Structures can do more than they do now. It’s the simple but powerful premise behind colocated systems—such as PV panels that double as noise buffers or highway bridges that carry utility pipes—which employ integrated sustainable strategies, including often-overlooked passive strategies. The century-old concept of the building-as-total-design can be carried out with more systems to achieve better energy conservation and productivity. It’s an idea that has been kept in play by the AIA’s 2030 Challenge, which also calls for greater density in our cities. It’s also an idea that has gained considerable ground already outside of the United States.

One way of thinking about colocation is “dense programming,” or the integration of multiple, often nontraditional functions into architecture: structures that transcend property boundaries and zoning. In this way, architecture takes on the characteristics of infrastructure, where opportunities for ganging up systems and functions are explored—usually out of necessity and for cost considerations.

At first glance, Atelier Bow-Wow’s 2001 book, Made in Tokyo, doesn’t seem very serious at all in its case studies: park-on-park (a park elevated above a parking lot), highway department store, double-layer petrol-station-and-office building. But these systems reveal the logic of colocation in one of the world’s densest and most technologically advanced cities. The more you read it, the more it starts to make sense for dispersed cities that may be trying to “shrink,” such as Detroit. Though Atelier Bow-Wow’s decade-old study omits PVs and other green systems, the firm conforms to a more stripped-down definition of sustainability through density and multitasking.

China’s goal of 400 new cities by 2020 presents another vision of colocation’s potential. Local governments in cities such as Beijing, Shanghai, and Guangzhou are leading efforts to improve the sustainability quotient of fast-paced development. Toward this end, the Beijing-based Dynamic City Foundation has been investigating strategies of colocation that mix infrastructure with architecture while incorporating renewable systems and materials—such as an elevated rail system that incorporates urban farms, PV arrays, wind turbines, water-filtration systems, and sewage-treatment power generation. “Dense concentrations within Beijing are not to be regarded as the problem but as the solution,” says Neville Mars, director of Dynamic City Foundation. Its studies highlight how the logic of so-called “dynamic density” makes cities more sustainable and livable.

Brazil’s favelas offer a more ad hoc approach to colocation. By grafting onto already dense environments, they create new systems that generate and conserve resources and power—one of Brazil’s key strategies for integrating the informal sector into the formal economy. The existing density presents opportunities for sustainable systems and ways of living that would be more difficult to realize in dispersed conditions such as suburbs.

The key to these favelas, and colocation in general, is to combine programmatic density, different systems, and advanced materials. Materials do not by themselves promote sustainability. They must be integrated with programmatic density of the sort seen in the high-tech Copenhagen energy plant and ski slope designed by Bjarke Ingels. The structure creates energy by incinerating waste while also functioning as a ski slope. It also reminds people of the city’s carbon footprint by emitting a 30-meter smoke ring whenever a ton of CO2 is released.

Rather than returning CO2, there is also the potential of returning energy to the grid, or at least aiming toward being more energy self-sustaining. One example is the Hearst Tower in New York City, whose builders not only conserved materials during construction, but whose architects created an opportunity for collected rainwater to filter into heating and cooling tubes as well as to irrigate plants.

Colocation incorporates green technology and materials while addressing issues of urban form and density, too.

“Integrating building systems with architectural features or building enclosures can be a useful way for architects to show how our designs can also improve the functional benefit of a system,” says William Worthen, AIA, LEED AP, director and resource architect for sustainability at the AIA. “Fritted low-E glass that automates shade controls with return air slots; solar-panel patterns on skylights that generate power and reduce heat gain; wind turbines integrated into building façades; living walls and green roofs creating habitat and reducing both storm runoff and the need for air conditioning inside the building; bioswales that filter parking-lot runoff, serve as landscape features, and eliminate the need for expensive and complex stormwater catchment systems; and raised floors systems allowing for HVAC supply each occupant can control and easy access for cabling—they all fit into the category of colocated or multipurposed materials and represent integrated, cost-effective design strategies.”

We are in the midst of what Worthen calls “an evolution to high-performance design, which means we all need to start thinking of green as normal.” Sustainability is evolving beyond the advocacy model of organizations such as the USGBC and Architecture 2030 to a governance model based on high-performance codes such as CalGreen and next year’s International Green Construction Code, which is slated for a March launch.

“Architects are complex problem-solvers,” Worthen says.“We need to stop trying to just be green or get credits, but instead take the time to understand how the architecture—not just its building systems—can directly benefit and improve a building’s long-term performance, human health, and best value—not just first cost.”

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