Mitchell Hall
From USAFA Folklore
Mitchell Hall (commonly known as "Mitch's") is the cadet dining facility, named after Brigadier General William "Billy" Mitchell. It is located on the southeast corner of the Terrazzo between Fairchild Hall and Sijan Hall.
It is one of the largest indoor dining areas in the world, with approximately 2 acres of uninterrupted floor space. Mitchell Hall is also unique architecturally in it has curtain walls. Curtain wall is a term used to describe a building façade which does not carry any dead load from the building other than its own dead load. These loads are transferred to the main building structure through connections at floors or columns of the building. A curtain wall is designed to resist air and water infiltration, wind forces acting on the building, seismic forces, and its own dead load forces.
Mitchell Hall was expanded in 1966 to accomodate the increased size of the Cadet Wing.
[edit] Architecture
(taken from USAFA's National Historic Landmark application)
The exterior is boxlike, roughly 308 feet by 308 feet, with a flat roof and a cantilevered overhang of twenty-one feet surrounding the building. There are two main entrances facing the Terrazzo, each approximately fifty-six feet wide- to accommodate cadet formations.
Academy planners directed Skidmore Owings and Merrill to build a dining hall capable of seating the entire Cadet Wing, with nearly 3,000 students, in one sitting. To create such a large space with no columns to impede visibility, SOM’s architectural team, headed by Gertrude Kerbis, developed innovative design and construction plans. The two-acre structure features a steel span roof of 266 feet, resting on sixteen exterior columns.
The roof span consists of twenty-three warren trusses, intersecting at right angles fourteen feet on center. The prefabricated trusses were assembled on the ground and jacked into place utilizing equipment and techniques normally reserved for precast concrete lift slab construction—the first long-span steel structure to be lifted into place. All joints, splices, and intersections were welded to provide structural continuity.
The site slopes downward away from the Terrazzo level, so the floor that is accessed from the Terrazzo is approximately three stories above grade at the rear of the building. Below the Terrazzo level, the dining hall is of reinforced concrete construction. SOM’s early design drafts employed a glass curtain wall on all four sides, with the kitchen, staging area, and services below the main dining floor, connecting the two levels by elevators and using heated dining carts for serving food.
With this plan, however, the architects were unable to provide the required level of food service, as expressed by the Academy Board, that they "serve two eggs sunny side up at the same temperature to all cadets." This requirement forced the team to include kitchen facilities on the main floor. To hide these functions, the architects designed the north façade to be finished with precast exposed aggregate concrete panels and aluminum fascia panels. The other elevations show grey tinted plate glass in aluminum frames.
The main entrance from the Terrazzo level features a freestanding geometrical staircase in the lobby, leading to a mezzanine level. The staircase displays white marble treads and a black steel open railing with an aluminum hand rail. The primary interior room, the dining hall, is a vast open space with a twenty-four foot height, featuring a coffered camp ceiling (a ceiling having the form of a truncated pyramid) on a 14' grid. The room is framed by gray tinted glass walls on the north, east, and west. The recently added shades can be drawn over the bottom half of the window walls. The flooring is polished brown terrazzo set in aluminum strips, which follows the grid pattern on the Terrazzo outside.
On the north elevation, it features a three-quarter-length mezzanine, raised approximately twelve feet from the main floor, providing an eating area for senior Academy personnel and guests. Often called the Staff Tower, it provides a platform for the announcement of daily orders and campus activities. The mezzanine floor is comprised of polished white terrazzo squares, outlined by narrow aluminum bands, following the grid pattern on the main floor. The railing around the mezzanine features frosted glass with a geometric pattern.
At the center of the mezzanine, a lobby extends toward the north wall with windows overlooking the Terrazzo. Under the mezzanine are serving, kitchen, scullery and dishwasher facilities. A service floor is eighteen feet below the dining floor. It provides space for freezers and food storage, bakery and employee facilities.
There are loading docks and other food-receiving departments at this lower level. On the north side of the service floor, under the Terrazzo, is a dining/banquet area that can be used for smaller functions and more formal dining events. An alternate exit/entrance leads from the service floor to the Terrazzo, to the west of the main entrance.
To accommodate more than 4,000 Cadets, in 1966, Mitchell Hall was expanded on the east and west sides based on designs by Leo A. Daly, Inc. and Henningson, Durham and Richardson. The result interrupted the open interior space with four supporting pillars, and obscured part of the open view toward the mountains.
