Imagine having to construct a building three football fields long and almost one football field wide. Now suppose it had to have two 450-foot-long unobstructed openings and had to accommodate several different types of aircraft.
Hangar 511 was just such a project. The massive building, and its attached apron, were recently constructed for the U.S. Naval Facilities Engineering Command (NAVFAC) at the Jacksonville, Fla. Naval Air Station and is now the Navy’s largest active aircraft hangar and administrative facility.
The $123 million design-build project, prompted by the military’s Base Realignment and Closure (BRAC) program, will accommodate the relocation of six aircraft squadrons to Jacksonville. Initially, the hangar will house the Navy’s P-3C Orion (99-foot wingspan) squadrons and a C-130 Hercules (132-foot wingspan) logistics squadron. Ultimately, the Navy will replace those aircraft with the advanced P-8 Multi-Mission Maritime Aircraft (117-foot wingspan).
Sustainability goals were important to the project, which aims at Leadership in Energy and Environmental Design (LEED®) silver certification. Achieving this goal was the responsibility of the project’s design-build contractor, M.A. Mortenson Company of Minneapolis, and the project’s architect and structural engineer, HNTB Architecture of Washington, D.C.
Hangar 511 was framed with structural steel. Domestically produced structural steel provides a variety of environmental benefits, including:
- An average recycled content of 93.3 percent.
- A recycling rate of 98 percent and can be recycled repeatedly without losing strength or chemical properties.
- A water recycling rate of 95 percent, with no external discharge (during the steelmaking process).
- A high strength-to-weight ratio, reducing the amount required in a project.
- A relatively low carbon footprint.
- Regional manufacture.
The domestic structural steel industry has decreased its energy use by 67 percent since 1980, its per-ton carbon footprint by 47 percent and per-ton energy intensity by 29 percent since 1990 and its per-ton greenhouse emissions by 45 percent since 1975. As the electric utility grid becomes more renewable, the embodied carbon in structural steel will continue to decrease. For more details about structural steel and sustainability, see www.aisc.org/sustainability.
Builders used BIM to track sustainable features outlined by the LEED program and assign points to the project’s sustainable features, such as translucent panel systems that provide natural light, solar shading, light shelves and heat-resistant designs.
A green-minded building is more than just the sum of sustainable features; it is the product of a sustainable design process that blends green materials, products and goals with a collaborative modeling, design and construction process.
Kevin Lewis is the office leader for HNTB Architecture’s Washington, D.C. office. Greg Fossett is a senior project manager for M.A. Mortenson Company. A version of this article originally appeared in the August 2009 issue of Modern Steel Construction and is reprinted with the permission of the American Institute of Steel Construction.