Lateral load-resisting structural members such as columns constitute an important class of critical structural components in a building frame during earthquake. Columns may be subjected to simultaneous shaking along two mutually orthogonal directions during earthquake. However, there exists no explicit guideline to account for such bi-directional interaction. In this backdrop, the present investigation attempts to systematically examine the impact of such bi-axial bending under selected far-field records using a simple reinforced concrete frame. Response of the frame, modeled using fiber element with appropriate constitutive rule, is evaluated through incremental dynamic analysis under both uni-directional and bi-directional excitation. Observations collated in the form of suitable fragility curve imply that the effect of bi-directional interaction may often be potential.

Keywords: Bi axial, Fiber, Reinforced concrete, Seismic, Incremental Dynamic Analysis (IDA), Fragility curve, Far-field record.