area load confusion greenhouse 1

[CivilMEng]

hello evryone,i am trying to model a greenhouse stucture in sap2000 and i would like your help,
i have desingned the material for LowDencityPolyEtylaneas a membrane section area and assigned very low bending moments such as 1*10-5,
How do i apply area Wind Loads?I have meshed AREA and FRAME sections and on area i have selected Auto Area Constraints...
Do i assign uniform load OR uniform to frames on my area objects(Area Loads)?,
Thanks for your time in advance

 

[Luceid]

It depends what you want from your analysis

Uniform loads will only be delivered at the nodes of the areas I believe. Therefore you won't get any load distribution along the supporting frame's length, except at eh discrete mesh locations.

Uniform to frame loads area based on the local axes of the area element and can be assigned as one-way or two way distributing. These simulate the way that force is transferred to the supporting frames by calculating distributed/point loads along the member length. These take a little more finesse to work properly. I have only ever used these with unmeshed shells (the area is one quad connected to the four intersections of the supporting beams).

If you want to design the individual frames - you'll need to have a reasonable mesh size with uniform loads OR unmeshed areas with uniform to frame loads with the load distribution/axes set up properly.

If you're just doing global overturning/deflection analysis - you can probably do fine with unmeshed areas and uniform loads. Depends if you want to have the area stiffness involved or not

 

[CuriousBearcat]

CivilMEng: For wind loads, I also recommend using: [tt]Define -> Wind Loads -> Cp coefficient -> Ener value and select "Two Way Distribution" [/tt]

-Just a curious engineer

 

[CivilMEng]

I want nylon film to participate in the stuctural model,
Question No1... Do i have to mesh my area objects at e.a.10X10,i have meshed it automaticly in intersecting frames.
Question No.2... I have read this in CSI manual about area edge constraints,does that mean that constraining my area objects on edges does affect my structure?
Thanks for your help in advance

 

[CivilMEng]

by structure i mean my frame section elements,sorry about my english