Seismosoft | Earthquake Engineering Solutions

In order to calculate the total overturning moment at the base you need to consider the moments and the individual supports, as well as the moments from the axial loads on the columns, M=(Force)x(lever-arm).
Seismosoft Support

seismosoft wrote: 27 Apr 2021, 09:55 In order to calculate the total overturning moment at the base you need to consider the moments and the individual supports, as well as the moments from the axial loads on the columns, M=(Force)x(lever-arm).
Seismosoft Support

Hi
Is it possible to determine the position and order of formation of plastic hinges after pushover analysis in Seismostruct?

You may set up the appropriate criteria in the Performance Criteria. After the analysis the Performance criteria log in the post-processor will tell you exactly which criteria (plastic hinge) was reached, where it reached, and the load factor at which it was reached, enabling you to track the progressive collapse.

You could, just as an example, set first yield criteria by specifying a strain equal to fy/E in the Performance Criteria. You could specify the formation of a plastic hinge by setting up a strain equal to some multiple (maybe 10 or more, but you and your supervisor should decide how you want to define a plastic hinge) of the yield strain. Finally, you could set a fracture criterion performance goal be specifying a fracture strain for the material you are using.

You may also view graphically the location of the plastic hinges (as performance criteria) on the deformed shape viewer.

Seismosoft Support

Good day!

May I know how to get the ultimate displacement in a pushover curve? I read in your forums that I have to assign a 20% residual strength to produce a declining curve. However, doing so causes my model to have convergence problems. It cannot sustain the loads I initially applied.

Also, Is the target displacement from bilinearization equivalent to the ultimate displacement?

Indeed, convergence problems may occur when applying a big decrease in the member's strengths, as the stucture cannot sustain the imposed lateral forces, but also the gravity loads.
The target displacement is displacement level expected at the design earthquake. With ultimate displacement probably you mean the displacement at end of the pushover analysis, which should be at least 150% the target dispalcement and well into the inelastic range so that to get a correct bilinearization of the capacity curve. You need to refer to the basics of pushover analysis, in order to better understand these concepts.
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