Tuesday, 26 May 2015

House of Commons

 Koumudi Patil & Joy Sen

Scholarship in architecture and building techniques has time and again urged us to study the scientific and sustainable rational embodied in evolved indigenous systems. Such practices have often adapted seamlessly to the topographic and climatic exigencies of our subcontinent. Moreover, they are also perceived as collaborative rather than confrontational; thus offering suitable solutions to the alarming man-nature conflict.

However, much of what was known is either lost or inadaptable to the contemporary living requirements. This study is not intended to eulogise or museumise our past. Instead, through a few collated instances, we attempt to bring on the table an urgent need to scientifically explore methods of rejuvenating some of these valuable practices, by gaining knowledge from onsite field experience as well as theoretical modelling and historical reconstruction. With careful analysis, many of these practices can address our contemporary needs of sustainability, safety as well as frugal resources. After all, it will neither be intelligent nor efficient to reinvent the wheel at every age.

As the summer settles in, it may be most appropriate to begin our dialogue with climate responsive architecture. How did ancient India survive the scorching summer, brutal winter, torrential monsoon and humid spring?

Classical texts of architecture such as Mansara and Mayamatam explain the established system of qualified sthapatis (architects), engineers, carpenters, plumbers and local masons working under the patrons of kings or kingdoms. A city described in these texts always comes across as planned and systematically executed construction. Puranas, Agamas and Shilpashastras list definite stages of city planning: bhu-sangrah (study of the site), bhu-pariksha (examination of the site), dikpariched (determination of the cardinal points), padavinyas (survey of the ground), bhu-vidhan (transferring on the ground the layout conceived in planning) and grihanirman (design/construction of the buildings). In fact, the idea of the vastu mandala is as old as the Rig Veda, where a whole sukta is dedicated to building traditions.

The 16 mahajanapadas, as recorded in the early buddhist and jain texts, were just not socio-political confederations, but a system of regional variations of architectural styles subject to varying impacts of climate, available resources, riparian impacts and the intensity of flora and fauna. For example, the Magadhan tradition in today’s Bihar (buddhist vihara) exhibited built-forms based on its relatively arid climate compared with the Anga-Pragjyotisha (Bengal-Assam) belt in response to the available fertile green land. Hence, even the colour, size and nature of bricks (called istaka) varied in the two mahajanapadas, besides the design of the courtyards and allied open spaces. The distant Assam-Bengal and Kerala built-form traditions displayed similar approaches based on a common pack of maritime and saline impacts of backwaters and sea-based commerce.

Sawan Bhadon pillars of Orcha
Likewise, wind catchers, intricate jaalis or hollow walls, amongst many others, are evolved techniques for temperature as well as humidity control. Wind catchers are airshafts, which capture the prevailing wind and circulate cool air to the underground halls of the royal durbars during summer months. The twin towers of Orchha, Madhya Pradesh, called the Sawan Bhadon pillars were perforated on the top to ‘catch the wind’. The base was connected to a reservoir of water ingeniously feeding the fountain — chandan katora. The hot wind caught by the towers was cooled down not only by its long downward passage, but also by the waters. Even simple perforated walls like the jaalis (deeply carved patterns) in Rajasthan minimise heat gain by providing shade. Such devices also result in increased convective transfer of heat because of increased surface area. Similarly, the thick wide walls sometimes made hollow, as in the Bhool Bhualliya of Lucknow or Akbar’s Fathepur Sikri complex near Agra, were good insulators of heat as well as sound.

The common man’s house, however, was a different tale. It is not known whether the sthapati was involved with the typology of the common houses. But irrespective of the sthapati, if there was any, it is well known that the vernacular structures were a result of community-shared knowledge. The vernacular knowledge of the courtyard effect, stack effect, use of local materials and efficient adaptation to local topography were well known in the practices of the past. In many famous instances like Nath-malji’s haveli in Jaisalmer built in the 19th century by Diwan Mohata Nathmal, the prime minister of the local ruler, as well as in most common houses, the courtyard is a common site. It acts as an air funnel discharging indoor air into the sky, resulting in improved thermal comfort of its adjacent areas. Similarly, recessed windows, jaalis and the light wells of Lucknow’s Imambara are not only a source of light, but also of ventilation and thermal transfer.

The value of water to Indians can be understood from the plethora of water harvesting and conservation systems found in different topographies across the country. Zings, vavs, tanks, kund, surangam and scores of other such structures are well established in the architectural typology of India. The most ambitious amongst these might be the water tank at Shringverpur, Allahabad, dating back to the 1st century AD. If the current hypothesis of renowned archaeologist and former director general of Archaeological Survey of India (1968 -72) Braj Bansi Lal is held correct, this flood harvesting technique channelled the flood waters of the Ganga for about a kilometre to feed the tank with a capacity of 6.5 million litres (storage tank alone). This huge construction  is divided into three tanks: inlet tank may have been used purely for desilting through sedimentation, from which water flowed into the storage tank for use by citizens; another storage tank that even had wells in its dug in its floor to further recharge the ground water during monsoon; and the last tank, which might have been a small votive tank followed by the spilling outlets through which the overflow was released back.

One of the ongoing studies at SandHI, IIT Kanpur suggests that the use of the beautiful steps at Chand Baoli in a little town of Abhaneri in Rajasthan made internationally famous by the latest Batman movie The Dark Knight might not have served an aesthetic purpose alone The tank was built by King Chanda of the Nikumbha Dynasty between 800 AD and 900 AD. Simulation of daylight on this structure has revealed that an inverted pyramid with a stepped motif is an optimal form for shadowing the wall which prevents its heating. Of course, lower heating results in lower evaporation. The folklore in Rajasthan, poetically describes the rational behind such a form — paani ko suraj ki chori se bachana hai. (Don’t let the sun steal the water.) With this mantra in hand, the non-engineering communities of Rajasthan have built ingenious water harvesting structures that are a perennial source of water supply in a region that receives less than 10 cm of annual rainfall. In particular, by encouraging a shift from ‘produce’ to ‘fixed’ and then to cash rents, the British administration upset the procedures and protocols between tenants and landlords over the question of the maintenance of such evolved water systems, leading to their gradual demise.

Computer simulations of Chand Baoli in Abhineri, Rajasthan that replicate the ingenious optimal wall shadowing which prevents water evaporation; A) east face at 12.30 in April; (B) south face at 12.30 in April; (C) west face at 15.30 in April; (D) south face at 15.30 in April

Wherever such colonial laws have been defied, indigenous systems are again proving resourceful. Rajendra Singh, the waterman of Rajasthan flouted these colonial laws umpteen times to build johads. This has not only replenished several dried wells, but also miraculously rejuvenated rivers that were lying dry for more than 60 years.

Not only the canals, but also much of the sanitation and storm water lines in Indus cities had perfect rendition of slopes, privy connections, inspection pits placed at grids, and a framework based on geometric patterns of brick kerbing and corbelling.

Over 75 per cent of the built environment of Mohenjodaro and Harappa was carved out of the famous ‘English bond’ known to Indians almost 5,000 years before the British claimed to introduce it in India. Knowledge of orthogonal geometry and town planning layout based on the ‘grid-iron’ pattern were known 1,500 years prior to the ancient City of Miletus (1,500 BCE) in Anatolia.

Earthquake safety has also been a matter of concern in many regions in India. Interestingly, it has been tackled effectively through simple frugal solutions that can only be described as beautiful. Construction and design practices like dhajji diwari, kathkuni, koti-banal, taaq and others have shown better seismic response than contemporary construction in the same regions. It was astounding to see the dhajji diwari of the Kashmiri houses withstanding the 2005 earthquake measuring a magnitude of 7.6. The term dhajji diwari may have its origin in Persian, referring to a “patchwork quilt wall”. The wall is made of a timber frame with a stone-mortar infill. Observing its seismic resistance, close to 10,000 houses in Kashmir were reconstructed in the aftermath of the earthquake using this age-old technique.
UNESCO poster on dhajji diwari system
Prof Durgesh Rai from IIT Kanpur has conducted multiple shaking-table tests to draw a detailed analysis of the earthquake resistant mechanisms of the dhajji diwari. Similarly, the kathkuni style cleverly uses interlocking wooden sleepers (usually cedar) and stones, forming a horizontal mesh with inherent elasticity to resist seismic force.

Of particular mention is the ingenious technique of using wedge shaped bricks to prevent well walls from falling inwards during an earthquake. Wedge shaped bricks lock together unlike rectangular or square bricks. Even the well-known Roman engineers used rectangular linings in the well walls, often resulting in their inward collapse due to the enormous pressure of the soil. Interestingly, there is evidence of the use of wedge shaped bricks in wells close to Allahabad, even until 1950s. This is of significance considering the continuity of this knowledge from Harappan times till now.

Besides building techniques, it is surprising to read the meticulously drafted rules and regulations guiding the use of personal buildings as well as other civic architecture. Amongst others, Arthashastra makes elaborate mention of fire safety regulations. The regulations imposed heavy penalty against any resident who did not separate the cooking stove from the wall with a line of water pots. Kitchen window or walls were prohibited from facing the kitchen wall of another house. In case of a fire mishap at a site in which fire safety regulations had been violated, the owner was forced to bear the reconstruction expenses of not only his own house, but also that of the property of other citizens, which was damaged due to his negligence.

Such detailed understanding of not only the design and construction of a building, but also of the civic responsibilities of a citizen, give a glimpse of the refined civic sensibilities of our civilisation. Alas! such knowledge as well as its practice has slowly disappeared from our contemporary living surroundings. Today, modernism has a tendency to achieve a universal lifeless homogenisation by suppressing free and creative attempts in local contexts and in local practice. Therefore, we assert a contemporary need to establish a dialogue with tradition, holistically framed through the lens of science and build a science-heritage interface.

(Dr Koumudi Patil is assistant professor in the department of humanities and social sciences and design programme at IIT Kanpur. Email: kppatil@iitk.ac.in

Dr Joy Sen is professor in the department of architecture and regional planning at IIT Kharagpur.

the article was published in Financial Chronicle, Tuesday April 28 2015

No comments:

Post a Comment