Abstract | The Nonlinear Static Procedure (NSP), also known as ‘pushover’ analysis, is widely adopted in earthquake engineering practice. It is used for the estimation of various engineering demand parameters that provide a measure of the demand (and the capacity) of structures (e.g. displacements, storey drifts, forces, curvatures). Apart from element, or storey-level quantities, many NSPs provide the so-called ‘capacity curve’, i.e. the plot of the roof displacement against the total base shear applied on the building. Alternatively, local or global estimates of the building’s capacity can be obtained with Incremental Dynamic Analysis (IDA), which generates percentile ‘capacity curves’ in terms of seismic intensity versus the demand parameter of choice. The latter method is based on Nonlinear
Response History Analysis (NRHA), and is thus more reliable and accurate compared to NSP. In this work, we study qualitatively the properties of the building capacity curves obtained with either NSP or IDA. We show that the comparison can be performed either in the framework of the static pushover or in that of IDA. When the static pushover setting is adopted, we show that pushover methods can be compared with the results of IDA by plotting the latter in the form of ‘dynamic capacity curves’ where the base shear instead of an intensity measure (e.g., spectral acceleration) is plotted on the ordinates. Alternatively, the comparison can be performed within the IDA setting if appropriate R-C1-T relationships are adopted. Each setting shows the different qualitative characteristics of the two approaches and has different practical applications.