What's BIM to You?
October 24, 2011
Wall and ceiling contractors are fix-up specialists. If they are first on the job site, their walls get punched full of holes as one by one the electricians, plumbers and other trades arrive and make fresh penetrations. The framing contractor must return each time to repair the breaches and bring the walls back up to UL codes-driving up job costs and eroding profit margins. How much? 30 to 35 percent is an acceptable industry value for the overhead cost due to rework. Alternatively, sometimes the framer is the last one on the job, in which case he must cut each stud to fit, an expensive process that wastes a lot of material.
This is the way it has always been done and humans are by nature resistant to change. But sometimes the benefits of changing the way you do something are so powerful that, a few months after making that change, you can’t imagine going back to the old way.
Building information modeling is changing the way buildings are designed and constructed. It facilitates two-way collaboration and communication between architects and the trades, resolving details and potential conflicts before the concrete slab is poured. It also requires that you change your work processes. BIM is like a train hurtling down the tracks-you can stand aside and watch it pass or treat it as a ticket to new business opportunities.
Why Does BIM Matter?The single most important reason is: It’s where the A/E/C industry is heading. It is rapidly becoming the standard in the industry. If you want to keep getting meaningful projects, you must look seriously at BIM. Your future livelihood may depend on it. It is the equivalent of when electronic drafting/CAD was introduced; within a few years, if you couldn’t hand over electronic deliverables, you were unemployed.
The second reason is that, in these tough economic times, BIM is a means to gain an advantage over your competitors and grow your business. The more interesting and profitable jobs-government and healthcare for example-mandate the use of BIM.
Third, BIM actually works! It allows you to meet tight project schedules and detect and solve construction issues before they require costly fixes in the field. As project schedules become more compressed, the need for close collaboration with other trades and disciplines becomes acute. Through BIM, multiple wall penetrations from all of the trades can be modeled in such a way as to eliminate clashes while maintaining structural, STC and fire stop ratings.
Fourth, there are now walls and ceilings-specific software tools that will allow you to be BIM-compliant without a lot of training. The majority of these tools work with Autodesk Revit, the most widely used BIM platform in the A/E/C industry.
BIM Tools for Making Construction Easier, Faster and More EfficientBIM Framing: One of the beauties of creating framing within the BIM model is that you no longer have to generate one-off wall types for a specific project. You can create your own libraries, document when certain conditions must be met and then replicate (or make global changes to) that wall type/condition throughout the model.
KHS&S Contractors of Anaheim, Calif., has created its own BIM framing and rating systems using MWF (metal/wood/framing) Professional (www.strucsoftsolutions.com/mwf.asp), an automated framing plug-in tool for Revit that allows you to build templates and Revit families of objects that can be re-used.
“You have to invest the time to build your wall library, but you can get tremendous time savings by being able to populate framing on large projects without having to place each individual stud,” says KHS&S Contractors’ Director of Construction Rob Walter. “The ability to fill out ‘type’ properties when creating wall templates can help you address a number of things the Revit model should include, such as fire stopping.”
“One of the things we found using MWF Professional was that we were able to get a better idea of what our framing conditions were,” says KHS&S Technical Design Coordinator David Lim. “It also makes it much easier to coordinate with MEP scopes, resulting in a smoother installation of all systems. As we look to price our BIM efforts at KHS&S, one of the large unknowns is how complex is the building? With BIM, you can use factors like deck height. Is it a wide open ceiling, is it compact, is it a hospital, does it include trades that you might not see otherwise? Coordination with other teams can have a big impact on the duration of the coordination effort and can be a black hole of time. Setting up an efficient process agreed upon by all holders is critical, and BIM really facilitates this process.”
Clash detection, as well as the ability to create and specify wall penetration openings, is another BIM advantage. “This capability is critical to being able to handle the kinds of projects we do,” says Walter. “We bring the other trade files into the BIM model and build our wall openings and penetrations around them. This is particularly useful for MEP assemblies.”
You can perform clash detection even if you are using a variety of systems. DPR Construction uses different systems for designing ductwork, piping and framing, and then pulls the model into NavisWorks, where they can overlay the model and run clash detection.
More Examples of Benefits and Technologies with BIMFirestop management is another reason to adopt BIM as part of your work process. Walls, doors, windows and MEP openings change continually in a project’s pre-construction phase, which can be very costly if you have to solve firestop situations in the field. By working in the same modeling environment as the architect and other trades, you can identify situations that need special attention and arrive prepared at the job site. In MWF Professional, you can quantify firestopping UL requirements. The software will group openings automatically based on wall type and wall properties such as size, fire rating and by the property and characteristics of what is penetrating the wall. Based on these, it will make the process of selecting the proper firestop product easier. It will automatically insert place holders into the BIM model with PDF links to assembly. This can be used by both framers and the MEP contractor.
Designing with Manufacturer's Component LibrariesDo you use ClarkDietrich components? You can now create information-rich interior walls and steel framing using ClarkDietrich components with the BIM Wall Creator (www.clarkdietrich.com/support-tools/bim), a free add-on tool for Revit. You can design walls with a result in mind, such as height, fire or sound rating. The wall type will be created to reflect the proper assembly of materials necessary for wall construction, including manufacturer and product information, types of sheathing, overall wall width, UL and STC data, wall height design, LEED information and product SubmittalPro data sheet links. By changing different components in your wall assembly (wall board types, lateral loads, studs, etc.) the corresponding ClarkDietrich component will be pulled up (i.e., you can make choices based on your design criteria). The ClarkDietrich component specifications are imported into the Revit model. <
Other Tools - Taking BIM to the FieldAnother example of the integration that BIM provides on the construction side is the technology offered by Get the Point. Total Station from Get The Point (www.gogtp.com) gives your field crew the layout of your 3D-coordinated drawings and BIM information on the jobsite. The GTP software provides routines for putting points in Revit drawings for wall contractors. These utilities can record the precise radius of a wall, the exact location of a penetration, or the beginning and ending location of track. It will add points to families within Revit or mark wall points and face points. These X,Y,Z coordinates are then exported from the Revit BIM model and transferred directly to the total station equipment in the field.
The total station is an auto-pointing robot, with on-demand target re-acquisition. One person can do the layout in the field shooting hundreds of points per day in the dirt, deck or on the floor.
Hop aboard the BIM train-opportunity awaits.