Construction plays an important part in architecture. Each nation or even region has its own developed techniques to construct the plans of the architect. India is no different. The wide variety of climates and regions means that in every part of India, construction techniques are different. In this article we’ll look at the construction techniques prevalent in north India.
Construction deals with materials. The most prominent materials used for construction in north India are brick, steel (mainly for reinforcement) and RCC, or reinforced concrete.
Brick is really the workhorse of Indian construction. Made in an almost standard size of 3”x4.5”x9”, it is used for everything from building walls and pillars, to partition walls in an RCC-framed building, and even flooring in some cases. Indian brickwork is made of laying down the bricks in courses, or patterns of laying down the brick. Popular courses – or bonds – are Flemish bond and English bond. Herring-bone bond is used when we want the brickwork to look decorative. |
Apart from courses, the thickness of a brick wall is another factor that determines how it is laid. Brick walls can be 1-brick thick, or 2 bricks thick. The standard thickness of brick walls ranges from 4.5” to 9” thick, with thicknesses greater than this being used for special demands of the architect. In places where we need the wall to be insulated from heat or cold a special type of bond called the rat-trap bond can be used, this bond contains air gaps within the wall that provides a layer of insulating air.
The disadvantage of using brick-only buildings – and this is quite possible – is that brick walls can go only so high before the bearing capacity of the brickwork is exhausted. This is why reinforced concrete (or RCC) is used for taller buildings, or more complex plans.
In this kind of building, the RCC forms a kind of frame for the structure with columns, roof and floor slabs forming the basic elements of this structure. Once this is done, the construction workers are free to fill in the rest of the building with brickwork to form the walls, partitions etc. It is to be noted that these days, lightweight elements have taken on the mantle of forming partitions, with brickwork only being used for external walls and for the elevation.
Concrete when used by itself has high compressive strength, meaning it can bear a lot of weight, but low tensile strength, meaning that it cannot be bent or take forces that try to make it bend. This means concrete by itself is unsuited for pillars, columns, and slabs. But there is another material, steel, which has high tensile strength.
This is why when concrete is poured, it is reinforced with steel bars of varying shapes and specifications. Steel bars when used within concrete form a kind of a framework around which the concrete is poured. Concrete used in this way forms what we call REINFORCED CONCRETE (or RCC) which is eminently suited for columns and floor and roof slabs.
Another feature or advantage of concrete is that it can be poured in all sorts of shapes, from standard columns and walls to more adventurous shapes incorporating curves, waves and so on. This means that concrete is well suited to more innovative architectural shapes like arches and more. Some of the most sculptural ways in which RCC can be used are evident in the Capitol Complex at Chandigarh. However using concrete in this way requires specialized knowledge both on the part of the architect, the structural engineer and the construction worker. Such knowledge is rare – and it takes a lot of experience on the part of the architect – and faith on the part of the client – to execute these kind of designs. They are often more expensive too than the standard ways of using concrete.
The third workhorse in north Indian architectural construction is steel. Apart from being used as reinforcing bars in reinforced concrete (as we have just seen), steel can also be used on its own to make up pillars, columns, and trusses or beams. For some reason (mostly cost-based and expertise-based ones) steel has not taken off as a construction material in the domestic construction industry. Its applications are limited to large-span structures such as warehouses and factories, airport hangars and industrial sheds.
Steel comes in various shapes which are usually judged and marked on the basis of their cross-section. Steel can be manufactures in circular cross-sections, in L-sections, T-sections and I-sections. All of these have specific advantages and disadvantages. For example, an I-section can be used for roof beams and an L-section is specifically suited to window frames.
When the standard section sizes do not match the construction profile or design, steel sections can also be ‘built up’ by combining existing standard sections into new sizes or shapes. This kind of work is often seen in tall buildings where beams and columns of steel consist of different sections being joined together.
Steel sections can be joined to each other in different ways. Two of the most popular techniques are riveting and welding. Each technique brings its own advantages and disadvantages, speed and ease of execution. Steel structures when constructed bring a higher degree of precision than traditional structures made of brick and concrete.
New firms, especially in metropolitan areas, have been slow to adapt to new technology and new ways of construction. Some places where innovative construction can be seen are India’s new airports and the new metro stations in Delhi. At these sites international firms have brought in new ways of construction along with the technical know-how needed to execute these designs.
To conclude, steel, brick and concrete have been used as the workhorses of Indian construction for at least a century now. The established industry of these three materials has a stranglehold over the ways in which construction is done. This has retarded trying new techniques in terms of materials and construction techniques. It is only when clients start to become more aware of new materials and begin asking constructive questions that some innovation is possible. This places a responsibility on the architect to educate his or her clients in such a way that a new dialogue on construction in architecture becomes viable.