families (such as rebar) into families. Now we have no issues with being BIM and using Rebar but we actually model nearly 95% of all the bar in the project which includes every column individually, strip footings, spread footings...etc. It is very BIM and much mroe so than even just using parameters to tell how much is in a paticular column.


          I agree that modeling the rebar is very bim, but how do you call out the reinforcement that is in a particular footing, column, or beam on construction documents? Do you tag the rebar separate from the host on each instance? Do you use footing schedules? If so, does your footing schedule only call out geometry and not reinforcement? Same for beams- I assume you tag beams that refer to a schedule of some sort or a detail. How can you ensure that the reinforcement shown in a particular detail or schedule remain consistent for all items with that same detail? If the rebar ( size and number of bars) is not associated with the host parameters at all, what is keeping the documentation consistent with the model? The only way I know that you could achieve this is by modeling and tagging all the rebar (each instance) like a shop drawing and don't do typical detailing and scheduling on the construction documents.

          If you have two footings, 6ft x 6ft x 18in, with different rebar sizes (one has #5 bars and one has #6 bars), how do you model that? Do you use the same footing family? Or do you duplicate it and create a unique tag for each one? How do you document the differing rebat sets in these two footings? It cannot be in a schedule since rebar doesn't schedule.

          I can see how this works on the construction side and would be very BIM, because you are working with final documents. On the engineering side, we are constantly changing the rebar and host sizes in response to changes made by the architects. Part of the beauty of revit is the propagation of changes throughout a project. Rebar doesn't seem to work that way (unless you were to group each set of identical rebar so that a change in one footing's rebar set propagated to all identical rebar sets hosted I'm all the same type of footing).


            Right now our method is not as BIM as I would like...we have our construction documents that use note, text, detail lines, etc and then our construction services team models all the bars and has their own set with tags for each instance.

            A pad footing like the 6x6x18 would be a Type 6 and a Type6A for the different reinforcing.

            Changes are our biggest burden with modeling is best to use TONS of groups they provied a nice safety net for changes. We do have to go in and change everything if changes are issue, but most of the contractors we work for see this being benificial.


              You do exactly the same thing I do, except that I'm just doing engineering and not working for contractors. Hopefully we'll get nested rebar in the future. ( I have done it with generic model with a subcategory called rebar ). Just have to get rid of the pesky system family.


                Originally posted by Alex Cunningham View Post
                What kind of benifits could one expect modeling all the rebar in a project?

                What negative would one expect when modeling all the rebar in a project?
                My 2 cts:

                positive: accurate QTO, detailing rebars and shop drawings ONLY in Revit and faster than in cad world (cut views), clash detection for huge diameters, connection between Robot and RST

                negative: none, if ALL the positive points are possible in RST one day, which is not the case today

                PS: dear Factory, I'm sure you know how should be a tool for rebar detailing and shop drawings, at least you know how works ASD (which is not the best in the World IMHO).
                So stop selling ASD with RST, make them have a child.....RST 2013?
                "Au royaume des aveugles, les borgnes sont mal vus!"
                P. DAC
                Follow me on Twitter @Jbenoit44 - Blog:


                  Originally posted by jbenoit44 View Post
                  So stop selling ASD with RST, make them have a child.....RST 2013?
                  Nice call Julien
                  Alex Fugère
                  technologue en génie civil
                  Douglas Consultants inc.


                    One step further would be to make the Revit and ASD link work better. The reinforcing options in Revit extensions is nice, but it is quite unstable. Also the export to ASD doesn't provide very good results.
                    Revit Architecture 2013 Certified Professional


                    Related Topics