Design of an Industrial Building and comparision of Codal provisions including Draft Code and use of Rolled and Tubular Sections

Abstract

Most design studies deal with cross section as variable. However weight can be reduced by using different shapes i.e., Square Hollow Sections (SHS), Rectangle Hollow Sections (RHS), and Cylindrical Tubular Sections (CTS). A humble attempt has been made here to identify weight difference with Rolled Sections and Tubular Sections, and to arrive at a minimum weight of the structure. The primary aim of the present work is also to find difference of weight of Rolled Sections and Closed Formed Sections per unit area for an Industrial Building. Ministry of Steel, the bureau of Indian Standards, and Institute of steel development and Growth has jointly circulated a new draft IS: 800, based on Limit State Method. An attempt has been made here to introduce the new codal provisions of Limit State Method. The Limit State Method for structural steel design is presented as per IS: 800 draft code. In Introduction to Limit State, how limit state method differs from elastic and plastic method is given. In Limit State Method the design is based on characteristic values for material strengths and applied loads, which take into account the probability of variations in the material strengths and in the loads to be supported. In Limit State Method of design partial safety factors for both material and load variability is considered. These partial safety factors are determined on probabilistic basis. In Working Stress Method of present code IS: 800-1984 we are applying the same factor of safety for different load combinations, whereas in Limit State Method of IS: 800 – Draft, there are separate partial factors for different load combinations. In design of Tension Member three governing criteria are given such as strength due to yielding of gross sections, rupture of critical sections and block shear. Compression Members usually fail by flexure buckling. In Flexure Members laterally supported and laterally unsupported cases are described with help of separate examples. Also for Member subjected to combined bending and axial compression and combined bending and axial tension are attempted with uniaxial and biaxial bending. Separate worksheets were prepared for all types of members that are discussed above for both the methods (WSM and LSM) with help of Microsoft Excel for the purpose of comparision. iv An attempt has been made here for designing an Industrial Building with help of Working Stress Method (IS: 800 – 1984) and Limit State Method (IS:800 – Draft). The results obtained by the both the methods are tabulated for the comparison.