The flaw of this logic comes from the fact that specialty contractors tend to resolve interface conflicts with a micro approach that provides the best solution for themselves and their trade, rather than a macro approach that looks at resolving conflicts for the overall best interest of the project.

At the same time, widely adopted BIM and 3D modeling software has evolved around the goal of making it easier to generate highly detailed 3D models loaded with information. But the downside is those models generate files size issues that constantly need to be dealt with. And the way the models are built often makes the process of applying updates and exploring different design iterations to resolve conflicts—where the real value and potential of parametric modeling lies—a painful, time-consuming and costly process.

ANOTHER WAY

An alternative approach calls upon GCs to lead the coordination process and assume the responsibility to develop a single, overall coordination model. The model becomes the central platform where all design information is resolved spatially with an overall approach. This lets the team focus energy and resources on resolving the interface between adjacent trades in a single platform that addresses primary and secondary structures, wall and roof envelope or, to optimize systems, explores best routing for MEP while considering structural and architectural limitations. The GC, then, provides trade contractors with spatially coordinated, trade-specific models extracted from the overall coordination model, which the trade contractors detail for fabrication.

To create the overall coordination model, GCs need to develop a modeling process and use technology platforms that let them work with live geometry and relational components. Such models are relatively easy to update and are optimized for the exploration of large numbers of iterations to resolve conflicts and optimize systems from spatial, rather than technical and fabrication requirements.

When responsibility is shared between the different stakeholders it will generate a snowball effect that positively impacts multiple aspects of the construction process. When trade contractors focus efforts and resources on what they do best it is reflected in their bids, the installation workflow and ultimately the overall construction schedule. This, in its turn, will end up helping the GC and owners.

AN EXAMPLE

Recently, Las Vegas –based GC, Hardstone Construction LLC, in charge of a $720-million mixed-use project, took that responsibility and  assumed the coordination role. A small team with modeling expertise developed and maintained an overall live model of the project for coordination, using CATIA software as a single platform. Hardstone’s model became the single source of information. Coordination meetings between specialty trades were eliminated.

This is why what we did at Hardstone was very efficient. When contractors build an in-house model, they focus their resources and 80% to 90% of the time they invest in the process is used to resolve the interface and the conflicts. Subs no longer need to stop working to prepare for coordination meetings.

On the project, trade contractors were responsible of installation only. They used plans and 3D models provided by the GC to detail their scope and to do installation work, and despite major changes to design during construction, the overall coordination model integrated all updates on time and provided the latest information to all trade contractors. The $350-million first phase of the project was delivered on time and on budget with almost no contractor or subcontractor claims. Some trades even reported up to 30% gains in workflow efficiency.