Case Studies

Better Construction Coordination Reinforces the General-Contractor–Subcontractor Relationship


In commercial building—as in virtually any industry—cost and schedule stand as the arbiters of success or failure of any project. Consequently, a strong general-contractor–subcontractor relationship depends on meeting budgets and deadlines.

Or, as Randall Natsch, director of virtual design and construction at McCarthy Building Companies, puts it: “General contractors like McCarthy strive to maintain cost and budget goals to keep clients happy, but that’s often difficult in an economy and industry where material and labor costs are constantly changing. Traditionally, the scope of work for subcontractors didn’t include time to detail constructability well before a project was built.”

In the world before building information modeling (BIM) and cloud-based computing, contractual ambiguity was often a part of the process—a hedge against unanticipated hurdles in a project.

But vagueness rarely inspires trust, and, prior to cloud-based coordination tools, unspecified project details often left general contractors and subcontractors on opposite sides of a dollar, communicating at arm’s length and averse to taking risks.

Today, according to Natsch, much has changed. Real-time, true-scale visualization and project-coordination tools are helping general contractors and subcontractors collaborate more effectively. By revealing structural and engineering problems prior to construction—and in front of computer monitors rather than through dusty clouds of Sheetrock—they are leading to higher-quality, lower-cost work. “The easiest way to describe it is that visualization helps invite more response earlier in the building process and elevates issues to the appropriate decision makers,” Natsch says.

Take McCarthy’s reconfiguration and update of the Marin General Hospital, a 259,000-square-foot addition now underway along the Bon Air frontage in Greenbrae, California. As a partner in the project, Peterson Mechanical, a company that has subcontracted for McCarthy on several builds, used Autodesk Fabrication CADduct and Fabrication CADmep to model the duct and heat-piping systems. These were then loaded into Autodesk Navisworks for viewing and coordination.

“Without the technology, it would have been very hard to convince the architect that the ceiling needed to be lowered, and he would have likely not agreed to it, causing friction among McCarthy, the architect, and Peterson,” says Greg Marks, plumbing piping manager for Peterson Mechanical.

Advanced simulation software not only staved off potential conflict, but also helped preserve the project schedule and kept costs in check. Consider the alternative. “When field construction got to that point, the physical items would have been installed in conflict with the ceiling,” Marks says. “A request for information would have been written and a response would have been decided. This would have been, typically, a two- to three-week process. After the response was provided, either the duct or ceiling would have needed to be reworked, costing anywhere from 20 to 80 man hours, on top of the construction schedule extension to do the work.”

Observed across a large, multicompany project, such labor and time savings add up. In McCarthy’s mammoth, 200,000-square-foot, three-level OdySea Aquarium in Arizona, it’s estimated the use of the cloud subscription service Autodesk Collaboration for Revit, along withBIM 360 Field, reduced the project time by more than 35 percent and saved some 17,000 hours of labor.

Cloud-based technology invites all parties to work off the same models at once, helps connect building teams, and brings greater accountability to the building process. For Michael Mutto, BIM Lead at Pan-Pacific Mechanical, that coordination has been crucial on numerous collaborations with McCarthy, including the Lawrence Berkeley National Laboratory and Oakland Medical Center.

His job, in a sense, is to build a building before it is physically built. That means integrating the contributions of each subcontractor into a singular, cohesive package—much like a record producer and mixing engineer would mix down multiple audio tracks into a single song. “Each subcontractor details their job in the 3D world, and we use that as a template to build the building,” Mutto says.

Collaboration tools such as Navisworks and BIM 360 Glue help with workflow coordination, sequencing, and construction layout. All project-building teams can simultaneously review the same file that contains, essentially, the same information. “We’re slowly moving toward a uniform file structure and seeing with each project greater transparency: who’s drawing what, when they’re drawing it, and if they’re meeting their dates,” Mutto says.

And when something doesn’t go as planned, the team can see exactly who should be held accountable. “I can design an entire plumbing or mechanical system down to the 16th of an inch of accuracy to what will be installed in the real world,” Mutto says. “If a conflict/clash arises in the real world, we can pull an elevation or dimension to verify who is in the right or wrong location. If the dimension is off, say a half of an inch, the party that deviates that half inch from the digital model is responsible to fix that clash/conflict in the real world.”

But accountability isn’t simply a game of “gotcha.” On the contrary, it is easing the repercussions of making mistakes. “Mistakes in the real world, in terms of labor and manpower, are a lot more expensive than mistakes in the virtual world,” Mutto says. “This way, we can minimize costly real-world conflicts by finding and alleviating the issues in the virtual world.”

He points to the three-story Kaiser Dublin outpatient diagnostic cancer center in Dublin, California. The 60-acre McCarthy project is now underway and includes a radiation oncology department with four linear accelerators and a chemotherapy infusion clinic, on-campus roads, multiple parking areas, and landscaped entry courts and plazas. Navisworks helped ensure the smooth coordination of an intricate, multilayered design. “I can run a clash report between steel and plumbing and find every instance where a plumbing fixture is conflicting with the steel,” Mutto says.

What cloud-based modeling and project management tools render, above all, is a reality check: an accurate, easily accessible representation of the facts on the ground. And with that reality, Natsch says, comes trust and the confidence to take a project in brave directions. “Now, so many people can see the problem, any weird little thing,” Natsch says. “We are all under it. As tradespeople sitting behind a computer monitor, we’re able to construct entire building parts and pieces, buildings of great complexity, inside an environment that allows for a more elastic product.”

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