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Known as the GPA-GWA Gloria B. Nelson Public Service Building, the new multipurpose complex in Mangilao increased the operational efficiency of both utilities by merging critical programs and services—from administrative and customer service duties to training, engineering, and central control dispatch—in one convenient location. With its energy-efficient features, it has also become the standard for sustainability on Guam.


Scope of Work

Core Tech efficiently constructed this fully reinforced, three-story pre-cast concrete structure with 117,825 square feet of office space in the central village of Mangilao. The Core Tech project team designed and constructed the facility to achieve LEED® Silver certification, with energy-efficient chillers and cooling towers; Direct Digital Control setup for the air conditioning system to optimize energy consumption; low-flow plumbing fixtures to minimize water consumption; motion sensors for light fixtures; double-paned windows with thermal break; solar water heaters; outlets for charging electric vehicles; a bike rack to encourage exercise and energy conservation; and efficient insulation for all exterior walls and ceilings. Core Tech also mit­igated water runoff from the Fadian Cliffside into the northeast shore (abutting Andersen Air Force Base) and the surrounding communities to the west by building a catchment and diversion systems. Additionally, we built a state-of-the-art, concrete-secure central control system that can monitor the island wide power sys­tem, including GPA’s power plants, substations, and metered households and one of the biggest server rooms on Guam.


Besides the interior, the work completed included architectural finishing and installation of perimeter fencing and asphalt paving, and underground sewer, water, and electrical supply systems, as well as construction of parking facilities with a capacity for 500 motor vehicles. We also managed the landscaping of green areas and the widening and enhancement of Route 15.



One of the pre-construction challenges involved the composition of the relatively remote 15-acre site itself, which sits on hard rock. To address this construction issue, we utilized our fleet of heavy equipment (bulldozers and backhoes) to bring the site to grade. Heavy trenching equipment was used to cut through the ground to be able to install utility systems (power, water, telephone and sewer lines). Moreover, extensive design changes were made with Core Tech coordinating closely with designer RIM Architects to analyze the design process drawings and specifications and offer constructability suggestions. This was done by identify­ing design items which needed to be completed in order to meet each milestone while maintaining the construction schedule.


Despite the many change orders and varying requirements added by fire and building inspectors, Core Tech was able to complete the project in record time and under budget. By finishing the construction of the facilities ahead of time, Core Tech made it possible for GPA/GWA to move in and resume services to customers by December 2014. Furthermore, with a final contract amount of $28.2 Million, the government was able to save $1.5 Million after project completion.



Start Date: 

Completion Date: 




April 2013

November 2014

Guam Power Authority

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