Feature: Do You Know BIM?
Professional Surveyor Magazine - September 2013
Clients are increasingly asking for building information modeling (BIM) in some form. Is your firm ready to meet the challenge? Take this quiz to find out how much you know about BIM.
By Cathi Hayes
If you’ve been watching market trends, you’re probably aware that building information modeling (BIM) has the potential to be big business. In the $4-trillion global building construction industry, BIM represents a way for owners to lower costs and increase quality.
BIM is a game-changing process where a building is designed as a virtual model with intelligent building components. With BIM, costly and wasteful rework is avoided because the entire project team coordinates and collaborates on the same model. Constructability problems are identified and corrected much earlier in the process so that any issues are resolved in the office and never make it to the field.
Successfully applying BIM on a project requires an understanding of what BIM is and how it affects each stage of construction. Test your knowledge with this quick quiz.
1. True or False: BIM is just marketing hype
Answer: FALSE. A study released by McGraw-Hill Construction
in 2012 noted that 71% of architects, engineers, contractors, and owners are now using BIM in North America, up from 49% in 2009 and 17% in 2001. Additionally, nearly 40% of BIM users said they do more than 60% of their work in BIM.* BIM is growing.
2. True or False: BIM is primarily an office process.
Answer: FALSE. In its most basic form, BIM is achieved through modeling software in an office environment. For many firms, this is where BIM begins. However, knowing how accurate that model is and where the data originated is also an important part of the BIM process. For this reason, even greater benefits can be gained by extending BIM from the office to the jobsite and from the jobsite back to the office. In fact, according to the McGraw-Hill Construction study, the top two emerging BIM field trends are as-built data capture (with laser scanners and total stations) and construction layout of the structure and mechanical, electrical, and plumbing (MEP) systems.
3. True or False: Laser scanning is an integral part of BIM.
Answer: TRUE. Many models are developed from as-built paper drawings that are outdated and inaccurate, which leads to problems in the field during construction. Informing the model by beginning with a solid foundation of accurate, reliable information is imperative to avoiding rework and to streamlining the process. Using laser scanners or multistations to capture real-world conditions is an easy way to take the guesswork out of the equation. The resulting as-built point cloud can then be converted to an as-built model or used natively to inform new construction.
For example, when the Beck Group
was charged with creating accurate as-builts on the North Texas School of Law, the firm used the Leica
ScanStation P20 scanner and Autodesk
Revit with Leica CloudWorx to quickly and accurately capture interior conditions after demolition to inform the renovation work. New construction was planned within the point cloud to assure that everything was designed around the reality in the field. This process substantially reduced rework in the field and kept the project on time and on budget.
This same practice can be applied to renovation projects, demolitions, and any situation where documenting the existing space can provide valuable intelligence that reduces rework and waste.
4. True or False: A 2D design process is sufficient for building projects.
Answer: FALSE. Translating 3D ideas and designs into 2D drawings is the source of many constructability issues that come to light during construction. Designing in 2D does not provide the insight needed to head off potentially costly problems in the field. We live in a 3D world and design three dimensionally, so translating a construction model to a 2D drawing is counter-intuitive. The longer we keep the information in 3D, the longer we’re able to maintain the integrity of the highly coordinated 3D model.
By using highly accurate total stations or multistations combined with intelligent software, we can apply construction layout points to the model, or lay out drawings from the coordinated model, and then automatically transfer those to the jobsite to create an easy-to-follow plan for the contractors and installers. Enriching construction with high levels of accuracy streamlines processes, reduces the risk of errors, and improves predictability.
A real-world example of this process is in the construction of two new 300,000-square-foot, ten-story towers plus a single-story entry building for C-Tech in Atlanta, where Holder Construction was charged with increasing the accuracy and productivity of concrete layout on the multistory building. Holder understood that, if the structure were built incorrectly, nothing else would fit as designed, creating a domino effect of problems.
Instead of relying on 2D drawings, Holder extended the accuracy of its 3D Revit models into the field by using total stations to replicate the layout points from the model on the construction site. Every point was located precisely, creating “paint by numbers” installation for the tradesmen. This process resulted in faster, more accurate concrete layout, as well as a savings in time and labor costs.
5. True or False: Every model should be validated with real-world data from the field.
Answer: TRUE. Change is inevitable on the jobsite. Formwork for concrete bows moves or gets kicked, or errors in steel placement are made. If the structure shifts or changes during construction, then other components such as MEP systems that are yet to be installed may not fit. One small error can bring the entire construction project to a screeching halt, as workers wait for the right parts to be delivered for rework. Avoiding this situation requires a continuous flow of information from the jobsite back to the office as construction occurs.
When construction began on Sutter Health Eden Medical Center in 2009, the construction team used a highly coordinated 3D model in the office. However, coordinating the MEP contractor’s work in the field was a challenge. Changes in the concrete and steel structure during construction frequently compromised the spaces allocated for building systems. To overcome this problem, Ghafari scanned the structure as it was erected and then merged the scan data with the model using Leica CloudWorx with AutoCAD and Bentley
Microstation to identify deviations. This process allowed Ghafari to quickly identify clashes or interferences. These insights allowed the project team to solve problems digitally, thereby preventing delays in the construction schedule.
By capturing the construction in progress using highly accurate laser scanners, total stations, or multistations and then merging the real-world data with the model data in the office, teams can validate the design as it is built and keep their projects on track and on budget.
BIM offers tremendous benefits in building construction, but these benefits can be fully realized only if the cycle is complete. By understanding what BIM is and how it can be applied successfully throughout a project, service providers can play a key role in this rapidly growing market. Providing highly accurate, real-world data turns construction models into data-rich, highly intelligent tools that add value at every stage of the construction process and throughout the lifecycle of the asset.
Cathi Hayes is an architect, BIM pioneer, and strategy leader and is the BIM business manager for Leica Geosystems, Inc. She can be reached at email@example.com. For more information about BIM workflow solutions, visit www.leica-geosystems.us.
*McGraw-Hill Construction, “The Business Value of BIM in North America SmartMarket Report,” http://construction.com/market_research/default.asp
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