Seismic Vulnerability Assessment of Soft Storeyed Structures with Plan Irregularity and Collapse Prevention

Abstract

Structures with soft storey configuration are most vulnerable under earthquake loading but the risk increases abruptly if the structures are also irregular in plan. In this paper an attempt has been made to assess the seismic vulnerability of such structures by equivalent static force method (ESFM), response spectrum method (RSM) and time history method (THM). Results are obtained and compared with different models and extreme response has been recorded for open ground storey (OGS) building. Due to plan irregularity torsional responses are also involved in structures. To mitigate the soft storey effect and torsional response shear walls are introduced in different locations at OGS, OGS columns are designed 2.5times of the ground storey moment and shear force, OGS columns are replaced by reinforced concrete filled steel tube columns (RCFSTC), and the best solution among these three techniques are presented.