×
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

Mansard Beam Design

Mansard Beam Design

Mansard Beam Design

(OP)
I am designing aluminum screen enclosures in Florida. The aluminum members are thin walled, self mating sections (two C channels that overlap to form a hollow box. THe most common roof shape is a mansard beam. The beam is connected to the host structure at one end and an aluminum post at the other end.

The Florida Bulding Code is requiring simultaneous loading of the roof and wall for design.

For simplicity, I've taken the wall load reaction(wL/2) and applied this force at the end of the mansard beam and designed the beam as simply supported.

If I apply the horizontal force to the end of my beam, I create a moment caused by the eccentricity of the force to the center of the beam. This moment of course reduces the capacity of the beam to handle the vertical load and the allowable spans are reduced.

My question is: Is there another acceptable method of design that would not be so conservative without doing a frame analysis? (There are too many variables and we do thousands of enclosures per year). It appears that other engineers are simply accounting for the horizontal load as an axial load without the eccentricity. This makes a big difference. Am I missing something?

Any suggestions for design alternatives would be appreciated.

RE: Mansard Beam Design

"The beam is connected to the host structure...."  is this the mansard beam of the previous sentence?

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