cold formed portal frame SAP200

[Islem]

Dear all;

i am designing a cold formed portal frame warehouse Using SAP2000 , almost of members are safe but the rest are Overstressed knowing that i am using the same Sections and the same loads as shown in the picture in attached.
Please can anyone from you give me a solution to solve this issue ,i'd like to get some from your large experience

Best regards.



islem

 

[KootK]

The picture that you mentioned didn't make it into your post. Can you make another attempt at sharing that with us? Sometimes the system here doesn't like spaces in file names. You might try eliminating the spaces from the file name of whatever you're trying to post.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[Islem]

Hi the picture has been uploaded successfully you can check now.

thanks



islem

 

[KootK]

You'll need to provide much more information in order to get a meaningful response here. What are the nature of the loads generating failure? What kind of cold formed cross section is being used? What is the nature of the failure being generated in the member? What member bracing assumptions have been made?

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[DaveAtkins]

It appears that the roof purlins and wall girts are acceptable, but the frames are overstressed. The frames should be hot rolled steel, unless I am misunderstanding something.

DaveAtkins

 

[Islem]

the loads generating failure are wind and snow and the vertical loads of roof and the own weight of structure,the section that i opted for my portal is C250x65x20 2,5mm of thickness ,concerning the nature of failure it's buckling but why just in one side my columns aren't safe
about the last question please are you meaning the section of my bracing members it's a C section 100x50x15 2mm of Thickness ?

thank you


islem

 

[DaveAtkins]

Columns are failing on the leeward side of the building, I assume, because they are experiencing additional compression due to wind overturning the portal.

I would not build a portal frame out of cold formed steel members, I would use hot rolled steel.

DaveAtkins

 

[Islem]

i think that i didn't distribute well the loads in frames i:e some loads are smaller then others in the wind for exemple ,but note that the snow loads are 0,34Kpa so it's very heavy for such cold formed portal with very important Pitch as well.
@DaveAtkins we are trying to improve and use cold formed portals the Most possible because is the futur of industrial buildings (light, fast and less expensive)



islem

 

[XR250]

we are trying to improve and use cold formed portals the Most possible because is the futur of industrial buildings (light, fast and less expensive)

I would be very careful designing one of these unless you are an EXPERT in light gage design and you have a testing program. I have seen a few firms around here try to design similar buildings and had the pleasure of reviewing their calculations and they were a disaster and they were using tube sections. Using Cee sections is alot more complicated.

As a former light gage designer, I'm with Dave Atkins on this - use red iron

 

[Islem]

Note that the spa is not very important concerning rafters,for columns are 4 metres so i don't see the obligation of using Hot rolled shape for this.
we have already designed and executed a portal of 26 m using cold formed steel shapes for trusses and Hot rolled for column because of its important hight 09 meters.


islem