While building codes are usually seen as limitations, they could also be propellers for out-of-the-box creative solutions. Federal and local laws in Mexico prohibit demolishing historical buildings, and the height regulations limit new structures to eight storeys.
The Historic Center is in a desperate need of a programmatic make-over. New infrastructure, office, retail, and living space are required. Historic Zocalo, the main plaza of Mexico City and one of the largest in the world, is bordered by the Cathedral, the National Palace and the Federal District Buildings.
Symbolic of various layers of history buried there, it was the main ceremonial centre in the Aztec city of Tenochtitlan. From the colonial period, the main plaza is the heart of the Historic Center of Mexico City. The plaza hosts year-round civic events including concerts, exhibits, public demonstrations, parades and more.
To accommodate new functions and still comply with the building and its historic preservation codes, BNKR Aquitectura has proposed a unique design solution — the Earthscraper. The Earthscraper is an inverted skyscraper that digs down 1000 feet through the different layers of Mexico City — built down, instead of built up.
Placed in the middle of the 240-metre x 240-metre Zocalo, the Earthscraper is a 65-storey steel and glass inverted pyramid. It is capped with a glass roof, and the habitable spaces are positioned around the central void, allowing natural light to filter down to even the lowest levels. The glass ceiling preserves the open space, without compromising on the historic environs of the plaza.
The Historic Center of Mexico City is composed of different layers of cities superimposed on top of each other. The Mexicans did not build new pyramids; they built over the remains of the previous one.
The first 10 floors of the Earthscraper will be a museum to showcase Aztec pyramids of the ceremonial complex below ground. The glass pedestrian surface in the plaza will allow people to get a peek through the vertical museum. The next ten stories are for retail and housing while the deeper 35 stories are offices. Every 10th floor of the underground structure will be an ‘earth lobby’, which will be the green garden floors. These will not only make the Earthscraper green and create a micro-climate but also facilitate natural and sustainable air filtration.
The inverted pyramid has horizontal as well as vertical green spaces. Vertical greenery on the inside of the barrier wall will help in air purification through various listed plants in the habitable spaces. Every ‘earth lobby’ is not only a communal space but has also knit nature into the built fabric of the inverted pyramid.
A double structural envelope has been designed to support the floor loads and retain the surrounding subsoil. The exterior barrier wall is not only the retaining structural membrane but also conveyor of infrastructure. The lower floors house the turbines, which will help pump up clean water through the exterior membrane to every floor.
The gray water from the toilets on every floor will come down to the turbines and be treated to be reused and pumped for irrigation.
Electricity to light up the inverted pyramid will be generated by the recycling function of the turbines and transmitted through the exterior membrane to every floor.
Estimated to cost $800 million, Earthscraper’s multi-use design may be a new approach to combat inevitable urban growth problems like population growth, curbing sprawl, preserving open space, and energy and water conservation.