Part 1 - Building Information Modeling Case Study from the Marshall Space Flight Center

By Tal Wammen

Ed. Note: This three-part article by civil and structural engineering student Tal defines Building Information Modeling (BIM) and takes an in-depth look at the process of evaluating its potential implementation at the Marshall Space Flight Center in Huntsville, AL. This first part focuses on the definition of BIM.

What is Building Information Modeling?
Building information modeling, or BIM, has recently become a valuable technology in the facilities industry. In its simplest terms, BIM is a building design and documentation process that is solely based around high quality data. This process allows design and construction teams to generate and manage information about the project, across its entire scope. As it becomes more widely known, BIM is changing the process, product and delivery requirements of the facilities industry.

Traditionally, the design process was made up of manually created, two-dimensional drawings. This has evolved into the use of computer aided design based software, which automated this procedure. Building information modeling is a completely different method. Going the traditional route means handling several 2D drafts of the projects, while BIM allows designers and contractors to work with a single 3D model. This model handles all of the tasks the 2D drafts are required to do, plus numerous other assignments. The idea of the BIM model is to allow professionals to explore a project's key physical and functional characteristics digitally, before it is built, and be able to interact with it during the entire building process.

BIM is not just a 3D model - it is a process. It is a method of carrying out the design process, from the original design development, to the actual construction of the project. Every bit of information that is gathered from start to finish is placed in the model. This means that all of the design data from structural, mechanical, civil, electrical and architectural engineers are entered into the same model in which the financial, planning and legal information is stored. This way, everyone who has access to the model can locate any category of data that they desire. The way this information is stored is key to the success of BIM. With the traditional 2D CAD based process, designers produce the construction drawings. These 2D documents are then handed to the contractors through which bidding, estimating, detailing and the actual construction phase take place. With BIM, the designers and contractors can work together through the model to increase the efficiency of the project by eliminating interferences and decreasing change during construction. Construction detailing informs the design rather than following it, allowing issues to be addressed earlier, which improves the quality of the project and lowers its costs. For this to be possible, a design/build contract format would be required. A key point in BIM is interoperability. Communication between each discipline is the only way BIM can be used successfully. The construction drawings, environmental conditions, procurement details and submittal processes make up BIM's fine details. If fully utilized, BIM provides the opportunity to prevent any information loss between the design team, construction team and owner. Each group has the luxury of referring back to the information in the BIM model.
Figure 1. BIM Flexibility Visualization.

There are many requirements that the project must meet in order to be called a BIM process. This is something that you cannot do overnight. To implement BIM, you need the right software tools. These tools will need to be integrated into your existing programs. Also, it is not something you can run on your old office computer, so more advanced hardware is needed. Depending on the extent of your model, you are going to need larger, multicore machines with a 64-bit operating system platform and more RAM than the computers you have now. Since the nucleus of the process revolves around the model, specific software is needed to fully encompass building information modeling. Major accredited BIM authoring software includes:

  • Bentley Architecture
  • Autodesk Revit Architecture
  • Graphisoft ArchiCAD
  • VectorWorks ARCHITECT

This software is very high powered. It is not simply an upgrade to your existing CAD programs, nor is it something you install one day and use the next. Typically, this software is three-dimensional and encompasses the building geometry, spatial relationships, physical characteristics, geographic data, and the properties and quantities of the building components. The model is built and maintained by everyone in the design process, from the owners and designers, to the engineers, contractors and specialty consultants. With this software, you have all of the needed project information and data right at your fingertips. For example, look at a wall from a building in design. This wall is placed in the model by the architect in his or her design sketches. Information (stud type and spacing, sheet rock, thickness, wall finish, etc.) about the wall is incorporated into the model by the engineers, and the constructors can add quantities of the materials needed. Estimators can then attach unit rates relative to the wall's material, and add in the time required for that part of the construction. All of this will then be used when computing the estimate of the project. Specialty consultants can also add information to the model, such as safety and security planning and light analysis, while the owners can also add in details and notes to make the model complete. As mentioned before, this prevents any loss of information between parties and allows for better efficiency, preventing conflicts. The primary focus here is that each discipline's software corresponds. They work together to create a model that combines data which are found across several documents, and they have the ability to share this information between other models. This creates an opportunity for better collaboration, which will inevitably produce enhanced, efficient design solutions.

What are the advantages/disadvantages of BIM?
With BIM, the pros certainly outweigh the cons. Though you will not have immediate results, once your BIM process gets up to speed, it is proven to increase your productivity. Sometimes change can be difficult, and because BIM may be a completely new process, it will take time to realize its advantages. Let's take a look at some of its strong points.

Obviously, new technology should bring increased benefits. The BIM process allows more flexibility, from the design of the project to the actual construction. Problems with today's building method deal mostly with changes in the project, either due to the designers and contractors themselves or the operations and maintenance. For example, once the design process is complete, the owner then has the ability to visualize the project, and can make changes to fit his need. Also, once the project is handed over to the contractors, they can then see problems and conflicts in the design before, during or after construction that may have an effect on the project. All of these changes result in a higher cost for the project, as well as delayed completion. BIM minimizes this by allowing the designer, contractors and owners to work together through the model to implement changes easily and efficiently.
Figure 2. Basic design process. (Click for larger view.)

The BIM process itself has many advantages, but most of its benefits are seen through the software. As previously stated, interoperability is key. With so much information being tossed into the model, what happens if something is changed or modified? With BIM, those changes are taken into account in each phase of the model. For instance, say that you get out to your job site and find that you have more room to work with than planned and the owner then decides that he wants an additional six feet added on to one side of the building. Conventionally, you would go back to the drawing board and modify every detail that this new dimension has affected. With BIM, you simply change it in one place and the changes flow through all of the affected details. When you alter a dimension or property of a component, it is recognized by the model, and it modifies every database that deals with that element. This helps avoid any conflicts down the road that would normally slow the building process.
Figure 3. BIM design process. (Click for larger view.)

The model also has the technology to produce several user-friendly documents that are needed during the course of the project. Today, designers would produce several 2D CAD-based plans. A typical design project ($10 million or more) can contain over 50,000 pages of documents. With BIM, all you have is the model, from which any one of these documents can be produced. This can eliminate field or shop drawings by having parties work within the shared model. Two-dimensional and 3D pdf files can also be generated to give the owner or employees better visualizations of the design process. These can be used for fixing conflicting elements, which are a common problem in today's design method. With the many documents needed for a given project, it is not uncommon for something to be overlooked, resulting in elements (walls, pipes, conduits, etc.) clashing with each other, ultimately disrupting the design process. (See Case Study 1, in the appendix(pdf).)

There are several other features BIM can offer. For example, 4D technologies, which utilize space and time, can be used for scheduling, sequencing and cost analysis. With 4D, you can digitally watch the project being built along a very closely estimated timeline, which gives an approximation of the time, money and other details needed for the entire project. The model is created and modified before construction, making it easier to visualize the building process and make any needed modifications, which will prevent the majority of the conflicts that normally take place throughout the project.

As mentioned, BIM offers the ability of specialized analysis tools to extract data from the design process to perform valuable analysis. Different fields of work use this capability for different tasks. For example, architects and engineers may use civil, environmental, HVAC and transportation data, as well as energy analysis and other abilities that are associated with sustainability, while contractors and owners may use different data for scheduling and cost estimating. Any category of data that is needed can be obtained from the work done in a BIM process. This gives every party the ability to speak the same language regarding the model, from the lead architect in the design even to the project's insurer.

Figure 4. BIM/CAD visualization. (Click for larger view.)

Since BIM is an emerging technology, it is going to have several risks and liabilities that go along with it. Obviously, one of the biggest risks a firm takes with BIM is errors in accuracy. Since the model is the core of the project, just one error in precision can be very costly. With today's project method, there are several different sets of plans that can be used to check one another and prevent such mistakes. With BIM, the plans are generated from the model, so they all reflect the same data, making it harder to catch small miscalculations that can lead to bigger problems.

Another setback that can arise is the price tag. BIM technologies, such as training, software costs and required hardware upgrades, are costly and it takes a lot of time to implement them into an existing process. Adequate training is needed in different areas, and levels of expertise can vary. The problem here is that because such a large amount of data is exchanged among team members, there is the risk that any weak link in the group could endanger the entire project. Also, staff buy-in is crucial to the success of BIM. There are general concerns that senior level management may not embrace BIM. Being higher in administration, they may not feel comfortable validating the costs and efforts associated with implementing BIM. Since they have been part of the organization for so long, they may be used to the current process, resulting in a hesitation to change the way they run their business.

Figure 5. BIM components.

BIM is a growing technology. Though it has its disadvantages, one positive fact to focus on is the future. BIM has the potential to become the leading technology of the building industry, and it is in the interest of most firms to begin their conversion toward its processes. The more BIM is used, and the more data that are collected and stored during the life of a project, the more benefits can be leveraged. As users gain proficiency with BIM, they will increasingly benefit from the technology's potential and push for new ways to gain advantages in every area of the project.

Ed. Note: Part 2 of this article will be published next Monday and will address the process of evaluating how BIM could be implemented at the Center, and discusses whether many BIM functions are perhaps already in place via its existing GIS.

Published Tuesday, June 8th, 2010

Written by Tal Wammen

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