Comparitative Non-Linear Static Analysis of Buildings in Different Seismic Zones With Soil Structure Interaction

High land prices and a lack of available open space, along with rapid urbanization and population mass migration, lead to the development of high-rise building clusters in major cities like Bangalore, Delhi, and Mumbai, where structures are frequently constructed next to one another without consideration for structural safety. Strong external forces, such as earthquakes, have a high likelihood of causing a dynamic interaction among closely built structures in these circumstances. For this reason, it is crucial to thoroughly study and comprehend the dynamic response of these structures by taking into account all potential contingencies that may negatively affect the response of the structure and giving safety and serviceability a higher priority. One of such theories is the interaction between soil and structure, which is a crucial consideration for designing earthquake-resistant constructions. The purpose of the study was to understand how soil structure interaction affected RC buildings. According to IS 1893:2016, multi-story structures with the same number of storeys (G+5) were studied. The models are considered to be located in all seismic zones and are meant to be supported on two primary soil types (Hard soil and soft soil). The effect of subterranean soil is simulated using Winkler's Soil Spring Model. ETABS v18 software is used to examine the models using both linear and non-linear methods. The models are analysed using both linear(Equivalent static analysis & Response spectrum analysis) and non-linear(Pushover analysis) techniques using ETABS v18 software. The non-linear static analysis is used to determine the structure's performance point, and the various performance levels for the various structural components are represented by different notations, such as Immediate occupancy (IO), Life safety (LS), and Collapse prevention (CP), which are all defined in FEMA 440 for zone IV & V cases.The outcomes of modelling the structures on a fixed base and on flexible base are studied. It is observed that the storey displacements increases with increase in the flexibility of the soil and base shear increases with the decrease in the hardness of the soil. When SSI effect is considered it is observed that the storey displacement increases and base shear decreases compared to the fixed base conditions for both hard and soft soils. It can be concluded that the effect of soil structure interaction increases with the increase in the flexibility of the soil, intensity of the seismic activity prevailing in that location, and increase in the height of the structure. However, the chances of failure of the structure are more in soft soil condition in zone V. Therefore, it is necessary to take into account the impact of SSI when building significant buildings in areas with high seismic activity and high soil flexibility.