International Journal of Science, Engineering and TechnologyAuthors: Ambuj kumar Yadav
Abstract: The seismic performance of buildings is strongly governed by structural irregularities and soil characteristics. This study conducts a comparative analysis of irregular RCC and Steel buildings using STAAD.Pro under three soil conditions defined in IS 1893:2016—Hard, Medium, and Soft. Plan irregularity (L-shape), vertical irregularity (setback), and mass irregularity are incorporated to assess their influence on dynamic behaviour. The Response Spectrum Method is adopted to evaluate key seismic parameters, including storey displacement, drift, base shear, time period, and mode shapes. Results indicate that soft soil significantly amplifies seismic demand, leading to larger lateral responses. Steel buildings display higher flexibility with lower base shear, while RCC structures exhibit greater stiffness and reduced displacement. Irregular configurations also exhibit notable torsional effects.
