Sticks, Not Stones, Make Homes in Indian Himalayas

Pitt engineering students tackle sustainability in one of the world’s steepest, harshest terrains

Posing on the road from Rimbik to Darjeeling are (from left) Pitt Swanson School of Engineering senior Derek Mitch; Bhavna Sharma, civil engineering doctoral student and recipient of an Integrative Graduate Education and Research Traineeship from Pitt’s Mascaro Center for Sustainable Innovation; civil engineering doctoral student Maria Jaime; and civil engineering professor and William Kepler Whiteford Faculty Fellow Kent Harries.

There is no formal method for testing the strength of bamboo for building structures, so Derek Mitch has to invent one. The Pitt Swanson School of Engineering senior’s only resources are three years of college, a working knowledge of concrete construction, and a 22-page chapter of general guidelines from the Indian Building Code.

A budding engineer couldn’t ask for a better challenge: “It’s a totally different way of looking at engineering,” Mitch says.

His conundrum—and opportunity—stem from a May trip to the Indian Himalayan regions of Darjeeling and Sikkim, where he investigated the design and construction of bamboo buildings. Fellow students who accompanied him tackled issues ranging from slope stability to clean energy. Together, the aspiring Pitt engineers, led by Pitt civil engineering professor and William Kepler Whiteford Faculty Fellow Kent Harries, cut their teeth by helping an Indian engineering group, Sustainable Hill Engineering and Design (SHED), create and promote a plan for sustainable construction in an area desperate for new approaches. Harries hopes to make the journey to India’s- Himalayan foothills an annual event.

Students would experience a level of involvement and need for innovation that few other environments could offer, Harries says. Sikkim and Darjeeling straddle the planet’s most unstable terrain. Traditional building methods involve masonry and concrete that have to be trucked along rugged, winding roads where untrained contractors and temporary workers cobble together buildings that list on the soft-soil hillsides and crumble from frequent mudslides and earthquakes.

Aside from being challenged by the terrain and resource limitation, engineers in this remote part of India lack access to the equipment needed to perform basic quality control and assurance testing. So, Pitt students like Mitch take the lead, drawing upon the Swanson School’s numerous labs—and sometimes creating test methods and standards that don’t exist.
“This is a fantastic environment for an engineering student because it presents a true engineering problem,” Harries says. “The issues—the terrain, the weather, the available resources—are everywhere, but the solutions to each are very different.”

Structural engineer Gayatri Kharel, a former graduate student of Harries from the University of South Carolina, leads SHED. The group promotes basic principles of sustainable engineering that are a major emphasis in the Swanson School—harvesting potable water, supplying clean and efficient electricity, and preventing landslides. Kharel and SHED take on local building projects and educate residents and contractors about the advantages of sustainability in terms of cost and preserving their homeland.

SHED largely focuses on repopularizing the ikra, a traditional bamboo-frame structure and the subject of Mitch’s research. Because of the soft mountain soil, modern construction methods pose a great threat to environment and safety in Sikkim and Darjeeling. So to move local construction beyond concrete and brick, SHED turned to the past. The group lauds the ikra as a more sustainable and affordable (in an economy based on tourism and tea production) structure that withstands regional rigors while preserving the delicate mountainsides. But SHED must counteract skepticism and a decades-old infatuation with modernity, says Kharel, a Darjeeling native.

“When reinforced concrete was introduced, it was modern and a status symbol,” she says. “People saw bamboo as the material of poor villagers. Concrete also looks safer than bamboo, but it’s not. We have to convince people that bamboo is safer.”

n a presentation to Pitt engineering students during a reciprocal visit to Pittsburgh in June, Kharel displayed photos of the 5.7-magnitude Sikkim earthquake of Feb. 14, 2006: severely damaged brick and concrete buildings followed by an unscathed bamboo-frame ikra. Some residents and builders in Sikkim and Darjeeling get the message in these photos, Kharel says.

“Many people are excited,” Kharel says. “They are happy we’re building with local material because they feel the traditional methods are dying. The bamboo structures are healthier for the environment and the economy, even in terms of tourism. People can visit Darjeeling and see traditional ikras instead of concrete buildings.”

SHED oversees several projects demonstrating ikra construction and other sustainable techniques, but these projects also illuminate the social and technical obstacles that remain. For instance, in building St. Joseph’s School in Mungpoo, near Darjeeling, SHED had to convince the rector that bamboo trumps concrete for safety and ease of construction—and to go against affluent alumni in the cement contracting and supply business, Kharel says.

Bamboo can crack, as Mitch observed at St. Joseph’s. SHED bolstered the material’s stability with a concrete foundation, but bamboo beams joined with bolts could split, Mitch says. Like a windshield crack, these tiny fissures grow. SHED needs to know the cause of the splitting, its relationship to the bamboo species used in construction, and the best methods for repairing and preventing the fractures. But the closest lab to Kharel lies down a treacherous road more than 50 miles away.

Upon his return to Pitt, Mitch set about developing an onsite material properties test that, like any other, would gauge the load a material can bear—except he’s testing a plant. One with about 1,000 species.

Mitch had no experience engineering bamboo, and his research suggested that few others do, either. He found two papers on the splitting of bamboo and the 22-page government manual on bamboo construction. To compare, the U.S. manual on building with steel contains about 2,200 pages and that for wood takes up more than 4,000, Mitch said.

“The Indian manual said an engineer’s job is to anticipate loads and design for them—that’s not guidance,” he says.

Since his return from the trip, Mitch has narrowed his approach to about 10 possible test methods, but he wants a single test, because that’s the only way most Indian contractors will use it, he said.

SHED also confronts a general informality in Indian construction and engineering: “There are professional engineers with a degree from North America or Europe and working with state-of-the-art engineering tools, but then you have to deal with implementation,” Harries says. “This is an area where construction methods are at times questionable.”

With limited resources and minimal oversight, contractors execute projects on the cheap and hire temporary workers that rotate every two weeks, Kharel says. Plus, most Indian engineers “learn to build on flat land,” not the slopes of Darjeeling and Sikkim, says Kharel, who earned her bachelor’s degree in civil engineering from Visvesvaraya National Institute of Technology in Nagpur, India.

Mitch’s construction experience is limited to that of a summer job, but while in India, he watched as a man in sandals tossed gravel into a cement mixer and concluded that the man wasn’t concerned with proper measurement. Nor did another man seem to find anything amiss in tamping concrete into the rebar-frame skeleton of a support beam with a hand trowel—while a machine meant for the job sat unused nearby.

“I saw some scary things,” Mitch says, scrolling through digital photos of completed buildings with their rusty rebar skeleton jutting through clumpy smatterings of concrete.

“I saw a four-story concrete building perched on a 60-degree slope with almost no foundation or pilings. That’s why I’m making a single test: Getting multiple tests done would be impossible. Any testing at all has a much higher chance of happening with just one.

“From an engineering perspective, India is very fresh,” he continues. “There’s very little code and enforcement. As a student, that can be good—you have to do everything yourself.”