Seismic fragility assessment of RC moment resisting frame buildings designed for different editions of Iranian seismic design code

Background and objective: Developing fragility and vulnerability functions are important tools in seismic reliability assessment of buildings and are widely used in regional seismic risk studies. To date sufficient studies for developing analytical fragility functions for Iranian code-conforming buildings have not been carried out. Performing such studies are necessary to assess the adequacy of Iranian seismic design codes.  Method: In this paper, by designing 4, 8 and 15 storey concrete reinforced concrete buildings based on the latest three editions of Iranian Standard 2800, seismic fragility functions will be estimated for the 9 different design results. For this purpose, after designing the structures defined in accordance with the procedures in Iranian Standard 2800 and the National Building Code, Chapter 9, a nonlinear model of each case was developed in the OpenSEES finite element software. Nonlinear material properties as well as P-Δ effects were considered in the models. Twenty-two reference ground motion records were used to perform the incremental dynamic analyses. The relative performance criteria according to publication No. 361 of the Planning and Budget Organization of Iran were employed in the evaluation of the results of nonlinear analyses. Findings: The results were applied in statistical analysis to estimate the seismic fragility functions and corresponding parameters. Conclusion: The results show the trend of change in the seismic fragility for the frames with different height and conforming different editions of the Standard No. 2800.