Wings of steel
Construction of PEBs in India is mounting as developers realise its advantages
Imagine being able to deliver a building just three weeks after the drawings have been approved. Also imagine the joy of the developer when he can be ready for site bolting after having ‘assembled’ the building. None of these things are, of course, possible under the conventional method of construction.
Much has been written about pre-engineered buildings in this magazine and elsewhere. While the manufacturing industry raves about it, and residential developers shudder at the thought of constructing a PEB for their residents, PEB structures are useful and good. Importantly, considering that more buildings are gathering height rather than width, building tall with steel also allows more floors and one can be assured of strength too.
PK Nagarajan, director & CEO, Tiger Steel Engineering (India), says, “Today, PEB has become the only viable option, when it comes to large clear span buildings, especially suited for hangars and similar structures. The same thing can be said about the bay spacing. By providing continuous Jack Beams, the column bay spacing can be extended up to or even more than fifteen metres, giving the client more column free area inside the building. With the possibility of providing large column depths and offering a fixed base option, one can offer a cost-effective solution for very tall eave height structures. For very heavy cranes mounted on such tall structures, PEB can offer a good solution, by providing stepped columns. Also when it comes to heavy long span crane beams supporting heavy crane girders, there is no alternative but to use heavy built-up section craned beams.”
Ever since being introduced in the Indian market in 1998, much after its inception in the US market, PEB has come a long way. It has gone through many innovations. It was introduced as a cost-effective alternative for conventional RCC, hot rolled steel structures or Hybrid of RCC and steel over the years. Slowly it dawned on people that it could be effectively used to construct warehouses, factories and multi-storied buildings.
Build and they will come
Considering that PEBs are mainly formed of standard sections, it significantly reduces design time. And during construction, since most of the steel is low-weight, it offers better resistance to seismic forces. It is some of these advantages that have led to an increased awareness among consultants and contractors who have begun to take on more PEB projects. It is getting its due credit as a reliable construction methodology.
For instance, Kirby Building Systems has constructed one of the largest single PEB building that has been functioning for some years now. The Renault Nissan Automotive India plant at Oragadam in Chennai utilises PEB structures totally for an automobile plant. The PEB covers a floor area of over 310,000m2 with a tonnage of over 20,000MT including process beams. The scheme of alternate technical offer vs the original scope of work reduced the tonnage by 4110MT which was the winning factor for getting the order.
With this, Indian pre-engineered consecution market is now experiencing a demand shift to new applications due to infrastructure development in the country like airports, multi-story buildings, stadiums, metro stations, etc. The country will see increased economic growth, and the removal of barriers to foreign investment will “spur demand for construction” over the coming few years.
Pune based Tata BlueScope Building Solutions, a division of Tata BlueScope Steel Limited (an equal joint-venture between Tata Steel and BlueScope Steel (Australia) supplies PEB solutions and takes single source responsibility for their design, manufacture, shipment and erection. With developing structures conforming to AISC, MBMA or IS standards, their spokesperson says, “Steel construction is evolving from boxlike steel structures to pleasing designs. Initial acceptance of metal building systems has been high in industrial applications, followed by infrastructure and commercial structures. However as awareness is growing, metal buildings are being considered for residential applications as well.”
According to Nagarajan, MBMA (Metal Building Manufacturers association) in USA is dedicated to development of PEB in terms of materials, design, and manufacturing. The MBMA guidelines are revised periodically and the latest version of 2013 is in use right now. These associations carry out extensive research work to support tre Revisions from time to time. In India most PEB companies conform to MBMA guidelines, resulting in providing PEB to global standards.
In terms of the design methodology, there is shift from working stress method to limit state method, making the design more realistic and efficient. Both the IS and International Codes have been upgraded to Limit State design methodology. There is also an increasing trend of getting the roofing systems tested in wind tunnels and qualify factory mutual standards. Also in terms of checking the fire resistance of the steel structures and their components, the testing and certification of products meeting UL (Under Writers Laboratories) is another area of development.
With Smart Cities and green construction becoming the norm, this is adding to the growth of PEB in India. So no more are the PEB manufacturers looking at mere steel structures, but also have developed high efficiency windows and insulation for roofs, walls, ceilings and floors. They are also realising the benefits of use of sky lights and solar panels on rooftops that will meet daylight and captive power requirements, while, at the same time, reduce emissions and gain carbon credits under Clean Development Mechanism (CDM). Many industry stakeholders are scouting for adopting multiple business strategies such as venturing into engineering design, project contracting, manufacturing heavy structural steel buildings, and focusing on vertical integration whereas, merger & acquisition strategy will support them to grow inorganically and enable them to broaden their geographic reach and product portfolios. Another vital aspect that works in PEB’s favour is the growing and much needed thrust towards eco-friendly construction. Metal building solutions are inherently green products and have a far smaller impact on the environment as compared to traditional brick and mortar construction. The energy efficient methods in producing steel used for these structures, and the high recycled content, help in substantially reducing greenhouse gas emissions. Interestingly, even after demolition, these buildings don’t accumulate wastage like asphalt shingles, concrete, brick and dust. The only by-product is metal scrap which is 100% recyclable.
However, a few years down the line, it is possible that PEB might come to be accepted among residential users also. Currently, there is a lack of awareness and resistance towards accepting PEB as a home product. Like Alakesh Roy, MKD of Zamil Steel India, says, “Most people in India are used to hanging pictures on walls and all kinds of paraphernalia find their way on walls. PEB structures will curtail this habit. However, we can convince people to go in for PEB residential structures and the mindset can only change through training. The government must encourage use of steel houses in hilly areas to protect the environment and hills. Being light weight in construction, its reach in remotest area is feasible. PEB is excellent for areas where availability of water and skilled labour is a limitation.”