Pushover analysis

[medo]

Non-linear hinges are considered an independent non-linear links for each degree of freedom in a given node. The interaction between different degrees of freedom is disregarded. For example, bending of a bar in one plane does not depend on bending in another plane and longitudinal forces.

But, if you consider column, then for sure the property of a hinge for column depends on the amount of axial force. As you now axial force may vary during analysis. As far as I know in other structural analysis software (i.e. SAP2000) you can define hinge with interaction.
In SAP2000 there are three types of hinge properties: default hinge properties, user-defined hinge properties and generated hinge properties. For example of default properties you have Default-M3, Default-P, Default-PMM, and Default-V2, as can be seen on figures in my previous post. Usually moment hinge properties (Default-M3) are assigned to beams and interacting hinge properties (Default-PMM) are assigned to columns.
In addition to moment-rotation relationships, a three dimensional interaction surface with axial force-bending moment interaction diagrams has to be defined for columns. Although SAP2000 could not update the moment-rotation relationships due to the variations in axial load levels during pushover analysis, the yield and ultimate moment values are updated by using the three dimensional interaction surface. Axial force-bending moment interaction diagrams about two major axes of each column section are utilized to determine the other three axial force-bending moment interaction diagrams required to define the three dimensional interaction surface.
With comparison of results obtained by ARSA and SAP2000 for RC frame quite big differences are obtained. I am trying to match the input data, but it seems that SAP2000 has more detailed input which obviously influences the results.

[Marios]

During pushover analysis is there any way to change the loading matrix from modal to uniform or triangular?

[pwkhang242253]

Hi, I am having the same issue. I am prompted with no convergence and type 3 instability warnings.

Have you guys found out the reason?

Appreciate it if someone could help...THANKS...

[supradhan08345878]

Could anyone help; how to calculate the user defined hinge properties of RC column for SAP2000 for pushover analysis