How can I find the location of plastic hinge?

[akash datta]

I am working on a three story RC frame with masonry infill. In case of pushover analysis, l want to find the location of plastic hinge on the frame & in Base shear vs. Deformation graph. How can I find it? Please, suggest me.

[seismosoft]

In the distributed plasticity model that is followed by SeismoStruct's frame elements, plasticity is concentrated in the element's integration sections. Refer to the material inelasticty section of the help system for a better understanding of the subject and the exact location of the integration sections.

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[Ana Santos]

Hi everyone,

I am doing a pushover analysis, and I what to know the location of the plastic hinges after the analysis... I can do it by adding a steelstrain performance criteria? When the section reach that criteria its means that a plastic hinge is formed?

Thank you,
Ana Francisca Santos

[ruipinho]

Ana,

Yes, of course. Indeed, plastic hinges form when the longitudinal rebars yield, hence a performance criterion on rebard yielding will naturally inform you of the location of plastic hinges.

Rui

[Ana Santos]

Rui,

Thank you very much for the confirmation

Ana

[Ana Santos]

Hi,

If I want to know if the plastic hinges are forming in the connections, how can I do it ?

[huffte]

Hysteretic plots of moment versus rotation available in the post-processor for link-type elements and for inelastic fiber elements provide an excellent, visual means of determining whether or not hinges have formed at a particular location. You might also be able to add performance criteria to alert you whenever the yield curvature has been reached for the various elements if you estimate such yield curvature appropriately. Best of luck.

[Ana Santos]

Hi,

thank you very much... I applied the performance criteria for the columns but for the connections how can I see it? the connections have a plastic behaviour, so if the hysterics curves achieve the moment resistance of the connections I can admit that it yields?

[huffte]

I assume you have link-type elements for the connections. The connection force-displacement (or moment-rotation) hysteresis will be a straight line if the link did not yield. It will show hysteretic-type 'box-shaped' plot if it yielded.

[fakharifar_mostafa]

In addition to Huffte's comment, I wanted to mention that you can also take advantage of the "section curvature" performance criteria. First one should have a good understanding of the model, as where the maximum demand regions exist that causes severe damage in the so-called plastic hinge (PH). Plastic hinges experience large inelastic curvatures, and they are typically assumed constant over the PH (then curvatures are integrated to find the member's tip displacement). Thus, you can find the variation of the curvature along your member length, and the regions with maximum section curvature are likely to form PHs. However, PHs depend on various parameters such as level of axial load, transverse reinforcement and shear span to depth ratio, which you can find the relevant information in the literature. Thus, the definition for your plastic hinge for your frame, if it is a building, is different for the base column compared to roof column! First you need to get an understanding of your frame prior to just assuming a PH is formed just by seeing steel yielding. I refer you to the below paper.And recommend taking advantage of Performance Criteria tab in SStruct carefully. Good luck on your work.

Bae, S., & Bayrak, O. (2008). Plastic hinge length of reinforced concrete columns. ACI Structural Journal, 105(3).