×
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

ACI-318-05 (Section 11.6.3a) û Torsional Moment Strength

ACI-318-05 (Section 11.6.3a) û Torsional Moment Strength

ACI-318-05 (Section 11.6.3a) û Torsional Moment Strength

(OP)
Hello Fellow Engineers!

Anybody can suggest solution and practical ideas if the stresses in Torsion + Shear exceed the limit by the Code stated above without increasing the section of the concrete beam?

Your comments and suggestions is really appreciated. Thanks guys....

RE: ACI-318-05 (Section 11.6.3a) û Torsional Moment Strength

Have you maxed out the reinforcing?

RE: ACI-318-05 (Section 11.6.3a) û Torsional Moment Strength

(OP)
Thanks JedClampett. Reinforcement is not an issue since i can still go with the requirements, but i am just worried about the capacity of my concrete because it exceeds as per code requirement.

RE: ACI-318-05 (Section 11.6.3a) û Torsional Moment Strength

You can add ties as required. What is the problem?

BA

RE: ACI-318-05 (Section 11.6.3a) û Torsional Moment Strength

Are you exceeding the limits set in ACI 318 Chapter 11.5.3?
Those limits are pretty high. I wouldn't exceed them.

RE: ACI-318-05 (Section 11.6.3a) û Torsional Moment Strength

Post tensioning is a way to solve the problem.

Moment curvature analysis,reinforced concrete column design and prestressed concrete pile design at www.structurexpress.com

RE: ACI-318-05 (Section 11.6.3a) û Torsional Moment Strength

(OP)
Yes JesClampett and that is the issue i need to solve without increasing the section of my beam (above Aci code is 2005 which u can find in Chapter 11.6.3, chapter 11.5.3 in Aci 2008 as you mentioned). Thanks jsha811 but Prestress is not allowed as an alternative due to un availability of such system in the area and beam section limitations.

Here's the forces for your checking:
Beam section/dimension is limmited to b=400mm H=700mm
Mu = 795kN.m
Vu = 460kN
Tu = 180kn.m
Fc' = 40MPa
Fy = 460MPa
Fyt = 420Mpa

RE: ACI-318-05 (Section 11.6.3a) û Torsional Moment Strength

I'm kind of flailing, but can you go to a higher strength concrete?

RE: ACI-318-05 (Section 11.6.3a) û Torsional Moment Strength

Not sure if this is even possible but maybe encased steel tube?

EIT
www.HowToEngineer.com

RE: ACI-318-05 (Section 11.6.3a) û Torsional Moment Strength

This isn't coming from compatibility, correct?

RE: ACI-318-05 (Section 11.6.3a) û Torsional Moment Strength

Can you re-frame your floor to eliminate the torsion? I try to avoid torsion whenever possible. I like to keep things simple. Why do you have torsion in the beam?

RE: ACI-318-05 (Section 11.6.3a) û Torsional Moment Strength

(OP)
JedClampett: i tried to increased the concrete to higher strength same as the columns (fc,=50MPa) but still failure occured. So it means that Aci 318 Chapter 11.5.3 shall be satisfied only by increasing the section, am i correct?

Thanks Cliff234, i'll try to reframe the structure in a way to reduced the stresses.

RE: ACI-318-05 (Section 11.6.3a) û Torsional Moment Strength

eeedesign,
Please answer PUEngineer's question. He (and I) are suspicious as to what kind of torsion you have. If you would describe the structure or show us a plan of the structural element in question, we could assist further.

RE: ACI-318-05 (Section 11.6.3a) û Torsional Moment Strength

(OP)
Hi PUEngineers: Yes, it is a compatibility torsion.

RE: ACI-318-05 (Section 11.6.3a) û Torsional Moment Strength

(OP)
hokie66,

Since it is compatibility torsion, i changed the torsional modifier (J) to 0.01 and got a smaller torsion effect. Am I going ryt for the solution? please advise. Thanks

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!


Resources