16|Feature Structural Steel Fabricators
Projects Info | 10 - 16 January | 2011
Proliferation of complex prefab structures will ensure huge business prospects
With the increasing complexity of large infrastructure projects and the growing use of structural steel in these projects, structural steel fabricators have a lot of opportunities in India. However they are confronting chal- lenges due to shorter lead time, difficulty in identifying specific load considerations due to lack of standard accepted building codes throughout the country and un-organised sector of fabricators pose a serious threat, finds Chandrashekhar Modi
entirely new building, it needs metal supports to build a strong foundation. For that purpose, one needs to alter the metal so that it best conforms with the project. This is exactly where structural steel fabricators step into action. Today structural steel fabrication has evolved in a huge sector catering to the complex requirements of the prefabrication industry.
Structural Steel &#x2013; Unique Properties Structural steel is steel con-
struction material, a profile, formed with a specific shape or cross section and certain standards of chemical compo- sition and mechanical prop- erties. Structural steel shape,
hile building a new structure, whether it be a home addition or an
size, composition, strength, storage, etc., is regulated in the developed part of the world. Structural steel members, such as I-beams, have high second moments of area, which allow them to be very stiff in respect to their cross-sectional area. Most steels used throughout
Europe are specified to comply with the European standard EN 10025. However, many national standards also remain in force. Typical grades are described as &#x2018;S275J2&#x2019; or &#x2018;S355K2W&#x2019;. In these examples, &#x2018;S&#x2019; denotes structural rather than engineering steel; 275 or 355 denotes the yield strength in newtons per square millimetre or the equivalent megapascals; J2 or K2 denotes the materials toughness by ref- erence to Charpy impact test values; and the &#x2018;W&#x2019; denotes weathering steel. Further let-
960 - although grades above 690 receive little if any use in construction at present).
Amit Bharana, President, Era Buildsys.
ters can be used to designate normalized steel (&#x2018;N&#x2019; or &#x2018;NL&#x2019;); quenched and tempered steel (&#x2018;Q&#x2019; or &#x2018;QL&#x2019;); and thermome- chanically rolled steel (&#x2018;M&#x2019; or &#x2018;ML&#x2019;). The normal yield strength grades available are 195, 235, 275, 355, 420, and 460, although some grades are more com- monly used than others e.g. in the UK, almost all structural steel is grades S275 and S355. Higher grades are available in quenched and tempered mate- rial (500, 550, 620, 690, 890 and
IT tools for accuracy With the increasing com- plexity of large infrastructure projects it has become essential to verify the quality of struc- tural steel components prior to delivery and to assure they are durable, safe and perform as designed. Steel remains the main cost for any such projects and optimised structural design with accurate detailing is one of the best ways to save sub- stantial cost. Detailing errors may become costly due to fit- up problems at site that in turn delays entire activities, affecting the schedules of the projects. In recent times Indian industry has realised the importance of accurate detailing while adopt- ing correct detailing standards and not just going for welded structures. One has to imple- ment 3D detailing software that helps to model in advance what is going to be built on site,
which ensures that there are no fit-up problems. Accurate steel detailing is the essence of any project and it defines almost the future of the project in vari- ous terms.
Challenges ahead &#x201C;The structural steel fab-
ricators are confronting chal- lenges due to shorter lead time, difficulty in identifying specific load consideration as no stan- dard pan India accepted build- ing codes, unorganised sector of fabricators pose threat as they are compared with high quality products provided by organised sector of fabricators. Pre-fabricated sector is
growing to cater specific indus- try need and ensures better structures and profitability. Down the line, with balanced growth by entering into green building concept, housing solu- tions and multi-storied struc- tures will increasingly house pre-fabricated structures in India,&#x201D; explains Amit Bharana, President ,Era Buildsys.
The mega project: Jawaharlal Nehru Stadium
Structural details: Ovalshaped building made of RCC; fabrication and erection of high-strength steel work; three independent structures of main stadium building i.e. lower tier, main building and supporting structure of PTFE membrane roof; earthquake resistant; twotier seating arrangement; seating chairs on upper and lower tiers; and boundary wall with 22 gates. Innovative features:
High definition television transmission with 2200 lux.; state-of-the-art sports lighting through 22 lighting pylons; modern PA system for spectators; PTFE (polytetrafluoroethylene) membrane roof of 54,000 sq. metres; underground tunnel through arena for ceremony (east end to west end); surface tun- nel for athletes (warm-up to main stadium); five accessible ramps; and 14 lifts and two escalators. The roof: The newly-constructed roof is supported by 44 &#x2018;X&#x2019; frames of 43 metre height and 44 &#x2018;V&#x2019; frames of 23 metre height amounting to more than 8,500 tonnes of steel; 54,000 sq. metre total area of membrane consisting of 88 panels manufactured in USA and fabricated in Mexico; cables supporting the roof fabricated in Germany; and 2,200 km long wires used in cables.
The stadium has been rebuilt at an estimated cost of Rs 960 crore. The stadium was constructed during ASIAD 1982. The Sports Authority of India had engaged the Central Public Works Department as its principal consultant for planning and execution of the stadium project. Inaugurating the stadium, M.S. Gill said that the JN Stadium was the most magnificent stadium ever built in the country in terms of design, architecture and engineering. &#x201C;The stadium has been converted into almost a new one with the help of advanced engineering and foreign consultants. The old stadium was around 30 years old and it took a lot of collective effort from all of us to give it this amazing shape,&#x201D; he said.
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