PROJECT	Oklahoma Hall: Bachelor Enlisted Quarter P-593
LOCATION & YEAR	Pearl Harbor Naval Base, Hawaii 2003
CLIENT	Department of the Navy Pacific Division Pearl Harbor, Hawaii
CONTRACTOR	DCK Pacific, LLC
ARCHITECT	RIM Architects, Inc.

Background
Oklahoma Hall is the first residential building in Hawaii (and possibly the nation) designed to meet the Department of Defense (DoD) Antiterrorism/Force Protection (AT/FP) Construction Standards. This new 5-story 5,250 square meter Bachelor Enlisted Quarters (BEQ) is located at Pearl Harbor, Hawaii. The $14.3 million design-build project features 104 living units that can accommodate 208 sailors.

Advanced Technology
The main structural challenge was to create an economical structural system that met the AT/FP and progressive collapse criteria without significantly impacting the architectural and functional requirements of the project. The most efficient scheme, dubbed the BASE Hanger System, is a multi-hazard solution that provides not only progressive collapse mitigation, but also resistance to other hazards such as earthquakes and hurricanes.

The BASE Hanger System is unobtrusively integrated into the functional layout of the building. Alternate load paths (in the case of a missing element) can develop because of the special detailing provided for the load bearing concrete walls between units. The interior demising walls are divided into two distinct vertical elements, an exterior and an interior. The separation between the two walls consists of a weakened (or fuse) section, a backup wall and a physical gap. At the top floor however, the interior and exterior portions of the wall are continuous. If the support at any level is lost due to an explosion, the continuous portion of wall is designed to behave as a hanger or deep cantilever beam, carrying the weight of the unsupported walls below. On a fundamental level, the BASE Hanger System is visually analogous to a giant hangman’s noose.

Client Benefits
Although not required by the DoD Standards, the efficiency of BASE Hanger System remains within the elastic range of behavior. A maximum calculated vertical deflection of only 16 mm is predicted using cracked section properties of the concrete. In addition, the inherent redundancy in the BHS actually allows more than one wall to be removed without progressive collapse. Equally important, the BASE Hanger System addressed and exceeded the military's AT/FP criteria at roughly 3% of the overall cost of the structure. Much of the extra cost is attributable to additional reinforcing steel and labor involved with the system’s unique detailing. Moreover, the progressive collapse elements did not alter the Contractor’s schedule or preclude them from using the same wall-forming system used on similar projects without the AT/FP requirements.

Despite the stringent security requirements, the architect was not constrained by additional structural framing. As such, the design of Oklahoma Hall provides a residential atmosphere that promotes a sense of community as opposed to a barracks (or bunker) type of atmosphere.

Recognition
Oklahoma Hall has been recognized by three separate judging panels:

• Structural Engineers Association of Illinois (SEAOI) – 2005 Excellence in Structural Engineering Awards in the Best Small Structure category
• National Council Structural Engineers Association (NCSEA) – 2004 Excellence in Structural Engineering Awards in the $10 - $30 million category
• Build Hawaii – 2004 Award of Excellence in the Design/Build construction category
• Hawaiian Cement – 2004 Concrete Achievement Award in the new construction category

Jurors’ comments for the 2005 SEAOI award include the following:

“Highly creative solution that may one day save lives. And saves money too!”
-Geoffrey Baer, Producer/Host, WTTW Chicago Public Television

“The structural engineer achieved a design that will lively be implemented around the globe for barracks facilities.”
-Arnie Tuperitis, Senior Vice President, U.S. Equities Realty

“An economic solution to one of modern day’s dilemmas – how to prevent progressive collapse under a terrorist attack.”
-Harold Sandberg, Chairman Emeritus, Alfred Benesch & Company

“The DoD AT/FP requirements for residential building have unique and demanding constraints. Incorporating AT/FP construction standards without compromising the architecture, the “quality of life” design, without having the upgrades appear obvious, at minimal cost and maintaining construction schedule is an accomplishment.” -William Davidson, Project Manager, Turner Construction Company