A structural demand model for seismic fragility analysis based on three-parameter lognormal distribution

Seismic fragility analysis, which quantitatively describes the dynamic relationship between earthquake intensity and structural failure probability, plays an important role in overall seismic risk assessment. An appropriate demand model can significantly improve efficiency of currently most commonly used is lognormal model. However, recent studies have shown that this model's rationality still doubt. In study, a novel for generating analytical curves form three-parameter distribution proposed investigated based on large amount nonlinear data using observed Japanese ground motions with wide range magnitudes epicenter distances. It shows better fitting effect than existing expected to be more applicable analysis. Through numerical analysis examples two common types, i.e., steel frame structure reinforced concrete structure, accuracy feasibility are proven.