Structure designers

JSPL introduces parallel flange sections to save cost. The design of steel structures involves the selection of most economical members to carry loads and withstand direct and induced forces to which the structure may be subjected during its lifespan. Parallel flange sections provide an economical and efficient solution for such steel structures. Parallel flange sections differ from tapered flange sections in terms of its shape. Unlike sloping in tapered flange sections, parallel flange sections have parallel flange with square toes and curves at the root of flange and web. It exhibits better sectional properties like sectional modulus and radius of gyration vis-a-vis a tapered flange section of equivalent weight. "Parallel flange sections are useful for longer spans, as member sizes look sleek aesthetically. Higher sectional properties of the members reduce fabrication time as compared to conventional rolled sections or built -up sections. Added advantage is the availability in higher grades of steel", says Ritu Ohri, Sr General Manager (Structure), Semac Consultants. Benefits These sections offer many benefits over the tapered flange sections, most important being the wide range. The other benefit is the availability of sections up to 900 mm sectional depth. The availability of large number of options provides flexibility to the design engineers and saves project cost. JSPL rolls out more than 120 parallel flange sections at its facility in Raigarh, Chhattisgarh. "Structural engineers have been using rolled or built up I beams as their preferred profile in case of metal design. However, universal profiles are going to be the choice of future for structural engineers working with steel as construction material. Parallel flange sections have enhanced structural and physical properties as compared to similar tapered flange I beams and gives better flexibility while detailing", Pratip Bhattacharya, Technical Director, MN Dastur & Co. These sections are also available in multiple grades starting from E250 to E410. The choice of higher grades reduces the total steel usage and cost of a project. Recently, JSPL has developed corrosion resistance grade for projects in coastal areas. "In our recent projects, we have recommended the use of PFB sections for available choice of variety of same size sections but of different self weights and sectional properties above X and Y axis. They give better moment of resistance in lateral directions and result in ease of connections" says SB Malekar, Senior Engineer, Sterling Engineering Consultancy Services. Considering the benefits of the parallel flange sections Bureau of Indian Standards adopted an Indian Standard IS 12778 for parallel flange sections. The sections in this code are named as NPB and WPB. "Jindal Steel & Power Ltd is the only producer of parallel flange beams in India. We have a unique placement and identity in the market for the same. Parallel flange sections are increasingly preferred over tapered flange sections for large constructions owing to their superior strength, cost savings, enhanced durability, and higher load-bearing capacity. These exhibit better sectional properties such as high sectional modulus and radius of gyration; providing higher load carrying capacity as compared to conventional sections of equivalent weight. Parallel flange sections are available with sectional depth of 180 mm-900 mm, with multiple sectional weights. JSPL rolls more than 160 sections of different dimensions and sectional weights depending on the industry requirements. Also, the products are available in different grades like IS 2062: E250 to E450 A/BR/BO/C, ASTM36, ASTM572, EN10025, Corrosion Resistance Grade and other international grades. Wide product range and superior sectional properties of parallel flange sections lends greater flexibility to a designer which leads to efficient and economical design,"adds Ashwani Kumar, AVP, Sales and Marketing, JSPL. Demand The demand for structural steel is also picking-up in real estate as increased population density, particularly in metro cities, is giving way to vertical construction. Also green building movement is increasing at a rapid pace in the real estate sector calls for use of structural steel as a modern building material for realising the benefits of sustainable design and construction practices. "Structural steel being recyclable up to 98 per cent, can be designed, detailed and pre-fabricated at low costs, with higher productivity and to a high precision with unmatched quality. Having executed a large no of complex, large span steel structures, Geodesic Techniques recommend structural steel for speedy construction of iconic buildings changing the skylines of India as it can serve most of the strictest requirements of modern buildings. The lifecycle cost of steel is lower than concrete and it offers slender, compact buildings with higher usable floor space", explains Anoop Mishrra, AGM, Geodesic Techniques. "Tapered flange section is an Indian phenomenon; the entire world market uses parallel flange sections. Indian design firms have also started realising the benefits of parallel flange sections. Entry of international players will also help in creating a wider market for parallel flange sections in India," says Subimal Sarmah, NSM-Structurals, JSPL. (Communication by the management of the company)