Development of hybrid earthquake vulnerability functions for typical residential buildings in Iran

Abstract

Residential building stock in Iran, with its diverse types, is exposed to different earthquake events each year that necessities the implementation of disaster risk reduction measures. Conducting seismic risk assessment studies, on the other hand, is crucial as one of the main perquisites of any earthquake disaster risk reduction efforts. Seismic risk assessment is an approach that requires dependable fragility or vulnerability functions, and the more valid these models are, the more realistic the risk assessment results would be. The main objective of the current study is to provide new hybrid seismic vulnerability models for typical residential buildings in Iran. In this regard, existing peer-reviewed fragility or vulnerability models are utilized as basic models besides the damage records of recent earthquake events in Iran. The logic tree approach is used to combine the basic models, and 26 seismic vulnerability models are developed based on three main attributes of material type, construction quality, and building height. The developed models are functions of PGA and are in the form of the cumulative lognormal distribution function. Additionally, the most recent national census data (2016) are utilized to combine vulnerability models via the logic tree approach and develop quality-independent vulnerability models that can be used in circumstances when precise information about the construction quality of buildings is not available. Developed models are finally validated using the real building damage data collected from the records of recent significant earthquake events in Iran.