×
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

Missile Barrier/Fence

Missile Barrier/Fence

Missile Barrier/Fence

(OP)
Dear Eng-tips forum users,

I am currently asked to work on a 35ft (high) missile barrier/fence and about 34.5ft in width.

The prelim layout has called for 5 equally spaced posts (4 x 8.88’ spacing) and metal mesh with 52% of open area is proposed. The metal mesh would run from about 6 inches of the base to the top of the 35’ pole. Also, there are horizontal members that span between posts to transfer loads from the metal mesh to the pole.

There are a few issues that I have run into while working on this structure as followings:

- Wind load calculation:
+ Fundamental frequency: I tried ASCE 7-05 Eq. C6-22a (p 294) for a prelim HSS 8x6x0.25 section, but the result seems to be too low (= 0.126). Could anyone point me to any different formula/method so that I can double check the about number?

+ Damping ratio: What would be reasonable values to use?

- Ice load calculation: I used the ASCE 7-05 Eq. 10-2 (p100) with a multiplier of 0.8 for vertical plate and the ice volume seems to be high. The commentary of ASCE 7 does not say much about ice loading. Has anyone run into this equation and thought about it already? Please share with me.

- Deflection limit: Somehow a limit of h/50 with unfactored wind load pop-up in mind my, but I could not recall where I saw it. Could anyone help me?

- Consideration for slenderness: AISC user’s note recommends keeping the kl/r not to exceed 200 for compression member. In the past, I have ignored this suggestion when dealing with secondary/redundant bracing member in transmission/telecom towers. What would you say about the recommendation for fence/barrier structures?

I would appreciate very much for any comment/suggestion.

Sincerely,

Hdn32

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