×
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

Moment Connection

Moment Connection

Moment Connection

(OP)
How does a moment connection differ from a fixed connection for a cantilever beam, and how does the calculations differ when analyzing the bending moment?

RE: Moment Connection

Well, this is an issue of structural analysis tha upon ordered study you won't have important doubt about. A cantilever is statically determined and the evaluation takes less, and can be made easily by hand. Fixity moments in inner members use to need a somewhat more complicated evaluation, yet in any case the methods to evaluate moments are well exposed in the texts.

RE: Moment Connection

A fixed connection is a SUPPORT, in which you attach a member to the earth, with no degrees of freedom.  The  moment connection, on the other hand fixes two members together, such that no movement is possible relative to the other member.  Different softwares allow you to create supports or moment connections in which you can limit which degrees of freedom are fixed, and to what extent.

For a cantilever situation, so long as there is no stability problem in the member to which it is connected, a cantilever that is analysed as a fixed member versus one that is moment connected should be identical, since the stiffness of the member to which it connects has no impact on load distributions to the cantilever.

RE: Moment Connection

Here's my 2 pennies worth.
A cantilevered beam can be a through-beam cantilever or an over-beam cantilever.  Both types of connections are designed to transfer 100% of the cantilevered stress back to the backspan beam, without adding a moment to the supporting member.  The supporting member should only see the shear reaction.
A moment connection is a connection that is typically designed to transfer the rotational force between perpendicular members.  
From a desgin standpoint, I would typically design a cantilevered beam connection to withstand the full moment capacity of the cantilevered element.  For a moment connection of beam to column, then I design for varying levels of performance.  
I am in a moderate seismic zone, and due to costs, do not want to reinforce my columns with web stiffner plates.  I would therefore design the connection for 200% of the calculated load, and size the members accordingly.  In regions of high seismicity, the connection is typically designed for the full capacity of the weaker member (beam)
HTH

RE: Moment Connection

I have a question regarding to a beam-girder connection.
Assume a rc beam supported by a rc girder, should the end of beam be fix or pin support?  and why??  I know that if the beam end is a fix support the moment will be less than the pin support but the girder have to consider torsinal moment from the beam...Any comment would be appreciate.

RE: Moment Connection

For RC you model the connection with NO releases. The software for analysis will deliver what torsion is induced in the supporting beam, and how much bending moment is then relieved of the supported beam.

Of course you can also put a pin at the end and the supported beam and it may still function within ordinary ways of construction but it will be less truer to the expected behaviour.

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