BIM / VDC-not easy, just Right

For all the clients out there who hear ‘BIM’ or ‘Revit’ or ‘VDC’ and have been led to believe it is a panacea for what is ailing our industry- I have to tell you it can and shouldbe; Now… understanding what that really means and what is involved is tricky. There is the initial wow factor when someone sees a model for the first time – but 3D is a minimal BIM Benefit and I avoid showing it until later.

OK- So what are the greatest benefits? In my opinion there are a few immediate practical benefits and more indirect ones down the road, so I will break it out from the Design aspect through the CA Aspect then into FM and Civil/Government aspects.

Before anything – there is the BIM concept wher the first paradigm shift to understanding BIM is the “Building Information Model” itself. When a BIM model is created – the Model, not “lines on paper” is driving the process. When treated properly the 3D model is inherently coordinated as all views come from the same model. The Plans, sections and elevations are extracted from the model almost like a by-product. Integral to the process is Information- which is all about the DATA- text, numbers, geometry, dates, weight, physical properties etc. What you want out of the model determines the amount of data required determines the amount of work put into the process. This is referred to as the LOD or Level of Detail in the US, or similar ‘drawing level’ in the UK. All this information must be assembled into the model in a way that makes sense- typically paralleling timelines, construction methods, phasing, etc. This is wher Design/Build and Virtual Design and Construction (VDC) shine.

From a practical standpoint VDC should be used to prototype any and every structure subject to any process from approval, permitting, HOAs, analysis and more. Statistically speaking- most people balk at the ‘all’ comment, but as VDC/BIM is typically used in large projects – benefits can be reaped regardless of scale.

In Design, the traditional method relies on “design intent” and then the contractor determines means/methods in the field. This is less efficient, and with contracts and legal obligations creates a sometimes adversarial relationship between the groups handing off the building, e.g. Investor to Architect to Contractor to Client, etc. as everyone is litigiously looking after their interests and protecting themselves out of an unfortunate necessity. Every time a transition happens, information is lost, accidents and errors creep in and things go wrong.

With the VDC we working out the issues in the computer before it ever gets built. It is more complicated to manage- more liability- unknown- which is why everyone has been steering away from it. But by getting the sub-contractors and trades that will build it involved while the project is being designed and committing to that solution has been recorded as saving as much as 18% in construction/change order costs. Additionally, everyone, including the client, knows what they are getting in a prototype before spending a lot of money to get it in place only to realize something is wrong.

With VDC a ‘digital prototype’ approach the fee structure must be different.  Consider when something changes in the model – it is akin to changing a building that is physically under construction; and the more complete the model, the more difficult it can be to make the change. So traditional CAD design fees are unrealistic; feesproportional to a physical building change in the field are more correct. As VDC overlaps SD, DD, CD, CA and on into FM (Facilities management) the differences in the fees are embedded into a whole, possibly turnkey process, so the difference is not as painful for a client when a substantial change is made during the design process- however design change orders will be more substantial than their CAD predecessors.

WBDG estimates that over 30 years 2% of a building overall cost is in design and construction while 6% goes to operations and maintenance and 92% to personnel. For a large structure an accurately maintained BIM/VDC model reduces the cost of change orders by up to 18% during the construction. For design/build during this transition that relates to a much broader profit margin. Considering the analysis aspect should illuminate the cost factors involved with other aspects of cheaply constructed buildings as opposed to those built to be more durable and lasting. Clients can reap the benefits of using better materials over a few years in addition to making the building less of a strain on limited electrical, water, construction and other critical resources.

As to Civil/Governmental/Regulatory benefits- if every building constructed had an as-built and maintained model with it, maintenance and renovation becomes much less costly. Other more intangible benefits include cities having detailed 3d models of buildings relative to one another so that adjacencies and other relationships can be easily determined. One example I like to share is a fire fighter trying to access the upper floors of a building wher the lower floors are fully involved in a fire- could use these 3d model maps to break through a wall in an adjacent building to rescue people on the upper floors. Cities can examine building systems to evaluate, manage, maintain and evaluate resources like water and electricity making it easy to tell if there were issues within a region, block, building or dwelling- and the benefits go on.

FM or Facilities management can shift from using huge stores of file cabinets located in the basement to interactive Trimble devices and property tags to go through and see structures with x-ray vision through the use of augmented reality and cloud based information kept within the building or stored within secure clouds and/or government GIS databases. Using Integrated Project delivery (IPD) the exact make and model could be reordered with the push of a button.

It is all about perspective and shift in awareness from trying to turn a quick buck and ‘just survive’ to realizing that a buildings have their own lifetimes and how much so very many things touch and interact with one another and how everything can benefit from a wholistic and systematic approach from concept through construction, occupancy, maintenance and eventual decommissioning.

Change is difficult, but in this case- it is just right.


Possible impacts of the use of Building Information Models (BIM)

2020-10-23 0:05:56


Design, Earned Value and BIM

2020-10-23 0:05:59

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