Open Ground Storey Buildings designed as per various International Codes – A Seismic Performance Comparison Study

Abstract

Open Ground Story (OGS) framed structures where the ground story is kept open without any masonry wall, mainly for parking purposes, are increasingly found in urban regions. Weakness of this kind of structures perhaps was exposed in the past earthquakes. OGS buildings are conventionally designed considering a bare frame analysis ignoring the stiffness of the infill walls present in the upper storeys. This analysis ignoring the stiffness of infill walls under-estimates the inter-storey drift and thereby the force demand in the ground storey columns. A Multiplication Factor (MF) is suggested by different universal codes to compute the design forces in the ground story columns. Present study focus on the assessment of seismic performance of a typical four storeyed OGS building designed with MFs recommended by major codes. The probabilistic seismic demand models, fragility curves and the reliability indices for all models are developed including bare frame and fully infilled frame.