In a series of features showcasing building materials,
PS Badrinarayan, Associate, Shirish Patel & Associates, highlights the role of steel in the Indian construction industry.
Steel has come a long way. From a default option for industrial structures to an essential building material that lends itself to a variety of uses, the evolution of the use of this material has indeed been remarkable. Structural Design Engineer PS Badrinarayan, Associate, Shirish Patel & Associates, a structural design consultancy firm based in Mumbai, traces the progression of steel as a building material in India and shares his thoughts for its future use in conversation with
Charu Bahri. Excerpts...
Looking backSteel buildings and bridges were being built in the latter part of the 19th century and early 20th century during the British era, in much the same way as such infrastructure was built in Britain and Europe. In the post-independence era, especially after industrialisation took off in the 1950s, steel was traditionally used to set up public and private factories, refineries, petrochemical plants, ports, railways, warehouses, etc; essentially structures in which architecture plays an insignificant role and projects largely managed by engineering professionals from design to construction. Steel was used as a default option in these structures because its inherent properties ensured that it commanded a high level of comfort with engineers. This usage pattern continued up to the 1990s.
During the 1960s to 1980s, precast concrete was also used in industrial applications, perhaps as it is more economical and maintenance-free, but this use was not widespread as it was associated with specific skills for design and construction. By the 1990s, the use of precast concrete had begun to gradually fade out. As far as industrial applications were concerned, pre-engineered buildings (PEB) began to gain popularity with clients owing to the convenience and speed of such erections, the possibility of turnkey design and construction, and off-site fabrication in the supplier's workshops. PEBs began to evolve beyond simply being reasonably economical structures modelled on simple vanilla designs.
Alongside the liberalisation of the country's eco颅nomy in the 1990s, steel began to be considered for app颅l颅ications other than industrial ones - such as tall buildings for offi颅ces, airports, metro transport systems, IT parks, multi-storeyed car parking proprietary systems, architectural structures, etc. Practically, however, the use of steel was curtailed by the high cost of steel construction vis-脿-vis concrete construction.
Cost concernsIn fact, cost is the reason why even though India is passing through a phase of economic growth akin to what the US underwent in the 1970s and 1980s, the country is nowhere near seeing the kind of lightweight steel-framed tall building construction boom that played out in the latter. While the use of structural steel is gro颅wing, tall building technology is still in its infancy in the country and India lags behind in adopting structural steel. Take Mumbai as an example. Inspite of being the home of skyscrapers in India, the city boasts no more than a handful of tall steel buildings.
Steel is unable to compete with concrete, as methods of construction go, in many applications. As far as bridges, flyover and viaducts for metro transport systems are concerned, advances in concrete construction for such applications through precast concrete and segmental construction have made concrete a natural choice owing to lower costs, ease and speed of construction, and almost zero maintenance. In fact, the Bandra Worli Sea-Link in Mumbai is built entirely in concrete. Concrete also continues to be the preferred mode of construction for high-rise buildings in India, again mostly because of cost concerns.
Availability of steelUntil about a decade ago, limited supply could also be counted as a factor hampering the use of structural steel. Tata Steel, Jindal Steel and SAIL are among the primary manufacturers offering hollow box sections, I-beam cross sections, plates, angles and channels in India. Corus Steel of the UK entered the market some years ago and this has improved the availability of structural steel. For instance, indigenous suppliers offer hollow box sections up to a maximum size of 300 mm 脳 300 mm, which are 8-12 mm thick. In comparison, Corus Steel offers hollow box sections sized as large as 800 mm 脳 800 mm and 40 mm thick. Fortunately, Jindal Steel offers a wide range of I-beam cross sections as per international profiles up to 900 mm depth.
Steel frames are more expensive but allow architects and structural engineers more leeway in the arrangement of design elements. Steel is a far more pliable material and can be used to express innovative forms. We chose to use hollow box sections of Corus Steel to practically express the complex shapes of an exhibition centre building project in Navi Mumbai. We were driven to create the building in steel because of the complex form that would not have been possible to build in concrete. Steel as a material of construction is used in metro stations and airport terminals for similar reasons - to express architectural form and large dimensions.
Short supply: management skillsAt present, the construction of steel buildings is also being limited by the paucity of skills. There is no dearth of appropriate software tools to develop and visualise complex designs. It is also not a question of the country not having appropriate equipment, as this technology is plentiful. The problem is that we still do not have systems in place at construction sites to use steel sections efficiently as is being done overseas. Our project management skills to supervise the construction of steel buildings are not quite there as yet. As a result, steel buildings that are typically faster to construct than conventional structures take longer to build in India. Skills to perform associated jobs like anti-corrosion painting and fire-proofing of steel sections are in short supply as well. In their absence, fire protective methods of concrete encasement are used ar颅ound the steel framing. But these add-on costs further dissuade real-estate developers from designing steel buildings. An industry-wide emphasis on skill-building might help turn around this situation in favour of steel structures.
Further, it is only recently that some fabrication companies - Indian and foreign - are setting up fabrication workshops with modern equipment to handle off-site fabrication, so that the process is executed under controlled conditions and proper supervision to ensure a quality product.
Real-estate market considerations
By and large, the construction of landmark steel buildings also depends on the revival of the sluggish commercial real-estate market. The graph denoting the creation of tall structures is said to go hand-in-hand with the trajectory representing a country's economic wellbeing. This is because most skyscrapers in the world are commercial buildings and are hence typically built only when business sentiments are positive. The 102-storey tall Empire State Building departed from this tradition - it was built during the Great Depression at a staggering cost of over $40 million. But the structure was completed in a record time of 14 months because the owners wanted to start earning rent as soon as possible!
With the Indian outlook for commercial real estate being less than rosy at present and visible indications suggesting that matters are not likely to improve anytime soon, we may have to wait before we see new major steel building projects unroll.
Other usesReinforcement grade steel used in RCC structures has always boasted of a large market in India and continues to do so. In the past decade, Grade 500 steel has been more widely used for high-rise construction in place of Grade 415. There are usually no issues surrounding the availability of reinforcement steel, except around times of price spikes. Stainless steel represents another niche application of steel in construction, with stainless steel fixtures increasingly being used in high-end interiors.
Quality is an issue every construction firm must control by testing material samples. It isn't about who the supplier is - we have tested random samples of steel procured from Corus Steel as well. It is about making quality control a part of the construction process. The quality of reinforcement steel can be of concern when it is obtained from secondary sources. Specifications for structural steel buildings are also clearly defined in the
BIS Handbook and in the BIS Code IS 800. The building community must follow these guidelines.
The Institute for Steel Development & Growth (INSDAG), headquartered in Kolkata, is promoting the use of steel in construction as well as educating the construction fraternity on the subject. It beings out an informative publication called Steel in Construction, and also publishes numerous manuals and white papers elucidating subjects like the design of steel structures.
The future of steel constructionAssuming that the country's economy provides impetus to large public/private projects, steel as an option for construction will have a future as long as the form of the structure unequivocally dictates the use of steel; a range of steel sections are available at a competitive price; well-equipped off-site fabrication workshops are available and operated by skilled manpower to ensure quality of fabrication; field management, construction and su颅pervision skills, testing expertise and app颅ropriate equipment at site are made available; collaboration with foreign agencies for construction/design is possible wherever needed; and overall skills in design, de颅tailing and construction are upgraded.
Evolution of steel: The overseas pictureNecessity is the mother of invention, they say, and the journey of steel has been driven by need as well. In the 1800s, the British turned to steel buildings as a low-cost housing option for the many people relocating from the countryside to cities, to work as labour to fuel the industrial revolution. In the 1900s, box-like prefabricated steel buildings grew in popularity on the other side of the Atlantic as well. Another development was simultaneously taking place in America in the first few decades of the century. Steel was increasingly being recognised for its inherent properties like strength, stability and durability that could be exploited to make buildings of previously unimaginable heights. This ushered in a new era, wherein steel was used as the backbone of tall buildings. No longer would high-rise buildings architecture be restricted by the constraints of load bearing masonry walls and reinforced cement concrete. Structural steel became the buzzword of the construction fraternities in the cities of Chicago and New York, and they competed for supremacy, striving to construct skyscrapers that would define their cityscape. Chicago actually went by the name of 'birthplace of the modern tall building' for being home to several high-rises built using a steel frame. These included the Monadnock Building South End, Fair Stor, Montgomery and Ward Building, and Chicago Tribune Tower. New York responded with the Empire State Building, which was completed in 1931. At 454 m, it was crowned the highest building in the world, a mantle it held on to for four decades.
Steel got its next boost during World War II. During the war, a need arose for structures such as barracks and maintenance facilities that could be pre-made in parts capable of being quickly assembled without any welding, and then containerised and shipped. Prefabricated steel component companies made the most of this opportunity. By the end of the war, it became clear that metal buildings were there to stay.
To share your experience with any construction material, write in at
[email protected]
In a series of features showcasing building materials, PS Badrinarayan, Associate, Shirish Patel & Associates, highlights the role of steel in the Indian construction industry.Steel has come a long way. From a default option for industrial structures to an essential building material that lends itself to a variety of uses, the evolution of the use of this material has indeed been remarkable. Structural Design Engineer PS Badrinarayan, Associate, Shirish Patel & Associates, a structural design consultancy firm based in Mumbai, traces the progression of steel as a building material in India and shares his thoughts for its future use in conversation with Charu Bahri. Excerpts...Looking backSteel buildings and bridges were being built in the latter part of the 19th century and early 20th century during the British era, in much the same way as such infrastructure was built in Britain and Europe. In the post-independence era, especially after industrialisation took off in the 1950s, steel was traditionally used to set up public and private factories, refineries, petrochemical plants, ports, railways, warehouses, etc; essentially structures in which architecture plays an insignificant role and projects largely managed by engineering professionals from design to construction. Steel was used as a default option in these structures because its inherent properties ensured that it commanded a high level of comfort with engineers. This usage pattern continued up to the 1990s.During the 1960s to 1980s, precast concrete was also used in industrial applications, perhaps as it is more economical and maintenance-free, but this use was not widespread as it was associated with specific skills for design and construction. By the 1990s, the use of precast concrete had begun to gradually fade out. As far as industrial applications were concerned, pre-engineered buildings (PEB) began to gain popularity with clients owing to the convenience and speed of such erections, the possibility of turnkey design and construction, and off-site fabrication in the supplier's workshops. PEBs began to evolve beyond simply being reasonably economical structures modelled on simple vanilla designs.Alongside the liberalisation of the country's eco颅nomy in the 1990s, steel began to be considered for app颅l颅ications other than industrial ones - such as tall buildings for offi颅ces, airports, metro transport systems, IT parks, multi-storeyed car parking proprietary systems, architectural structures, etc. Practically, however, the use of steel was curtailed by the high cost of steel construction vis-脿-vis concrete construction.Cost concernsIn fact, cost is the reason why even though India is passing through a phase of economic growth akin to what the US underwent in the 1970s and 1980s, the country is nowhere near seeing the kind of lightweight steel-framed tall building construction boom that played out in the latter. While the use of structural steel is gro颅wing, tall building technology is still in its infancy in the country and India lags behind in adopting structural steel. Take Mumbai as an example. Inspite of being the home of skyscrapers in India, the city boasts no more than a handful of tall steel buildings.Steel is unable to compete with concrete, as methods of construction go, in many applications. As far as bridges, flyover and viaducts for metro transport systems are concerned, advances in concrete construction for such applications through precast concrete and segmental construction have made concrete a natural choice owing to lower costs, ease and speed of construction, and almost zero maintenance. In fact, the Bandra Worli Sea-Link in Mumbai is built entirely in concrete. Concrete also continues to be the preferred mode of construction for high-rise buildings in India, again mostly because of cost concerns.Availability of steelUntil about a decade ago, limited supply could also be counted as a factor hampering the use of structural steel. Tata Steel, Jindal Steel and SAIL are among the primary manufacturers offering hollow box sections, I-beam cross sections, plates, angles and channels in India. Corus Steel of the UK entered the market some years ago and this has improved the availability of structural steel. For instance, indigenous suppliers offer hollow box sections up to a maximum size of 300 mm 脳 300 mm, which are 8-12 mm thick. In comparison, Corus Steel offers hollow box sections sized as large as 800 mm 脳 800 mm and 40 mm thick. Fortunately, Jindal Steel offers a wide range of I-beam cross sections as per international profiles up to 900 mm depth.Steel frames are more expensive but allow architects and structural engineers more leeway in the arrangement of design elements. Steel is a far more pliable material and can be used to express innovative forms. We chose to use hollow box sections of Corus Steel to practically express the complex shapes of an exhibition centre building project in Navi Mumbai. We were driven to create the building in steel because of the complex form that would not have been possible to build in concrete. Steel as a material of construction is used in metro stations and airport terminals for similar reasons - to express architectural form and large dimensions.Short supply: management skillsAt present, the construction of steel buildings is also being limited by the paucity of skills. There is no dearth of appropriate software tools to develop and visualise complex designs. It is also not a question of the country not having appropriate equipment, as this technology is plentiful. The problem is that we still do not have systems in place at construction sites to use steel sections efficiently as is being done overseas. Our project management skills to supervise the construction of steel buildings are not quite there as yet. As a result, steel buildings that are typically faster to construct than conventional structures take longer to build in India. Skills to perform associated jobs like anti-corrosion painting and fire-proofing of steel sections are in short supply as well. In their absence, fire protective methods of concrete encasement are used ar颅ound the steel framing. But these add-on costs further dissuade real-estate developers from designing steel buildings. An industry-wide emphasis on skill-building might help turn around this situation in favour of steel structures.Further, it is only recently that some fabrication companies - Indian and foreign - are setting up fabrication workshops with modern equipment to handle off-site fabrication, so that the process is executed under controlled conditions and proper supervision to ensure a quality product.Real-estate market considerationsBy and large, the construction of landmark steel buildings also depends on the revival of the sluggish commercial real-estate market. The graph denoting the creation of tall structures is said to go hand-in-hand with the trajectory representing a country's economic wellbeing. This is because most skyscrapers in the world are commercial buildings and are hence typically built only when business sentiments are positive. The 102-storey tall Empire State Building departed from this tradition - it was built during the Great Depression at a staggering cost of over $40 million. But the structure was completed in a record time of 14 months because the owners wanted to start earning rent as soon as possible!With the Indian outlook for commercial real estate being less than rosy at present and visible indications suggesting that matters are not likely to improve anytime soon, we may have to wait before we see new major steel building projects unroll.Other usesReinforcement grade steel used in RCC structures has always boasted of a large market in India and continues to do so. In the past decade, Grade 500 steel has been more widely used for high-rise construction in place of Grade 415. There are usually no issues surrounding the availability of reinforcement steel, except around times of price spikes. Stainless steel represents another niche application of steel in construction, with stainless steel fixtures increasingly being used in high-end interiors.Quality is an issue every construction firm must control by testing material samples. It isn't about who the supplier is - we have tested random samples of steel procured from Corus Steel as well. It is about making quality control a part of the construction process. The quality of reinforcement steel can be of concern when it is obtained from secondary sources. Specifications for structural steel buildings are also clearly defined in the BIS Handbook and in the BIS Code IS 800. The building community must follow these guidelines.The Institute for Steel Development & Growth (INSDAG), headquartered in Kolkata, is promoting the use of steel in construction as well as educating the construction fraternity on the subject. It beings out an informative publication called Steel in Construction, and also publishes numerous manuals and white papers elucidating subjects like the design of steel structures.The future of steel constructionAssuming that the country's economy provides impetus to large public/private projects, steel as an option for construction will have a future as long as the form of the structure unequivocally dictates the use of steel; a range of steel sections are available at a competitive price; well-equipped off-site fabrication workshops are available and operated by skilled manpower to ensure quality of fabrication; field management, construction and su颅pervision skills, testing expertise and app颅ropriate equipment at site are made available; collaboration with foreign agencies for construction/design is possible wherever needed; and overall skills in design, de颅tailing and construction are upgraded.Evolution of steel: The overseas pictureNecessity is the mother of invention, they say, and the journey of steel has been driven by need as well. In the 1800s, the British turned to steel buildings as a low-cost housing option for the many people relocating from the countryside to cities, to work as labour to fuel the industrial revolution. In the 1900s, box-like prefabricated steel buildings grew in popularity on the other side of the Atlantic as well. Another development was simultaneously taking place in America in the first few decades of the century. Steel was increasingly being recognised for its inherent properties like strength, stability and durability that could be exploited to make buildings of previously unimaginable heights. This ushered in a new era, wherein steel was used as the backbone of tall buildings. No longer would high-rise buildings architecture be restricted by the constraints of load bearing masonry walls and reinforced cement concrete. Structural steel became the buzzword of the construction fraternities in the cities of Chicago and New York, and they competed for supremacy, striving to construct skyscrapers that would define their cityscape. Chicago actually went by the name of 'birthplace of the modern tall building' for being home to several high-rises built using a steel frame. These included the Monadnock Building South End, Fair Stor, Montgomery and Ward Building, and Chicago Tribune Tower. New York responded with the Empire State Building, which was completed in 1931. At 454 m, it was crowned the highest building in the world, a mantle it held on to for four decades.Steel got its next boost during World War II. During the war, a need arose for structures such as barracks and maintenance facilities that could be pre-made in parts capable of being quickly assembled without any welding, and then containerised and shipped. Prefabricated steel component companies made the most of this opportunity. By the end of the war, it became clear that metal buildings were there to stay.To share your experience with any construction material, write in at [email protected]
