Issuu

International Research Journal of Engineering and Technology (IRJET)

e-ISSN: 2395-0056

Volume: 10 Issue: 07 | July 2023

p-ISSN: 2395-0072

www.irjet.net

SEISMIC ANALYSIS AND RETROFITTING USING STEEL BRACING IN A MULTI-STOREYED BUILDING Ameena Muhammed A1, Ifthana M N2, Minnu Kurian3 ,Shilpa Sajil4 ,Merin Mathew5 1UG Student, Dept. of civil engineering, Mar Athanasius College of Engineering, Kothamangalam, Kerala-686666 2UG Student, Dept. of civil engineering, Mar Athanasius College of Engineering, Kothamangalam, Kerala-686666 3UG Student, Dept. of civil engineering, Mar Athanasius College of Engineering, Kothamangalam, Kerala-686666 4UG Student, Dept. of civil engineering, Mar Athanasius College of Engineering, Kothamangalam, Kerala-6866662 5 Assistant professor, Dept of civil engineering, Mar Athanasius College of Engineering, Kothamangalam, Kerala-

686666 ---------------------------------------------------------------------***---------------------------------------------------------------------

Abstract - In today’s scenario of rapid population

protects from high winds and earthquakes. It is the moderation of an existing structure to make them more immune to seismic tremor.

increase and the unvarying land mass available, multistoreyed buildings have become inevitable. The structures are more vulnerable to earthquake loads and wind loads as the height of the building increases which will produce lateral displacements and thus accumulates deformations in various members of the building i.e., beams, columns, etc resulting in storey drift. These parameter values may exceed the permissible limits or can even lead to failure of the building. Seismic Retrofitting is the modification of an existing structure to make it more resistant to damages caused to the building due to various earthquake loads. India is divided into four seismic zones i.e., zones II, III, IV and V based on historical seismic activity by the Bureau of Indian Standards among which zone III and IV are considered. Steel Bracings are one of the efficient ways to help the building be seismic resistant. A G+12 storey building is to be analysed using E TABS 2019 software for seismic zones III and IV. The building is analysed against the seismic loads for models that are unbraced, with X bracing, V bracing, Inverted V bracing, K bracing and diagonal bracing at middle and corner configurations. The main parameters to be compared are lateral displacement, storey drift and base shear and the most suitable bracing at both middle and corner configuration among them for both zones III and IV are identified.

A G+12 building is assumed to be in seismic zone III and zone IV, and it is analysed for seismic adequacy using ETABS 2018 software and any seismic inadequacy of the building is satisfied by providing steel bracings as the retrofitting solution.

2. BUILDING SPECIFICATIONS The building that has been selected for the analysis is a G+12 storey residential building with 2 3 BHK and 2 1 BHK apartments in each floor. The building is assumed to be located at Mumbai at a wind speed of 44 m/s in seismic zone III and located at Mumbai at a wind speed of 47 m/s in seismic zone IV founded on type II medium soil, The building selected is first drafted in AUTOCAD and then modelled on ETABS 2018 unbraced and after providing various bracing systems. The information used for modelling the building is given in Table 1. Table -1: Building Specifications Building type

Residential

Foundation

1.5 m below GL

Key Words: Earthquake, Seismic Analysis, Steel Bracing, Multi-storey Building, ETabs software

Typical floor height

Wall thickness

230mm

1.INTRODUCTION

Slab thickness

150mm

Column size

500mm x300mm

Beam size

300mm x 230mm

Staircase details

Rise- 150mm

Seismic analysis comes under structural analysis, and it includes the calculation of the responses of a structure to earthquakes. In regions where earthquakes are prevalent, seismic analysis is a part of structural design. For the analysis ETABS 2018 software is used which is incorporated with all the major analysis used to analyse and design the buildings. Seismic retrofitting is a solution for seismic inadequacy. It makes a building safer and

Impact Factor value: 8.226

Tread-300mm

Superstructure

Brick Masonry

Grade of concrete

M30

ISO 9001:2008 Certified Journal

Page 222