Earthscraper Concept Takes Sustainable Design Underground0

Emily Gertz | Mon Nov 21 2011 |

Earthscraper has become the architectural equivalent of a shot heard ’round the world. Since first surfacing this past summer on a handful of major design and tech blogs like archdaily.com, thetechnologyreview.com, and gizmag.com, this conceptual design for a 65-story, 82,000-square-foot inverted pyramid underneath Mexico City now commands over a quarter-million stories in diverse publications around the globe.

Why has the experimental skyscraper design, created for a 2009 “Skyscrapers of the Future” competition in the architecture magazine eVolo, attracted so much attention?

“We were expecting to have some controversy,” says Emilio Barjau, Chief Design Officer and Design Director of BNKR Arquitectura, the Mexico City firm that created the concept. “But this recent boom is really amazing, it really surprised us. We were not expecting this to be all over news.”

Barjau thinks that Earthscraper may have burst the bounds of the architectural world because it has taken a truly new approach to escalating megacity problems like planning for population growth, curbing sprawl, preserving open space, and conserving energy and water.

In the process, however, the concept also incorporates respect for the city’s past, by seeking to integrate the centuries of Mexico City’s history into its proposed solutions to present and future problems, rather than obliterate them.

Futuristic solutions for an ancient megacity

Mexico City is the second-largest urban agglomeration in the western hemisphere—a tad smaller than Sao Paolo, but bigger than New York City. Home to around 9 million people within its official 573 square miles and with about 19 million in the greater metropolitan area, it is among the world’s top ten “global cities”: a crucial hub of international commerce, finance, and culture.

BNKR sited the Earthscraper design on Mexico City’s major public plaza, the Zocalo, in part because the space is the city’s historic, cultural, and physical heart. Once the site of the Aztec city of Tenochtitlan, the plaza hosts year-round civic events including concerts, exhibits, public demonstrations, parades, and more.

The Earthscraper’s multi-use design is aimed at curbing urban sprawl and its attending problems.

At a massive 188,976 square feet, the Zocalo is also one of the few sizable open spaces left in Mexico City, a hard-to-resist lure for architectural dreams. But it comes with extremely restrictive zoning codes aimed at preserving surrounding landmarks, including the Metropolitan Cathedral, the National Palace, and nearby remains of Templo Mayor, a significant Aztec temple.

The building restrictions render the area “under-developed,” says Barjau. But the only direction to go is down.

Earthscraper from top to bottom

The Earthscraper concept begins with a glass roof replacing the opaque stone surface of the Zocalo. This “ceiling” preserves the open space and civic uses of the Zocalo, while allowing natural lighting to flow downward into all floors of the tapering structure through clear or translucent core walls.

The tower’s first 10 stories are dedicated to a museum displaying the different layers of Mexico City that an actual excavation would reveal. “They used to build one city on top of the other, since pre-Columbian times,” says Barjau. “So we’d have layers of different artifacts and other elements that we will find,” perhaps in part by showing the surrounding underground through clear glass walls.

It will be insulated by earth [while] the gardens would create microclimates inside the tower.

The inverted pyramid’s next 10 stories are intended for retail space, followed by 10 stories of apartments. The structure’s deepest, tapering 35 floors are pegged for office space.

Reining sprawl, cleaning the air

The Earthscraper’s multi-use design is aimed at curbing urban sprawl and its attending problems. Although by law a project of this size would normally have to plan for 10 – 15 thousand parking spaces, Barjau says the concept omits parking in favor of promoting improved connections via Mexico City’s public transportation system—already the largest in Latin America.

“It’s an example of micro-intervention,” he says, “to hold different activities, and hundreds of thousands of people, so they can go back to the center instead of spreading 360 degrees around, spreading traffic and pollution.”

The interior design concept also incorporates a system of gardens occurring roughly every 10 stories, to help generate fresh air. “It will be insulated by earth [while] the gardens would create microclimates inside the tower,” says Barjau. “[So the] energetic cost is going to be lower because you are not going to need HVAC systems” pulling in air from the outside.

Reality Checks

Some facets of the Earthscraper design are so conceptual as to need inventing. One of these would involve finding a way to build so deeply into the water-soaked soil that supports—or fails to support—contemporary Mexico City.

When the Aztecs first built Tenochtitlan in 1325, this area—a valley ringed by mountains and volcanoes that reach heights of over 16,000 feet—was mostly covered by Lake Texcoco, with no natural drainage.

The Aztecs expanded Tenochtitlan’s area by filling the lake immediately around it, and created dam and channel systems to control the lake’s height.

It’s a project that actually has a chance to get built.

After conquering Tenochtitlan in 1521, Spain established Mexico City atop its ruins. Efforts to drain the lake commenced in the 17th century; today nearly the entire valley is paved over. Pumping out the groundwater has caused parts of Mexico City to sink as much as 30 feet into the soft clay lakebed. The city also struggles with pumping wastewater and runoff out of the valley, as well as flooding.

These problems are a major reality-check to the Earthscraper concept, says R. David Scheer, an architect and energy modeler with the design software firm Autodesk. “It’s a really bold proposal that deals with an iconic location in Mexico City,” he says. “It would be nice to see them address some of the realities of building services. How would they pump up all the waste? How are they going to get water down there?”

Barjau agrees that groundwater and wastewater issues are among the design’s major challenges. “We would need to have new technologies in order to make this building actually work,” he says. “There might be ways to use the water around the site, filter it, use it in the building, then maybe return it to the earth.”

Jeremy Faludi, a sustainable design strategist teaching at the Minneapolis College of Art and Design and a contributing writer to ecomagination, calls Earthscraper “a really fun idea, bold and grandiose, and it would be a beautiful place to visit, clearly…if you found a good location for this, it’s an interesting experiment from a green building standpoint.” But he takes issue with two of the design’s signature concepts: its clear glass roof and underground site.

“It looks like it’s designed to daylight the spaces well, which is good—lighting is [a] main concern for a low-energy building,” Faludi says in email. But “I think it would work much better in a dry area in a northern, colder climate, where solid ground keeps you warm, and the glass top acts as a greenhouse. In a hot climate, putting a building underground removes many ventilation opportunities—and you don’t want all that heat.”

If all that were not daunting enough, says Faludi, “Good luck getting digging permits through all the archaeology of that Zocalo…and the public buy-in to transform that public space.”

These and other critiques of Earthscraper may have some potential to be more than further variations on a thought experiment, according to Barjau. “The project started as a proposal for a competition, an exploration of what we could do to solve several problems for Mexico,” he says. But thanks to all the attention it’s receiving, “now it’s a project that actually has a chance to get built.” The firm is hoping to formally present the proposal to Mexico City’s secretary of urban development, he says.

One thing is already working in Earthscraper’s favor, according to Barjau: There are laws that regulate building upwards in this part of Mexico City, but no laws for building down.

“They will have to develop new laws to stop this from happening,” he says. “I hope they don’t [find the] time to do that.”