×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

shear wall stiffness modifiers

shear wall stiffness modifiers

shear wall stiffness modifiers

(OP)
Hello,

I came across on how to adjust SM of shear walls,pls. see below;
"Typically I initially assign a 1.0 factor to f11, f22, and f12 along with a 0.01 factor to m11, m22, and m12 (so that the shearwall essentially has no out of plane stiffness and acts as a classical in-plane only resisting element). I then run the model and check axial stresses against the modulus of rupture to see if the assumption that the wall is uncracked (f11,f22,f12 = 1.0) was correct. For those portions of the wall that are cracked, I reassign with the lower 0.7 crack factor to f11,f22, and f12.”

My questions above are the following;
1. “I then run the model and check axial stresses against the modulus of rupture to see if the assumption that the wall is uncracked (f11,f22,f12 = 1.0) was correct. “
1.1 How will I do this in ETABS? How will I know if the wall is cracked or uncracked?
1.2 What values I will use in checking axial stresses(Load Cases or Load Combination)?
1.3 Where can I find the values for “modulus of rupture”?

RE: shear wall stiffness modifiers

1.1 check the moment at which the wall section cracks (for example when the Tensile Strength at the extreme tension fibre is exceeded).

1.2 usually whatever the gravity part of the seismic load case is for your code. For example in my local code it's G+0.3Q (plus lateral seismic load).

1.3 should be covered in whatever concrete code you are working to. Usually it's something like 0.5 sqrt(f'c) or similar (0.5 might vary depending on code)

The 0.7 factor you quote is often a fudge/average, and will in reality vary either depending on code, level of axial load and the reinforcement ratio.

RE: shear wall stiffness modifiers

Hi. The code I use has a modulus of rupture as 0.7*sqrt(f'c).

Now I have a shear wall modeled in ETABS, which has a f'c of 30 Mpa, so modulus of rupture = 3.83 Mpa.

To check if the shear wall is cracked/uncracked, what is the shell stress that i need to check in ETABS?

If I am right, it should be S22? If the shell stresses in S22 crosses 3.83 Mpa, the shear wall section is cracked.

Please correct me if am wrong.

RE: shear wall stiffness modifiers

AbhiCrux, yes you're correct. You may need to refine your mesh to increase the accuracy of where you deem the wall to be cracked.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


Resources

White Paper - Smart Manufacturing for Semiconductor
New technologies and approaches present great opportunities for semiconductor manufacturers to achieve high levels of innovation, yield and improvement. This white paper explores some of these cutting-edge technologies and how they can be applied effectively in the semiconductor industry. Read about how Smart Manufacturing is transforming the semiconductor industry. Download Now
White Paper - Analysis and Simulation in Aircraft Structure Certification
Organizations using simulation and analysis tools effectively see the benefits in their ability to achieve certification faster and with drastically less total cost than those who do not maximize these tools. Read this White Paper to learn about how digital tools such as analysis and simulation help in aircraft structure certification. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close