×
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

End Length Offsets vs Insertion Points

End Length Offsets vs Insertion Points

End Length Offsets vs Insertion Points

(OP)
Hi all,

has anyone got a reasonable explanation of the difference between the frame end length offsets and insertions points in ETABS?

I have to model a simply supported beam resting on a corbel at the column face, this eccentricity will generate an additional moment on the column centroid, which function is better in this case?

I have used both and found that there is a moment being generated at the column centroid when I use End Length Offsets but the results are not balancing out and not comparing with a manual analysis.

RE: End Length Offsets vs Insertion Points

Hi there,

In this case, end length offsets is used to get the real lenght of a beam taking into account the dimension of the column. EX: Real lenght =span-0.5*Dcol#1-0.5*Dcol#2. I think Etabs do it automatically.

Insertion points move the element around his axis, but I never really took the time to try it.

Maybe you can try to model the corbel as a small cantilever beam?

Best of luck,

Ben

RE: End Length Offsets vs Insertion Points

If you think of a frame element with x along its longitudinal axis and then Y and Z perpendicular to the frame member's longitudinal axis:
-End length offsets affects placement in x axis
-Insertion point affects placement in y and z axis

You would be looking for end length offsets for a corbel condition. As for moments not balancing out or meshing with your hand checks, check to see if you have any forces leaking into your slab (assuming you have one modeled). It may be helping you when you don't intend it to. Also your moments may not balance out if you have different spans and/or loadings on the different sides of the column. Really shouldn't cancel out even if you do because you should be looking at pattern live loadings. ETABS doesn't do pattern loading until the design phase for frame members.

RE: End Length Offsets vs Insertion Points

Be aware that if you click the "Transform stiffness" option, strange internal forces result may appear. For instance, high axial force values will be reported at beams under pure bending. You should check this especially if you perform an automatic frame design.

Jason McKee
proud R&D Manager of
Cross Section Analysis & Design
Software for the structural design of cross sections
Moment Curvature Analysis
Reifnorcement Design etc.

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