Banner Photo: The award-winning and LEED-certified MGM National Harbor features 1,200 architectural precast pieces. Photo courtesy of Alex Fradkin, Courtesy of SmithGroupJJR
By Deborah Huso
Just across the Potomac River from the nation’s capital, the MGM National Harbor, a $1.4 billion hotel and casino in Prince George’s County, Md., has redefined the skyline. The project met ambitious goals for sustainability in both construction and performance, which earned it the U.S. Green Building Council’s LEED Gold certification.
The project also won a Washington Building Congress 2017 Craftsman Award for visual excellence thanks to 1,200 profiles and panels of architectural precast concrete. WBC recognized the structure’s 300,000 square feet of precast not only for its grand scale but also for the level of complexity.
Precast helps MGM meet the gold standard
HKS Architect’s Houston office served as the design architect, capturing the client’s vision for a grand entertainment venue, while SmithGroupJJR of Washington, D.C., was responsible for analysis of the design and optimizing performance. The designers prioritized environmentally preferred technologies and materials, including the use of precast concrete.
Precast was the logical material for a building of such scale with sustainable design goals. While precast provides the feel of stone, it allowed the design to stay within a reasonable budget and reduce energy usage and waste during construction compared with actual stone.
Greg Mella, SmithGroupJJR’s director of Sustainability, said demands for performance and environmental sustainability also had to meet high standards for construction and materials. Additionally, pressure came from the ambitious timeline of 30 months. Mella said documentation and verification for each decision was essential, from design to construction.
“A lot of our strategy was coming up with a manual, a kind of matrix, which made very clear what we were trying to accomplish with material selection and provided a means where each designer could document his or her choices, and how they contributed to the goals for the project,” he said. “Precast was part of our plan to maximize use of local materials to support the local economy as well as to minimize the life-cycle impact of production.”
The 1,200 profiles and panels of architectural precast clad the plinth, a stepped structure serving as the dramatic base for the complex and housing for the tiered parking garage. The use of precast panels reduced job site construction waste and increased the speed of construction. Assembly of the precast panels generated less waste compared with cast-in-place concrete as well.
The proximity of the precast plant to the construction site also earned points toward LEED Gold certification. Precaster Arban & Carosi’s plant was just 20 miles from the construction site, falling well within the 500-mile allowable radius needed to qualify the precast as an environmentally preferred product. Not only did the plant’s location lead to lower levels of pollution from vehicle operation and ancillary vehicle waste associated with refueling, vehicle manufacturing and eventual disposal, but less energy was used in production. Fabricators can optimize the replication of pieces using the same form, as compared to on-site fabrication where each structure requires an assembled individual form.
A monument to monuments
The 1.7 million square foot MGM National Harbor’s exterior echoes those of Washington monuments, mirroring the steps of the Lincoln and Jefferson Memorials. The parking levels are clad in tiered, angled columns of precast set at a 45-degree incline. This leverages the natural 95-foot rise in elevation of the landscape from west to east, giving visitors a grand entrance while elegantly incorporating a 5,000-car parking structure inside.
Positioning the parking facility underneath the entertainment complex also mitigates the urban heat island effect by decreasing solar energy gains. Above, the structure rises 23 stories. The effect is a striking monument of engineering.
Eddie Abeyta, HKS Principal and Design Director, said the design of MGM National Harbor serves as a gateway into Maryland from Washington, D.C., reflecting its proximity to the monuments on the National Mall and the rolling hills of Maryland.
Awe-inspiring scale and magnitude
Now in place, the precast panels’ individual scale and magnitude can be difficult to appreciate. However, as each of the approximately 30-foot-long and 7-foot-tall panels arrived to the waiting cranes on the job site, the scale was anything but forgettable. Despite the size, the installation process went like clockwork.
Abeyta remembers watching this process. Struck by the efficiency, he casually checked the length of time it took to move each panel by crane from the flatbed and then rotate it into place where a waiting welder secured it in place. The process, from flatbed to welding, took about five minutes for each massive panel.
“That’s the beauty of modular construction,” Abeyta said. “All of the embodied energy is produced ahead of time. The construction process goes quickly and quality control is easier to maintain.”
The finished product includes 2.2 million square feet of covered, below-grade parking clad in architectural precast. The horizontal expanse of bright white tiers practically floats on the Potomac River when lit at night, blending effortlessly into the sophistication that marks both the historical and contemporary buildings across the river.
“As soon as you start hitting that bridge (from D.C.), you’re going to see MGM,” Robert Stowe, vice president of facilities at MGM National Harbor told the Washington Business Journal during a mid-construction video interview. “We don’t need any billboards. The billboard is going to be the building.”
Deborah Huso is a freelance writer specializing in construction, real estate, finance and agriculture.