Effect of Floor Height Variation on Seismic Performance of RCC Buildings Using ETABS

Abstract: This paper studies how floor height variation affects the seismic behavior of a G+10 RCC building using ETABS.In modern cities, reinforced concrete buildings are often built with different floor heights for parking, commercial space, or architectural needs. While this is useful in practice, it can change how the building behaves during an earthquake. This study examines the effect of floor height variation on the seismic performance of a G+10 RCC building using ETABS. Three cases are studied: a uniform-height building, a soft-storey building with a taller ground floor, and a building with alternate floor height variation. The results show that floor height variation increases the fundamental time period and lateral displacement, while reducing base shear. It also increases drift at the irregular storey, especially in the soft-storey model. These findings show that vertical irregularity should be carefully considered in seismic design, because even if strength demand seems lower, serviceability and safety may become critical.

Keywords: Floor height variation, seismic performance, G+10 RCC building, soft storey, ETABS, response spectrum analysis, inter-storey drift, vertical irregularity.