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Revit Structure
5

Revit Structure

Revit Structure

(OP)
Has anyone here tried to use Revit as an analysis tool?  I've used it before to do 3-D modeling, but that is the extent of my knowledge of it.

RE: Revit Structure

Revit doesn't do structural analysis itself - it allows you to build the model in Revit and then transfer to a structural software package like RISA-3D.

RE: Revit Structure

It will also integrate with Woodworks.

Mike McCann
McCann Engineering

RE: Revit Structure

With Woodworks? Really? I'd be interested to see how that one works.

RE: Revit Structure

Clansman:  You're right.  My mistake.  

Mike McCann
McCann Engineering

RE: Revit Structure

When the structural model is created in Revit, what happens at the nodes?  Does Revit make adjustments to the lengths of the beams to fit outside the column flanges or webs?  Or is it like STAAD where the member lengths are node-to-node?  Does the engineer have to zoom into the beam-column connection and actually draw the beam offset from the column flange, draw the connection plate/angles, draw the bolts...?  Or are the connections detailed automatically based on the attributes (bolted connection, welded connection, moment connection, beam to column web or flange) assigned to both the beam and column similar to how Descon details connections?

RE: Revit Structure

I think Revit has the visible beam entity AND it has the theoretical beam "line" - both co-exist within revit.

One is all about the drawing/representation of the beam and the other is the theoretical beam position used by the associated analysis programs.

You can display either, neither or both.

RE: Revit Structure

I have not used Revit and do not personally know any engineers who have used it.  Yet.  Going to check on some seminars.

RE: Revit Structure

2
Im using Revit Structure 2008 right now.  I have drawn the structures in Revit and then exported them to both RAM and ETABS.  Once the analysis is complete, you can reimport the designed sizes back into Revit.  As said above, Revit doesnt do the analysis.

Revit automatically produces a setback that can be changed.  The node is actually at the workpoint of the connection.  When you go to cut the section Revit generates the 2D column and a beam.  That's it.  Very bland.  So you have to DRAW IN BY HAND IN 2D all the bolts, clip angles, welds, text, EVERYTHING.  And if you update the beam size, your hand drawn stuff DOESN'T update with it.  It sucks.  Everyone I know hates it.  Have been to the 3 day training course and even the trainer says they a lot of people are let down when they get into it because a lot of the sales pitches are deceptive.  It's so much more work for nothing gained.  The company hasn't been profitable on any Revit jobs.  It doesnt help coordination issues like they claim.  Beware

RE: Revit Structure

But how is that still not better than "drawing by hand" all the AutoCadd details that don't update anything when you change a beam size?

At least with Revit, you can model the structure, view it, rotate it, understand it, export it to analysis software, etc.

I'm not arguing with you - just trying to marry your displeasure with what I've seen done elsewhere...

We've been using Revit on another segment of our business (precast) and most of the guys are starting to buy into it.

RE: Revit Structure

Thanks for comments Atomic and JAE.  For the coordination with other consultants like the architect and MEP, are you integrating their Revit models into yours?

RE: Revit Structure

JAE, if you currently draw every section with EXACTLY the correct beam sizes, then you wouldn't be bothered by this.  But, there are many times where the exact member sizes really don't make a difference in what you're trying to convey.  It forces you to be exact where you don't really need to be, and I just don't think our fee reflects that amount of detail.

We have architects and MEP in house, so yes we have integrated models and its easier because we're all on the same network.    Coordination seems to be something everyone's interested in.  BUT there's a big but.  The way its set up, (which is the way autodesk recommends) Architectural has a model.  Then structural makes a model and links the architectural model in.  It's essentially the same thing as Xrefing a base drawing in autocad.  Their 3D model shows up as a block and you draw all the structure over that block.  You "freeze" out layers you dont want to see.  It will not catch coordination issues like drawing a column over a wall.  The only coordination feature is a thing called "copy monitor".  You designate certain elements in the architectural link with copy monitor, and then if architectural moves them, it pops up a general window saying "Do a coordination review".

Having several people working on the same file makes things a bit more complicated....too complicated to type here.  I recommend if you're genuinely interested you look on www.augi.com forums.

RE: Revit Structure

(OP)
My firm is just starting to jump on the "BIM" wagon.  The firm I previously worked for used Revit, so that is the only software I have experience with.  Does anyone have any other recommendations?  What about AudoCAD 3D?

We have everything in house here...architecture, structural, mechanical, electrical, civil...etc.  Is there a good base program to use for all of these disciplines?

RE: Revit Structure

How do the problems with architects constantly changing things work out, or do they get worked out, when using BIM software?

RE: Revit Structure

That's the same question I have, UcfSE.  I work with several architects, all outside my office, that make changes and issue new CAD bases at least once a week.  Often, more often than that.  We are left on our own to determine where the changes were made because they refuse to spend time either writing a revision summary or clouding the areas that were revised.

When the notice "do a coordination review" pops up, is it easy to determine what changed?

RE: Revit Structure

We have been using Revit and the Bently 3D package.

UcfSE asked about architects making changes. This practice will not stop, in fact it may get worse. You see, when something is modeled in 3D it APPEARS more finished than it really is. The architects mass model in a wall. Said wall appears on the 3D image but the architect doesn't work out the details of the wall section until much much later. Thing is, you need the wall section NOW to set the building grid and to see how complicated areas are going to fit together. People think the architects are getting close to complete because some semi-defined mass wall element has been placed.

Placing an object in 3D also gives the false impression that it has been thought through. Just because somebody placed the element doesn't mean it's right. Things get placed to take up space rather than placed for a specific design purpose.

Don't get me wrong - I see 3D as a very useful tool, especially for owners to "see" what they are getting beforehand. Beyond that, it seems to permit the designers to "show" more with less real design work. Design work that eventually must be performed and used to be performed sooner rather than later!  

RE: Revit Structure

(OP)
So, is 3-D modeling even worth it for a firm to invest in right now?  I haven't heard much positive feedback about it.  Even with all of its quirks, in your opinions, is it still better than 2-D modeling?

RE: Revit Structure

For those of you using Revit, are you giving the model to the contractor to be used for cost take-offs and detailing?  How much data is in the Revit model with regards to member sizes, connection info, etc?  A contractor that we work with on alot of projects called to see if we were using any BIM software.  He wanted to know if he could get the 3D model and get everything he needed to know about materials from the model without having to do the same cost estimating effort he's always done.  Also, he wanted to know how much detailing the 3D model contained and if his steel fabricators could use it to cut out some of the steel detailing lead time.  Since we don't use BIM or Revit, we couldn't answer his question.

RE: Revit Structure

My firm uses Bently Structural (Triforma).  Our drafters have been using it for quite a few years and I can't speak for how the transition worked.  At this point, it only takes slightly longer for us to model something than draw it 2D, but the benefits outweigh the extra time.

It works really slick now.  Probably 90% of the jobs we do are modeled.  My drafters pick up conflicts all the time.  They don't use a conflict detection module, but it's pretty easy to see any conflicts (duct through a beam, etc).

One thing to think about is the order of how drawings are delivered.  The structural efort is big up front because everyone wants to tack something onto your structure.  Something to think about during scheduling.

Bently's aquisition of RAM and STAAD creates a promising situation.

RE: Revit Structure

You need to evaluate the pros and cons to make a companywide investment decision.

No, we dont give the models to contractors or fabricators.  Nobody has asked for it yet.  Even if they did, I'm sure we'd ask a fee to cover our increased liability.

 

RE: Revit Structure

Gump, we are looking at our first BIM project in the next month or two, in Triforma.  Would you have any other advice or bits of information you can share?

RE: Revit Structure

UcfSE,

I've heard the first couple of projects with Triforma are pretty rough.  Whenever we bring in a new drafter, it takes about a year for them to get up to speed on 3D modeling.  We've even had drafters leave because they couldn't wrap their heads around the 3D concepts.  

Bently is pretty responsive to our questions and requests.  I think it's important to communicate usability questions and problems to them so that the software is continually improved.  It's in their vested interest to make us happy and keep us from jumping ship to Autocad.

Don't give up after the first try.  The first project may be difficult, but I think it will get easier after that.

RE: Revit Structure

I suggest all of you check out TEKLA Structures. It is one awesome Structural BIM program. In ten years revit still wont be close to where TEKLA is. And if they are, thier file sizes will probably be close to 1 GB. The one thing Revit has that Tekla doesn't: Marketing Power.

RE: Revit Structure

I have used Revit Structure for about a year now, and I have used it in conjunction with Risa Floor/Risa 3d. I believe it is very much quicker, once you are familiar with the program, to set up the initial take of the structure in Revit with the very Basic gravity load cases and dump to Risa. Supposedly you can do cyling back and forth between the two now with the latest link, but I have not tried it because of scheduling reasons/fear of polluting my model(s). I have dumped maybe 3 models.  Most of the other time I simply have designed it with Mathcad as I built the model in Revit.  Most of my structures are fairly simple.  But if the Revit Risa link works as advertised, it should be slick.  

I wonder if anyone else has done the model dump to RISA and I would like to know the success/failure they have had.

I attended a seminar the other day where a principle in a Structural Engineering firm 30 people) gave a speech. They are supposedly leading in Revit Implementation , and they said they used Etabs. He indicated that there were issues with the strucutral model dump, and I can say it is not smooth with Risa right now, but it does give you a great leg up on the Risa model.

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