Rapid Visual Screening method for vertically irregular buildings based on Seismic Vulnerability Indicator

Abstract

Seismic vulnerability assessment of a large group of buildings can prove to be extremely difficult as it requires huge amount of time and resources. Rapid Visual Screening (RVS) alleviates this problem by classifying buildings into different classes of vulnerability thereby limiting the need for detailed analysis only to a few selected vulnerability classes. RVS survey of five G+1 houses were conducted using Arya et al. method, Sinha et al. method, Jain et al. method, FEMA Level 1 and FEMA Level 2 method. The lack of details regarding irregularities resulted in the same RVS score for buildings with significantly different configurations. This renders the RVS procedure difficult to be used for comparison. This paper provides a qualitative comparison of seismic vulnerability among vertically irregular buildings in terms of mass, geometric and stiffness irregularity through Rapid Visual Screening. 3D Response spectrum analysis of reinforced concrete buildings have been done using STAAD Pro software and Seismic Vulnerability Indicator (SVI) values are calculated for comparison of seismic vulnerabilities with respect to vertical irregularities. Mass irregularity near the mid height of building or stiffness irregularity below the mid height of building is found to be more critical among the possible locations of irregularity. Elevation asymmetry above mid height is found to decrease the seismic vulnerability of a building. Presence of stiffness irregularity is found to be significantly more critical than mass or geometric irregularity.