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In recent years

In recent years, the technical and scientific community dealing with steel structures has devoted a considerable effort to the development of efficient (safe and economical) procedures and formulae (interaction equations) for the design and safety checking of steel members (i) subjected to different combinations of internal forces and moments and (ii) susceptible to global buckling phenomena, namely flexural buckling (members under compression) and/or lateral-torsional buckling (open-section members under major-axis bending). Indeed, it is well known that the failure of most thin-walled steel members, such as the I-section beams dealt with in this work, is governed by a combination of instability and plasticity effects ? while the latter are more prevalent in stocky beams, the former dominate in the more slender members. In the particular case of beams subjected to major-axis bending, their failure often involves lateral-torsional buckling, a complex three-dimensional global instability phenomenon involving torsion and minor-axis bending, which is mainly triggered by the low torsional stiffness exhibited by open-section thin-walled cross-sections. Naturally, the ultimate strength and collapse mechanism of the aforementioned beams can only be adequately predicted provided that in-depth knowledge about their lateral torsional buckling mechanics is acquired.
As far as steel members are concerned, the vast majority of available studies deal with I-section members, by far the most widely used in the steel construction industry. Steel sections have been used for construction purposes in India since long time. Greater advancement has been done in the area of Technology, Analysis and Designing of these complex steel sections. In the recent time Moment Resisting Frames (MRF) structures are being largely used in the field of construction, as they offer greater resistance to seismic forces and are very superior then the conventional method of construction. Indian Hot Rolled Tapered flange and Parallel flange sections are used in the design and manufacturing of steel structures. Tapered flange sections are conventional sections which are being used in construction industry since longer times, but now a days much more modifications has been done and as a result of which Parallel flange sections are very much popular among the people. These Parallel Flange section offers greater lateral stiffness and is very economical as lesser material is required for the same depth of the section and at the same time its moment of inertia (I) and plastic moment capacity (M) is also higher than those of Tapered flange section. Indian hot rolled tapered flange section has the maximum depth of 600 mm for all (ISLB, ISMB, ISWB and ISHB) steel section, and as per SP 6(1) 1964 the moment of inertia(I) and nominal plastic moment capacity(M) of ISWB 600 is highest which is then followed by ISMB 600. In comparing with Tapered flange section, the maximum depth of parallel flange section can be upto 900 mm and its flange width is also more.
Safety and stability of the structure depends on various factors and elements of which this structure is made up of, some of the prominent parameter include strength, ductility, stiffness and cross sectional property. Connection in steel structure offers greater durability and resistance against various external forces and also against internal stresses generating due to these forces. These connections should be properly designed and thoroughly analyzed as they work, as the backbone of any construction related to steel structure. Any carelessness at any stage of design, manufacturing and construction may leads to the failure of the structure.
Many researchers have given their views regarding performance and practical application of these Parallel and Tapered flange section, It is evident from various research work that parallel flanged section has greater superiority and much more possibility of being used in various high rise structure in seismic prone area and it also has larger probability of technological and sectional modifications in the coming future, with slight change in its manufacturing and designing method much more advancement can be done in this area and its performance can be enhanced. It is due to this reasons parallel flange sections of beam and column elements are in great demand and lot of research are still being going on these steel sections in India as they not only reduces the dead weight of structure but also provide greater strength and saving of money at the same time.