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Floor vibration

Khawaldah
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Hi,

I'm studying the floor vibrations on a model that consisting of three floor A, B and C, despite floor A and C are symmetric, they show different ultimate acceleration because STAAD considers one of the girders only for calculating the results of combined-mode, how can I select which girder to be considered in the calculation of combined mode or how can I view all the possible results. Kindly find the attached model for more information.
I have huge number of load cases, can I get a floor vibration report of all cases without check them one by one.

Regards,

DAR08118-R0-2.std

  • 0 Offline
    The floor vibration report can only be obtained one load case at a time. Regarding the difference in peak acceleration between the panels, I see that the joist spans are not identical for the two decks. However it is little surprising how the equivalent panel weight for the combined mode is coming out so different for the two decks. I have to look into it in more detail and will revert back.

    An unrelated observation. You do not need to do a DIRECT ANALYSIS as far as floor vibration is concerned. You could simply use a PERFORM ANALYSIS for the vibration cases.



  • 0 Offline in reply to Sye

    Thank you so much for your help, Unfortunately there are only a limited threads addressing  the Composite Deck issue.

    I changed the model to be symmetric, you can find it in the attachment. The Direct Analysis has nothing to do with Composite Deck , I'm using it instead of the effective length method.

    I noticed that STAAD chooses one of the Girders and one joist only to account for the combined mode regardless of which case it may be more critical for the composite deck, Do agree with me.

    Regards,

    2703.DAR08118-R0-2.std

  • 0 Offline in reply to Khawaldah
    I think this has been answered now in another post but just for the records, the difference in results between the deck A and C is stemming from the fact that the software calculates the results for the combined mode considering the first beam/joist and the first girder only. This is going to be changed in the next release.

    A more detailed discussion on this topic is available at
    communities.bentley.com/.../396419



    Answer Verified By: Khawaldah 

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