BIM Case Study

One example of a project team that came to incorporate BIM as part of its best practice involved a new four-building campus and theater called the Letterman Digital Arts Center, or LDAC, to house LucasFilm Ltd. In that case, the use of BIM proved invaluable, credited with saving more than $10 million on the $350 million, 865,000-square-foot project.

By creating a 3-D structural model and then importing the architectural and MEP systems through the utilization of a integrated design-review tool, literally hundreds of design and construction discrepancies were found and corrected throughout delivery of the project, which was built on the grounds of San Francisco's Presidio National Park. "By incorporating the contractor's shop drawings as another layer in this process, additional errors were found which, left unchecked, would have resulted in considerable costs to the contractor and delays in the construction schedule," recalls View By View's Boryslawski.

One compelling example of such a near-miss was caught when a daily round of on-site photography, routinely conducted to compare actual building construction with the digital building model, discovered incorrectly positioned concrete formwork. With three more floors to be built above the floor in question, the error about to be made would have been a serious and costly one. Fortunately, the BIM model confirmed the impending mistake and the contractor's team was alerted, literally minutes before the concrete was poured. Yet another case of BIM providing an important safety check was the discovery of a steel truss penetrating an aluminum curtain wall, during a regular visual conflict check. The error was automatically reported to the project management team, and although the steel frame had already been manufactured by the steel fabricator, it had not yet been delivered to the site, so the frame could still be modified in the shop.

BIM also enabled the owner, George Lucas himself, to actively take part in the design process. "George wanted to see everything digitally before approval, so we were providing him with digital renderings while he was finishing Star Wars in Australia," relates Boryslawski.

Key to the whole BIM process for LDAC was a highly compressed technology to consolidate large amounts of 3-D data from different applications into one model. This design-review tool "reads all the major BIM applications file formats," according to Boryslawski. "Without it, there would be no BIM coordination process." The software's "clash detector" module also came in handy when the team wanted to make sure that the mechanical piping systems installed in the parking levels met the Presidio fire department's height requirement. Similarly, the owner also has the option to perform other emergency simulations such as emergency egress routes.

At the end of the day, utilizing BIM as a virtual design-and-construction tool for the LDAC project did more than identify design conflicts and clashes early, providing cost-effective means to resolve them. BIM also led to better design solutions with "what-if scenarios" developed at an early stage and tested for constructability. Cost estimating was also found to be more accurate than expected. Plus, digital mock-ups of critical areas meant that complex details and assembly methods could be better understood.

In terms of CM, the approach led to lower costs from the subcontractors by providing them with the virtual model and information for their scope of work. Schedule performance was optimized by simulating the best sequences and maximizing the labor crew sizes. The number of change orders and requests for information were modest, too.

Last, George Lucas and his team got 3-D as-built models both for review and for use in facilities management, including all of the MEP and equipment object libraries.

C.C. Sullivan is an author and consultant specializing in architecture and technology.