General contractor EllisDon Corp. is making significant use of building information modeling (BIM) to coordinate sub-contractors at the $474-million Waypoint Centre for Mental Health Care in Penetanguishene, Ont.
The new forensic hospital and building addition project is a 350,000-square-foot P3 (public-private partnership) design, build, maintain project and aims to achieve Leadership in Energy and Environmental Design (LEED) Gold certification.
Building challenges include coordination with existing services, complex mechanical layouts, and coordinating precast concrete panels with steel and concrete structures. To meet those challenges, the design team implemented BIM technology during the early stages of the design phase. EllisDon also assigned a full-time BIM specialist to the project.
“It’s a pretty big project, with many collaborators producing 3-D content,” says Thomas Strong, director of Virtual Construction at EllisDon.
“We’re collecting models from the various sub-contractors and each party is developing that content for their own purposes. As a general contractor we’re bringing this model content together and integrating it. Obviously there’s a challenge in that because not all of the software likes to talk to each other.”
At the end of the design process, the building model is assembled into a 4-D visualization of project construction.
“We take the Primavera schedule and relate each activity to its associated geometry and run a simulation of the project schedule,” says Strong.
“This is very useful to us, to explain to all parties involved in the project what they’re going to do, how they’re going to do it and when they’re going to do it. We don’t maintain that model when we go into construction, because it would almost be a full-time job to maintain it, but it’s useful at the beginning of the project.”
Once architectural, mechanical and structural models had been integrated and locked down, sub-trades began to develop their content, most often using Revit software.
Concrete work was carefully integrated using BIM. For example, excavation models helped to identify issues with the locations of tiebacks prior to the pouring of the foundation.
“We were using models for quantity takeoffs, so we could quickly evaluate the quantity and volume of concrete required,” says Strong.
“We also superimposed the CAD lines from the precast sub-contractor onto the 3-D model and coordinated between the intersection of the precast panels and the structural steel. We evaluated each elevation to make sure that every single window opening, penetration and foundation wall was positioned accurately.”
Strong says that asking sub-contractors for a model of what they will produce is more productive than providing them with a model of what’s needed.
“It’s much more effective for us to pull their model work from them, and integrate it into our work, so we can check it and give them our feedback,” says Strong.
“It also ensures that they’re responsible for making sure that what they do in the field matches that model.”
Strong notes that BIM implementation on the project has resulted in a significant reduction in coordination meetings, faster decision-making and a more constructible design.
“Problems always get solved, but the goal of this process is to end up solving problems sooner at less cost,” says Strong.
Completion of the project, which broke ground in February 2011, is scheduled for mid-2014.
Strong spoke at the Fall 2012 convention of the American Concrete Institute, held in Toronto.