unsupported length 1

[allimuthug]

Hi ,

Can any one let me know the unsupported length of top beam and LY of the transverse beam .
For some it may look simple but i have some confusion regarding that . Please see the attachment .

[link or some it may look simple but i have some confusion regarding that . Please see the attachment . ]Link[/url]

 

[allimuthug]

http://files.engineering.com/getfil...e3-4c99-828f-b932b20be4b0&file=pipe_rack.xlsx

 

[allimuthug]

http://files.engineering.com/getfil...c8e-452d-9770-c5ecca315ea2&file=Pipe_rack.png

 

[allimuthug]

HI
I want to know the Unsupported length of top flange and the Ly of main transverse beam .
Please see the attachment for clear understanding ,

 

[delagina]

3.5m.. the horizontal bracing will prevent lateral torsional buckling of the compression flange..

 

[delagina]

also LY = UNT and UNB.. UNT and UNB for bending capacity.. LY and LZ for axial capacity..

 

[allimuthug]

I am asking the UNT of extreme transverse beam , The mid longitudinal beam is connected to transverse beam by shear connection.
In this case the top flange is is not connected so how top flange is restrained , hence i am confused.

 

[KootK]

It is very common to assume that typical shear connections are able to brace beams against rotation even when no connection is made to the flanges. If the shear connection engages a substantial portion of the web depth and the beam tying in isn't excessively flexible, it will work just fine. Remember, the goal is not to brace the compression flange. The goal is to prevent rotation of the beam being braced. Compression flange restraint just happens to be an effective way to prevent beam rotation in a number of common scenarios.

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.

 

[delagina]

@kootk, if there were no horizontal brace, can we still assume beams as restrained in the middle?

Also in the case of a very long trolley beam, if the top flange of I trolley beam is supported by the bottom flange of supporting beams, can trolley beam be assumed restrained at support. I assume it restrained at support because trolley beam size becomes ridiculously large if I don't.

 

[KootK]

if there were no horizontal brace, can we still assume beams as restrained in the middle?

I vote no for weak axis compression buckling but yes for lateral torsional buckling.

if the top flange of I trolley beam is supported by the bottom flange of supporting beams, can trolley beam be assumed restrained at support. I assume it restrained at support because trolley beam size becomes ridiculously large if I don't.

I assume so too. I guess that it would depend on the specific connection detail though. Can you have at least partial height stiffeners in the trolley beams at the supports without interfering with the trolley? Having the load applied at an elevation lower than the support is favorable although not necessarily sufficient.

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.