Nonlinear Seismic Assessment Of Reinforced Concrete Buildings

Abstract

Reinforced concrete buildings in seismically active regions increasingly rely on performance-based design (PBD) 
rather than conventional force-based procedures, since the latter offers only an implicit and often unreliable 
estimate of actual structural behaviour under strong ground motion. This study evaluates the seismic performance 
of three reinforced concrete buildings of varying height, eight, twelve, and sixteen storeys, situated in Seismic 
Zone IV, using nonlinear static pushover analysis and the capacity spectrum method as prescribed in ASCE 41
17 and FEMA 440 guidelines [1]. Structural models were developed in ETABS with plastic hinge assignments at 
beam and column ends calibrated against experimental moment-curvature data. Pushover curves, performance 
points, inter-storey drift ratios, and Park-Ang damage indices were extracted for each building and compared 
against target performance objectives of Immediate Occupancy, Life Safety, and Collapse Prevention. The results 
indicate that taller buildings exhibited progressively higher concentrations of drift near the mid-height region 
and correspondingly elevated damage indices at beam-column joints, a pattern that raises questions about the 
adequacy of uniform ductile detailing across height. Building A satisfied the Life Safety objective comfortably, 
Building B approached the threshold with localized joint distress, and Building C exceeded acceptable drift limits 
at three storeys, suggesting a need for supplemental damping or stiffness modification. Comparison with five prior 
studies confirms that the present findings are broadly consistent with regional trends reported for similar 
structural typologies, while also revealing discrepancies attributable to differences in hinge modelling 
assumptions. The study concludes that performance-based evaluation provides a more defensible basis for seismic 
retrofit prioritization than code-based drift checks alone, particularly for mid-to-high-rise reinforced concrete 
construction in zones of high seismicity [2].