Assistant Professor, Structural engineering Department, Birla Vishwakarma Mahavidyalaya, Gujarat, India3

Abstract: Damage to the structure is initiated through the weak plan of the structure and these weak plans exist in the structure due to irregularities. Structural irregularities are induced in the structure due to irregular distribution of mass and stiffness in horizontal or vertical direction which in turn causes the torsional irregularities or plan irregularities. Complex shape (plan irregular) buildings do not have the predefined principal plan axis as regular structures may have and it is not predefined that lateral load acts along the principal plan axis as there is uncertainty in the location of the epicentre. Vertical geometric irregular buildings are also having stiffness, mass, and torsional irregularity. Study shows that torsional irregular buildings are sensitive to the different angle of earthquake incident. Therefore, not only Horizontal (plan) irregular buildings but also some vertical irregular buildings having the setback are vulnerable to different angles of earthquake incidents. The present study evaluates the plan irregular structure under the different angles of earthquake incidents. For seismic analysis of the structure, the Response spectra method using IS 1893:2016 and linear time history analysis is used to derive the Engineering demand parameters. For linear time history analysis far-fault and near-fault ground motion data is selected for the seismic analysis. Results indicate that structures with eccentricity in both directions (Torsional coupled) are more sensitive to the different directions of earthquake incidents. There is a significant increase in the responses of the building model was reported in a particular angle of earthquake incident.

Keywords: Angle of incident, Plan irregularity, eccentricity, Response spectrum analysis, Time history analysis.

| DOI: 10.17148/IARJSET.2022.9596