Contractordck pacific construction, LLC
LocationPearl Harbor, Hawaii
BEQ P-593 (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. It is a new five-story 56,532 SF Bachelor Enlisted Quarters (BEQ) at Naval Station, Pearl Harbor, Hawaii. The $14.3 million design-build project has 104 living units that can accommodate 208 sailors.
Although not required by DoD Standards, the efficiency of the 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 BASE Hanger System 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.
The Science and Design of Structural Engineering
The main structural challenge was providing an economical structure 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, providing 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 as a giant hangman’s noose.
Oklahoma Hall has been recognized by four 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 Associations (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 saves lives. And saves money too!”
-Geoffrey Baer, Producer/Host, WTTW Chicago Public Television
“The structural engineer achieved a design that will likely 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 buildings 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