International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 12 Issue: 04 | Apr 2025
p-ISSN: 2395-0072
www.irjet.net
Analysis of Soft Storey Mechanism with Advanced Structural Configurations Manikandan C1, Dr. P.Manibalan2 1PG Student, M.Tech Structural Engineering, SRM Institute of Science and Technology, Chennai,
India
2Assistant Professor, Civil Department, SRM Institute of Science and Technology, Chennai, India
---------------------------------------------------------------------***--------------------------------------------------------------------1.1 Soft Storey Mechanism: Abstract - The presence of soft storeys in multi-storey building has been a critical concern in structural engineering, especially under seismic loading conditions. A soft storey, typically characterized by a significant reduction in stiffness or strength compared to adjacent storeys, often occurs due to architectural requirements such as open ground floor for parking. These irregularities can lead to catastrophic failures during earthquakes. This project focuses on the detailed analysis of soft storey behavior in a 15-storey reinforced concrete building using ETABS software. Loads are applied according to IS 875 for gravity loads and IS 1893 for Earthquake forces. Various advanced structural configurations such as bracings, Blade columns are incorporated to mitigate the adverse effect of soft storey mechanisms. Comparative studies are performed between conventional and improved configurations to assess changes in parameters like inter-storey drift, base shear, lateral displacement. The study aims to understand how different design configurations can improve the structural performance and overall stability of buildings with soft storeys. This research highlights the importance of early identification of soft storey vulnerabilities through computational modelling and analysis, ultimately contributing to safer building practices.
In many multi-storeyed buildings, the ground floor is often designed with fewer partition walls or open spaces for parking or commercial use. This results in a significant difference in stiffness between the ground level and the upper floors, which typically have more infill walls. This stiffness irregularity causes the upper storeys to behave as a rigid unit, while the ground storey experiences most of the lateral displacement during an earthquake. Such a condition, commonly referred to as a “soft storey” leads to excessive movement at the base of the structure, creating a swaying effect similar to that of an inverted pendulum. This amplifies the seismic force on the ground floor columns and beams, making them highly vulnerable. To ensure structural safety, it is crucial that these elements are designed with sufficient strength and ductility to resist such dynamic effects.
Key Words: Soft storey, Seismic, ETABS, Bracing, lateral Stiffness, Drift
1.INTRODUCTION Soft storey failures in multi-storey buildings have become a major concern in seismic-prone regions. A soft storey typically occurs at the ground level due to open spaces for parking or commercial use, leading to reduced stiffness and strength in that storey. This irregularity can cause severe structural damage or collapse during earthquakes. This project aims to analyze the behaviour of a 15-storey reinforced concrete building with a soft storey using ETABS Software. According to the seismic code IS 1893 (Part 1): 2016, a soft storey is mentioned as one whose lateral stiffness is less than 70% of that of the storey immediately above it or less than 80% of average lateral stiffness of the three storeys above.
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Fig -1: Soft Storey Mechanism
1.2 Purpose of the research: The primary purpose of this research is to conduct a comprehensive analysis of the seismic performance of reinforced concrete buildings incorporating a soft storey at the ground level. Soft storeys, typically characterized by
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