A study to evaluate the performance of the
existing building by the development of fragility curves was introduced in this
paper. A typical five-story residential government RC building becomes the
target building, designed based on BS 8110 without incorporating any seismic
action. It consists of plan and elevation irregularities. The target building was
analyzed by performing Incremental Dynamic Analysis (IDA) and excited by
several ground motion records through equally scaling from 0.1 g to 0.8 g with
every 0.1 g increment. Nonlinear time-history analysis was executed using STERA
3D software and recorded the structural response in terms of maximum inter-story
drift ratio (IDRmax). This
study initiated two different methods of developing fragility curves: (1) using
a limit state of five levels of performance-based seismic designs, and (2) the
conditional probability of IDRmax
exceeded the specified limit state of IDR
with the aid of static pushover analysis. Both X- and Y-directions were
examined to investigate the irregularity effect of the target building.
Findings indicated that X-direction is weaker than Y-direction for both methods
to reach or exceed specific performance levels and for the conditional
probabilities of exceeding the targeted limit state at a given peak ground
acceleration (PGA).
Keywords: Fragility curve, performance levels, limit state, incremental dynamic analysis