From 2005 to 2009, building information modeling (BIM) technology experienced a 160% increase in use by the mainstream architectural community, according to a recent survey by the American Institute of Architects (AIA), Washington, D.C. The survey also reveals that more than 75% of responding architects reported “very heavy” or “heavy” use of BIM technology in their projects in 2009. “We're well past the tipping point now,” says Markku Allison, resource architect for AIA. “At our 2005 convention, the opening plenary session was about BIM, and of the nearly 4,000 architects in the room we got the impression that 85% had never even heard of BIM. Now when we go on the road, everyone knows what BIM is, and the audience can offer up success stories about using BIM.”
In fact, architects currently make up the largest group of users of BIM technology. In 2008, a SmartMarket Report published by New York-based McGraw-Hill Construction revealed that more than 43% of architects were using BIM on more than 60% of their projects. Furthermore, the report, “Building Information Modeling (BIM): Transforming Design and Construction to Achieve Greater Industry Productivity,” predicted 54% of architects would become heavy users of BIM in 2009.
Nonetheless, the use of BIM requires more than the adoption of its technology by one group in the architecture, engineering, and construction (AEC) industry. In essence, BIM as a project delivery method contains two elements. The first part is a 3-D modeling desktop computer application ruled by an information database used to detect conflicts of operating parameters and ensure construction clearances. The second component comprises a collaboration process in which the architect, engineer, and contractors on the project cooperate from the design phase to the end of construction — and sometimes even into the maintenance phase — in an effort to improve coordination in construction administration, reduce change orders, and facilitate upkeep. For that reason, BIM is a team sport.
Therefore, in conjunction with architects, engineers and contractors are adopting BIM technology and practices at a speedy rate. In 2008, 35% of all engineering disciplines combined reported using BIM on at least 60% of their projects, according to the McGraw-Hill Construction SmartMarket report, which estimated that, in 2009, 16% of engineers would be “heavy” users of BIM and 43% would be “very heavy” users. Additionally, the report's authors expected all combined contractors to adopt BIM at an even faster rate. In 2008, only 23% of contractors reported using BIM on 60% or more of projects, but a 15% increase at that level was expected for 2009, leading to a total of 38% (click here to see Fig. 1).
Despite these leaps in rates of BIM adoption, the electrical industry lags behind other trades, although some electrical contractors may be using BIM software without realizing it. (For more on this, read “Barriers to BIM,” published in the March 2009 issue of EC&M and available on the Web site at http://ecmweb.com/market_trends/industry_lags_bim_adoption_0301/). The frequency of modeling all electrical design elements is low among electrical engineers and contractors, says the McGraw-Hill SmartMarket report, which attributes this trend to the relative lack of content for electrical elements. Currently, BIM software vendors do not provide an out-of-the-box application that comes with electrical content, and very few electrical manufacturers offer BIM objects. The report also argues electrical elements require less space in buildings compared to structural and mechanical systems. As a result, the lack of coordination issues for electrical components makes modeling less critical.
Likewise, results of a 2009 survey funded by the National Electrical Contractors Association (NECA) and published in the fall 2009 issue of the Journal of Building Information Modeling reveal only 21% of responding electrical contractors were using BIM technology in their projects. The 79% of responding contractors not using BIM offered a variety of reasons for not doing so (click here to see Fig. 2). Unfamiliarity with BIM was cited by 64%, followed by a lack of technological experience reported by 24%. Incompatibility with existing software was credited as the cause by 13%, and 11% cited the prohibitive cost of software and hardware. Finally, 8% claim BIM has not been required by customers or design teams.
Speed of BIM
Notwithstanding two years of experience in BIM software, for every hour the BIM team at the Ashland, Ore.-based office of Douglas Engineering Pacific, Inc. puts in on design time, it spends up to an additional 3 hr dealing with its characteristics and performance. “Sometimes it's like swimming in honey,” says Myron Hudson, CSI, VP at the firm.
The slow work speed has caused Hudson to postpone his own introduction to the software until next quarter. Instead, Hudson writes the specifications for and manages the BIM projects, leading the five team members already working in it and coordinating the trades. “It fell to me to look at the big picture because the team was bogged down in the BIM implementation,” Hudson says. “It was necessary that somebody be working at something other than BIM software speed.”
The way the BIM software uses the memory on the machines is partly to blame for the slowdown in design, according to Hudson. Although the firm upgrades its computers every three years, the BIM software still clogs the machines. “It doesn't spread itself around,” says Hudson, who adds the team must also make sure all other applications are closed before opening the BIM program. “They've had to strip down their desktops.”
The file structure required by the BIM software in Hudson's office also contributes to the slow work pace of the project. The file structure in BIM is far more critical than with CAD, according to Hudson, who adds that in CAD, the file structure can be set up within any number of parameters, can vary between firms and team members, and can be altered if necessary as a project progresses. “With CAD programs, there's any number of ways to cross-reference drawings or arrange your files,” says Hudson. “Unless somebody changes something, all you have to do is repath to a different file.”
On the other hand, BIM is less flexible and more susceptible to user-generated problems. “It's very finicky,” notes Hudson. “You have to set up the families a certain way and you have to set up specific coordination views. It's just a lot more complicated and cumbersome.”
However, once BIM is implemented throughout the industry, this negative attribute could quickly become an asset. “As long as AutoCAD's been around, we've encountered some really awkward and sometimes backward and unsystematic approaches to file structure with clients,” says Hudson, who hopes BIM's file structure will become a standard soon. “Finally, everybody will be doing things the same way.”
In addition, other delays can be attributed to various bugs in the BIM software. “There are other problems that I can't begin to understand, but I know it can result in two or three guys standing around one machine trying to work through a problem that should be a simple fix,” Hudson says.
For example, in Hudson's experience, the software will show the load and circuit number of a panel, but then the model will change and the outlets will no longer be snapped to the walls. However, when that situation is corrected, the program will lose the circuit.
This is different from CAD, in which you simply stretch components to their new location. “In terms of editing power, I would say it's nowhere close to CAD,” Hudson says, attributing the difference to drawing systems in 2-D or 3-D versus building them in 3-D. “Editing a line or symbol is less destructive to the overall drawing than revising objects that are more representational.”
Currently, Hudson's team is working on a large federal project. To track the time his team spends on problems related to the BIM technology, Hudson had to set up a sub number within the project for the team members to assign their time to that would go purely to BIM software issues as opposed to design issues. “We needed to more accurately track that overhead so we know it didn't take that many hours to design the project,” Hudson says. Recently, Hudson's team was able to increase speed by adding memory and adding external solid-state hard drives running Windows 7.
Most of the projects in which Hudson's team uses BIM are single-story educational buildings. However, Hudson thinks it will probably be quite some time before BIM is used on small projects in the private sector. “It's going to have to be really slick and mainstream by then,” he says. “Only large projects could absorb the time spent on the BIM software. It's not worth the time for the small ones.”
Yet, BIM currently isn't appropriate for large-scale projects either. “It's at an awkward point on the curve right now,” Hudson says. “Right now, the demands of a large project in terms of the size of the model and amount of information are really pushing the limits of what BIM software can deliver.”
It's certainly not cost-effective for small projects, notes Hudson, but as a production tool it leaves a lot to be desired for large projects. “We're still working on this big project, but if we had done it in AutoCAD, we'd be finished already — and we'd have more detail on the drawings,” he says. “It's just the way it is right now.”
(For more information on the differences between CAD and BIM, read “Making the Transition from CAD to BIM,” published in the March 2009 issue of EC&M and on the Web at http://ecmweb.com/design_engineering/bim_switching_benefits_0301/index.html.)
Economy of scale
Three years ago, as the design build manager at a California-based electrical contractor, Michael Sine was part of a project team using BIM on the design and construction of a public elementary school. Although Sine believes BIM can be valuable tool when used correctly on the right size project, this one was too small. The design of the 2-story school consisted of tilt-up concrete walls and contained classrooms, hallways, and a kitchen. The electrical contract totaled approximately $1 million. “It was a fairly simple job,” says Sine.
Because of the size of the project, the preconstruction phase grew out of proportion with the design requirements. “Everybody was a big proponent of making sure we all met together at the same time, and anyone not in attendance had to account for that “ says Sine. “There weren't very many items where the resolution was left for subsequent meetings. If there was a problem, it was brought up. But sometimes the best decision could have been not to have everyone involved in the decision.”
By the same token, there were multiple design charrettes, which resulted in prolonged discussion. “There were a couple of instances where they took too long and didn't always realize the impact on anyone else,” says Sine. “Sometimes subcontractors would have been more productive somewhere else. It was for the most part a consensus decision, but I obviously was not going to comment on structural items, and the structural guy wasn't going to comment on my items.”
Moreover, the project was not complex enough to warrant the amount of detail put into the BIM 3-D models and database. “The customer wasn't sophisticated enough to use the information,” says Sine. “Unless you start getting things over a couple of inches in diameter, it doesn't make sense to model it.”
At the construction site, an overbuilt model can delay the work. To access the model, there must be a computer equipped with viewing software on-site. In addition, a dedicated BIM team member must have the knowledge to manipulate the model and address any changes. With such a large model and an inexperienced team member, access to the design sometimes required two or three team members. “We didn't need all of that,” says Sine, who admits that the clash detection for cable tray was helpful but not necessary. “Because it was a basket tray, it was pretty adjustable. If we didn't have it absolutely perfect every time, it wasn't the end of the world. We could make some bends and move it around.”
Yet, despite the amount of detail, other components that should have been included in the design, such as footings, were left out of the model. The seismic requirements in California require an undisturbed “angle of deflection,” which is the 45° angle around the footing. “The locations were picked under the premise that it would not be a problem for us to stub up anywhere,” says Sine. “It was a problem, but the issue was sloughed off even after we tried to explain to the team that we really needed to take the time to model the footings. Only those in the electrical world thought that would be of use.”
Missing electrical components are common in BIM software. On average, a BIM library contains more than 50,000 objects, but firms usually have to create them from scratch. “I haven't seen a lot of components within the electrical world that are modeled in 3-D,” Sine says. “Even if we know it's a 75-kVA transformer, we couldn't go to a manufacturer's Web page and pull down a 3-D representation of exactly what it is. We can't go in and grab a specific light fixture or a piece of switchgear or a transformer.”
In the absence of a sophisticated library, most electrical engineers and contractors make up the components as a block. “If it's a transformer, it's approximately 3 in. × 3 in. × 3 in. square in the model,” says Sine.
A positive evolution for BIM software regarding electrical components is the addition of energy modeling capabilities. “Energy modeling software is starting to tie a lot more into the BIM world,” says Sine, who has been focusing a way to model real loads and tie them into the BIM model. For instance, if the rooftop unit in the model is changed, the software calculates the net change in energy use. However, lighting calculations in BIM programs are still deficient. “When you get down into the lighting, the team always just looks at the engineer or the electrical designer and asks how many watts per square foot,” says Sine, who agrees that mechanical and structural components are more advanced than electrical. “It's also not based on actual fixture installations.”
The structural engineer on the California school project was able to export its own CAD program into a fabrication system to have the pieces cut by laser-guided machines. Nevertheless, many smaller ancillary connecting pieces, such as bracing, gussets, and weld plates, weren't modeled within the structural drawing. “Some of the places where we were trying to put sleeves in didn't always hit quite where they were supposed to,” Sine says.
According to Joe Davis, P.E., LEED AP, CEO of Custom Engineering, an Independence, Mo.-based mechanical and electrical engineering firm, mechanical and electrical subcontractors have two choices when it comes to adopting BIM software and processes. The first choice is to adopt BIM and bring it in-house by investing in the hardware and software, as well as hiring a BIM technician.
On average, subcontractors are smaller firms relative to general contractors, so they have a more difficult time absorbing the costs of adoption, according to the McGraw-Hill SmartMarket Report, “2009 Building Information Modeling Study.” “It's expensive if it's their first project, or they don't do very many projects that use BIM,” says Davis, who estimates the first year of BIM adoption could cost a firm around $80,000. The costs include $6,000 for the software, $4,000 for hardware (at least one high-performance computer), and around $60,000 to hire the BIM coordinator. In addition, it can cost around $10,000 and take up to three years for the coordinator to build the objects library. “There is some free content,” says Davis. “You can search the Internet and find some things that have been created, but you might have to do it yourself.”
Furthermore, the variety of BIM software applications may add costs and also cause interoperability issues. Therefore, another option for subcontractors is to hire an engineering firm to coordinate with the project team and add the electrical or mechanical systems to the 3-D BIM model. “They can hire somebody like us on an ongoing basis or for a lump sum fee,” says Davis. “Sometimes it's just easier to hire the service out. We can do it for much less than what would be invested. It's a way to ease into it.”
For subcontractors not using BIM at all, the major reason is lack of client demand. However, according to the McGraw-Hill report, general contractors are increasingly mandating BIM from key trades, and owners are demanding it from entire teams (Models Required on page 22). On the federal level, the U.S. General Services Administration (GSA) requires BIM for spatial validation and the U.S. Army Corps of Engineers mandates complete BIM for many of its standard building types. At the state level, both Wisconsin and Texas require BIM for new projects. Many private owners are also mandating BIM use from their project teams. John Moebes, director of construction for Crate and Barrel, Northbrook, Ill., runs an all-BIM nationwide program. “More and more, general contractors are requiring their subs to provide BIM coordination drawings and coordinate with the other disciplines,” says Davis. “Often, the contractor is creating a 3-D model and is telling the subcontractors that if you're going to work with us, you're going to have to coordinate your discipline in BIM.”
Sidebar: Models Required
Through its Public Buildings Service (PBS) Office of Chief Architect (OCA), the U.S. General Services Administration (GSA), considered the nation's largest real estate owner/operator and responsible for $10 billion annually in new and renovation construction activity, has encouraged the use of building information modeling (BIM) since 2003. Initially, results from nine projects were used to judge the success of its BIM program. Since that time, the GSA OCA has expanded the BIM pilot program into more regions and involved more design consultants, contractors, and technology partners. In 2007, the agency began requiring basic models for all projects and encouraging more complex models incorporating energy performance and construction scheduling. OCA has led more than 30 projects in its capital program and is assessing and supporting 3-D, 4-D, and BIM applications in more than 35 ongoing projects across the nation. According to GSA, the power of visualization, coordination, simulation, and optimization from 3-D, 4-D, and BIM computer technologies allow the organization to more effectively meet customer, design, construction, and program requirements.
In 2009, Wisconsin and Texas began requiring BIM for their state projects. In Wisconsin, the state began exploring BIM after an executive order signed by the governor in 2006 required all state buildings to conform to high environmental and energy-efficiency standards. In July 2009, after a 13-project pilot program, the state became the first to require advanced models for all state projects with budgets over $5 million and new construction projects over $2.5 million. The state requires BIM 3-D models from several members of a project team, including architects, structural engineers, and mechanical, electrical and plumbing (MEP) engineers. However, it does not require the team to work on a single model or in a particular modeling software, accepting models created in five software packages.
Texas requires BIM use for all new state projects. Renovations and legacy projects may soon follow. The Texas Facilities Commission (TFC), the Austin, Texas-based agency within the State of Texas that oversees the state's real estate development as owners and operators of state facilities, encourages a single BIM 3-D model that can track changes over time for each project. The model is stored on a state server that project teams can access. The state prefers all models to be made using one particular brand of modeling software to avoid differing platforms in the future.