Composite Deck

please let me ask in different way, because I need a good understanding for this issue.

1- What would be the difference if I assign the small concrete density (for example 0.001) in the composite deck properties and Include the deck weight in the load cases (so I can consider the rip weight precisely )? is that has to do with the result of floor vibration.

2- the concrete above the flute is the concrete slab only without rips, Right ?

3- the thickness of the concrete slab above the flute, width of slab and steel section determine the stiffness of the composite member. I can neglect the portion of concrete within the rib if I it runs perpendicular to the joist form the stiffness point of view but what about the rip weight ?

4- what if the rip runs perpendicular to the joist, how to include the stiffness of rip portion?

Regards,

Since you are manipulating the deck parameters, these may get wiped out depending on what changes you are making to the model. What you can do is, keep a copy of the COMPOSITE and the CW command lines and once you are done making all the other changes, replace the current commands by the lines you copied earlier. Weight of the concrete above the flute is considered for selfweight calculation. The portion within the rib is ignored. You can manually apply the additional load.

Thank you, that works good but once I went back to the modeling and try to make some changes, the old data are restored, Is there any way to lock these changes.

another question:

I've Include the Dead load of composite deck  slab in the load cases and assign concrete density to be 0.001 in the composite deck properties to avoide duplication in deck weight. am I right ? I noticed that the result of floor vibration increased tremendously.

does the concrete thickness above flutes means the concrete slab excluding rip thickness ?

Does Staad pro neglect the weight of rips in the calculations in general and in floor vibration as special case. because I get different results.

how could that be defferent when the rips run in perpendicular or in paralell to the joist direction.

Maybe I made a mistake by assigning floor deck for the whole area and it would be  better if it is divided for three separated areas .

I've attached my model for clarification.

Regards,

4300.DAR08118-R0.std

Just as you can take out a beam from the list of composite members and take out the corresponding CW parameter to get the software to design it as a non-composite section, likewise you may add beams to the composite list and add corresponding CW parameters for those so that these are designed as composite beams. It has to be done following the same process as mentioned in my last post.

thank you that was helpful,
But I have another question, how can I assign both the girder and joist to be composite even they are orthogonal to each other ?