Structural question on dynamic load analysis 1

[faisal45]

Dear All,
Do you think flat plate design is alright for dynamic load analysis?
explain your thoughts.

Thank you.

Regards

Engr. Faisal

 

[PicoStruc]

Yes. Use adequate shear walls and design the slab as diaphragm.

 

[hetgen]

faisal45 What do you mean when you say "alright"?

 

[faisal45]

Dear Hetgen,
alright means okay. . .
and my question was "Do you think flat plate design is okay for dynamic load analysis? is there any problem?
explain your thoughts.

 

[bookowski]

Faisal - I don't think your question is clear. Are you asking if flat slabs are ok in general for high wind/seismic loading? Or are you asking something about the analysis - i.e. how to model flat slabs for dynamic analysis etc. It's not clear what you are looking for.

 

[faisal45]

bookowski - my question is whether flat plate is ok in general for high wind/ seismic loading? and i also want to know is there any problem of doing flat plate in case of dynamic load?

Thank you.

 

[bookowski]

Yes, generally speaking flat plate is fine for high seismic regions. You need to follow all detailing requirements for your seismic zone or SDC etc. for your code - other than that no problem. There are tons of flat plate buildings in high seismic regions such as san francisco, some of them very large/tall. Same goes for wind, tons of tall flat plate buildings - probably 1/2 of NYC. Your shear walls will be taking lateral load - depending on your seismic region and local code you may have to design all the slabs for deformation compatibility under the lateral loads for punching shear etc., that depends on your location though.

Not sure what you mean by a problem with doing dynamic analysis. If you mean modeling I would say the only thing off the top of my head is that you should not be modeling the full slab in your dynamic model. Or if you are including it you need to reduce the stiffness significantly. A lot of people replace the slab in a lateral model with equivalent frames using an effective width and appropriate cracking stiffness reductions.

 

[asixth]

Slabs are used as diaphragms to transfer lateral force to lateral resisting elements like cores. Likewise they are also used to transfer lateral forces due to staggered or offset shear walls. The diaphram does need to be designed for this in-plane behaviour. Normally concrete shear strength alone is sufficent but sometimes reo needs to be used.

I think you should be more specific with your questions rather than asking what people think of a broad topic.