Pushover analysis is a non-linear, static structure analysis, which enables presenting structure behavior caused by different
types of loads resulting from an earthquake.
The following limitations are currently in place.
- All non-linear properties which determine possible structure damage due to forces resulting from an earthquake are concentrated
in non-linear hinges. Remaining non-linearity types (longitudinal forces, P-delta analysis, tension/compression bars, and
others) may be considered together with non-linear hinges, but their role in the structure behavior during pushover analysis
is not significant.
- Non-linear hinges are applied only in frame (bar) structures. They are not taken into account in structure elements such as
plates, shells, and solids which use planar or volumetric finite elements.
- Non-linear hinges are treated as independent non-linear connections for each degree of freedom at a selected node. Interaction
between different degrees of freedom is ignored.
- Location of a non-linear hinge is determined by the user.
The pushover analysis consists of the several stages listed below.
- Defining non-linear hinges in a structure calculation model.
- Assigning non-linear properties to the hinges (force-displacement or moment-rotation diagrams).
- Performing structure modal analysis to determine one mode.
- Defining a set of lateral forces (dependent on the mass matrix type used in the modal analysis).
- Defining a control node as well as direction and value of the allowable displacement.
- Determining parameters of the non-linear analysis.
- Starting the non-linear analysis. The analysis result is the equilibrium state curve V = V(D) where the shear forces are defined
as the sum of reactions for a given direction caused by the appropriate set of lateral forces.
- Determining the capacity curve , where is spectral acceleration and S d is spectral displacement.
- Smoothing of the capacity curve.
- Determining (step-by-step analysis) the performance point.
Details concerning the pushover analysis can be found in the appendix.