Out with the new, in with the old

The only buildings in Hodko to survive the earthquake were traditional circular bhungas swissinfo.ch

The villagers of Hodko in Gujarat are rebuilding their homes after last January's devastating earthquake.

In a project supported by the Swiss Development Agency, they are copying the style of the only buildings to remain standing after the quake.

“When the shaking started, we had no idea what was happening,” said Ramaben Khaset, whose husband is president of the village assembly. “We were all terrified and we all rushed out into the open. Afterwards there were so many aftershocks, even now when we hear the rumble of a truck, we are frightened.”

Hodko has about 2,000 inhabitants. Several distinct communities make up the village and these are scattered over an area of about two kilometres.

The 500-strong Harijan community lost 97 houses. The only buildings to survive unscathed were four traditional round structures called bhungas – essentially a circular room with a conical roof.

In the state of Gujarat, the earthquake killed 18,000 people and destroyed 125,000 homes.

Built to withstand earthquakes

“We saw immediately that the round bhungas were better suited to withstanding earthquakes,” said construction engineer, Khimjibhei Charda.

“Even if we have a more severe earthquake, we are confident that these houses will not collapse. And even if they do fall down, no one will be injured because there are no big stones.”

“This is a structure which is very stable in an earthquake because it doesn’t have any corners,” added architect, Sandeep Virmani, who coordinates the shelter programme for Abhiyan, a network of non-governmental organisations, which is supporting the rebuilding programme.

“It’s only when we were having discussions with the masons and elderly people in the villages that the origins of the bhungas came out as developments from earlier earthquakes about 200 years ago.”

Rammed earth is another traditional construction technique. A mixture of earth and cement is rammed into a hollow frame – nowadays made of steel – until it is totally compact.

The entire room is made in one piece. When the frame is removed, the wall must be cured or sprayed with water for up to four weeks until the soil and cement mix sets solid.

“After the earthquake we had to come up with techniques which were fast and which didn’t require skilled labour,” said Virmani. “We just give the villagers a steel frame which they put on their foundation and then they ram the earth into it.”

Poor man’s building material

In some villages, the inhabitants have been reluctant to adopt the rammed earth technique as mud is perceived as being a poor man’s building material.

However, the people of Hodko needed no persuading. “We really believe that because our houses were built of mud, there were no injuries,” said Bhimabai Khaset, president of the village assembly. “Because of that, the villagers readily agreed to this type of construction.”

To make the structure seismically safe, three horizontal steel bands are added at sill, lintel and ceiling level. In other types of construction, vertical bars are also wrapped around the wall. Sandeep Virmani says they hold the building together.

“These horizontal and vertical reinforcements basically form a cage around the entire room which holds the building together,” said Virmani. “What normally happens in an earthquake is that the wall starts cracking at the top first. The crack travels down to the bottom and then the wall falls.

“The moment the wall falls, the ceiling falls – so it is not the ceiling which needs to be redesigned in an earthquake situation. It’s the walls.”

Back to the drawing board

After the earthquake, it was back to the drawing board to work out which technologies – given the limitations of local conditions – could best resist earthquakes.

At Abhiyan’s demonstration site in the town of Bhuj, some 70 kilometres from Hodko, architects and engineers are experimenting with different types of buildings and materials to try to prevent the mistakes of the past.

They also offer training programmes for masons and engineers from all over the region to introduce them to new ideas.

Following the earthquake, several building practices using stone had to be changed, said Virmani.

“One of the mistakes that was regularly being made was that header stones – the stones which tie the wall together – were not being used and as a result, in an earthquake situation, the walls tended to split open.

“Another mistake was in the corners which are the most vulnerable portion of a building in an earthquake. The cornerstones have to be placed very carefully so that they weave into each other. They have to be larger stones and they must weave together. If that is not done, then the corners break open.”

Extremely stable

Compressed mudblocks and rammed earth structures are all on view at the demonstration site in Bhuj. So too are domes, another traditional ceiling system which is extremely stable but has fallen out of fashion because of the introduction of reinforced concrete.

“Millions of dollars are going to be spent on the reconstruction process so it’s important that the economy remains within the village,” said Virmani.

“That’s why it’s important to promote these kind of technologies which people can do themselves. It’s also important from another point of view because when people do things on their own, it rebuilds their confidence in being able to handle crises better.”

Immediately after the earthquake the villagers of Hodko erected temporary shelters with whatever was available – grass and tarpaulin, plastic, tiles and sheets.

Now the permanent building programme is underway and the Harijan community will eventually put up 76 new bhungas, with intricately carved ceilings, the walls decorated with geometric and floral patterns.

Bhimabhai and Ramaben Khaset put up the first bhunga in the village. “People from all over the area come and view, it so we’re proud of what we’ve done,” they said.

by Vincent Landon