Pushover Analysis Method for Performance Based Seismic Design

In this paper is describes a non-linear static (pushover) analysis method for reinforced concrete structures that predicts real nonlinear (both material and geometrical) behavior including all stages of loading, starting from the initial application of loads up to and beyond the collapse of building. In other words from appearance of first plastic hinge until last hinge which represent collapse of building. Some important aspects which are implemented in EC8, FEMA-273/356 and ATC-40 documents regarding to pushover analysis and performance evaluation of buildings are discussed. Modeling of structural elements is made by linear elements approach. Nonlinear behavior of structural elements is made by plastic hinges when inelastic behavior is concentrated at plastic hinge locations in both ends of elements. For monitoring structural degradation of beams, bilinear Moment-Rotation relationship is considered. For monitoring structural degradation of columns, PMM interaction surface is considered. Nonlinear geometrical effects are taken into account by incorporating both local (P-δ) and global (P-Δ) in analysis. An eight story reinforced concrete building is analyzed. Distribution of lateral loads is accepted by first mode of free vibration. Results are given in terms of Global Capacity Curve, sequences of plastic hinge formation, plastic hinge distribution in structure, performance levels in terms of local behavior of structural elements and global behavior of structure.