Seismic reliability assessment of typical soft-storey rc building in manipur region

Abstract

Significantly low stiffness and strength in any storeys compared to adjacent storeys is commonly referred to as soft -storied buildings. When car parking space is provided in the ground storey like in an open ground storey building (OGS), the building invariably becomes a soft-ground storey. These types of buildings are found to be the most affected in an earthquake as seen from the past Indian earthquakes. The ground storey columns of this type of buildings are the weakest element that may experience failure due large inter-storey drifts. For such ground storey columns, magnification factors (MF) are suggested by the design codes. The present study is focus on the seismic reliability of typical OGS building configurations in Manipur region (Ukhraul), which is one of the most vulnerable regions in India. Reliability indices for each building are estimated by combining fragility curves with the available hazard curve of the Manipur region. Building frames with different heights (6, 8 &10 stories) and MFs considered for the design. Fragility curves are developed for each type of buildings by conducting nonlinear dynamic analysis. Thirty natural time history data ar e selected, and modified to match with Indian response spectrum. Uncertainties in concrete and steel are included. Conclusions are drawn based on the reliability indices obtained.