Response Spectrum Development for Seismic Demand Comparison of a Building in Indian Context

Abstract

Earthquake is a natural hazard that causes damage or sometimes complete collapse of man-made structures. It is measured as ground excitation with acceleration and time data points measured at various locations through digital instruments. All ground excitations measured do have potential to cause damage to the structures but strong ground motion do. Strong Ground Motion is characterized by various parameters like Peak Ground Acceleration (PGA), Frequency Content, Root Mean Square (RMS) Acceleration, Arias Intensity and Duration of strong ground motion. Strong ground excitations poses varied seismic demand on structures. In the present study, out of 184 ground motions recorded at 23 recording stations of Indian subcontinent, about 67 ground motions are quantified as strong ground motion based on PGA and Duration of the motion. Response Spectrum for each strong ground excitation is developed. A mean, mean plus one standard deviation and maximum response spectrum are developed for each strong ground motion using statistical analysis. Seismic demand posed by each response spectrum and IS specified design spectrum on four storey Reinforced Concrete (RC) shear frame building are evaluated. Comparison among seismic demand represented by peak acceleration and base shear are carried out. It is found that seismic demand posed by IS specified design spectrum for building is quite high as compared to mean response spectrum. Similar results are obtained for mean plus one standard deviation and maximum response spectrum except few strong ground motions that posed high seismic demand on building as compared to IS specified design spectrum.