Commentary: Optioneering Site Master Plans Using BIM
As profit margins shrink, savvy owners and construction firms are harnessing technology to match sites with their intended uses before acquiring the land. Using a type of 3D modeling software known as macro BIM [building information modeling], which produces real-time cost estimates, estimators can practice site “optioneering” to quickly evaluate the merits and costs of alternative designs.
For years, developers have relied on historic square-foot averages to predict land development costs. Unanticipated site problems could substantially inflate a project’s price tag. Preconstruction pros on the developer’s side are starting to recognize that the wrong site can be fatal to a proposed project.
One of my clients, a director of preconstruction services for an upscale shopping mall developer told me: “Designers can play around with the buildings, elevations and finishes on a project to meet the budget, but the site…we can’t control that. It has to be engineered. The sooner we know what the issues are, the better.”
Before technical tools became widespread, the time required to create an estimate usually prevented developers and owners from practicing extensive “optioneering.”
Optioneering refers to making clear and structured decisions in situations where the consequences are significant. As part of my integrated project delivery and lean construction training, I often evaluate alternative designs using the “choosing by advantage” approach. It uses a selection-and-ranking process based on the relative advantages and costs of the each project element in accomplishing a client’s goals and objectives.
Fortunately, now we have macro-BIM authoring tools that use parametric variables and inferencing capabilities to build data for quick analysis. Most commercial macro-BIM products are meant for use before the design phase (and in some cases through schematic design) to create accurate costs for design concepts.
I’ve spent the last decade of my 30-year career focused on creating conceptual master-planning estimates for major development projects. Macro-BIM software helps me determine project costs while there’s little information.
In early 2010, I began work on a proposed $100-million site development project, creating a conceptual master plan with detailed costs.
The last major parcel in a prime location poised for future growth, the site was appealing—on paper. In reality, the terrain posed challenges. The 50-acre infill lot had dramatic 30-ft elevation changes across the site. According to the napkin sketch, more than a dozen buildings—retail, office, residential, parking structures—would be housed on the site. Add an internal network of roadways and pathways, and the project was a mini-city in the making.
The unusual features made it important to confirm the site’s viability for the project, so I went to my macro-BIM software to start optioneering.