Composite floor design in Staad Pro. SS4

Dear Sirs,

Please advise for the below issue As soon as possible :

I have a composite floor for design contains from main beams to columns ( moment connection ), & secondary beams connected to the main beams ( simply connected ) , now I have doubt for which beams I need to define the composite section in Staad pro ?? is it for secondary beams , main beams or Both ??

if the composite section need to be defined for both , what is the consideration regarding the concrete width of the main beam, as the secondary beams transfer the load to the main beam so the effective width can be defined for the secondary beams but the main beam effective width still my doubt >!

Which code supported the composite floor design in STAAD Pro SS4

Looking for positive reply ASAP.

Regards,

  • It depends on which beams have the composite action. Composite in the STAAD terminology means an I-shaped steel beam over which there is a metal deck and a concrete slab on the deck. You can find a sketch of this in section 2.4.2.9 of the Technical reference manual which is reproduced below.

    If the arrangement for your structure enables composite action to be developed for secondary as well as main beams, and if the primary steel section for both these is I-shaped, you can assign the property type as Composite for both. The width of the slab that is to be used in the property calculation should be specified during the property assignment phase by you since the program does not calculate it on its own.

    In the editor, it will look like this:

    UNIT KIPS INCH

    MEMBER PROPERTIES

    57 TA CM W14X34 CT 5.0 FC 3.0

    The design of these sections is available only through 2 codes in STAAD - AISC ASD 9th edition, and AISC LRFD third edition. The principles used in the design for these codes is explained in sections 2.4.1.7 and 2.4.2.9 of the Technical Reference manual. For the AISD ASD code alone, there is a parameter named WIDTH that can be used to specify the slab width again (for the design phase alone) in case it is different from the value used during the analysis.



    Answer Verified By: SAMEER ALSADI 

  • Thanks for your reply, I have defined the below floor as a composite deck one way action for the secondary beams. does the STAAD will consider the composite action of the main beams ?  

    at the end of the floor I got problem in the slab which is between column numbers (32,33 & 36,35 ) I cant defined the effective width of the slab hence the shape of the slab is irregular .

    Please advice .

  • From the figure you have attached, it looks like you are using the composite deck facility of the Geometry page. The diagram indicates that a composite section is assigned only to members such as 98, 99, 100. Members such as 6, 78, 79 are most likely just receiving a pure steel section (non-composite). We have to take a look at your model to confirm.

    In case the slab is irregular, you can bypass the Composite deck facility and instead manually assign the properties as a composite section from the General properties page. See the figure below.



    Answer Verified By: SAMEER ALSADI 

  • Hi,
    Is it possible to use I shape concrete beam in place of steel beam for composite deck.../

    plz help me ASAP.../
  • You cannot use the composite deck feature in STAAD.Pro to model concrete beams. Composite deck is only formed with steel beam and concrete deck.

    However you can define an I shaped concrete beam as shown next. The deck may be modeled separately using a plate mesh.