Pushover Analisys

Hello,

This is my 3rd thread and seems that no one from Bently staff seems to bother to give me a reply. I am still writing to try my luck once more.

I am applying a pushover analysis on a steel structure. But I am stuck at the application of hinge properties. Apparently FEMA has a default linear Moment-rotation curve, hence I want to add a new curve. But I do not know how to define the Yield Moment and Yield Rotation. Also when it comes to apply the hinge properties for braces how do I do it because braces need another type of hinge but StaadPro appears to have only Moment-Rotation type of hinge.

Can anyone help (is Benltly Forum still operating?)

Parents
  • In section 4.5.2 of the Pushover Analysis documentation, you can find the description and an example for the input that needs to be specified for a user-defined moment hinge.

    If you have a data set you wish to specify and if you can upload it to this thread, we can provide you with a sample model containing that data.

    For braces, we assume you are looking for an axial hinge. Such a hinge is not available in STAAD at present.

    We were not able to find any other post created by you on the BE Communities forum on this topic. If you can provide us the link to those, we will look into those.



  • Hello Sith,

    No problem, the other threads have been about different topics which are not relevant now.

    About this question i changed my mind and I am going to use a FEMA hinge because my structure is quite complex and I don't want to calculate the properties for each member/ group of members.
    My question then is: since I am doing the pushover analysis for a blast design force, do the Seismic Parameters in the pushover DEFINITION affect my design? Or, is there any parameter that i have to modify to adapt the pushiver to a blast type of loading (e.g. i think a Load Distibution using Method 3 is more relevant)?

    Another question about steel design:
    I am doing a deflection design check (dff). My structure members are splitted in smaller elements but i have specified JD1 and JD2 for every member. But still when I get the results from the File-Reports it gives me design results for all the small members. How can i get the results for the members i have specified using jd1 and jd2? And, how can I get these results graphically?

    I would really appreciate your help.

    Many Thanks
  • This Wiki post should answer your question: http://communities.bentley.com/products/structural/structural_analysis___design/w/structural_analysis_and_design__wiki/16165.limiting-section-assignment-or-member-selection-to-specific-cross-sections

    In addition, I would suggest you to create a new Forum thread if your new question or issue is not related to the original question of the forum thread.



  • Thank you very much Modestas, this was really helpful.

    And, sorry I will open a new thread next time.

    Regards,

    Skerdi
  • Hello Kris,

    I had a problem with the pushover analysis. When I tried to add/create another steel material with different E value and yield strength the analysis gave an error stating that pushover can be done only for STEEL.

    Also, when I tried to change the E value of the default steel material from 205GPa to 210 GPa the results of the pushover were erroneous.

    Does the pushover analysis allow you to modify/create a new steel material?

    Thanks
  • Pushover analysis in STAAD.Pro is limited to steel structures only. So you cannot have a material by a different name. You should however be able to modify the value of E for STEEL and the analysis should work. I have attached an example file with E value of approx. 210 GPa used for steel. 

    ExampPush01.std



  • Hello Sye,

    I just ran the example and it gave me the same answer as for my model. It appears as the structure stays elastic all the time, if you check the capacity curve is a straight line.

    Even if I increase the pushover steps/base shear/displacement the capacity curve remains straight. Whilst, as soon as I change the E (elastic modulus) back to original the analysis gives a realistic curve with a plastic region.

    I also increased the displacement limit for your example and still get the same result: the capacity curve remains straight.
Reply
  • Hello Sye,

    I just ran the example and it gave me the same answer as for my model. It appears as the structure stays elastic all the time, if you check the capacity curve is a straight line.

    Even if I increase the pushover steps/base shear/displacement the capacity curve remains straight. Whilst, as soon as I change the E (elastic modulus) back to original the analysis gives a realistic curve with a plastic region.

    I also increased the displacement limit for your example and still get the same result: the capacity curve remains straight.
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