G.22.214.171.124.6 Define Pushover Analysis Solution Control
Pushover analysis will continue until any of the following three conditions is satisfied:
Cumulative base shear is less than or equal to the base shear defined by the user
You must define base shear up till which pushover analysis will be performed since design base shear (specific to particular seismic code) excludes non-linear effect. When the structure is subjected to strong earthquake the actual base shear may be very high compared to the design base shear. Under this condition there is no guarantee that the structure will maintain desired performance level. This option is chosen when the magnitude of base shear is known and the structure will be able to support that load.
Displacement at the control joint in the specified direction exceeds specified displacement
This option is chosen when the amount of displacement is known i.e. how far the structure will move but the amount of base shear that the structure will be subjected to is not known. While defining this option please make sure that the displacement component chosen at the control joint increases monotonically during loading. The control node shall be located at the center of mass at the roof of the building.
The structure becomes unstable
This happens whenever hinge formation is such that it renders the structure on the verge of collapse. If neither base shear nor displacement at control joint is known, define a higher value for both these options. During analysis instability will arise due to collapse of different members and make the structure unstable.