By Junjian “JJ” Tang, LEED AP, FAIA, F.SAME
The best design more often than not arises from finding solutions to difficult problems. This is especially true when the project is a highly technical building and the construction location is one of extreme conditions.
Building a headquarters and operations center for the U.S. government underneath the desert sun on the continent of Africa proved no exception. Prior to construction, the owner, Naval Facilities Engineering Command Atlantic, working closely with the design team from HDR and design-builder, Caddell Construction, interviewed all user groups on site to fully understand their current and future missions, functional requirements, and to identify major challenges and solutions. Solving these problems both economically and practically became the overarching design inspiration.
Design the facility for maximum flexibility and maintainability. Due to frequent mission changes and its remote location, with limited access to readily available equipment and materials, it was especially important to maximize flexibility and adaptability in program organization and building systems—a major factor in the success of this project.
Design and construct a sophisticated project in a logistically challenged location. With a lack of trade laborers in the area, it became paramount for the success of the project for the design team to create a simple, straightforward solution to allow construction by the local workforce.
Achieve LEED Silver certification in a desert climate. The design team had to develop affordable, sustainable approaches that would be suitable for the hot, desert conditions while also meeting seismic requirements.
Meet seismic requirements. The project also would have to be designed to meet stringent seismic requirements.
After researching local climate conditions, construction methods, and digesting the complicated program and requirements, it became clear that “less is more” was the best approach for the new headquarters and operations center. In essence, the team needed to break down the complexity of the building design to its essentials, so that logic, mission and functionality could prevail.
This principal guided the team in making each decision, from architectural programming and planning, to building systems selection, to designing the site and landscape. The new facility serves two different groups: headquarters personnel and operations center staff. By organizing and grouping various spaces belonging to the same functional zone together, the design demarcated the entire facility (with numerous user groups) into three different functional zones: public, semi-public, and private.
The public and semi-public spaces were grouped along the building perimeters and formed the main façades. The windowless private spaces were embedded in the center of the building block. By categorizing the organizations into three zones, paired with a raised access floor system for the entire building, the design streamlines the mission operations and building management while allowing for a flexible and adaptable layout for future mission change. From the building exterior design perspective, the fenestrations of the semi-private spaces along the main façades offer much needed opportunities to be able to articulate the exterior design.
Interior design was guided by the requirement “to be able to easily maintain building infrastructure support systems.” Each zone was organized into a single open “loft” space with exposed duct work, light fixtures and a concrete deck located above for easy inspection, to maximize flexibility and adapt to future changes and expansion. A few offices in each of the zones are placed together in the middle of the “loft” space with spaces requiring separations grouped together along the walls or at the entrance.
For the headquarters facility, offices are located together to form solid “banks,” while administrative cubicles are positioned in an open work environment that allows natural light in through windows in the exterior walls. Partitions separating different functional spaces incorporate knock-out panels within them so that all spaces can be combined into one large, undisturbed operation “hall,” if a future mission requires such a move. A single modular furniture system allowing various configurations was utilized throughout the entire facility.
This streamlined layout also provided huge benefits during construction. By permitting reduced security requirements in the building shell and the majority of the interior spaces, it allowed for use of more local workforce during construction.
STRUCTURE AND UNITIZED SYSTEM
Cast-in-place concrete is the predominant construction method in Africa. The team studied the various structure systems and compared them against cost, the available labor pool, and seismic design. It was evident that a pour-in-place- concrete structure would not only be the most economical way to go, but would also meet the project’s stringent seismic requirements.
Due to the base’s logistically challenged location, the design team had to strip down the interior and exterior design to its essential elements. This ensured the local labor force could build it with limited construction skills and equipment on site. For instance, there is only one size opening for all windows; each south-facing window has a 3-ft-deep U-shaped unitized aluminum sunshade device that was simply bolted to the concrete wall; and the large entrance canopy was also unitized into a few pieces, shipped and assembled on-site, then anchored directly to the exterior wall.
One of the project requirements was to achieve LEED Silver certification—a substantially harder task given its location. Every sustainable strategy had to accommodate local construction and ensure minimal maintenance, both for now and into the future.
Sustainable measures include sun-shade devices on all exterior glazing; providing 30 percent hot water consumption by placing solar hot water panels on the roof; and designing and placing colored rock gardens, with heat-tolerant native plants and bio-swales to achieve Low Impact Development. The most innovative sustainable design idea for this project was to collect the condensate from the chilled water system and use it for landscape irrigation.
The facility has to be cooled year-round, meaning its chillers have to be in use and constantly generate condensate water. In most designs, the condensate is discharged into the building sanitary system. However, in the hot desert climate, water is a precious resource and should be saved if at all possible. The design team determined that the chilled water system can generate approximately 700-gal of condensate water per day, which can be collected and connected to a drip irrigation system to use on the landscape. Condensate water is essentially pure, clear water that contains no impurities or organics, such as what is found in greywater. The production of condensate matches the usage demands of the planted landscape gardens. As the temperature increases, condensate production increases and the uptake from the plants increases.
Due to the base’s logistically challenged location, the design team had to strip down the interior and exterior design to its essential elements.
The system also includes a holding tank, sized for daily irrigation water consumption, a pump, and supply lines to the drip emitters in the planter areas located at the front and rear of the building. Excess water will be drained to the sanitary system. Eliminating the excess condensate beyond daily requirements ensures the water does not become stagnant. Collecting and reusing the condensate also helps to maintain a more attractive outdoor setting. Otherwise, wasted condensate could create unsightly stains and algae growth, or pooling against building foundations, causing damage. The system was easy to install and requires little maintenance.
The design aesthetic of the headquarters and operations center acknowledges its geographic locale with a predominantly French-Arabic architectural style that provides visual relief to the repetitiveness of the one-size window fenestrations and adds human scale to the building by incorporating arches, articulated horizontal bandings and reveals on the exterior walls. These articulations were easily formed into the concrete walls.
The exterior design emphasizes the main entrance and the main stair tower. Visually, it enhances the classic three-part division of a façade that includes the base, the body, and the head. The vertical green strips form a strong horizontal roof line, while the projected sunshades and the continuous window sills add depth to the façade’s French-Arabic architectural expression. Visually appealing, environmentally conscious, and mission-focused, this facility will be a sustainable asset for the United States—helping enable long-term regional stability, prevent conflict, and protect U.S. and coalition interests.
J.J. Tang, LEED AP, FAIA, F.SAME, is Principal, Federal Programs, HDR; firstname.lastname@example.org.
[Article first published in the November-December 2017 issue of The Military Engineer.]