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January 5th, 2008 admin Comments off

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BIM Construction Management by Odonnell & Naccarato

One of the most glaring facts about the construction industry as a whole is encapsulated by the US Department of Commerce, Bureau of Labor Statistics finding that the construction industry has had continual losses in productivity since 1964, in stark contrast to all other non-farm labor, which has almost doubled productivity in the same 40 years. BIM construction management is poised to strike at the heart of this issue, as it addresses the fundamental, underlying reasons behind this anomalous situation.

One of the prime reasons for declining labor productivity in the construction industry has to do with the traditional process by which a project is conceived and delivered. The “design-bid-build” paradigm is a fragmented process, where the owner contracts with separate professionals for the design and construction of the project, and each phase follows the previous one. Any collaborative involvement between the design professionals and the construction professionals is highly limited, leading to change orders, errors and other issues when the “best-made plans” are confronted with construction site reality. Secondly, CAD-based design processes are themselves fragmented and liable to inconsistencies, errors and inefficiencies. BIM construction management provides the technological framework for a much more collaborative system, as the parametric models allow for substantive input and analysis of designs by MEP engineers and construction professionals early on in the design process so that potential conflicts or problems can be headed off, saving tremendous money. In addition, BIM construction management allows a general contractor to bring constructability, sequencing, and value discussions into the process at a point where such decisions can have maximum cost savings.
There are many flavors of collaboration which BIM construction management allows for. The allocation of risk is usually the deciding factor. “Glamour” BIM utilizes only the 3D visual models of a project, eschewing the much more powerful parametric database which lies under the hood of those graphic depictions. Basically, this is BIM construction management as a marketing tool. “Lonely” BIM is basically a balkanized use of the technology: only one project team member, usually the architect or structural engineer, has the ability or desire to use BIM. This can be a matter of not wanting to open up liability by sharing the model, or the fact that BIM expertise doesn’t exist in the other project teams. Thus the deliverable is probably still 2D shop drawings, with only a modicum of value derived from the use of BIM, as the data that comes with the 3D to 2D translation is very limited. This type if BIM is usually encapsulated in tradition Design-Bid-Build projects. What has become known as “Social” BIM is the sharing upstream and downstream of models and their data-rich objects so that true collaboration can take place. This, again, is a decision that includes risk allotment and usually goes together with a Design-Build contract or a true, co-located IPD (Integrated Project Delivery). The main difference between these two project organization paradigms is that IPD is a true collaborative affair with risk and responsibility allotted and shared amongst the team members. Design-Build is a single-entity risk assignment, with a “Master Builder”, either contractor or architect, taking the responsibility and risk of the entire project. The insurance industry is still trying to come to grips with a true IPD project organization, as the “fault-based” stance of traditional insurance finds no common ground with the “no-fault” organizational strategy of an IPD arrangement. BIM construction management can play a critical part in the success of both of these ventures, as it allows for the front end collaboration of construction professionals in the design phase, where the ability to save money in the construction phase is much higher. Contractors and subs get a much deeper understanding of the design intent, while the architects and engineers get a light shown on up-to-the-minute construction techniques, so that conflicts between execution and design can be worked out in the office on the model inexpensively and not on the job site which is orders of magnitude more expensive. So BIM’s benefits are in direct proportion to the amount of collaboration built into the project organization.
Beyond the design phase, BIM construction management has important uses in the bid, construction and post-construction phases. While the greatest savings and efficiencies are derived during the design phase of a BIM construction management project, sequencing, cost estimation, fabrication and site control during the construction phase can all be powerfully impacted by the use of BIM technology. In post-construction phase, maintenance, system analysis, asset management and disaster planning are all significantly enhanced by BIM construction management models.
In the Construction Phase, BIM construction management modeling has its greatest impact in construction sequencing and labor/resources utilization and estimation. This is what has become termed as 4D BIM, since it is modeling of the building through time, i.e the construction phases. Elements of a model are analyzed and assigned a logical construction sequence, as well as integrating quantity take-off, location-based quantities, labor costs, crew-sizing and productivity rates. A full animation of the construction sequence can be constructed, with the embedded data noted above allowing for precise scheduling that can then be analyzed and proofed to eliminate crew overlap, reduce buffer times, manage cash flow and materials order and delivery. The ability to compare the model with onsite conditions now exists, too, giving GCs the ability to foresee conflicts, redo schedules which automatically ripple through the construction animation and its parametric data, altering ordering amounts, schedules, deliveries, work crew scheduling and more.
The use of BIM construction management for steel detailing and fabrication is another avenue of post-design efficiency whereby the fragmented traditional process is streamlined and errors substantially reduced. With separate architect design drawings, structural engineer construction drawings, and then steel detailer creating shop drawings, with material specifications, sizes, dimensions, as well as connection-specific welding and bolting specifications, the possibility of error being introduced into the process is high at each transition point. In the end, detailers are creating field drawings at a 2 stage remove from the design. With BIM construction management, the steel specifications come directly from the actual design model, so that the detailing is precisely aligned with the geometry. Most BIM software can produce CIS/2 files which can be used directly in the detailing solutions and CNC fabricators. Once again, like the onsite construction processes, fabrication specifics are brought forward in the design process, so that inconsistencies or value engineering can be accomplished early on, with maximum financial impact.

In the post-construction phase, BIM construction management has the potential to play a role in maintenance, building system analysis, asset management, and disaster planning. Of course, as with all previous examples, the extent to which the full effect of the BIM construction model can be brought to bear on the post-construction phase depends upon the degree of collaboration amongst the many project members as determined by project organization, contractual landscape and technical expertise. The more that a central model is shared and meticulously updated, the more downstream users like building managers are able to derive value. A “record” model such as this, handed off from the construction manager to the building owner/manager at the end of the project should hopefully include all the as-builts from subcontractors, eliminating surprises and inconsistencies when one refers back to design documentation that has been altered onsite. Since BIM construction management models have a massive amount of data associated with each object, operations characteristics, maintenance requirements and warranties can all be centrally accessed. Record models can be interfaced with Building Automation Systems (BAS), though the state of this technology is in flux right now, and industry adoption has been spotty at best. In many ways, BIM construction management and post construction is at the same place engineers and architects were 7 or 8 years ago, taking the first tremulous steps into a new technology. The need for mature Construction Management and Facilities Management BIM integration software is crucial, as well as training and skill within the industry in using parametric modeling, which can bring immense efficiencies and power to CM and FM functions. These benefits are essential in closing the labor productivity gap between construction and manufacturing industries.