A pushover analysis setting ( PA ) specifies the rules according to which the load is increased and the iterative calculation of the target displacement ends. A standard analysis type is preset. You can adjust this type at any time or create additional pushover analysis settings.
The 'Pushover Analysis Settings' dialog manages the settings of the analysis type selected in the 'list' on the left.
Incrementally Increasing Loading
In this section you can define how the horizontal load should be increased gradually.
Initial Load Factor
The value k0 represents the start factor. As a rule, the analysis starts with 1.0 times the lateral load. In EN 1998-1, Eq. (B.1), for example, the output load is described with the following relationship:
| ¯Fi | Related Horizontal Force |
| Mz, Rd | Design value of the allowable bending moment about the local z-axis |
| Φi | Related Displacement |
load factor increment
The factor Δk specifies the step size with which the load is increased in the course of the analysis. The smaller the factor, the longer the calculation takes. On the other hand, if the factor is too large, there is a risk that the target displacement will not be determined with the required accuracy.
Refinement of the last load increment
This input field allows you to subdivide the critical area of the last load step with finer load steps. This means that even with relatively coarse factors Δk, a quick calculation with good result accuracy can be carried out.
Maximal number of load increments
The calculation ends as soon as the maximum number of load levels is reached. This prevents the analysis to determine the capacity curve from running endlessly or from no convergence due to oscillating effects.
stopping condition
In this section you can define the target criteria of the calculation.
End of capacity curve
The capacity curve expresses the ability of the structure to withstand lateral loads. Two options are available in the list as the target for calculating this curve.
- Limit deformation: The calculation ends as soon as a certain deformation is reached. You can specify this limit deformation manually in the field on the right. It depends on the target displacement and thus on the earthquake force (response spectrum). In many cases, 5% of the building height can be used as a guide.
- Collapse: The horizontally acting loads are increased until a singularity occurs and the system has failed.
Automatic selection of the highest node
The checkbox is checked by default. The highest node in the building thus represents the control node for the limit deformation or for recording the deformation in the capacity curve. If you remove the check mark, you can specify a different node in the model.
Options
The ' Iterative method check box, if the difference between dm * and dt * is greater than ε ', enables the accuracy for the iterative determination of the target displacement dt * to be adjusted. This iterative procedure is referred to in EN 1998-1, B.5; it corresponds to the N2 method according to [1 ]. You can use the value ε to influence the permissible distance between two iterations as a termination criterion and thus increase the accuracy of the result.