Steel Weight - A Conversation, Further Thought and Another Method

• A Conversation

Mike: "So, the Revit weight schedule calculates using volume?"


Me: "Yes"


Mike: "So when you put a service hole in a beam, it subtracts it from the volume?"


Me: "Yes"


Mike: "But when you buy steel, it doesn't come with holes in. Shouldn't the weight takeoff reflect this?"


Me: "Ahh... Good point"

• Further Thought

In order to overcome this, the weight can be calculated using kg/m multiplied by length. In my mind, this presents a couple of issues:

1. How to get a steel length from a column
2. How to make it multi-category, so it all appears on one schedule

Fortunately, our families all contain cross-sectional area figures 'A', calculated automatically by formula based on the parametrics of the profile. The kg/m value 'M' is calculated from this:

• Another Method

The solution to both problems is to introduce a new shared parameter, 'Section Length' to all the steelwork families. This is set to 'instance' and set as a reporting parameter. A dimension is then run from one end of the beam/column to the other and is set to this parameter. Because it is a reporting parameter, whatever length the beam/column is, its value is fed back to 'Section Length'. This can then be used to calculate the weight. The following video demonstrates this concept

Steel Weight - A Method and Some Thoughts

There are a lot of bit and pieces online regarding steel weights in Revit Structure. The aim of this post is to pull some of it together and to add my own thoughts. The video goes through the procedure for creating the schedule and the information below discusses the finer points

• Before You Start, Content is Critical

We abandoned the OOTB steel families early on and generated our own family content. This allowed us to take a much more holistic approach to the content. In the video example, there are 'Universal Beam' members of both 'Structural Column' and 'Structural Framing' Categories. These families are driven by identical parameters, profiles and most importantly, Type Catalogues. All our steelwork families contain two parameters, 'Section Type' and 'Section Name'. These are only ever used in Steel Families and they allow us to isolate steelwork in schedules. In the case of the example, the values of these two parameters are consistent in both 'Universal Beam' of 'Structural Column' and 'Structural Framing' categories. This allows us to consolidate all 'Universal Beam', regardless of family category, together in a multi-category schedule

• Some Points on Volume
  
  In the 'Material Take-Off' schedule, the parameter 'Material : Volume' is used to calculate the weight. The material parameters in Revit Structure are only available for the following family categories:
  

• Revit will calculate volume based on the medium level of visibility. Another reason we abandoned the OOTB families is that for all rolled sections, the root radii are omitted in the medium level of detail, so the weights were coming out incorrect. Hence our content shows a full profile for both medium and fine detail to get the correct volume.


• The calculated value in full is Volume multiplied by Density. The syntax is:
  (Material : Volume/1)*7.85
  
• The parameter 'Material : Volume' must be divided by 1 to neutralise m³ to a number to avoid an 'Inconsistent Units' error.
  
• 7.85g/cm³ is the metric density value of mild steel (in old money, this is 0.284 lb/in³).
  
• Elements must have physical material applied to them in order to appear in the schedule. I'd recommend that a generic steel material is applied in the family by default so they will show up regardless
  

So that pretty much sums it up. Hopefully this will be of some help

There is now a Concrete Circular Column Family

in the Waterman Library. It's called W_COL_C-Circular and is where you would expect.
We have also tweaked the other Concrete column families. so if you are already using them you may want to reload the latest.

Lining up the outside flange of columns and keeping them in line ..

When modelling portal frames for example and you want the flanges of the columns to line up regardless of the column size or if the column size changes.
The trick is to use a reference plane and lock the flange of the column to this reference plane.

Let me try and explain.

Put in a reference plane, say, 160 off of grid ( the trick is to PIN the reference plane in place ) and then place your column and align and lock the flange to the reference plane.

Now if you change the size of the column the flange will stay aligned and locked to the reference plane.

Angle section Columns ..

I ( with help ) have created some Angle section columns and these can be found in the normal place masterdocs\CAD\Revit\Waterman Library\Families\Columns and are called W_COL_EA.rfa ( for equal angles ) and W_COL_UEA.rfa ( for unequal angles ).

Over the last couple of weeks we have been updating

our Beam and Column Families. I have now made these available and they are in the usual place MasterDocs\CAD\Revit\Waterman Library\Families\Columns & MasterDocs\CAD\Revit\Waterman Library\Families\Steel

The new Column ones are called W_COL_??? and the Framing ones W_FRA_??? and all include the Waterman Reference number.

We have also created some Advanced Steel Families ( UKB , UKC etc ).

If you are using the old versions I have put these in a sub folder called superceded.

Rotating Column Tags.

I found a good tip regarding Rotating Column Tags in the AUGI Forums and I've changed our tags to incorporate this.

A parameter has been added so that you can define any angle you require within the tag. So you don't have to make a new family with a different angle.

I have also added these tags into our standard template.

Asymmetric Plate Girder & Asymmetric Plate Column

We have developed two new families for Asymmetric Plate Girders ( W_ASPG.rfa ) & Asymmetric Plate Columns ( W_ASPC-Column.rfa ).
Once loaded their use should be self explanatory.

These can be found in MasterDocs\CAD\Revit\Waterman Library\Families\Steel and MasterDocs\CAD\Revit\Waterman Library\Families\Columns.

New Beam and Column Families

We have created some new Beam and Column Families that incorporate the Waterman abbreviated naming.

These can be found in Masterdocs\Cad\Revit\Waterman Library\Families\Steel &
Masterdocs\Cad\Revit\Waterman Library\Families\Columns
They are the ones pre-fixed with a W_

To complement these there are a new set of Tags which can be found in Masterdocs\Cad\Revit\Waterman Library\Annotation
If you are using the Abbreviated naming then the Tag to use is W_Structural Column Schedule Tag-45.rfa

You will also notice that a couple of Tags have a “CO” or “CU” in their name. These can be used to tag a Column Under or Over.