A Comparative Evaluation of a 13-story G+ Building with a Soft Storey, Using Pushover Analysis, with a Focus on the Impact of Different Placement of Shear Walls

Abstract

Asymmetrical structures with varying degrees of irregularity have proven to be a significant factor in causing collapses, damage to property, and injury during earthquakes. Despite extensive research on asymmetric buildings, there are currently no established guidelines for multi-story structures of this type. A soft storey, also known as a weak storey, is a level in a structure with insufficient rigidity or ductility to sustain earthquake-induced damage Pushover analysis has been thoroughly investigated by scholars since the 1994 Northridge earthquake and other major earthquakes globally. The goal of pushover analysis is to establish design strategies that result in structures exhibiting a defined level of seismic performance during seismic events. The objective of paper is to study the pushover analysis for a framed structure with shear wall at corner, at center and for a framed structure with soft storey. This study will address the analysis of the RC building frame, that is, the PUSHOVER analysis, which is a static nonlinear process that estimates seismic structural deformations using a simplified nonlinear technique. Pushover analysis may give substantial information into the weak links of a structure’s seismic performance. Shear walls are often employed to counteract lateral forces. The composite action of the beam, column, and wall increases the strength and rigidity of the structure. With the use of Shear walls, lateral deflection in both directions is significantly reduced. When shear walls are added to a structure, it becomes more rigid than it was before. The study assessed the behavior of reinforced concrete structures with and without soft stories, considering various parameters such as story drift, story displacement, and base shear. According to IS 1893:2016, a pushover study was conducted on models of 13-story buildings of bay size 40  40 m. Structure having grade of concrete M25 and grade of steel Fe500. The floor height is 3 meters between each floor and 4 meters in the case of the soft storey. Using ETABs, five unique models were selected for testing. The results of each model’s storey displacement, storey drift, storey stiffness, and base shear are acquired, and a comparative analysis is undertaken to choose the model with the best performance. The greatest yielding occurs at the softest storey; hence, the greatest plastic hinges form despite the increasing base force. Therefore, soft storeys are safer on high-rise building upper levels. The bulk of hinges found on beams, whereas just a handful appeared on columns. The use of plastic hinges in columns of soft storeys at ground level is not an acceptable safety design requirement. The shear wall gives the structure with high stiffness, ensuring its stability. Shear walls may minimize the displacement and drift of a building’s storeys effectively. This will minimize the damage caused by lateral loads, such as during an earthquake. Prior research has shown that the performance of shear walls varies depending on their position inside a structure.