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Metal Mania

Design

With new solutions for the country’s high-paced growth being found in the use of structural steel, Elizabeth Thomas delves into the virtues of the alloy and examines how sustainable it can be in the Indian context.

With its over 1.1 billion population growing at a rate of 2.1% per annum and a GDP that showed no signs of fatigue even during recession, it is about time India looked at materials and technology that are not just a means to construct four walls and a roof. The challenge is to find solutions to address the future demand for housing.

That is where steel as a construction material gains importance. While it is increasingly being recognised as a smart and viable option for residential housing throughout the world, India has been quite reluctant to trust steel – until recently. Geographically placed in a tropical climate, where the height of summer temperatures can rise to 45o Celsius, constructing a steel apartment block may seem insane.

But an award-winning building design from the UK-based architecture firm of designer Piercy Conner for the West Bangor city of Kolkata dispels many doubts with its sustainable project for the masses.

Called SymHomes Mk1, the design used steel for cladding and shuttering as well as for the internal structure. The winning entry of The Living Steel International Architecture competition in 2005, it also won the MIPIM AR Future Project Sustainability Award in 2007.

Could this be an answer to the swift urbanisation process taking place in Indian cities? Whether it is or not, it’s an indication of things to come, as there is remarkable potential for steel in the Indian market.

Frame of preference
Steel is a versatile and reliable building material. Unlike in the 19th century, when it could not be mass-produced, it is now accepted worldwide as one of the most reasonably-priced building materials. Globally, steel is by far the most frequently used metal building material. And with the number of skyscrapers mushrooming in densely-populated developed cities, structural steel is among the most-sought-after solutions.

“The project and construction segment, which includes the real estate sector, is second only to the agriculture sector in terms of its share of GDP and employment generation. Almost five per cent of the country’s GDP is contributed to by the housing sector. In the next five years, this is expected to rise to 6%,” says Vinod Mittal, vice chairman and managing director, Ispat Industries.

According to estimates of the 11th Five Year Plan, there is a shortage of 26.53 million dwelling units, including the backlog. Thus, over the next 10 to 15 years, even by estimates given by the 10th Five Year Plan, 80 to 90 million dwelling units will have to be constructed – with a majority of them catering to middle- and lower-income groups.

Apart from this huge demand, India also scores high on the construction front. A McKinsey report reveals that the average profit from construction in India is 18 per cent, which is double the profitability for a construction project undertaken in the USA.

With this background and with the recent ongoing growth of steel in construction, the future scenario is robust for the steel industry.

“Steel has entered the high-rise commercial buildings sector as the main structure along with glass facades. Technically speaking, structural steel finds its advantages where spans are large – for example, in the case of airports,” says Sushim Banerjee, director general, INSDAG. He lists a number of qualities that make steel the building material of choice – among them “economical, safe, flexible and elegant.”

 

Steel exhibits desirable physical properties that make it the ideal choice for the primary framing. Its strength, uniformity, light weight and ease of use makes it appropriate for numerous structures such as steel bridges, high-rise buildings and towers.

Being an alloy suitable for prefabrication, a workshop can manufacture finished components which are mounted on to the building site. With standardised components and high dimensional accuracy, it saves time – and saved time means saved money as well.

The flexibility of a steel building makes it economical. With a complete design in hand, a workshop can manufacture components that just need to be transported to the site and fixed.

“A structural steel building has a complete knock down (CKD) formation – you just have to put the nuts and bolts back, and a building is ready. There are no hassles, as standard material and technology is used; and design complexities are the same,” says Manjunath Raghavelu, head, international relations, Arcelor Mittal.

With standardised components and high-dimensional accuracy, industrial production of structural steel looks rational. There is less interference of third parties and lower costs during the construction period.

This gives steel buildings long life and salvage value, making it a major investment. Around 88% of the material can be dismantled, taken to a new place and re-assembled; while the leftover scraps can be recycled.

Steel can also afford open-beam pillar schemes with the possibility of large span steel structure. A steel frame provides good opportunities to graduate to bigger structures when needed, as reinforcements can be easily welded on when resistance needs to be increased.

“In fact, these buildings have great longevity as compared to cement concrete or brickwork buildings because of the low dead load,” says Amit Oberoi, head, corporate communications, Everest Industries. “As the famous saying goes: Earthquake does not kill people, buildings do. Steel buildings are light yet strong, and they offer 3-4 times more seismic resistance than conventional roller compacted concrete buildings.”

Affordable technology?
Steel structures are produced using controlled industrial processes based on technology developed at a high technical level and with computerised tools. The modern steel building being a collection of many individual segments, has changed over time thanks to computer aided design (CAD).

Earlier, structural design was done manually with hand drawings – but now with CAD softwares, designing has become easier and quicker. Models of structures, drawings and drafting can be easily manipulated by using structural CAD design and drafting services. This leads to a more efficient manufacturing process, as most steel buildings have become pre-fabricated.

“Every bit of detailing is done through the computer and there is no gap or no room for any error,” says architect Kamal Malik.

Steel detailing services provide an accurate image of each structural element, its placement, connections with other components and precise dimensions – which contributes to flawless construction.

Smaller pre-fabricated steel buildings are simple enough, but larger steel buildings require professional construction workers to ensure proper assembly.

“The Indian pre-engineered building requirement is over half million tonnes as of today, and Everest share is about 5 %,” says Oberoi of Everest.

“Indian pre-engineering building market is expanding at about 15-20% year-on-year, and this market will continue to grow at least 20% year-on-year, as all players would try to grow the market together by converting conventional steel buildings in the commercial sector to pre-engineered ones,” he adds.

Pre-engineering is one of the major factors that makes a steel building affordable and low-cost. The pre-engineering capability of steel helps you take into account future growth as well as longevity of a project before it is actually designed. This makes a design futuristic and also takes care of physical, environmental and economical factors before the actual engineering is done.

“The technology adopted in India for ‘steel making’ is updated and modern. But all steel sections are not manufactured till date. Once the demand for those sections increases or the need for them is felt, the manufacturers will be willing to manufacture them. Otherwise the opportunities may slip towards imports,” points out Banerjee.

But Malik begs to disagree. “We are not a mature steel building industry yet. We have a long way to go before we start using advanced or innovative technologies that are now common in Western countries,” he says. “Design is about relevance. It is not about likes and dislikes, or what is fashionable today. Indian structural engineers do not have the needed refinement and detailing when it comes to building structural steel buildings.”

India has been reluctant to embrace structural steel engineering for construction solutions.
 

“Labour is cheap and abundant here… but steel construction needs skilled fabricators and erectors, who are scarce in India,” says Banerjee, who feels that the parameter of ‘time’ as a factor of cost is not considered.

“When compared to concrete buildings, builders take the direct cost and not the time cost and life cycle cost of steel.” According to Oberoi of Everest, “In a lifecycle analysis of 10 years, pre-engineered buildings offer at least 20% economy over conventional buildings.”

Malik, however, feels that structural steel in India is 25-30% more expensive than concrete.
 

“For the next three decades, we will have a labour-intensive construction set-up. We cannot just be putting up skyscrapers. We have to think of the relevance and application of the material used. Steel cannot be the answer to India’s structural needs for the next 20 years, at least.”

One of the major challenges in the pre-engineered building sector still remains money – the ever-increasing steel prices, its volatility and nature of fixed price contracts.

“We need to get fixed price contracts with steel suppliers,” says Oberoi of Everest. “Another challenge is non-availability of a specific code for India. All manufacturers should take out an India-specific IMBMA (Indian Metal Building Manufacturers Association) code to promote the use of pre-engineered buildings,” says he.

Although, compared to 20 years ago, India has seen a surge in steel detailing service providers who provide expert and experienced engineers for accurate and cost-effective detailing services.

 

“There is obviously a need to have better fabrication techniques and design engineering. Today, with the large amounts of steel being used in India, this technology will also catch up,” says a more optimistic Raghavelu.

The ‘ease-of-access-to-steel-in-the-form-needed’ is an important factor that will trigger the steel demand from builders and construction companies. “It is important to spread out steel service centres, fabrication shops and retail outlets close to ‘consumer zones’,” says Mittal.

Green house effect
It is believed that every time you use steel for a building frame, you save a tree. Pre-fabricated steel structures have proved to be easy on the eco-system.

Most steel sold today has been recycled, and nearly all that’s taken from demolition projects is 100% recycled. The recycling rate is also the highest when compared to any building material.

While other products can only be recycled into a lower quality product (down-cycled), steel can be recycled over and over again and remade into new members without any loss of quality (multi-cycled).

This makes it the first and only true cradle-to-cradle building framing material.

As structural steel is fabricated regionally in off-site facilities and erected on site, there is no pollution from the debris and rubble as in construction sites where brick and mortar is used. There is minimal waste generated at the fabrication facilities and construction sites, and any waste generated is fully recyclable and resaleable.

Steel buildings can also be easily deconstructed, enabling the reuse of steel members. There is minimal maintenance required and they are highly durable with a long life span. Steel allows easy integration of mechanical systems, resulting in low floor-to-floor heights, less building volume and lower energy consumption.

“Steel is probably the greenest of materials, though steel-making is not,” says Raghavelu.
“Steel is produced from iron ore. Its ingredients include materials like coal, coke, limestone, etc – which are all sourced from mining. I doubt whether steel making can be called green,” adds D K Das, senior structural engineer, Tata Steel Long Products.

However, structural steel is continuing to improve its environment- friendly position by reducing greenhouse gas emissions. And the global structural steel industry has been proactive in pursuing measures that would lower emissions.

Is steel really the answer to India’s needs?
The demand for steel in India rose more than 8% in 2009, buoyed by the government’s focus on infrastructure and revival in the automobile and consumer goods sectors. With strong growth predicted for the auto and housing sectors in 2010, the demand for steel is set to grow in double digits.

“As houses have much shorter spans, the use of steel in this sector can be made popular by innovative design, combining steel with glass,” says Banerjee. But there is obviously a need to have better fabrication techniques and design engineering. And, today, with a large amount of steel being used in India, this technology will also catch up. But there’s still a long way to go.

“The Indian project and construction industry is witnessing the use of steel increasingly, albeit slowly and in spurts. With the introduction of modern living structures and green building concepts, the trend of steel-intensive construction is positive, though not abundant. For this, there is one more significant factor responsible – the steel supply chain dynamics,” says Mittal.

Malik has an interesting take on the increased urbanisation and the use of ‘steel for everything everywhere’. “It has to be relevant and applicable,” he says.

“There is no such thing as steel is universally applicable for every situation. Steel is a lightweight material, extremely easy to lower and it handles sway better. So, we use steel where all these factors are relevant,” he says.

According to him, the urban solution should be a mixed one – steel, concrete and other materials, depending on the space, place and structure. Structural steel high-rises alone are not a solution to the urban problem, he believes, adding that with 70% of the Indian population still living in rural areas, the solutions need to be more extensive and all-inclusive.

Inputs: Sapna Kulshrestha

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