BIM for Contractors

               The traditional style in which contractors went about estimating and then building a particular building was off of a classic 2D building plan set. This plan set included the civil, MEP, structural, etc., drawings to complete the building. A General Contractor would get those plans and divide them up and send them out to their subcontractors. This process takes a while and in the end many issues with fitment of mechanical systems or other systems crossing each other in the wrong manner will occur especially in a very large building. This causes change orders to be sent to the GC and eventually the owner because it costs money to fix these issues. This also causes the schedule to get behind and set the completion date of the building back further than it probably already is by the time some of these subcontractors are on site.

               Everything I just spoke of could be avoided and many companies are switching to BIM to try and avoid the issues. The idea of a BIM program is to be able to take those 2D drawings the engineers produce and create a 3D model which the owner and contractors can look at and walk through. This helps the owner visually see what their building will look like allowing them to change what they don’t like before they see it physically in the building. While, at the same time allow the general contractor to voice their concerns or possible issues with constructing this building before they come up in the construction phase. What a BIM program like Revit allows the contractor to do is to find all the problems, clash detections, before the building is even constructed. This eliminates the need for change orders saving the owner both time and money. The more detailed the contractor can make the model the less surprises there will be in the field. Another benefit to using a BIM program is the ability some of them have to aid in the takeoff and eventual estimate of cost for the project. The contractor needs to put an estimate together and if the program they are using can do all the takeoff, clash detection, some calculations, and more it will only make the estimate more accurate. In turn, the more accurate the estimate is the more money the contractor could stand to make, and the more jobs they will win because they are not over-estimating or under-estimating.

               Another consideration that could be made with using a BIM program to build and estimate the job is that you could possibly implement a process of Lean Construction. The construction industry is the most wasteful industry for many reasons like over estimation of materials needed, not properly storing materials so they get damaged, and an overall culture that has been engrained in the minds of many project managers, superintendents, and laborers. What lean construction aims to do is lessen the amount of waste by upwards of 90%. This therefore allows the contractor to make more money on the job all because they may have budgeted to use more material or they were able to win the job with a higher profit margin due to the reduced direct cost. This type of construction also lends itself to tight urban environments, because the contractor does not have a large space to store materials for the next month’s work.

Reading

C. M. Eastman, “Chapter 6: BIM for Contractors,” in BIM Handbook: A Guide to Building Information Modeling for Owners, Managers, Designers, Engineers, and Contractors, 2nd ed., Hoboken, NJ: Wiley, 2011, pp. 263-304.

COMMENTS:


Mark Odorizzi

You had made some interesting points and I believe you are right in that our generation will be the

one to fully embrace Revit. I believe that if the industry in general moves to this type of 3D design

that it will only make the construction process move quicker. There will be less issues and change

orders if a building is designed in Revit (BIM Program). Also, the need to print as many 2D plans

will be lessened, since superintendents will carry an iPad around with the BIM model on it instead of

a stack of rolled up plans. I believe this will make the construction of a building more accurate and at

the same time easier because the super will be able to show a laborer what it should look like in 3D

instead of trying to explain it to them from a 2D plan. The building delivered should also match what

the client or owner envisioned much better.

Dee Dee Strohl

You bring up a very useful property Revit has. I did not know that Revit had the ability to be worked

on simultaneously and updated in real time. This, like you had mentioned, allows the various

engineers and architects to alter things at the same time and not have to a few weeks later learn that

everything they were designing for is completely wrong because the architect moved a major

structural wall you were counting on using to run the duct work. Revit let’s all the disciplines know at

the same time, allowing them to adjust and speed up the overall design process. Which, since I

worked in the construction industry, this would limit and drastically reduce the conflicts and the

construct-ability issues certain designs have. Overall, I believe and have seen some evidence for the

fact that with BIM the overall design and construction process will be much quicker.

Kerry Milligan

Obviously BIM programs have many upsides to them. These programs are taking over the design and

construction industry very rapidly because of the abilities they have. There are a few issues with them

though, the biggest being the learning curve involved to actually understand and know all of the

capabilities one of these programs like Revit has. As you had said this is probably one of the biggest

drawbacks, which is probably why many construction companies that I know of are creating new

departments to simply deal with 3D modeling. Even civil construction companies are modeling

bridges that you see on the turnpike so that their laborers know what it should look like or how they

may go about constructing something. By dedicating a department with two or three modelers in it,

they can focus simply on creating the model and bettering their abilities in the program.