Sensitivity of Structural Demand to Ground Motion Selection and Modification Methods

The use of Non-Linear Dynamic Analyses provides significant uncertainties on the seismic demand, especially when real records are used. As these uncertainties strongly depend on the Ground Motion Selection and Modification (GMSM) methods, the spectrum-compatibility criterion and the method based on the minimization of the scaling factor are compared in this work. The variability of the engineering demand parameter obtained by subjecting ten reinforced concrete structures to different groups of records is studied through a sensitivity analysis called "Tornado Diagram Analysis". The analyses results show that the variability of the structural demand produced by the variation of the ground motion profile is significantly amplified with the increase in the complexity and the irregularity of the structures. More specifically, for regular structures, the selected GMSM criteria provide very similar variability while with the increase of irregularities, the spectrum-compatibility criterion produces a minimization of the demand uncertainty.