Krishnan et al. Res. Trends Int. J. Technol. Innov., July - September 2026, 1 (3) : 17-25
1Department of Civil Engineering, National Institute of Technology, Tiruchirappalli, India; 2Department of Civil Engineering, Delhi Technological University, New Delhi, India
Article History
Accepted : 22 Jun 2026
Published : 10 Jul 2026
Publication Issue
Volume 1, Issue 3
July - September 2026
Page Number17–25
Many mid-rise reinforced concrete buildings in moderate seismic zones were designed to older code editions that did not mandate ductile detailing, leaving their true seismic capacity uncertain. This paper conducts nonlinear static pushover analysis on a representative 8-storey RC office building designed to a pre-2002 Indian code edition, comparing base shear capacity and inter-storey drift against current code demand curves. The building exceeded the life-safety drift limit at the fourth storey under the design basis earthquake, indicating a soft-storey vulnerability that a targeted column-jacketing retrofit reduced to within acceptable limits.
Keywords - seismic vulnerability, pushover analysis, reinforced concrete, soft storey, retrofit
A substantial stock of mid-rise reinforced concrete buildings in moderate seismicity regions predates modern ductile-detailing requirements, and retrofit prioritisation requires quantitative vulnerability assessment rather than blanket assumptions of deficiency.
A representative 8-storey RC office building, detailed per a pre-2002 code edition lacking capacity-design provisions, was modelled in nonlinear structural analysis software and subjected to displacement-controlled pushover analysis under a first-mode lateral load pattern, with capacity curves compared against code-prescribed demand spectra for the design basis earthquake, followed by evaluation of a column-jacketing retrofit scheme.
The unretrofitted model exceeded the life-safety inter-storey drift limit of 2 percent at the fourth storey under the design basis earthquake demand, consistent with a soft-storey failure mechanism driven by discontinuous infill walls at that level. The column-jacketing retrofit increased base shear capacity by 34 percent and reduced peak inter-storey drift to 1.4 percent, within the life-safety limit at all storeys.
Pushover-based assessment identifies specific vulnerable storeys in pre-code mid-rise buildings and allows targeted, cost-effective retrofit rather than uniform strengthening. Future work will extend the assessment to a building population study across a representative city building stock.
[1] ATC-40, Seismic Evaluation and Retrofit of Concrete Buildings, Applied Technology Council, 1996. [2] FEMA 356, Prestandard for Seismic Rehabilitation of Buildings, FEMA, 2000.
© 2026 The Author(s). Published by IJEIA Editorial Office. This is an open access article under the Creative Commons Attribution 4.0 International License (CC BY 4.0).
Naveen Krishnan, Shreya Pandit (2026). Seismic Vulnerability Assessment of Mid-Rise RC Buildings Using Pushover Analysis. IJEIA, 1(3), 17-25.