Abstract

The main objective of this paper is to evaluate the load-displacement capacity of steel moment-resisting frame structures using the conventional non-linear static analysis method and incremental dynamic analysis approach. Emphasis was put on the influence of different lateral load patterns on the plastic hinge of structural components and also on the seismic behavior of the structures which is influenced by the behavior of their components [(EEsof, electronic engineering software)]. Firstly, to get an idea, two simple frames were selected and analytically tested using the conventional push-over and then the results were compared with dynamic analysis approach using a simple harmonic time-history. The results show that the axial forces in columns obtained from dynamic approach are smaller than those of the other non-linear static methods and this influences the plastic hinge lengths. Then three sets of steel moment-resisting frames were loaded under different load patterns frequently used in conventional push-over analysis methods. The outputs of the structural analysis, in the forms of story shear versus story drift ratios of upper, middle and lower portions show that in general, nonlinear static analysis results in smaller axial forces in columns which cause smaller component deformations, thus weaker structural load-deformation capacities.

Key words: Performance- based engineering,nonlinear static analysis, lateral load pattern, plastic hinge.