Comparative Study on Rcc Industrial Chimneys by Using Existing (Is 4998 Part 1:1992) and Draft Code (Ced 38(7892) Wc

Abstract

This  paper is aimed at knowing the differences between existing code (IS 4998 part 1:1992) and the draft code CED 38(7892) with respect to its codal parameters and final design based on geometric parameters and various wind speeds. This study considers various height to base diameter ratios such as 23, 25, 29 (the most preferable ratios as per IS 6533 (Part 1): 1989. Structural performance under lateral dynamic loading will be subjective by the geometry of the structure. This is because geometry will influence the stiffness parameters first and foremost. Based on related environmental conditions basic dimensions such as height, diameter at exit etc are there in case of chimneys. 54 cases of RCC chimneys are analyzed using existing code IS 4998 of heights 220m and 250m were studied and also 54 cases of RCC chimneys were analyzed using Draft Code CED 38(7892):2013 of same heights. Major difference after studying the draft code and existing code is draft code is based on Limit state design and existing code is based on working stress method. After analysis the design results are in accordance with the existing principle “limit state design is economical”.