Backbone Curve Graph

[Kirkaguel]

Is there a way that we can see the backbone curve (whether bi-linear or trilinear) adopted for a non linear component i.e. plastic hinge in accordance with asce 41 guidelines?

One critical aspect of the backbone curve is the post peak stiffness assumption to capture cyclic degradation.

https://www.dropbox.com/h

[seismosoft]

Since SeismoBuild is a fibre based program, this is not possible. Note however that in the next release a plastic hinge frame element with a multi-linear backbone curve will also be available.
Seismosoft Support

[Ralazem]

Is there another method to model the post peak stiffness assumption for cyclic degradation modelling?

[seismosoft]

Unfortunately, no.
In fiber modelling this is automatically taken care by the constitutive material models for concrete and steel.
There is no need for the user to calibrate it.

Seismosoft Support

[Ralazem]

I am unable to obtain a degrading hysteteric behaviour under cyclic loading. What might be the cause?

[seismosoft]

There can be numerous reasons. For instance, relatively low loading level, presence of large transverse reinforcement that leads to large confinement factors for concrete, lack of adequate vertical loads, deactivation of 2nd order effects.
Seismosoft Support

[Ralazem]

What do you mean by deactivation of 2nd order effects? How can I activate those?

[z.gronti]

Dear Ralazem,

If you select the 'Include Geometric Non-linearities' check-box in the Analysis tab of the Project Settings, then the P-Delta effects will be taken into account.

[Ralazem]

oh, well, all of the items you have mentioned are taken into account in my model, yet my hysteretic curve does not display degradation. Is it a must to include link elements for degradation to be modeled?

[seismosoft]

You might want to activate performance criteria of code-based checks with residual strength upon reach of the criteria. Refer to the manual for Code based Checks and Performance Criteria for more details.The particular setting is the Strength Degradation Parameters, where you need to choose 'No Residual Strength' or Residual Strength equal to say 20%, instead of 'Keep Strength'.
Seismosoft Support