Shear center for I section with base plate 1

[Techfrendz]

Hi,

How to estimate the position of shear center for an sym I beam with base plate welded to the bottom of flange?

Regards,
Mukund.

 

[KootK]

I recommend posting a sketch of your situation. That will improve the quality of responses that you get here. I'll assume that we're discussing a wide flange beam with a bottom flange reinforcing plate installed symmetrically about the flange. In that case:

1) the shear center will lie along an axis aligned with the web and centred on it.

2) to find the location of the shear centre along an axis running through the web, find the combined centroid of the flanges and the bottom plate but, in the calculation, replace the areas of the elements with their moments of inertia about and axis aligned with the web. This will be an approximate value.

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.

 

[Techfrendz]

Hi,

Thanks very much for your response.
I here with attached the image for your reference.
For RHS with bottom plate, is there any way to identify the shear center or is it be advisable to ignore the bottom plate?

Thanks
Mugundan.

 

[CELinOttawa]

Unless you're doing a lot of thiz just ignore the contribution, while detailing to sustain the torsion effects.

 

[KootK]

I agree with CEL. For the CHS section, it is certainly possible to figure out the shear center. It just may not be a profitable endeavor unless your doing them en mass.

To work out the exact-ish shear centre for the CHS, you'd need to resort to fundamental mechanics of materials stuff. Something like:

1) Apply a dummy transverse load.

2) Work out your shear forces and shear flows.

3) Calculate the cross section torsion due to the shear flows.

4) Divide the section torsion by the applied transverse load to find the point at which torsion would be balanced (the shear centre).

With the CHS, the response ought to be dominated by the closed cell shear flow loop through the CHS. As such, an approximate method to find the shear centre would probably just be to ignore the plate altogether. Or at least the outstanding leg of the plate.

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.

 

[Techfrendz]

Thanks for your valuable responses.