Layered shell for 2d fem model of RC beam/column

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Asad005
Posts: 29
Joined: Sat Dec 07, 2019 6:50 am
Location: Italy

Layered shell for 2d fem model of RC beam/column

Post by Asad005 » Mon Aug 17, 2020 10:17 am

I am using layered shell element in STKO for 2d model of the beam/column and I have a beam of 300X300 mm then how to add the area of the Longi. steel and stirrups in the shell along with concrete section?

I added the equivalent area of L.Steel by diving area of one bar by the spacing (for bottom/top) along the width of the beam.
THen how the area (to be divided by the length of the beam) of the stirrups will be added from the below options?

1. We will consider x-area of one bar of stirrups or we have to multiply it with two number (as per the two vertical legs)
2. or we have to multiply x-area of the stirrup bar with 4 (2 vertical and 2 horizontal sides of stirrups)?
3. Or we have to add the area of the vertical portion (by adding 90-degree bar) of stirrups separately and the horizontal portion (0-degree bars in) separately?
4. If I use 90-degree bar for vertical legs (along z-axis) of stirrups and 0 degree bar for long. bars (laid along x-axis). How to add the area of the portion of stirrups laid along the y-axis (out of plane in this case)?
Attachments
Lshell.png
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STKO Team
Posts: 279
Joined: Tue Oct 29, 2019 8:45 am

Re: Layered shell for 2d fem model of RC beam/column

Post by STKO Team » Mon Aug 17, 2020 12:59 pm

Since you are doing and equivalent 2D model, you just need to add 1 layer of steel, whose equivalent thickness is:
phi/S*N
where:
phi = area of the rebar
S = spacing between the rebars
N = number of same rebars in the thickness direction

Asad005
Posts: 29
Joined: Sat Dec 07, 2019 6:50 am
Location: Italy

Re: Layered shell for 2d fem model of RC beam/column

Post by Asad005 » Mon Aug 17, 2020 3:58 pm

Thanks for the response.
I already added the longitudinal steel in the layered shell by in terms of equivalent area = area of one longitudinal bar divided by its spacing along with the thickness (width of the beam).
But the issue is:
1. what will be the difference b/w section without and with shear reinforcement (stirrups)? Will the layered shell of both will be the same?
2. If the section/layered shell will not the same for both then how to consider the number of stirrups in the layered shell to differentiate the section with stirrups from that of having no stirrups (like the joint core of non-seismic designed RC beam-column joints as shown in the attached screenshot of beam-column joint assembly)?
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joint.png
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Clarabella
Posts: 30
Joined: Wed Jul 08, 2020 3:50 pm

Re: Layered shell for 2d fem model of RC beam/column

Post by Clarabella » Tue Aug 18, 2020 7:29 am

Dear Asad,

Thank you for contacting us. You should discuss with your advisor about this, it is a RC question not related to our program.

Best regards

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