International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056 Volume: 08 Issue: 04 | Apr 2021 www.irjet.net p-ISSN: 2395-0072 © 2021, IRJET | Impact Factor value: 7.529 | ISO 9001:2008 Certified Journal | Page 2331 Effect of Irregularities on the Capacity and Ductility of Steel Structure by Pushover Analysis Chetan Jaiprakash Chitte Department of Civil Engineering, R. C. Patel Institute of Technology, Shirpur-425405 Dist. Dhule, Maharashtra, India, ---------------------------------------------------------------------***---------------------------------------------------------------------- Abstract - A structure can be classified as irregular if it contains irregular distributions of mass, stiffness and strength or due to irregular geometrical configurations. The introduction of irregularity in the structure creates complex design and construction problems as irregular structures behave differently from regular structure. This section deals with the comparative study which is carried out in order to compare the behavior of the structure with the effect of various irregularities on the capacity and ductility of the structure. In this paper pushover analysis is performed on regular shaped G+4 steel building. The same building is analysed by pushover analysis with consideration of different irregularities such as mass irregularity, vertical geometric irregularity and with inclusion of chevron type brace Key Words: irregularity, mass irregularity, vertical geometric irregularity, capacity spectrum, pushover analysis, 1. INTRODUCTION India is prone to strong earthquake shaking, and hence earthquake resistant design is essential. Irregular buildings constitute a large portion of the modern urban infrastructure. The group of people involved in constructing the building facilities, including owner, architect, structural engineer, contractor and local authorities, contribute to the overall planning, selection of structural system, and to its configuration. This may lead to building structures with irregular distributions in their mass, stiffness and strength along the height of building. When such buildings are located in a high seismic zone, the structural engineer’s role becomes more challenging. Therefore, the structural engineer needs to have a thorough understanding of the seismic response of irregular structures. The revision of IS 1893 (Part 1): 2016, "Criteria for Earthquake Resistant Design of Structures" have been published by Bureau of Indian Standards recently in December 2016. IS 1893 (Part 1): 2016 defines mass and vertical geometric irregularities as follows. Mass Irregularity: cl.7.1, Table -6, as per new code, mass irregularity is considered to exist when the seismic weight of any floor is more than 150 % of that of the floor below. In buildings with mass irregularity and located in seismic zones III, IV and V dynamic analysis shall be performed, Fig. 1 Definition of Irregular Buildings: Mass Irregularity Vertical Geometric Irregularity: cl. 7.1 , Table – 6, as per new code, the vertical geometric irregularity shall be considered to exist, when the horizontal dimension of the lateral force resisting system in any story is more than 125 % of the storey below. Fig. 2 Definition of Irregular Buildings: Vertical Geometric Irregularity 2. PROBLEM STATEMENT In current study the behavior of the structure with the effect of various irregularities on the capacity and ductility of the structure analyzed. In this paper pushover analysis is