Design of Steel Structure -I

IntroductionDesign of Steel Structure -IProperties of Structural Steel As Per IS 800:2007 (Code of Practice for Structure Steel) following clause covers the properties of structure steel.2.2.4 PropertiesThe properties of structural steel for use in design, may be taken as given in 2.2.4.1 and 2.2.4.22.2.4.1 Physical properties of structural steel irrespective of its grade may be taken as:Conti........a) Unit mass of steel, p = 7850 kg/mb) Modulus of elasticity, E = 2.0 x 10 N/mm (MPa)c) Poisson ratio, p = 0.3d) Modulus of rigidity, G = 0.769 x 10 N/mm (MPa)e) Co-efficient of thermal expansion = 12 x10 / c

Conti......2.2.4.2 Mechanical properties of structural steel The principal mechanical properties of the structural steel important in design are the yield stress, fy; the tensile or ultimate stress, fu; the maximum percent elongation on a standard gauge length and notch toughness. Except for notch toughness, the other properties are determined by conducting tensile tests on samples cut from the plates, sections, etc, in accordance with IS 1608. Commonly used properties for the common steel products of different specifications are summarized in Table.Indian Standard Rolled Sections Steel Section of any shape and size cannot be cast on site, like concrete. Since steel needs very high temperature to melt it and roll into required shape. Steel sections of standard shapes, sizes and length are rolled in steel mills and marketed. Available section in the market are called regular Steel Sections. Some steel sections are not in use commonly, but the steel mills can roll them if orders are placed. Such Steel sections are known as special sections Various Types of Rolled steel sections are manufactured are listed below Rolled Steel I SectionRolled Steel Channel Sections Indian Standard Junior Channel- ISJCIndian Standard Light Channel- ISLCIndian Standard Medium Weight Channel-ISSCIndian Standard Special Channel- ISSC

Rolled Steel Angle/Tee SectionsThese are classified into the following two series:(a) Indian Standard Equal Angle ISA (b) Indian Standard Unequal Angle ISA

Rolled Steel Tee Sections Indian Standard Normal Tee bars- ISNTIndian Standard Heavy Flanged Tee bars- ISHTIndian Standard Special Legged Tee bars-ISLTIndian Standard Light Tee Bars-ISLTIndian Standard Light Tee Bars- ISJTRolled Steel Angle/Tee Sections

Rolled Steel BarsRolled Steel Bars are Classified into the following two Series:Rolled Steel bars are designated by ISRO followed by diameter in case of round bars and ISSQ followed by side width in case of square bars e.g: ISRO 16ISRQ 20

Rolled Steel Bars

Rolled Steel TubesThese sections are designated by their nominal base size. in each size there are three classes, Namely The difference is due to difference in their thickness. Hence their cross sectional properties are also different. For example, a 40 mm tube has 3 types, thickness are 2.90, 3.25, 4.05.Rolled Steel Tubes

Rolled Steel Plates Following thicknesses are available5,6,8,10,12,14,16,18,20,22,25,28,32,36,40,45,50,56, 63,71,80 mm.They are rolled in the widths160,180,200,220,250,280,320,355,400,450,500,560,630,710,800,900,1000,1100,1250,1400,1600,1800,2000,2200,2500mm.These plates are designated by ISPL followed by length,width and thickness e.g. ISPL 2000 x 1000 x 6Rolled Steel Plates

Rolled Steel StripsRolled steel strip is designated as ISST followed by width and thickness. These sections are available in the following width and thickness.width: 100,110,125,140,160,180,200,220,250,280,320,355,400,450,500,560,630,710,800,900,1000mm.Thickness: 0.8,0.9,1.0,1.1,1.2,1.4,1.6,1.8,2.0,2.217Rolled Steel Strips

Rolled Steel FlatsFlats differ from strips in the sense that the thickness of flats is 5mm onwards and their width is limited. Flats of the following width and thickness are listed in IS Handbook.Width: 12,16,20,25,32,40,50,63,80,100,125,160,200,250 mm.Thickness : 5,5.5,6,7,8,9,10,11,12,14,16,18,20,22,25mmThey are designed by width followed by letters ISF and thickness e.g: 80 ISF 10 means, 80 mm wide Indian standard flat of thickness 10mm.