8.1 The material properties given in this Section are nominal values, to be accepted as characteristic values in design calculations.
8.2 Structural Steel
8.2.1 The provisions in this Section are applicable to the steels commonly used in steel construction namely, structural mild steel and high tensile structural steel.
8.2.2 All the structural steel used in general construction, coming under the purview of this standard shall before fabrication conform to accepted standard [6-6(6)].
8.2.3 Structural steel other than those specified in 8.2.2 may also be used provided that the permissible stresses and other design provisions are suitably modified and the steel is also suitable for the type of fabrication adopted.
8.2.3.1 Steel that is not supported by mill test result may be used only in unimportant members and details, where their properties such as ductility and weldability would not affect the performance requirements of the members and the structure as a whole.
However, such steels may be used in structural system after confirming their quality by carrying out appropriate tests in accordance with the method specified in accepted standard [6-6(7)].
8.2.4 Properties
The properties of structural steel for use in design may be taken as given in 8.2.4.1 and 8.2.4.2.
8.2.4.1 Physical properties of structural steel irrespective of its grade may be taken as:
a) Unit mass of steel,
b) Modulus of elasticity, (MPa)
c) Poisson ratio,
d) Modulus of rigidity, (MPa)
e) Coefficient of thermal expansion
8.2.4.2 Mechanical properties of structural steel
The principal mechanical properties of the structural steel important in design are the yield stress, ; the tensile or ultimate stress, ; 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 accepted standard [6-6(7)]. Commonly used properties for the common steel products of different specifications are summarized in Table 1.
8.2.4.2.1 Steel tubes
Steel tubes used in building construction shall be hot finished tubes conforming to the requirements specified in accepted standard [6-6(8)].
8.2.4.2.2 Tubes made by other than hot finishing processes, or which have been subjected to cold working, shall be regarded as hot finished if they have subsequently been heat-treated and are supplied in the normalized conditions.
NOTE — Grade ERW YSt 22 tubes specified in accepted standard [6-6(8)] with a carbon content less than 0.30 percent, may be considered as hot finished for the purpose of 8.2.4.2.2.
8.2.4.2.3 Electrodes
The electrodes used for welding steel tubes shall conform to the requirements of accepted standard [6-6(9)].
8.3 Rivets
8.3.1 Rivets shall be manufactured from steel conforming to accepted standard . They may also be manufactured from steel conforming to accepted standard provided that the steel meets the requirements given in accepted standard .
8.3.2 Rivets shall conform to accepted standards [6-6(12)] as appropriate.
8.3.3 High Tensile Steel Rivets
High tensile steel rivets, shall be manufactured from steel conforming to accepted standard [6-6(13)].
8.4 Bolts, Nuts and Washers
Bolts, nuts and washers shall conform as appropriate, to accepted standards [6-6(14)]. The recommendations in good practice [6-6(15)] shall be followed.
8.5 Steel Casting
Steel casting shall conform to accepted standard [6-6(16)] or accepted standard [6-6(17)].
8.6 Welding Consumable
8.6.1 Covered electrodes shall conform to accepted standards [6-6(18)] or [6-6(19)], as appropriate.
8.6.2 Filler rods and wires for gas welding shall conform to accepted standard [6-6(20)].
8.6.3 The supply of solid filler wires for submerged arc welding of structural steels shall conform to accepted standard [6-6(21)].
8.6.4 The bare wire electrodes for submerged arc welding shall conform to accepted standard [6-6(22)]. The combination of wire and flux shall satisfy the requirements of accepted standard [6-6(22)].
8.6.5 Filler rods and bare electrodes for gas shielded metal arc welding shall conform to accepted standards [6-6(23)], as appropriate.
8.7 Other Materials
Other materials used in association with structural steel work shall conform to appropriate Indian standards.
Section 6 (c) General Design Requirements
9 GENERAL DESIGN REQUIREMENTS