ContractorFTSI Phelps Joint Venture
LocationJoint Base Pearl Harbor-Hickam
Located on Ford Island at Joint Base Pearl Harbor-Hickam in Hawaii, Building 26A was originally constructed in 1935 as an aviation storehouse and airplane hangar for the Navy’s Fleet Air Base. The Navy elected to convert Building 26A into a training facility for the Center for Security Forces (CENSECFOR), which entailed upgrading the structure for current seismic, hurricane and antiterrorism (including blast) criteria.
In order to change the use of the 80-year old building to a training facility, the structure needed to be upgraded to resist current earthquake, wind, and blast loads. But the existing unreinforced masonry exterior walls presented a significant challenge to achieving this goal. The original Request for Proposal indicated fiber-reinforced polymer (FRP) strips to be provided on every exterior wall, on both interior and exterior faces. BASE instead proposed and designed a steel bracing system that could be installed only on the interior. This solution not only avoided the removal of historic exterior finishes that would have been required for FRP installation, but it also provided a much lower cost to the Owner due to a significant reduction in material costs and labor requirements.
The Science and Design of Structural Engineering
This design-build renovation presented several unique challenges. First, the tall exterior walls were constructed of unreinforced and ungrouted masonry and thus had limited capacity to resist current out-of-plane design loading. Second, maintaining the building’s distinctive historic design significantly restricted options for structural modifications. Finally, significant structural deterioration, such as corroded steel members, rotted plywood roofing and cracked masonry was prevalent.
Previous conceptual planning studies recommended the use of fiber-reinforced polymer (FRP) strips to increase the capacity of all exterior walls. This solution presented difficulties from cost, schedule, historic and constructability standpoints. Given the challenges, an alternative structural steel bracing system was developed that reinforces the walls completely from the inside of the building.
Repair Building 26A was recognized by the General Contractors Association of Hawaii with a 2017 Build Hawaii Award in the "Design-Build/Design-Assist Construction: $15-20 million" category.