Shear area SAP2000 vs ETABS

[pxsm]

The shear area in 3 direction of an I section is different in SAP2000 and ETABS as shown in the image. Can someone please explain me how the shear area is calculated in SAP2000 and ETABS? I read the manuals but I couldn't find any difference. Thanks in advance

 

[centondollar]

Considering the difference (33.129 vs 29.1667), one program might include more of the flange (and possibly the corner rounding in a rolled section/weld in a built-up girder) than the other program.

If you do not find the answer in the software company theory manuals, an email to their customer support should do the trick.

 

[JoshPlumSE]

What versions of the program are you running? I can check with the latest version of each and let you know what they say.

It is possible that the programs could not be in sync with each other, especially if one of them is a few years older than the other.

 

[IDS]

I have not used SAP2000 or ETABS, but I have checked the section properties for the given shape (with no corner fillets, as defined) using Strand7 and Robbie van Leeuwen’s SectionProperties program (with my Excel front end) and I find that:
- All 4 programs agree exactly on the Area, Ixx and Iyy
- Strand7 and SectionProperties agree within 0.2% on the shear areas, with A_s11 = 2750.5 mm2 and A_s22 = 1810.4 mm2, which are significantly less than the SAP2000 or ETABS results.

SectionProperties input and output:

Doug Jenkins
Interactive Design Services

http://newtonexcelbach.wordpress.com/

 

[Settingsun]

The 29.167 cm2 answer is 5/6 times the total flange area, being the number for a rectangle. Can't help with the other, maybe something to do with shear strength instead of stiffness?

 

[IDS]

The 29.167 cm2 answer is 5/6 times the total flange area, being the number for a rectangle. Can't help with the other, maybe something to do with shear strength instead of stiffness?

19.2 is the web area, but both that and the 5/6 flange area are rough approximations, whereas the SectionProperties and Strand7 values are based on an FEA of the actual cross section shape.

Doug Jenkins
Interactive Design Services

http://newtonexcelbach.wordpress.com/

 

[Settingsun]

Yeah, I meant the 33.129 number. But shear area is kind of academic mostly: either small so approximations are fine, or the member is short so you need to consider other factors.