Simplified Pushover Analysis of Moment Resisting Frame Structures

Seismic assessment of a building will typically require consideration of its nonlinear force–displacement response. Such information can be estimated from pushover analysis, also referred to as nonlinear static analysis, in which the structure is analyzed for incrementally increasing lateral loads and the nonlinear structural behavior is accounted for during the analysis by updating the stiffness matrix at each load increment. A number of computer programs are now available to permit the application of pushover analysis in practice. However, it is argued that there is a need for simplified pushover analysis methods to permit independent checks of computer outputs and also to inform engineers of the key characteristics of the structural system being assessed. This work builds on previous contributions in the literature to provide a simplified pushover analysis approach for reinforced concrete (RC) frame structures. A novel procedure for the assessment of the displacement profile of RC frames is provided, with guidelines to account for different types of yielding mechanisms. By comparing force–displacement response predictions with those obtained from rigorous nonlinear static analyses for a range of frame configurations and mechanisms, it is shown that the proposed approach offers an effective means of undertaking simplified pushover analysis.