Fragility Analysis of Steel Building Frame Considering Different Nonlinear Material Modeling

Nonlinear time-history analysis is used to assess a structure’s ability to resist future earthquakes. The nonlinear behavior of the buildings is greatly affected by material nonlinearity considered during the analysis. This paper examines the nonlinear time-history analysis of steel frame by taking four different nonlinear steel material models into account, namely steel with elastic-perfectly plastic behavior which fails at yield strength, Menegotto and Pinto model with isotropic hardening, Menegotto and Pinto model with kinematic hardening and Ibarra–Medina–Krawinkler (IMK) model. Menegotto and Pinto’s model is used to simulate cyclic response. This is uniaxial material model and is used to describe the steel response in fiber-discrete cross-sections and under normal stress. IMK model is a deterioration model which takes degradation of material properties like strength and stiffness into account. In order to study the effect of material nonlinearity on the behavior of six-story building frame during an earthquake, the fragility analysis on these models is conducted by multiple stripe analysis.