Camouflaged confinement

In the early 19th century, the solitary confinement doctrine embodied by Philadelphia's Eastern State Penitentiary attracted the interest of criminologists around the world. An estimated 300 prisons based on Eastern State's radial floor plan were subsequently constructed. Open in 1829 as part of the controversial movement to change the behavior of inmates through "confinement in solitary with labor," Eastern State quickly became the most expensive and most copied building in the young United States. Abandoned in 1971, it is now open for tours.

The current state-of-the-art in confinement philosophy is represented by Philadelphia's new Metropolitan Federal Detention Center. It is the most recent of similar facilities that have been constructed in seven U.S. cities. A center in Honolulu is nearing completion.

Basic plans for the federal detention centers are similar, according to Scott Higgins, chief of design and construction for the U.S. Bureau of Prisons in Washington. Building configurations are generally either triangular, as is the Philadelphia center, or rectangular. Administrative and support functions are located on lower levels and inmate housing on upper floors.

"We had to deal with a very high-visibility urban site in an area that's fairly historical and has numerous important buildings," says John Gerbner, design principal with the project's architect/engineer, Philadelphia-based Ewing Cole Cherry Brott (ECCB). Adjacent structures include the Cast Iron Building and Mellon Bank Center (formerly Lit's Department Store, a full-block conglomeration of 19th century buildings with two cast-iron façades). Independence Mall is a block away.

Not surprisingly, the environmental-impact review process for the project drew objections from people who were concerned with the facility's proposed location. The site was selected because of its adjacency to the federal courthouse across the street.

The building exterior expresses the classical organization of base, shaft and capital. Its base relates to adjacent buildings; at its top, a large cornice provides a sense of scale.

Scale and detail are expressed through the application of three textures applied to the center's 28,000 square feet of architectural precast- concrete cladding. At the base of the building is 5,000 square feet of ground and polished concrete panels that resemble terrazzo, according to the project's precast supplier, Denver, Pa.-based High Concrete Structures Inc. Above the base, the panels have a textured appearance that suggests natural stone. Panels that clad inmate housing floors have deep rustications.

"By varying surface treatments, we were able to create the impression that multiple materials were used, even though we were restricted to concrete for reasons of security and economy," says project designer Thomas Appelquist with ECCB. "We pushed the concrete to its limits, resulting in a lively building façade that was achieved in a relatively inexpensive manner."

In addition to varying the texture of the precast cladding, the designers attempted to make the appearance of the center compatible with neighboring buildings through the use of similar joint lines. The objective, according to Gerbner, was to create enough visual interest that the nature of the building would not be obvious. The detailing, for example, helps to draw attention away from the building's slit windows, which are inset into beveled recesses to make them appear larger than they are. Score lines, reveals and projecting sills and lintels enliven the building's mass.

While designers worked to make the cladding attractive, they didn't want it to project an expensive appearance — an undesirable trait for a government building. The repetitive nature of the panels helped to economically incorporate these features.

The project's biggest challenge for the contractor was building a 120-ft.-long tunnel from the basement of the detention center to the courthouse, with an intermediate section that passes through the basement of an adjoining federal office building. Because of constricted space, it was not possible to use a boring machine, according to Daniel Dirscherl, project executive with the project's Bala Cynwyd, Pa.-based contractor, Keating Building Corp. The 14-ft.-wide passage, which is 30 feet below street level, was basically created by hand digging. Tunnel construction progressed at a rate of only 4 feet to 6 feet per day.

The contractor's initial task was to get the building out of the ground. Below-grade work required the construction of 67 caissons, some as large as 96 inches in diameter, that extend to a depth of as much as 125 feet. The building required the placement of more than 20,000 cubic yards of concrete. It has miles of in-slab conduit for security systems. Dirscherl says the tight site provided literally no staging area, which complicated project scheduling.

Keating was awarded the project on the basis of a lump-sum competitive bid. Dirscherl attributes the success of the project largely to the partnering effort spearheaded by the Bureau of Prisons. "In a public bidding environment, it's rare to have this type of relationship," he says.

The Bureau of Prisons' Higgins notes that the center is a holding facility for detainees who are awaiting trial, sentencing or transfer to a correctional institution. It houses primarily individuals who are under the jurisdiction of the U.S. Marshals Office.

The Philadelphia center has 628 cells of general housing, each with an area of 80 square feet. Slit windows — one per cell — are 5 inches wide. The exterior walls, which have embedded steel reinforcing, provide the center's ultimate security. This is a departure from facilities that house sentenced prisoners, where security is provided by a double line of fencing, Higgins notes.

The Bureau of Prisons generally utilizes standards developed by the American Correctional Institute. Additionally the bureau's technical guidelines cover areas such as security and mechanical/electrical systems.

Owner: U.S. Department of Justice, Federal Bureau of Prisons

Architect and structural engineer: Ewing Cole Cherry Brott

Interior architect: Susan Maxman Architects

Mechanical/electrical engineer: Ewing Cole Cherry Brott

General contractor: Keating Building Corp.

Construction manager: The Temple Group

Area: 320,000 gross square feet

Number of floors: 11

Construction time: January 1997 to June 2000

Construction cost: $68.3 million

Delivery method: Design/bid/build

Architectural precast: High Concrete Structures

Security windows: Hope's

Roof system: Siplast

Elevators: Thyssen Dover Elevators

Access floor: Tate Access Flooring

Entrances: Vistawall

Ceilings: USG Corp.