Seismic Assessment of Vertically Irregular RC Frame Buildings Designed Using Direct Displacement-Based Design Approach

In recent years, open-ground story (OGS) RC buildings have been famous in India due to the availability of high parking spaces. On the other hand, OGS buildings are among the most common forms of vertically irregular RC buildings, where irregularity lies at the ground level. This study evaluates the seismic response of OGS RC buildings under earthquake ground excitations. Direct displacement-based design (DDBD) approach is used in designing the case study of eight-storied OGS frame buildings. RC buildings are adopted in three different structural configurations, having the same plan area and height but with different plan-aspect ratios. The seismic evaluation is performed by nonlinear dynamic analysis under various earthquake records. The selected earthquake ground motion records are all far-field earthquakes having a hypo-central distance of more than 10 km. Therefore, the tremors are compatible with the design target response spectrum of Indian Standards. The seismic assessment uses maximum displacement and inter-story drift ratios from the nonlinear dynamic analysis. A life-safety damage state of 2% is considered the target performance objective per FEMA-356. The results indicate that OGS buildings designed by the DDBD approach can easily be implemented and successfully satisfy the target performance objectives.