A round table of architects discusses the pros and cons of structural steel
The exchange throws light on the potential of the material, its constraints and noteworthy edifices that use it
What kind of projects do you think benefit most from structural steel?
Gayathri Shetty and Namith Varma: Steel is highly efficient in the case of constructions that require large spans, flexible curves and/or heavy industrial or commercial uses. Steel possessing high tensile strength is more versatile than concrete structures. Nowadays, construction demands an early assembly and an immediate occupation, which steel structures can easily provide
Akshay Sekhri: Even though steel is a naturally strong material, proper welding techniques can augment its quality further. This process makes steel suitable for high-pressure applications such as columns and I-beams in commercially designed buildings.
Nirmal Mangal: Structural steel is a very versatile structural system suitable for a wide variety of projects. The benefits include speed of construction, future adaptability and suitability for excellent seismic compliance. It is also the preferred material for super tall structures and long-span structures such as airport terminals, trains stations, bus terminals as well as convention centres.
Do you see structural steel being used to its full potential in the country? Any critiques on current application methods and design?
Shetty and Varma: As of now, steel is not to being used to its maximum potential in India. Instead, there is more familiarity with working with materials like concrete. The building industry in India is not fully aware of how this material is to be treated. More time is needed to witness the use of steel to its optimum potential. We are seeing this change happening gradually, and Gayathri and Namith Architects are adapting to the market demands. We experiment with steel in non-commercial projects such as museums, exhibition spaces, public gathering spaces, etc, where large spans and flexibility in design are required.
Sekhri: No, we have along way to go. India’s massive construction sector must increase the use of structural steel to accelerate the development of commercial and residential complexes, while retaining the indigenous cultural appearances. A shift from the concrete-based conventional method of constructing buildings to steel structures will halve the completion time to two years.
Mangal: In India, we have been hesitant to use steel for structural systems, primarily due to cost constraints. Lack of familiarity and use has led to lack of proficiency in the design of steel structural systems, limited steel fabrication capabilities and limited market support.For owners and builders, structural steel offers excellent speed of construction. Steel structures provide better quality of construction and reduced construction timeline at a modest premium. The real estate industry is not sufficiently evolved to consider the cost benefit of reduced construction duration. For contractors, steel structures offer better quality of construction and much tighter construction tolerances. They are hesitant to embrace it because of lack of market support, lack of equipment necessary for steel construction, and lack of skilled steel workers/laborers.The architect must be the change agent in the design and construction industry. The architectural industry has been slow to embrace structural steel in architectural design. This comes primarily from lack of familiarity and expertise in architectural design using steel as structural system. Most architects fall back on what they know better, and very few are willing to experiment outside their comfort zone. Architectural colleges and universities also pay very little attention to structural steel in building design because their faculty also lack such experience.
Gaurav Das: End-users (particularly in the case of residential projects) are not very receptive to the idea of a home made in steel, hence the technology – in spite of its benefits – is not being used to its full potential.
What are some of the constraints/challenges while working with this material?
Shetty and Varma: A high level of proficiency is expected from laborers when working with steel. An orientation among the existing labor force needs to be made to formally train then while handling steel structures. Since steel structures need constant maintenance and there is a lack of skilled laborers, the quality of steel structures is inconsistent.
Sekhri: Component fabrication problems, anchor bolt installation problems, steel installation problems and deformation of components are some of the major challenges.
Mangal: The constraints and challenges for the structural steel are similar to all emerging technologies. These challenges include but are not limited to engineering capabilities, high cost of steel structures and lack of market support for steel structures. The cost differential between steel structures and concrete structures have been declining over the decade. The cost can come further down substantially if there is a greater volume of use of structural steel in the building industry. The engineering design of steel structures is lot more precise than concrete structures. The engineering community in India is more familiar with concrete structure, which leads to an inherent bias towards concrete structures. The engineering industry has been lagging behind in updating its structural design capabilities for steel structures. Our engineering capabilities needed during design and during the fabrication of structural steel are not at par with global standards and capabilities. The stock on hand-based CAD/CAD structural design is common in the developed countries. Given the population and size of the construction industry, the market for structural steel is very small. Most of the steel manufactured in India is normal mild steel and smaller steel sections. Here, we also tend to use more recycled steel, which has lower strength vis a vis non-recycled steel. Large steel members needed for high-rise buildings and long-span structures are not fabricated in India, so they have to be imported from China, Japan or Europe. It is a demand-based cycle; unless there is substantial market demand for larger steel sections, the manufactures will not manufacture them in India.
Das: The biggest challenge is lack of skilled and experienced workforce required to deliver these kinds of projects to reap the true benefits.
Where have you seen exemplary use of structural steel recently?
Shetty and Varma: Most projects by Santiago Calatrava use steel to its greatest potential. We recently had the opportunity to see the railway station in Liege, Belgium, which was designed by him and shows an exemplary use of steel.
Mangal: Some of the good examples of use of structural steel include high-rise buildings and long-span structures such as airport terminals. Mumbai International Airport’s Terminal T2 required a tall column-free space for the public concourse. The design solutions for public spaces are creative and inspiring. Jawaharlal Nehru Stadium, New Delhi, was completed in 2010. Its design is unique and creative, and uses structural steel to accomplish design objectives. The original Bangalore International Airport Terminal was designed as a steel structure. The new expansion increases the size of the terminal several-fold seamlessly, thanks to the expandable quality of steel structures. The renovated terminal is a creative solution for the third busiest airport in India. At 442m height, World One Tower in Mumbai would be one of the tallest residential buildings in the world; the wonders of structural steel make its height possible. The design of the tower is creative and sculptural.The Jawaharlal Nehru Stadium, New Delhi, is Nirmal Mangal’s pick for a creative steel structure.