Probabilistic Seismic Demand Models for Multi Span Continuous Steel Girder Bridges Using Fractional Order Intensity Measures

摘要

Probabilistic seismic analysis of structures involves the construction of seismic demand models, often stated as probabilistic models of structural response conditioned on a seismic intensity measure (IM). The uncertainty introduced by the model is often a result of the chosen intensity measure. This paper introduces the concept of using fractional order intensity measures in probabilistic seismic demand analysis using multi span continuous steel girder bridges as a case study. It also demonstrates the advantage of fractional order IMs relative to conventional intensity measures like peak ground acceleration, velocity and displacement. Metrics such as efficiency, sufficiency, practicality and proficiency are measured to assess their optimal nature. The proposed fractional order intensity measures provide improved statistical tools and demand models that can be used in site specific probabilistic seismic demand analysis.