BIM-Driven Engineering: Structural Design Without Redundant Workload

SETH ROSWURM: Well, first of all, thank you everyone for being here. And a big thanks to Autodesk for giving us the opportunity to present. Leveraging BIM technology in structural engineering is a topic I get really fired up about. And I'm excited to share that with everybody, today.

My name is Seth Roswurm. I'm a licensed structural engineer with design experience in a wide variety of building structures. Prior to joining Enercalc, I had the opportunity to work on a lot of different structural projects, ranging from multi-frame, multi-family-- excuse me-- wood frame multi-family developments to the steel framing of the presidential hangar that houses Air Force One.

For anyone who may not be familiar. Enercalc is a software provider that's been serving structural engineering industry for nearly 40 years. In my role within Enercalc, I'm the lead developer for an all-new product line that takes the engineering power of our existing calculation platform and integrates it seamlessly into the Revit BIM environment.

MACK ELTARHONI: Hello, everyone. My name is Mack. And I am the principal and owner of Elta Design Group. We're a structural engineering firm based in Oklahoma City.

We provide general structural engineering services, as well as delegated design services for the specialty engineering of cold form steel framing. I'm a long time Enercalc user. And I was very excited to partner with Seth to develop this case study for you, using Enercalc for Revit to demonstrate its capabilities and real world applications.

SETH ROSWURM: So in the first part of our talk today, I'll be discussing the daily challenges that structural engineers face and how those challenges kind of form the philosophical basis for working more efficiently, by thinking in a BIM-driven and Revit-driven manner. Our talk today will focus on three main topics.

First, I want to talk about the challenge of parallel work that many engineers face, and how that impacts profitability. Secondly, we'll be talking about how engineers and firms can recalibrate to think in a more BIM-focused manner and manage their models, accordingly. And finally, we'll be looking at a practical case study that shows really how efficient BIM-integrated structural design can be.

So first of all, let's talk about parallel work. Fundamentally, the concept of parallel work refers to the fact that a structural engineering team really has two large tasks, instead of just one, to accomplish on every building design project. So the first of these two tasks is the design.

This is the part of the project that requires the engineering team to leverage technical expertise, knowledge of governing codes, various computational tools that they're using to produce a set of calculations that verify the safety and efficiency of the building. But that's not the end of the project. The neighboring mountain that the team also has to climb is the documentation.

And for all practical purposes, this is the real deliverable for most engineers, because this is how the results of the design are communicated, both to other disciplines for coordination and to the contractor who will construct the building. So looking into what goes into these two mountains of work, on the design side, you'll have some hand calculations. You'll have some spreadsheets and other proprietary in-house tools that your firm uses.

Some projects require 3D frame analysis, using commercial software packages. You'll have some individual component checks or capacity calculations, and some form of foundation design. Now on the documentation side, your ultimate deliverable is to produce a set of signed and sealed structural drawings.

And for a large portion of our audience today and the industry at large, the leading tool for producing these drawings is Autodesk Revit. Now, as most of our audience likely already knows, Revit is an industry leading BIM environment. And it's commonly used by both architects and engineers for design of buildings.

Now, one of the difficulties that structural engineers encounter frequently in building design is that these two kind of parallel tasks of design and documentation don't happen sequentially. They really happen simultaneously. And that's because as the design progresses, the drawings and modeling also need to progress, in order to meet your submission milestones and needs for coordination between different disciplines of the design team.

So how does the structural engineer cross the gap between these two parallel workflows? And unfortunately, this is your answer. In order to bridge that gap, the structural engineering team continuously makes trips back and forth between the documentation environment and that mountain of various calculations that comprise the design process.

And these trips really occur in both directions, because the two parallel workflows inform each other. You can't have one without the other. And there's a variety of different kinds of information that the engineer carries back and forth across the tightrope.

So how does this all tie in with the broader life cycle of building design? Well, we all know from experience that the design of a building is not a simple, linear, straightforward process. It's really kind of a complex, dynamic process that's influenced by a lot of different factors, including the client's needs, the vision that the architect has for the project, the available funding, the site conditions, and lots of other factors.

So the design really progresses over time by a series of rolling updates and changes. And when these normal evolutions occur, the structural design team goes through a cycle of evaluating the upcoming changes, assessing how it'll impact the design calculations, and then making appropriate changes to the documentation as a result. And this design cycle kind of results in multiple trips across the tightrope each time the cycle repeats.

And this consumes not only valuable time, but also introduces many layers of potential error, because of the manual transcription of various data between the different environments. And the time cost of this workflow is further worsened by the fact that model updates usually happen manually, after the design calculations are updated.

And this process is kind of a whole cycle unto itself, where the structural model gets marked up for changes by a lead engineer. Changes are performed by BIM staff or junior engineers. Then, the changes have to be reviewed and approved, et cetera.

The process isn't always this formalized in that exact manner, but this is fundamentally how the work gets done. And for firms who use BIM staff or entry level engineers to do the heavy lifting in Revit, the cycle repeats many, many times over the life of the project, costing time and accuracy as you go.

So the question we wanted to answer here at Enercalc is, how do we relieve the pain of this parallel work process? And more specifically, kind of the deeper question is, what if we could approach the entire structural design process in a radically Revit-centric manner that completely upends those conventional workflows that engineers are normally forced into?

For me, as an experienced design engineer, and Enercalc as an experienced software provider, that all starts with thinking about that tightrope that we described earlier. Clearly, the fewer trips you make, the better off you'll be in terms of accuracy, profitability, et cetera. And it's no secret that your firm already invests so much time in modeling structure in Revit for various reasons, including coordination, documentation.

Why can't we also leverage it for design? And so the question is, how could this be done? What kind of capabilities does Revit have that make this possible? Well, the cornerstones of Revit's capabilities range from annotation, 2D drafting, dimensioning type work, to powerful 3D modeling and dynamic 3D live views of the model itself, robust parametric framework for parametric design and intelligent scheduling, and an industry leading programming interface that lets either users or vendors extend that functionality.

So for Enercalc as a provider of engineering tools, we're interested not just in how we can use the platform, but much more importantly, how our users already use that platform to do their daily work. Because understanding that is what really allows us to provide a high quality, intuitive experience that changes the game for our users and for the whole industry.

Now, before we get deeper into discussing third party enhancements to the design process, I want to just quickly address what users can do to have the best experience in a powerful environment like Revit. And I'm going to briefly discuss that, just framed in terms of some general best practices to help you get the most out of your structural models.

So first of all, Revit is a very data-rich environment. And it really should be used accordingly. That means avoiding workflows that are data-poor, that are non-parametric, and that are static, meaning not easily modified throughout the course of a project.

And the reason for that is because thorough and accurate modeling really helps unlock the full power of the platform. And the best practices that we're going to run through here are applicable for a wide variety of different ways of working, from basic model management to scheduling and takeoffs, and even ultimately, actual Revit-driven structural design.

Now, we're not going to get too bogged down into the weeds of specific drafting and modeling practices. But I do want to highlight some very specific issues here, just because I've run into them so many times, both in design practice and in user support situations. Some of these things may seem very fundamental, but I can tell you from experience, they do happen and they do they do cause problems for engineers in the field.

So these are just some things to watch out for as your team builds your Revit structural models. So the first thing I want to mention is just avoiding the use of line work as a representation for framing, when that framing could be modeled in 3D instead. And similarly, avoiding the use of line work as a substitute for parametric scheduling.

Focusing on joins, cutbacks, and Z-offsets, and proper use of each of those tools and methods for geometry control in your structural Revit model, making sure that you have well-conditioned floor support geometry, and making sure that the supports relate properly to the floor and slab edges the way they should, assigning accurate structural types and usages as you create structural elements in the model is going to help ensure a well-conditioned Revit structural model.

And in a similar manner, assigning appropriate materials to elements as they're created, and making sure that you don't have a situation where the default material doesn't accurately reflect the proper behavior of the element that's being created. So once you know that you're creating a well-managed structural model that optimizes your use of Revit, where do you go from there?

And you could look at commercially available standalone design software that connects to Revit. But for our engineers and the audience today, if you've done that process before, you already know that it doesn't necessarily solve a lot of the challenges that we've already discussed. You're most likely going to be looking at a bulk export process to another environment that involves the use of data exchange files, or some sort of import export process.

You're going to find yourself managing Revit analytical modeling, which includes a parallel model that now exists in an outside platform and has to be reconciled with your Revit documentation environment. And so, you're going to find at the end of the day, you're still making laborious trips back and forth between your design and documentation workflows. And you'll find yourself asking, is there a better way to do this?

So in my time as a practicing design engineer, I've absolutely felt this frustration. And as a developer, I had a picture in my head of a process where I could perform structural design without these painful trips to outside environments. And Enercalc for Revit, which we'll be talking about today, was born out of that vision.

Enercalc for Revit is a Revit-centric design program that gives engineers that immersive structural design experience from directly inside Revit, so that you can let Revit be the convergence point for your design tasks, meaning no longer forcing your team to make those tightrope walks between environments and eliminate the risk of those data transcription errors.

So before we get into the Revit side, I want to just give everyone a brief introduction to Enercalc's structural engineering library. SEL is a powerful program that has over 40 different structural engineering calculation modules for a wide variety of different design tasks. That includes things like design of structural components like beams and columns, various structural analysis modules including 2D frame and rigid diaphragm torsion, earth retention modules, as well as 3D frame analysis and finite element solutions.

So Enercalc for Revit provides structural engineers with the ability to use that familiar engineering power of Enercalc's SEL from directly inside Revit. And this starts with just a simple set of controls found on the same familiar Revit ribbon bar that houses other native commands that Revit users are used to. And these tools show up automatically, right in your Revit environment, when you install the plug-in.

Calculations are easily launched from directly inside Revit. And launching those calculations from Revit gives you the ability to leverage the already modeled structural elements that your firm and your team have spent time and resources to create. So you can automatically determine design parameters like span geometry, section size, member spacings for tributary width, and so on.

And Enercalc for Revit users also get the advantage of automatically transferring reaction forces between structurally connected element designs. For example, from beam to girder, like I've shown here. It also gives you the ability to take advantage of Revit's rich visual environment for tasks like highlighting graphics to show passing or failing members and other design overview tools, as well as real time oversight of model changes that impact your element designs, because Enercalc for Revit has a built-in monitoring system that watches the Revit model for significant changes that could jeopardize previously completed structural calculations.

And when those changes do occur in the Revit model, your calculations can be quickly updated using the bulk recalculation tools that the program provides. And with that, I'm going to go ahead and hand it over to Mack, who's going to look at our actual structural steel design case study using Enercalc for Revit.

MACK ELTARHONI: So first, I want to start with an overview of the case study structure that we chose for this demo today. This is a local, single-story steel framed convenience store that I designed using Enercalc for Revit. The structure is composed of standard metal deck, open web bar joists, steel beams, steel girders, and steel columns and brace frames.

SETH ROSWURM: So I'm really excited for you guys to see the case study that Mack has picked out for the talk today, because you're really going to get to see a nice progression, starting from the most basic use case moving up to scenarios where Enercalc for Revit, and the powerful Revit platform itself, really flexes its muscle and shows the ability to save significant time for a structural design team.

MACK ELTARHONI: One of the really cool features that I'll be showing repeatedly today is how Enercalc for Revit allows to design faster, by taking advantage of Revit area loads. So I'll start out by just quickly refreshing your memory on how you easily can just apply area loads to the roof structure in our study case model.

So we've already modeled the structural decks, as you can see here. So we'll start by making sure that we've enabled the analytical model for these decks from the panel-- property panel in the left hand side. Also, I want to make sure that the analytical model, the analytical floors, are visible in this view by just checking that box.

To apply the loads to the roof, I'll go to the Analyze tab. And I'll select Hosted Area Loads. You can see on the left hand side, we have Roof Live Load Case. And all we need to do is just click on the deck that we want to apply the load to.

In a similar fashion, we just go ahead and change that to a dead load case. And then, we click on the deck again that is receiving the load. To confirm that the decks received both of the area loads, you can select them and just click on the filters.

This will show you that we have two area loads applied on the deck, signifying dead and live load. And pretty much just like that, we have already applied the roof loads. And we're done and we're ready to do some design work.

SETH ROSWURM: And I'll just briefly mention here, some engineers may not be used to working with this particular aspect of Revit. But even if you've never worked with Revit area loads in the past, it's definitely worth a look because of the time that you can save. And whenever you get with me to onboard and do training using Enercalc for Revit, we always spend some time getting everyone up to speed with understanding and managing Revit loads.

So like we mentioned earlier, this process starts out kind of with the most basic use case before moving on to some more advanced designs. And so, Mack is going to be starting out here with just a typical edge beam. And this design will give you a nice overall picture of what this process feels like-- to perform a Revit-driven design of steel beams-- because you're going to be able to see how he launches the calculation from Revit.

And then, it arrives fully populated in Enercalc with all the crucial information that you'd otherwise be stuck transferring by hand. And this includes everything from span and section size to accurate loads and even tributary width.

MACK ELTARHONI: So you can launch a new design from the Revit ribbon bar above. And you'll notice that it automatically detects the beam support condition, and in this case in blue, which is the two columns. It asks you to confirm the selection or select your own supports, manually.

In this case, we'll just go ahead and confirm that. And we'll confirm that there are no tributary beams. And just like that, we will have a calculation that opens in the Enercalc interface, automatically.

So if we go to the span load, we can confirm that the dead load, the live load, the tributary widths are all correct. We also have the ability to insert additional loads. In this case, we'll add just a snow load directly from Enercalc.

And while I'm assigning a name to this calculation, you'll note that we can modify flange bracing conditions, or change between ASD and LRFD design methods, or we can do a lot of things. But for now, we'll just save and return back to Revit.

When you turn on the unity check highlighting visual, you can see that this beam is red. It's failing. If you go to the Element Manager, you can see additional information, for example, like stress ratios.

And in this case, you can see that the beam is failing and beam bending. So we can easily resolve this by simply reopening the calculation, just like before, and change the beam size. So once the interface opens, just jump to Span Data tab and change the beam to a W12 by 22.

Then, we can review that the calculation has updated. And then, we just save and close and return back to Revit. Now, you notice that the beam is green. And the size has changed in Revit to the size that we specified in Enercalc.

Also, the stress ratios have updated as well, to reflect the new calculation. This two-way communication-- or two-way control-- of beam design and of the parameters, and the control over the parameters, really allows for such a great flexibility.

SETH ROSWURM: Another common engineering challenge is having a deck opening adjacent to a beam. This is kind of a subtle wrinkle that can add a lot of complexity to your calculations, in some cases.

So as Mack runs through this design, you'll be able to watch how Enercalc for Revit interprets the variations and tributary width on the fly, and builds a detailed beam calculation without him needing to manually apply loads, because we're leveraging the power of the Revit platform with accurately modeled deck and slab and so on. And the demo also spotlights the benefit of two-way control over design parameters, including two-way management of loads and so on.

MACK ELTARHONI: So in this demo, we're going to see some added complexity. And that's not just from the change in tributary width due to the opening, but also an accounting for the added loads from the rooftop units at this opening. So let's start by launching the beam design from the ribbon bar, just like before.

And we'll confirm the support conditions. And we confirm that there are no tributaries. Also, you have the option to ask it to remember the selection for future launches.

And once the calc opens and we review the loads, I will add additional point loads to account for the RTU. So let's go ahead and jump into the Span Loads tab. If you look under the Span Loads, you can see that the software already reduced the tributary width at the opening, automatically.

Now, that's good. I'm going to go ahead and apply two kips load on both sides of the RTU. So we can do this by just populating the dead load, and watch for it on the right hand side as it pops up in the diagram. In a similar fashion, we add a second dead load of two kips.

And we watch for it on the right hand side for visual confirmation in the diagram. And it sure did. So let's also go ahead and change the beam size from the beam span data. We'll cycle to a W12 by 14. Once we're done, we save and close and return to Revit.

So we can check to make sure that the beam size changed, which it did. Also, we can visually confirm that the two RTU point loads that we added in Enercalc are shown in the Revit environment. Let's go ahead and open the calc again, just to highlight that we can apply loads in either environment, vice versa, and we get it to show in both environments. And that's highlighting the two-way control that we were discussing earlier.

So let's close a return back to Revit. And when we're back here, let's turn on the unity check visual. And indeed, the beam is green and the design is safe and good to go.

SETH ROSWURM: So we've seen a couple of different beam design conditions. And where we're going to get to see Enercalc for Revit really start to show off a little bit is when you progress from a beam design to the design of the actual supporting girder. So in this demo, Mack is going to be taking advantage not only of the ability to easily generate accurate point loads for the joists, but also use the direct linking of his edge beam reaction into the girder design as a point load at the tip of the cantilever.

MACK ELTARHONI: So we'll start this process by launching the girder point load generator from the ribbon bar. And we'll confirm this suggested support conditions, as shown in blue. And again, those are the two columns.

And we'll go ahead and confirm the tributary members, as auto detected by the Enercalc for Revit. Now, we get this nice interactive table. And as you cycle through the numbers in the table, the corresponding number lights up in the Revit environment. The edge beam that we previously designed has all of the value zeroed out, because the reaction is not calculated based on tributary width. Rather, the reaction is linked from our previous calculation that we performed earlier.

Also, all of these highlighting features, not only do they work in the 3D environment but also work in the 2D plane view. And this is extremely helpful when it comes down to verifying dimensions. For example, you can see here, the spacing is 5 feet or the joist span is 20 feet. And that matches up with the table that was generated automatically.

So if all is good, we click on Generate the Reactions. And once the reactions are generated, we can just simply launch the steel beam calculation just like we've done before. Once the Enercalc interface opens, we'll go ahead and click on the 2D diagram. And you can see there that the roof joist reactions have been applied to the girder.

Let's go ahead and change the name of this calculation to cantilever girder, so we can easily find it later. And when we're done with that, we want to jump to Span Loads tab. And that would be Span Load One.

And if you see there, you can see that the reactions that were generated are correct. And also, the linked reactions are displayed where they do not modify warning. This way, you don't accidentally change those linked reactions.

If you jump into Span 2, you see that everything looks correct. You cycle through them. Everything is good. If you're satisfied, which we are, we'll go ahead and close and return back to Revit.

And if you turn on the unity check visual, you can see that the girder is green. And therefore, the design is safe and complete. And of course, as always, you can quickly check the stress ratio from the Element Manager, as you need to.

SETH ROSWURM: Another common design challenge is for an engineer to find themselves managing a group of beams that you expect will have similar behavior and sizing, because of design reasons. And so in this demo, Mack is going to speed up his design of the entrance canopy, by actually creating a parent child grouping that lets him tie multiple individual beams in his Revit model to a single Enercalc calculation.

MACK ELTARHONI: So when we look at the canopy, you'll see that these beams are modeled as a beam system. And that's just a Revit term that means they have a Revit-defined parametric relationship with each other. This is indicated in the property panel here on the left hand side of the screen.

When we launch the tool, the tool will auto detect the supports. So let's go ahead and launch this calculation and pick the parent beam that we want to design. And once it gives us the support conditions, we want to select manually by selecting the column as the only support, hence making it a cantilevered beam.

We don't have any tributary beams, so we skip. And since the beam that I picked is part of a beam system, the tool suggests the rest of the beams as child elements. You'll get to either confirm or pick children manually. We'll just go ahead and confirm. And once we're done, the calculation is launched.

So let's click on the 2D diagram and jump into the Loads tab, the Span Loads tab, and quickly verify the dead load, the live load, tributary width, snow load. Everything is appropriate. And of course, a good practice is always to rename the calculation to something that you can easily identify in the future. We'll go with entrance canopy beam.

So once we're done, we click on the Beam Span Data. And let's change the size from a 12 by 2 to a 12 by 6. And now, close the calculation and return to Revit.

You can instantly see that all of the beams have changed sizes to 12 by 6, because we chose to make them children of the main beam. This gives us the ability to manage all of this from a single calculation. And if we open the Element Manager, you can see that we have six children to this beam.

And as you cycle through the table, you can see them highlight in the 3D environment. You also have the option to remove parent child relationship. And for this, we'll go ahead and remove three beams-- remove this relationship from three beams-- for demonstration purposes.

Now that we're done with this, let's go ahead and launch the calculation for the parent beam, and change everything back to the 12 by 2. So jumping back into the Beam Span Data tab, let's find the 12 by 2 beam. And once we do that, let's close and return back to the Revit environment.

You can see that only three beams have changed size. And that is because the other three beams are no longer children, since we remove this relationship that they had with the main designed beam, the parent beam.

SETH ROSWURM: So one of the hallmarks of Enercalc engineering tools over the years has always been the ability for engineers to kind of rapidly iterate their structural designs with what if scenarios, so you can easily respond to design changes with updated calculations. Now obviously, in the dynamic Revit environment, this ability is becoming more important than ever.

So Enercalc for Revit includes a powerful framework for monitoring changes, and recalculation tools to help the structural teams stay on top of an evolving building design project. So in this demo, Mack is going to walk us through a series of examples showing significant changes to the Revit model, and how he can easily tackle those what if scenarios and quickly update his design, accordingly.

MACK ELTARHONI: So the first scenario I'll be looking at in this demo is a change to the dead load on the roof, after the design is already in progress. So if I turn on Status Highlighting in the model, we can see that several of the beams in the back half of the roof have already been designed and they're green.

So let's jump briefly into the Element Manager. And as soon as we open it, I want to take note of the existing unity check of the edge beam that we designed earlier. And currently that shows as 0.43. So now, we'll go ahead and make a change to the model by modifying the magnitude of the dead load to 30 psf.

And as soon as you do this, Enercalc gives you a warning that the change will impact elements that we've already designed. If you decide to move forward with this, you'll see that red highlighting to indicate impacted elements. So we can also see more details from the Element Manager about the type of warning.

And in this case, it's the applied load to their tributary loads have been modified. So when we're ready to update the calculation, I can easily do so by using the bulk recalculation tool provided by the ribbon bar. So I'll choose this option to recalculate the impacted elements.

And once the calc starts, everything happens automatically. You don't have to approve anything. And when it's done, it just pops up a window here from the Element Manager to give you all the information you need.

So if you check the edge beam, now the stress ratio went up to 0.45. And while we're here, I want to take a note of the current unity check on the cantilevered beam. And that is a 0.2 on the cantilevered girder.

So we're going to run another scenario, another what if scenario, where we shift the column support a little bit to the right, changing the cantilever distance on the beam. And of course, as soon as you do this, you will get a pop-up warning where you can just accept the changes. And then, the beam will turn red, telling you that it's been impacted.

And once you do this, you can click on the Element Manager. So you see, again, the type of warning. And it says support, so you know the supports changed. To resolve this warning, all we need to do is just update the calculation by using a single elementary calc on the affected beam.

This process, again, is instant. And it doesn't require opening the full editing view of the Enercalc engine. And as soon as you're done with this, you can see that the beam is green and is good to go. And from the Element Manager here, we can see that the girder went up-- the stress ratio went up all the way to almost 0.6, indicating that the calculation indeed took place.

So this concludes the demonstration of how useful the tool has been really, for us, the practicing engineers. And personally, I think this tool has been helpful in many ways. I like that it generates calculations instantaneously.

You can edit existing calculations with fantastic two-way control. It takes advantage of the powerful Revit visuals, like the green and the red highlights. I also like that it can quickly-- you can quickly check different scenarios as you apply different loads, and just use the bulk re-calculation feature to know what kind of impact you will have on your design if you decide to change your mind and change the loads.

It definitely improved my record-keeping, significantly. And that's because of how easy the process of creating and documenting your calculation really is. Lastly, my favorite feature is the load linking feature.

This saves me so much time and obviously, potential errors, from having to take a particular reaction and moving it to a girder, or just carrying all of this manually. Now, just everything happens quickly and automatically. With that, I will pass it back to Seth to wrap up.

SETH ROSWURM: So the great news for our audience and for our users today is that steel beam is just the beginning of this integration process. Soon, Enercalc users are going to have this ability to perform immersive Revit-based design for a huge variety of different types of engineering calculations, including beams and columns of various materials, sheer walls and slender walls of various materials, foundation elements, and even specialty analysis modules like rigid diaphragm torsion.

If you're interested in learning about deploying Enercalc structural engineering library and Enercalc for Revit at your firm, please feel free to contact me. My information is shown here. I'd love to hear from you and get you started on that process.

With that, we want to give a huge thank you to Autodesk University and to Autodesk. We've been honored and privileged to present to everyone today and we want to go ahead and open it up for our open Q&A with the audience. And thank you, very much.