Building Information Modeling

Every few years a technological revolution comes along that completely changes the construction and architectural world. The current development is something called Building Information Modeling (BIM). While the theoretical principles behind BIM have been around for decades, it has only been widely adopted in the past couple of years. These days you would be hard pressed to open a construction trade journal without seeing a reference to it.

In essence, BIM consists of creating a very detailed database of an entire construction job during the design phase. Literally every single piece of the job has an entry containing its size, position, color, model number, and structural properties. This includes structural members, pipes, wires, finish elements, mechanical devices, furniture, and every other component. The process is often likened to “virtually” constructing the building on the computer. The software uses the database to generate all of the plans that are needed for field use and approvals. This stands in contrast to traditional drafting techniques where a draftsman prepares each page separately with drafting software.

BIM software is not limited to 2-dimensional plans, however. Today’s systems can generate a full 3-dimensional virtual reality model. The software is sophisticated enough that it even puts in the correct lighting for a specified time of day. Because the software also keeps track of the project schedule, it can render the job at any phase of construction, not just completed projects.

The advantages of these systems promise to be enormous. The amount of the information contained in the model allows for very complex analysis. For instance, many BIM systems contain tools for structural analysis that can save the structural engineer many hours. The architect can do lighting and energy analysis. In the past lighting design has required a lot of guesswork. Any good BIM model can provide the exact number of lumens at any point in the building at any time of day. Mechanical designers can model air and water flow throughout their systems. The energy efficiencies which can be realized simply by engineering improvements are huge. Many green building advocates are in favor of BIM technology simply because of all the electricity it can save.

BIM is a great tool for estimating as well. Actually, in a manner of speaking it is not even estimating any more. Knowing the exact amount of concrete, lumber, or any other material is a matter of a few clicks. Any construction manager knows that you can save a lot of money by having the right amount of materials available at the right time. BIM will make it much easier to do just that.

Perhaps the most important benefit from BIM comes in at coordination time. Even small buildings are often designed by dozens of different professionals. The architect draws the overall building but consultants design subsystems such as electrical, heating venting and air conditioning (HVAC), fire sprinklers, and many more. The consultants then meet with their plans and “coordinate” them to make sure that their various lines, pipes, conduits, and ducts are not running into each other. The idea sounds simple but coordination can often take weeks. Even then, some “crashes” slip through. Often conflicts between mechanical systems are not discovered until installation time, resulting in wasted hours of labor, reordered materials, and completion delays.

With BIM coordination is easy. Every building system is in the same database. The job is rendered in 3D and it is obvious to everyone when systems are in conflict. Some of the programs even have a function to flag all the crashes. I still remember the first time I did a BIM job. The general contractor plugged his computer into a big-screen TV and suddenly we were looking at a beautifully rendered version of the parking structure we were building. He scrolled along and showed me two places where my pipe was running into beams and one where the plumber and I were trying to run pipe in the same place. The incident was embarrassing, but it made me a believer in BIM for coordination. It only took me a few minutes, back at the office, to move my pipes. If the problems had made it all the way to the field we would have needed to tear out thousands of dollars worth of pipe while the other trades waited on us.

BIM technology seems wonderfully useful and powerful. There can be no doubt, however, that it is going to change the whole construction world. The advantages of BIM are only available if every company on the design team has the hardware, software, and training to use it. A basic computer workstation for BIM costs nearly twice as much as an ordinary drafting workstation (somewhere around $10,000). Actually the price tag is higher because no one BIM software suite dominates the market. A contractor needs to have copies of the software used by every other company it works with (at $6000+ per copy). For many small companies this is just too much to spend. Some of them even still draw jobs by hand. BIM will leave them behind. They will be forced out of the ground-up construction market entirely as contracts go to bigger, more technologically advanced companies. I have already seen construction contracts that require the contractor to have and use a particular type of BIM software. This is probably a growing trend.

Small construction companies have always brought energy and ingenuity to the industry. It will get harder for small companies to break into the industry and harder for existing small companies to stay in. The big established companies will have the advantage, which could all too easily lead to stagnation.

As the equipment gets more advanced, the knowledge required to run it also increases. In the past many construction managers and designers came up from the trades and learned to design on the job. Construction jobs that use BIM are so complex, though, that people with advanced degrees have a real advantage. As time goes on and ever greater education is required for these jobs, we will see massive professionalization of the construction industry. This is good in that it will ensure high pay and standardized training for people who do highly technical, life critical work. It is bad because it will deepen the gulf between the building trades and the building professions. Tradesmen will have less and less idea of what goes on “upstairs in the engineering department” or why they do things. Meanwhile we will see a generation of managers and engineers with very little job-site experience. The construction engineer will go from being a master builder to being a master computer programmer.

The possible adverse effects of BIM technology could create real problems. Even so, the likely advantages are sizable. The industry is investing a lot of time and money into BIM and it is likely to be a powerful force in the construction world from now on.



Posted on March 22, 2009, in Essays and tagged , , , , , , , , . Bookmark the permalink. Leave a comment.

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