Las Vegas is home to a wide array of large buildings boasting unique architecture and the creative use of metal products. Now it also boasts CityCenter, a mixed-use retail, dining and residential complex in the heart of the Las Vegas Strip.
CityCenter is a project of firsts. It is the largest private development, the largest green development and is also one of the most technically savvy projects in the nation. With literally thousands of activities happening hourly on the 8 million-square-foot (1.7 million-m2) project, Perini Building Co., Sylmar, Calif., utilized an array of project management and construction-modeling software tools to manage millions of pieces of information, including tracking and updating budgets, orchestrating around-the-clock construction logistics, and coordinating over 10,000 construction craftspeople working on-site.
CityCenter was the largest project in the history of Las Vegas to implement building information modeling and 3-D modeling for construction coordination.
Perini, through its parent corporation Tutor Perini Corp., Sylmar, deployed, deployed the Cisco Unified Computing System on the project. Primavera P6 Enterprise Project Portfolio Management software was utilized for scheduling and logistics, in addition to Prolog Construction Project Management software.
“Modeling in 3-D allowed Perini to draw structural elements that impacted mechanical, electrical and pumping coordination, including walls, concrete slabs, exteriors and structural steel,” said Joe Miller, vice president of operations-special projects for Perini. “The ability to visualize the exact placement of thousands of MEP components on the 18 million-square-foot project and graphically depict how they overlap in advance of construction is a powerful tool. Three-dimensional modeling helps to limit installation conflicts in the field and enhances field coordination and scheduling logistics.”
Visualizing thousands of interwoven components also encourages innovation among team members. As MEP drawings were updated and shared, Perini encouraged its subcontractors to recommend ideas and solutions resulting in a more streamlined construction effort. When construction started, the majority of the MEP challenges/obstacles had been resolved before construction started.
Dining in 3-D
The most extensive use of 3-D modeling and BIM implemented at CityCenter was on Crystals, a 645,000-square-foot (59,921-m2) retail and dining facility. Designed by Studio Daniel Libeskind, New York, Crystals’ extremely complex design required the use of advanced technology—BIM and 3-D rendering—and coordination for steel fabrication and erection. The structural steel facility includes a one level below-grade garage and three levels of retail and a one-of-a-kind roof.
The garage and levels one through three of Crystals are made with typical grid steel-frame construction. According to Miller, the roof is what elevates the project into a class of its own. The roof is made up of thousands of leaning columns, curving trusses and straight members that do not line up with any other piece of steel. The roof actually consists of 19 separate roofs that are intermingled and overlap one another. It includes 13 planar roofs and six dramatically sloped arcade roofs that were the most complex element of the project. The Crystals roof has no right angles, nor does it follow a pattern or have any repetitive placements of steel.
Similarly, the connections of the lower floors were standard but the roof system required distinctive solutions at almost all end-points. More than 500 unique sketches were generated for these roof connections. Each of these connections then had to be manually modeled into the Tekla Structures software—a steel detailing program—as no single macro could accommodate these variations.
In total, 16,455 pieces of steel were input into Tekla software, a program that interfaces with other programs such as Revit and AutoCad that created BIM models for all of the trades and consultants working on Crystals.
Co., Phoenix, the fabricator and erector; BDS Steel Detailers, Tempe, Ariz.; and structural engineer Halcrow Yolles, Las Vegas; spent 12 months in a design-assist capacity strategically planning the project using advanced BIM technology.
“Crystals was similar to planning and building a complicated 3-D jigsaw puzzle: Every piece had to fit perfectly,” said Gary Provencher, project engineer for Schuff Steel.
According to Mike Nunn, project executive for Perini, “Another big advantage of 3-D and its role in structural steel was the ability to see the exterior stainless-steel cladding, interior gypsum drywall and metal stud framing conflicts at the design stage rather than during the costly construction phase, which would have impacted the project’s completion schedule. We literally had structural steel members on 3-D sticking through the exterior skin and poking out through interior drywall walls. Three-dimensional let us see these and fix the problems.”
Added Dick Rizzo, vice chairman of Perini: “Three-dimensional modeling was imperative on this project. Without the use of technology the project would have been too cost prohibitive to plan and build.”
Technology Helps Manage Size and Scope
To help convey the size of this project, those involved liken the construction of CityCenter to building 12 major resort properties all opening at one time. To complete the project, Perini utilized an array of project management and construction-modeling software tools to track a record 50 million construction hours, 230 subcontracting firms, more than 10,000 craftspeople and a professional staff of more than 500 people. With that said, coordination and logistics were perhaps the most significant challenges of CityCenter.
With literally thousands of activities taking place hourly, technology was imperative to efficiently manage the millions of pieces of information, including tracking and updating budgets, orchestrating around-the-clock construction logistics, and manpower coordination. Technology also enabled Perini to deliver CityCenter on time in just three years and eight months.
Tutor Perini Corporation
Sylmar, Calif.
www.tutorperini.com
