Future for Concrete in Revit

[E-Key]

Leaning tools of Revit Structure 2 I found that Revit isn't so convenient to work with Rebar and concrete as to work with metal framing. There are some limits of analytical model performance for concrete monolithic walls, columns and slabs. Now CAD software market has some specific application for AutoCAD allowing to draw and calculate Rebar (RCAD, for instance) very productively. As I can see Revit can't be competitive to these specific applications now.
I'd like just to listen the forecasts from Revit community members can we expect for improving for concrete monolithic structures in Revit? I feel we need it very much. And you?

[david_peterson]

Well since just about every building out there requires concrete, I think it's only logical that RS be capable to do concrete. RamCad Studio started out as a basic steel only package (from what I remember) because steel has defined shapes and properties. Concrete varies so much, I'm sure it take a little long to write the software for it. Concrete is a free form building material. I'm sure in future releases concrete will get more and more robust. If it doesn't, I think you're right when you say that Adesk will be missing the boat if RS can't do concrete.

[BWG]

It would be definitely a downfall of revit not to ramp up the functionality of this since there are still several buildings being built in this fashion, not to mention that every building has a foundation, albeit, not always of concrete.

Send this to support as a wishlist item through your subscription.

[rmcelvain.103137]

I am really nervous about tackling my first concrete joist/beam system project. I think it's going to pretty intensive to create the standard pans and joists. Concrete is not going away and you are correct that Revit will need to continually increase it's capabilities in this area. The more I use it, the better I like it. Once I start that project, I'll post any findings here and recommendations in the wishlist forum. If we all do this, we'll have a much better product in the future.


Good thread!

[Dimitri Harvalias]

This is one of the issues (the term 'complaints' seems too harsh :) ) structural engineers have related to me in my neck of the woods. We tend to do far more concrete vs. steel construction in Canada than is done in the US and Autodesk, in an effort to get the package to the biggest market, has probably spent more time on developing the tools used by the majority of their customers, ie the US market.
I'm not a structural engineer but would love the opportunity to work more with consultants who use the Revit platform. We have to remember that this product is in its infancy and, if the track record for development on Revit Building is any indication, there is hope that it should improve by leaps and bounds as time goes on.
Providing Autodesk with this kind of feedback is great and can only help the factory apply time and energy to the tools most valuable to those actually using the software in the real world.

[Tom Weir]

Hi all,
My first Revit project was a 5 story 500' parking structure with PT beams and slabs and concrete frames. I started that after doing tutorials for about 8 weeks (posted below). I find Revit very well suited to doing concrete and masonry work. I have even modeled the Rose Bowl with Revit, almost all concrete.
One big flaw is its inability to produce warped slabs, but I believe the developers will be improving that substantially this year. You are also correct that rebar functionality needs improving. The Rebar Sketch and Place functions have been added but is still not quite enough.

For concrete and masonry walls the ability to edit in sketch mode is a great plus. In many ways Revit does better with concrete than with steel.

How many buildings have you actually produced? Maybe more production will make you feel more comfortable with the software as you move away from 2d drafting. And what other specific problems are you finding?


Tom Weir
Los Angeles

[E-Key]

Hi all,
Maybe more production will make you feel more comfortable with the software as you move away from 2d drafting. And what other specific problems are you finding?
All our projects have reinforced monolithic skeleton. Now me use some specific software for reinforced concrete and we'd like to get at least the same productivity in Revit. If can't put Rebar automatically in Revit yet it would be nice to get productivity by other ways. Now we can avoid to duplicate the geometry of concrete elements, already created by architects (thanks them). But moving deep into Revit to monolithic constructions we get some limitations. For instance:
1. CopyMonitor tool doesn't allow to monitor bearing walls and structural slabs. Architect can even delete a bearing wall and I'll never know about that! I think, all items that are in analytical model could be controlled by structural engineer with that tool.
2. Joining concrete beam to structural slab doesn't create T-shaped monolithic figure to transfer it to analysis software.
Maybe I don't know some about Revit and these limitations are just a mirage. Everybody is welcome with his opinion.

[Jos Arpink]

We are using Revit for concrete hi-rise structures here in Canada, as well as for some of our jobs in the US.

It's clear in using Revit that it started out as an architectural product, and that much of the development in RS was geared towards structural steel, but I believe Autodesk is listening here. I've had several discussions with the development team on how we work in this industry, and what we expect as conventional behaviour.
Keep at it, expect problems, find workarounds, or, in some cases, just move on (but not without posting your problem here).

[Tom Weir]

Hey Jos,
could you post us a sample of some of your concrete work. It would be very intersting to see one of your high rise concrete structures. A DWF 3D would be even better.

Have a great weekend....

Tom

[James.Lupton]

We are Structural Engineers in the UK and have been using Revit (RB) since V2 (5 years)

We now do all our concrete work in Revit as well as steel structures and we still don't have RS in the UK

As with everything in Revit you have to start at the thick end of the wedge since you need to develop the families before you get any productivity gains.

This means that you can only do a bit at a time on each project

If we were a bigger company we could probably keep family development on going all the time as an overhead but most of the time we have to stop and earn some money.

We have now built all the UK RC content families for different bar arrangements and use linework scribed on the face of a void to represent typical call offs.

Using these 3D objects with 2D linework we get quite good productivity in creating RC drawings and we have also set up shared parameters to create the RC schedule automatically.

The schedule formatting in Revit is not quite as good as excel so we still tend to use our RC schedule sheets to create final copy. That gives us a nice double check although it ads to the time.

We have recently been nesting the bar groups into solid components to create pre-reinforced elements with the bar lengths changing depending on the size of the hosting component. Again this has taken a lot of effort to get going but it is now starting to pay off.

Next thing we want to look at is linking the hosted component into the design routines using the API this will be even more time consuming but will give us very quick definition of the project components which are pre-reinforced and which respond to the output of the design API. with a bit more work on the scheduling (version 3 we hope)

To get the best from Revit you have to think about using it in a different way. Keep at it
and I think you will find Revit has lots of potential for RC work since it can do the scheduling automatically.

[E-Key]

Hey Jos,
could you post us a sample of some of your concrete work. It would be very intersting to see one of your high rise concrete structures. A DWF 3D would be even better.

Here it is our high rising building. It's not a final model. But it could be interesting to somebody.

[Tom Weir]

Very interesting model. Was it modeled in Revit? How did you create the typical floors and control the changes? Was it used for construction documents or for conceptual purposes only?

Tom

[christopher.pynn]

Guys,

Been reading with interest your comments on Concrete in RS. We have looked at the software quite recently with a view to implementing in the office.

However with having experiences of problems modelling concrete in other 3D packages that was the first thing I checked.

I admit that I have not spent a great amount of time on this due to work commitments and I'm by no means an expert on Revit.

However would appreciate if you explain further on the methods in which you have modelled in concrete. Perhaps posting a sample concrete plan in the process.

It seems to be that RS is perfectly capable of modelling in concrete. The problem is the amount of manually drafting required after the fact in order to make the plans and sections look accurate. Would people aggree with that ??

As an example of this, Concrete beams drawn with the top at the same level as the slab do not show as hidden in plan view. Where as if you lower the beam down to the slab soffit the sections and elevations are then incorrect.

Is there a trick to this that Im unaware of without having to edit individual lines appearances.

Appreciate your comments.

thanks in advance

[Jos Arpink]

Yes, much has already been said about the handling of hidden lines in concrete slab/beam systems, which are technically monolithic, but Revit handles them as discrete elements. Revit will only handle hidden lines if one element is beneath the other.

My workaround was to modify the concrete beam family as follows:
Introduce a parameter for "slab depth" to reduce the concrete depth, without reducing the beam depth 'h'. (see attached .jpg)

Stubbornly, Revit will still want to place the beam so that the top of concrete is at level, so I also introduced a model line (invisible) which is constrained to 'h'. This will force the beam's soffit to where we want it. It's the toothpick in the 3D view (attached).

This works.

You definitely don't want to start forcing linework with the linework tool.

Increasingly, we are modeling complex slabs/beams as in-place families.

Hope this helps.

[Tom Weir]

Hi,
I have also taken Jos's approach with a special PT beam family that allows for the depth of the PT slab. It seems to work pretty well.
The hidden lines in plan view are created using symbolic lines in the beam family. In section the beam and slab are joined.

Tom Weir
Los Angeles

[Jos Arpink]

Using these 3D objects with 2D linework we get quite good productivity in creating RC drawings and we have also set up shared parameters to create the RC schedule automatically.

I think I like this approach.
It sounds like a good way to schematically represent the reinforcing in a computable manner. How are others handling this?

[christopher.pynn]

Tom, Jos,

Thanks alot for your replies.

That seems to be exactly the solution I have been looking for and something that should definately be added to future releases of RS.

Thanks again. Much appreciated.

Cheers
Chris

[christopher.pynn]

Tom, Jos,

I have just tried attempting re-creating a new rectangular beam family and profile.

Just wondered if you could point in the right direction here. This is my first attempt.

Am I right to say that we need to adjust the profile in order of getting the parametric constraints working and then simply apply that new profile to the sweep.

If so what is the best way to constrain the profile ??

We have the parameters b and h. We then add a new parameter for slab depth.
How do I constrain those so they act about the top of the beam not the centre reference plane. My first attempts seemed to be moving about the centre ref plane rather than the top.

Basically I'm thinking that if H = 600 and the Slab Depth = 200 then the bottom of the profile should be 600 below the top plane or if you like 300 below the centre ref plane. The top of the profile would then be 200 below the top plane and 100 above the centre plane.

Would be grateful if you could let me know whether I'm on the right track and if not where I'm going wrong.

Thanks in advance

Chris

[Tom Weir]

Chris,
Create a reference plane at the bottom of slab. Use the align tool to move the sketch line to that reference plane, then click the blue lock to lock the line into place. Then create a labeled dimension parameter for the slab depth to that reference plane.

Let me know if that works...

Tom

[Jos Arpink]

Chris,
If you're working (as I did) with the 'out-of-the-box' rectangular concrete beam family that comes with RS, I think you also need to introduce a model line constrained to depth 'h' to get it to work as I've described.

While Tom's approach is similar, I'm not sure it was modified from the same template. Tom?

[christopher.pynn]

Jos, Tom,

I managed to get the profile to change as required.

I then loaded that into the Beam Sweep profile.

My question now is how do you then get the Profile to match the constraints of the Sweep family.

Do you have to reapply the slab depth parameter and if so does the profile parameter for the slab read that set in the Sweep family ??

I have attached what I did thus far.

thanks

Chris

[john.hainsworth]

It bothers me somewhat that Chris & Tom's family workaround assumes a similar slab depth on either side of the beam - but what about when the slab depth differs?

In reply to the original poll - I have yet to acheive satisfactory results on this issue - and since linework tool doesn't 'stick' on copied views, I've had to export outlines & modify in Acad, and link back in - v cumbersome and not 'live' !)
Any other workarounds would be very welcome....

[Jos Arpink]

Christopher, unless there's something I don't understand about how profile families behave (quite likely), I would create the beam's profile "by sketch" as opposed to using a loaded profile family. Constrain the top of it with the slab-depth parameter you've defined. It should respond to changes in slab depth.

[Jos Arpink]

[QUOTE=john.hainsworth]It bothers me somewhat that Chris & Tom's family workaround assumes a similar slab depth on either side of the beam - but what about when the slab depth differs?[QUOTE]

John, I don't think it's a workaround as much as a solution more suited to precast concrete, structural steel, or timber, where we're dealing with predefined shapes. For cast-in-place work of any complexity, we are using in-place families to model our slabs and beams together as a single entity. You can be very creative that way.

[john.hainsworth]

As I see it Chris's issue is simply about how a 'common' slab and beam' line looks when the slab abuts a beam tops flush...so I'll continue on that point...
Creating a new beam family with its top flexing to the soffit of the slab IS a good approach but IS a workaround and won't 1) sell the concept of RS to a wider audience or 2) work on a project with different slab depths.

That said, with no license at home I've had a thought ...what about a forcing the oustide lines in the beam family to hidden style - that won't solve the issue when you've a fold/step on the beam edge, but that case is the exception. I wonder whether the slab lines then are themselves hidden and what we're seeing up to know is two hidden lines over each other = solid ?? to fuel this I recall that when you export to dwg you're prompted wrt hidden line removal !

I'll have a play when I get this job out....

[christopher.pynn]

Jos,

Thanks for your help. Will try the approach you mentioned about using the Sketch outline and see how that works.

On your idea as a beam and slab system how are you going about that. ??

Am I right to say that your structural framing plans are quite regular.

We are doing a lot of condo's which dont really have any strict pattern to them. So basicall we just need all out slabs and beams to be monolithic regardless of where they are. !!

Cheers

Chris

[Jos Arpink]

Chris, we similarly do a lot of hi-rise residential work.
Our slabs are anything BUT regular. That is why we are modeling many of them as in-place families, with all manner of solid/void extrusions and blends, to achieve the result we need.

[christopher.pynn]

jos,

it seems we are aiming for the same things here. Due to my project constraints though I do not have the time to play around as much as I would like.

Would it be possible if you could post or email me an example of how you are solving this problem.

Would be really appreciated but I understand if it is not possible to do so.

cheers

Chris

[Jos Arpink]

Christopher, sorry it's taken so long to respond to your request.
Here's a screen shot of a cropped model which hopefully conveys how we are doing this.
Note the transfer slabs. These are modeled as in-place families using solid and void extrusions. We have found it to be the best way to model complex slabs.

[christopher.pynn]

Jos,

No worries, I too haven't really had the time to look into this since my last post. Too many struggles with B Structural. !!!

I will perhaps look at your suggestions as it seems to be an obvious solution.

Having no prior experience of doing this I may be back with a few questions though.

Cheers

Chris

[Tom Weir]

Hi,
It seems that the more experience I gain using Revit Structure the more I use the in-place families to construct concrete shapes, like Jos is saying. I am getting to where I can make almost any kind of shape too.
It might interest you to know how I evolved to this point. I will use an elevator pit as an example.

The first time I did it I decided to construct a 6" floor at about -4', then 4- 8" walls that went to the underside of the slab-on-grade. Nothing wrong with that. Then I needed to add a 12" slab edge around the edge of the pit floor, and I was basically done. But all those pieces took a bit of editing when changes occurred, and the slab edge never worked that great to begin with.

So the next time I thought I would make a sweep solid form for the floor in order to accomodate the dropped slab edge. That worked OK.

But the thid time I made a dramtic change. I realized I could make an elevator pit family using solid and void forms. First, I made a solid block extrusion for the volume of the entire pit below the slab. Then I made a void extrusion block to hollow out the pit so only 8" remained at the perimeter. Finally, I used a blend void form to hollow out the correct dropped slab edge at the bottom of the pit floor (the inner side was at 45 degree angle). Those three solid objects are members of the elevator pit family and all I need. Using this method you can create different types of elevator pits for each job without rebuildng.

So the point is the evolution in how I am modelling. You will probably go through this same progression of thinking, like we have.

I hope that helps.

Tom Weir
Los Angeles