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| Himanshu Burte / Jul 18, 2010, 00:03 IST |
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The bamboo dome of India’s pavilion at Shanghai’s Expo 2010 offers a fresh, green vision for the architectural future.
Can a mere bamboo dome pose important questions about the buildings and cities of the future? Surely the urban form of the future will be shaped by industrial materials like glass, steel and aluminium, as in Gurgaon? The designers of the Indian pavilion at Expo 2010 in Shanghai, which opened on May 1, hope that their bamboo dome covered with live vegetation will shake some of these certainties. I have not visited the project, but my discussions with its architects and the available information, drawings and photographs suggest that it deserves more public debate.
BUILDING FOR A SUSTAINABLE FUTURE
The theme of the Expo is ‘Better City, Better Life’. One glance at the pavilion reveals how little it accords with the industrialised world’s vision of the good urban future. It might well be the biggest bamboo dome in the world, but it looks like a cute, even ‘vernacular’ artifact, compared to the Chinese pavilion. The latter is stereotypically ‘futuristic’ — a big, shiny, whale-meets-spaceship form built with high-technology materials.
The contrast between the two buildings is a contrast in philosophy. The design of the Indian pavilion showcases an approach to architecture that involves consuming less non-renewable resources (including fossil fuels), and causing less damage to the planet (including by carbon dioxide emissions).
DOME DESIGN
Four Indian architects collaborated on the design. They were Sanjay Prakash, Pradeep Sachdeva and Tanmay Tathagat of New Delhi, and Mohan Rao of Bangalore. All have special expertise in sustainable architecture.
The pavilion (covering 2,800 sq mt and costing about $3 million) is an enclosed area with a domical exhibition space at one end. According to the official design concept, the dome echoes that of a Buddhist stupa, a form which is common to India and China.
Conceptually, it must be said, this design appears forced and looks like a leftover from the old Festival of India pattern book. The traditional stupa, after all, is a solid masonry mound. Domes are hollow, and this one is in very light bamboo. The design is thus a missed opportunity to explore a form that emerges largely from the unique strengths of bamboo as a material.
That said, the structure and vision are important. The dome is deceptively simple in form. Structurally, it resembles a basket placed face down. Thirty-six bamboo ribs spring from the base and converge at the crown. Each rib consists of six bamboos laid end to end and joined together. The ribs are connected by 10 bamboo and four steel rings, at different levels. The steel rings were used mainly to ensure that the bamboo structure was built to the correct geometry on site. There is one concrete ring at the bottom and another at the top.
This structure supports a two-inch-thick outer shell of micro-concrete, covered by a waterproof membrane. On this are fixed three layers of an innovative geo-fabric — a soil substitute that holds and delivers water and nutrients from a drip irrigation system to the green roof. Over 125,000 herbs were hand-planted in a multicoloured pattern. The plants are watered in part with water recycled from the toilets. They help insulate the building while capturing carbon from the air and releasing oxygen. An aero generator (an exhaust fan driven by small drafts created by temperature differences between inside and outside, not electricity) at the top of the dome helps ventilate the indoor space and avoids energy-intensive air-conditioning.
CONCEPTUAL SIGNIFICANCE
The project is significant for three reasons. First, it is ecologically benign. It uses a renewable natural material — bamboo — that grows quickly and degrades completely, leaving little waste. (Incidentally, after the Expo ends in September the dome is slated to be dismantled and re-assembled on another site.)
Second, it is very ‘contemporary’ even if it uses old materials and forms. It is engineered using the latest design techniques (including computerised energy and other simulations) and satisfies the latest international fire and structural safety codes. The management protocols involved in its construction were like those of any major international project.
And third, it shows that a big niche exists between high-tech, on the one hand, and crafts-skills in construction, on the other — which is relevant even for prestigious international projects.
FUTURE PROSPECT
The project makes a strong case for a scientific exploration of natural and renewable materials, especially bamboo, in building. It shows that one does not have to use large quantities of cement, steel and glass to achieve sensible architectural goals attractively. Quite the reverse. Industrially produced construction materials like cement, steel, glass and aluminium consume huge amounts of fossil fuel energy.
Meanwhile, India is rich in natural materials and techniques of building with them. In recent decades, Indian architects and engineers have developed dependable ways of constructing modern buildings in bamboo, mud and stone. The future clearly belongs to the sensible application of technological advances to maximise the effectiveness of natural materials.
If this bamboo dome sparks a debate on these issues, in India and elsewhere, it will have more than paid for itself.
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BUILDING THE DOME
This was a challenge because of the sheer newness of the idea as well as the collaborations involved. Reconciling different technical visions from different countries and fields was part of the challenge.
Design-C (led by D R Naidu), a unit of HTA Pvt Ltd, was lead designer. It was appointed by the client, the India Trade Promotion Organisation. Architectural design and detailing were the joint effort of four architects and their firms (see main story). Dr Simon Velez, a Colombian authority on bamboo construction, was a special consultant. Lead contractors Shibu C, and local contractors China Jingye were responsible for ensuring that the design met the local building code.
The bamboo chosen was the edible Chinese Moso (Mao-Zhu, or ‘hairy bamboo’), sourced from Anji district 200 km west of Shanghai. A bamboo furniture factory agreed to process the bamboo. There, the bamboo was treated with hot boric-borax and lightly curved in a jig.
Joints were a crucial area of detailing. Tolerance for natural size variations in bamboo pieces had to be built in, to ensure the final form had a perfect geometry. Small quantities of industrial materials were judiciously used to make sure the final shape was right. Steel bolts were used to join bamboos together, and cement grout injected into the bamboo nodes near the joints. To absorb the differences in diameter of bamboo pieces at joints, a steel plate larger than the largest diameter was used. This plate also acts as a stopper for the cement grout in which the bolt is embedded.
CHOOSING THE PLANTS
Mohan Rao of Integrated Design, Bangalore, was responsible for landscape design (‘greening’ the dome). He describes the complex task:
“A two-hour drive would take us to nurseries where I would choose a plant, whose name was noted based on the nursery person’s pronunciation in Mandarin, validated and corrected by another Chinese person later. This then was used to track down the nearest common Mandarin/English plant name. More tantrums and sleepless nights led to its Latin name, all of which were recorded based on its growth character, flowering season, water requirement, medicinal properties, etc. I personally did this with the help of two Indians, two Shanghainese, one French [person] and one Chinese-American over five weeks. The compiled list was vetted and the species shortlisted in subsequent visits — four times over!”
To Rao’s dismay, the challenges of intercultural communication almost led to his work being overlooked by the contractors. Some quick action — involving Rao clambering about on the dome to redraw the pattern within a few hours — saved the day.
THE TREE OF LIFE
The pattern on the plant-covered dome is derived from the stone carved jali depicting the ‘Tree of Life’, in the Siddi Syed Mosque in Ahmedabad. The ‘branches’ are beaten copper sheets, and literally hold the entire composition together. A variety of plant material that changes with the seasons, represents the ‘leaves’. The tree pattern visually integrates the energy-producing components of the pavilion (the photovoltaic panels and aero generator), and helps the pavilion always ‘face’ the viewer, no matter what angle it is seen from.
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