Getting High Design from a Low-Tech Approach

Eschewing complex forms and technology, socially minded architects rely on age-old building techniques to create modern marvels
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From Architectural Record
Josephine Minutillo

Up market

Vegetable vendors occupy many of the market's stalls (above). Compressed earth blocks, formed with a hand-press machine, were used for roofs as well as for walls (bottom left). Large arches support dome-shaped roofs (bottom right).

Photo © Amir-Massoud Anoushfar (top); Laurent Séchaud (bottom two).

 

Farther north on the African continent, a government program to stimulate economic growth led to the creation of an extraordinary project. The landlocked nation of Burkina Faso is one of the poorest in the world, with few natural resources. Most of the population is engaged in agriculture (despite crops' vulnerability to periodic drought), and a large part of the male labor force migrates annually to neighboring countries for seasonal employment.

A section of the Central Market in Koudougou, Burkina Faso, reveals a series of arced shops (top). The market's orthogonal layout covers an area of 312,000 square feet (below).

 

In Koudougou, the country's third-largest city, the construction of the Central Market helped provide jobs and develop masonry skills among local workers. Once completed, its 1,200 shops-encompassing 312,000 square feet-offered a vibrant civic space for commercial and social exchange.

The market, which was honored with the Aga Khan Award for Architecture in 2007, was built under the direction of the Swiss Agency for Development and Cooperation in collaboration with the Burkina Faso government. The principal architect, Swiss-trained Laurent Séchaud, has resided in Burkina Faso since 1997. "The climate and living conditions here are quite difficult," Séchaud says, "but the people are very welcoming."

While buildings made of earth-whether rammed earth, cob, mud bricks, or compressed earth blocks-are largely alien to people in the developed world, much of the rest of the world's population occupies such buildings. The one-story houses throughout Koudougou were, until recently, built from earth blocks. Construction of these homes, along with that of the city's administrative buildings and urban facilities, is now almost entirely of concrete block and other costly, imported materials.

Designers of the Central Market, including fellow Swiss Pierre Jéquier and local engineers, reclaimed the traditional building technique, using the humble, locally made product to create a sprawling bazaar of vaults, domes, and arches.

Photo © Amir-Massoud Anoushfar

 

Compressed earth blocks provide the precision and versatility of bricks but can be made of virtually any kind of soil, require very little moisture, and do not need to be fired in a kiln-making them less expensive and more environmentally friendly to produce. Earth for the market's blocks was manually extracted from a hill 11⁄4 miles from the site. A small percentage of cement was added to the mix as a stabilizing ingredient.

The blocks were made on-site using 12 hand-press machines, each supported by a rotating staff of four workers. Up to 9,500 blocks of varying sizes could be produced per day, totaling 4 million for the entire project. Smaller blocks were used in the vaults and domes. Larger blocks measuring 111⁄2 by 31⁄2 by 51⁄2 inches filled in the walls-the longest dimension representing the wall's depth. The blocks were cured in the sun in two stages, each 14 days long.

The market's orthogonal layout mimics the colonial grid characteristic of Burkina Faso's cities. Around its periphery are shops that stay open past general market hours, animating the city center. In an effort to open up views, minimize solar exposure, and provide adequate air circulation within the dense market, the internal layout, while still linear, is quite diversified. Shops oriented east−west along the width of the market form alleys, as north−south oriented shops delineate small gathering spaces. An open, domed area supported by a series of high arches contains additional stalls.

The one-story compound incorporates 85 domes, 658 vaults, and 1,425 arches. Since timber is a precious resource in the region, most of these were constructed without the use of formwork. A few of the larger arches that required temporary support used timber, but for most, earth blocks were cut and shaped to form makeshift structures.

The labor-intensive project generated more jobs than would have been possible had concrete been the building material of choice. In the process, hundreds of local workers-many of them women-gained certification as masons, and now work as freelance entrepreneurs.

 

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Originally published in Architectural Record
Originally published in October 2008

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