BIM Article

Emerging Technologies Committee
BIM White Paper
 

CMAA’s Emerging Technologies Committee has prepared a white paper on Building Information Modeling and is soliciting member comments on the draft as part of its ongoing effort to support CMs and firms in adopting BIM.
 
Some say that with this adoption, the way projects are designed and constructed will be turned on its head.  The committee is intensely focused on producing reference material to guide members as they consider adopting BIM processes.  A BIM Standards of Practice is presently being drafted to be issued for CMAA internal review at the National Conference.  This will be followed by development of the CM’s Strategic Guide to BIM.  For this guide to be most successful, member input is needed. 
 
Professional service firms should be in control of their information sources.  Yet, as integration of design and construction proceeds, protecting public health, safety and welfare becomes most critical.  A licensed professional must be identified who is capable of monitoring and guiding the entire process to conform with the intent, design constraints and requirements of the design. 
 
Should this be the role of the construction manager?
 
After reviewing this draft, please forward your comments to the committee via info@cmaanet.org.

Building Information Modeling and the Construction Management Practice: How to Deliver Value Today?

Authored By: CMAA Emerging Technologies Committee Members: Soad Kousheshi, P.E. and Eric Westergren, A/E/C Strategy, Inc.

The Problem
It is generally accepted that the construction industry has lagged behind the general US economy in productivity gains in that last half century.  It has been reported that as much as 30% of the cost of construction is wasted in the field due to coordination errors, wasted material, labor inefficiencies and other problems in the current construction approach⁽¹⁾.  This waste and inefficiency is not readily discernable or tracked in project cost data.  But over time, the price of this waste has been accepted as a part of the cost of doing business and is built into every estimate, budget, subcontractor bid, contractor markup, contingency, allowance, and the like.

The Construction Users Roundtable, an association of executives representing some of the largest consumers of the construction industry, reports that its members regularly experience cost and schedule overruns.  These losses are in excess of the built-in inefficiency and waste referenced above.  Therefore, when considering the construction industry’s share of the US gross domestic product (GDP), the significance of productivity and waste statistics in the industry becomes starkly evident ⁽²⁾.

The Cause
A major contributor to inefficiency in the delivery of capital projects is the horizontal and fragmented supply chain of the A/E/C industry.  A unique combination of designers, consultants, subcontractors, and vendors is assembled to deliver each project in an increasingly accelerated time frame and is promptly dismantled, only to reassemble in a different combination for the next project.  Each entity has unique interests which, over time, have been protected through defensive and complex contractual mechanisms.  These interests and the business structure that has developed to accommodate these diverse and misaligned interests have become impediments to collaboration and innovation in the design and construction process.  Exceptions to this rule are observed, on occasion, when forward thinking owners modify the risk model and enable design and construction teams to work outside of the norm and extend their traditional comfort zones.

In the last two decades, a number of new project delivery approaches have been developed to address the inherent problems in the traditional building supply chain typified by the design-bid-build process, including construction management (CM), CM-at-risk, design-build, and a number of other hybrids.  Although these new approaches have enhanced the delivery process, primarily in reducing the total project duration, improved scope management, quality control, and risk allocation, they have not significantly reduced the cost of waste and inefficiency in the design, procurement, and construction process.  The use of critical path method (CPM) scheduling was another attempt by the industry to introduce some level of predictability, but scheduling techniques only address the time dimension of the process without the necessary visual link to the geometric elements of the facility.

The BIM Approach
To significantly improve efficiency in project delivery, the building design and construction process must, through better integration of information and process optimization, achieve levels of coordination far in excess of the current norm.  This desired level of optimization is similar to that achieved by the manufacturing industry through prototype development and product refinement prior the start of production.  Within the last two decades, large manufacturers have converted from the costly exercise of physical prototype development for iterative testing and optimization to virtual prototyping where the same process is duplicated faster and far more cost effectively.  Today the manufacturing industry enjoys the benefits from this conversion by speeding a product’s time to market, increasing product quality, and reducing engineering change orders once production begins.  These improvements became possible only after the development of the same technology that now forms the backbone of the building information modeling (BIM) applications now being adopted by the A/E/C industry.  This technology holds the promise for the building industry to achieve significant improvements and reduce waste through simulating the building process in a virtual environment.  The potential advantages span a wide range of outcomes including a better tool for design and engineering documentation and analysis, more robust cost estimating, improved trade coordination, optimized means and sequence of work, a powerful communication tool for design intent and construction plan, and an information rich as-built model for facilities management.

What is a Building Information Model?
BIM is a process by which digital representation of physical and functional characteristics of a facility are built analyzed, documented, and assessed virtually, then revised iteratively until the optimal “model” is documented.  The process then continues through construction and construction as-built documentation and again during the lifetime of the facility.  As such, it serves as a shared knowledge resource for information about a facility forming a reliable basis for decisions during its lifecycle from inception onward ⁽³⁾.  BIM is more than 3D modeling, although the 3D model is the geometric platform on which BIM operates.  The ability to assign attributes and data to the objects in a 3D model is an important consideration in differentiating a 3D model from a building information model.  A building information model may be best described by its key features:

3D parametric modeling
3D modeling is a superior design environment when compared to traditional 2D CAD.  Mainstream 3D modeling applications have the ability to parametrically capture design intent which facilitates model creation and editing and therefore reduces the likelihood of coordination errors.  Although preparation of the 3D model may be the significant part of most BIM efforts, a model alone does not constitute BIM.

Engineering Analysis
At the core of BIM lies a digital database where objects, spaces, and facility characteristics are each defined and stored.  These characteristics make it possible to use BIM as a virtual representative of a physical facility and are hence able to perform qualitative and quantitative analyses.  These BIM-enabled analyses, be it for structural, energy consumption, day light analysis or a number of other performance simulations, can significantly enhance the efficiency and efficacy of the design, planning and building processes.

Clash detection
Since the 3D model represents virtual true space, a BIM process known as “clash detection” can be utilized to check for interferences by searching for intersecting volumes.  It is often the case to use a third party application to not only clash a single model but combine and clash multiple models from disparate sources in a common environment. 

4D Schedules
A 4D BIM scheduling application can link CPM schedule activities to 3D objects.  This allows for a graphically rich and animated representation of the planned construction sequence set against time.  4D schedules are a powerful tool for phasing, coordinating and communicating planned work to a variety of audiences including project stakeholders and those directly responsible for executing the work.

Cost attributing
As part of the BIM process, cost data can be associated with each element resulting in a detailed cost schedule.  This “cost attributing” is parametric and dynamic so that any change to the model will result in a change to the bill of materials and project cost estimate. 

General information attributing
3D objects can also be linked to a variety of source documents via hyperlinks.  This enables the model to function as a graphical information system (GIS) for the building.  Project correspondences, technical data, O&M records, and links to manufactures’ websites are all possible in this environment.  Information attributing via hyperlinks can add value to all phases but is typically associated with facility management functions.

Process Simulation in Building Construction
Process simulation creates a virtual feedback loop such that design and construction coordination challenges including interface and sequence can be identified prior to commitment of field resources.  Simply stated, BIM identifies changes at a time when changes are still inexpensive to make.  Since the construction supply chain is primarily horizontal and information is passed from one party to the next in a linear fashion; it lacks an efficient feedback loop.  This condition has been exacerbated by the advent of the fast-track construction approach.  Presently problems that are identified during the erection or construction phase are relayed back to the A/E for resolution - but at what cost?  In addition to the disruption, solutions at this stage are sub-optimal and mid-stream revisions are a typical source of contract claims and disputes.  Often, the cost of field changes includes a significant non-value added component that far exceeds the betterment value for the revised scope of work.  These non-value added costs include premium costs associated with change orders, schedule delay, impact on other trades and the effort required to coordinate and manage changes during the construction phase.  It has been said that a construction Project Manager’s primary role is to solve problems.  We believe it is possible to reverse this role from a troubleshooter to a conductor whose energy is focused on implementation of a well-rehearsed plan.

In short, process simulation enabled by BIM significantly increases predictability in the project delivery process by compressing all pertinent project data giving a single user a global and synoptic view of the project.  This predictability encompasses all major elements of the project including geometric (visualization and physical conflicts), behavioral (engineering and operational analysis), and temporal (phasing and scheduling) and cost (estimating and budgeting).  Traditional “field level” issues are flagged earlier in the process at a time when changes are still inexpensive to make.

It has been said that virtual prototyping is not applicable to the building industry because our products are not mass-produced and therefore there is no return on investment from modeling and simulating a project that will be built only once.  This argument is based on a false premise.  Consider the fact that we only get one chance to build a facility and we commit very expensive resources when the physical production phase begins.  We are engaging in physical prototyping and yet our final products themselves are a “rev zero” prototype!  Therefore, since we don’t have the opportunity of physical prototype development - an occasional mockup panel notwithstanding - nor the luxury of familiarity with expertise and competence of the various teams we depend upon, virtual coordination of the process before start of construction is all that more important.  Although cost saving metrics from a comprehensive and large-scale study is not currently available, every project that has adopted this approach, even on a limited scale, has reported significant savings in cost and time.

The Opportunity
Introduction of BIM processes to the A/E/C industry presents a unique opportunity, in particular to the CM profession, to fundamentally alter the traditional approach to project delivery.  Although the implementation of BIM processes can significantly improve the practice of building architecture and engineering, and the management of facilities’ maintenance, we believe it is the construction manager who, as the manager or conductor of a project from “conception to operation,” is in the best position to leverage this process and optimize the benefits for the owner.  Although the notion of a “conception to operation” BIM where all parties participate and collaborate in the development of the master model may be the ideal, it represents such a departure from our current business models that we question how many years before it becomes the industry reality.

The construction management profession in a position to deliver many of BIM’s benefits through implementation of the virtual construction techniques without significant modifications to the current business models.  The CM is the central information hub for the project and as such is in the best position to manage the high value BIM process, defined as an information integration and process simulation tool.  The CM, in its current role, must coordinate information related to design intent, building components and functions, budget and time of completion and develop strategies for procurement, fabrication, means and methods and sequence of work to deliver the completed facility contracted by the owner.
 
Large savings can result from employing the predictive capabilities of BIM through:

• Using cost attributing features of the model to assess alternative design and construction schemes.
• Virtually coordinating contract documents and shop drawings to identify and resolve geometric conflicts in advance of construction.
• Creating a 4D schedule to optimize sequence of construction, manage project logistics and communicate the project plan to subcontractors in coordination meetings and proactively make adjustments based on their feedback.
• Use the 3D and 4D models to demonstrate the scope of work to subcontractors during the bidding process, eliminate ambiguities, and reduce cost contingency in sub bids through increased clarity.
• Quickly assess and quantify the impact of scope changes on all trades and overall project plan.

All of the tasks outlined above are within the customary responsibility of CMs, except they are enhanced and optimized through process simulation.  CMs have the responsibility to recommend best practices to their clients and deliver the highest possible value for their services.  Owners should also encourage the project architect and engineers to adopt 3D modeling, even if current practice favors retaining traditional drawings and specifications as Contract Documents.

Conclusion
Influence on project cost is reduced exponentially as the project moves from planning through design and into the construction phase.  Therefore, increased predictability through the use of BIM moves decision making up earlier in the process so greater control can be exercised over the project cost.  In short, BIM processes introduce increased visibility and predictability and therefore enable the identification and implementation of necessary or desired change at a time when changes are inexpensive to make, i.e., before commitment of expensive field resources.  Because they occur in a virtual environment, BIM processes reduce the risk of implementing changes or experimenting with new ideas and approaches.  Hence, the new business project delivery model using BIM will in effect encourage experimentation and collaboration because it creates an environment that stimulates free exchange of ideas.  Collaboration is not a prerequisite to the implementation of BIM, but it’s facilitated by its use.  Managing the processes described above, whether in traditional form or virtually, is within the professional responsibility of the CM.  Therefore, construction management professionals should embrace and promote this new approach as one that is beneficial not only to their firms but also to the client and the industry as a whole.

Footnotes
⁽¹⁾ Construction Users Roundtable (CURT) publication WP1202; Collaboration, Integrated Information and the Project Lifecycle in Building Design, Construction and Operation.  Also, see New Wiring, The Economist, January 13, 2000 issue.
⁽²⁾ According to Commerce Department data, the value of construction put in place in 2004 was $1 trillion, more than 8.5% of the GDP of $11.7 trillion.
⁽³⁾ Based on National Institute of Building Sciences (NIBS) definition.