×
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

3' wide double tee capacity

3' wide double tee capacity

3' wide double tee capacity

(OP)
WDM (Structural) Sep 18, 2003
I am inspecting an old road bridge made from (6) 36" wide double tees.  The double tees are 19" overall depth, 5" flange thickness, webs at 24" on center, with (2) 0.5" strands in the bottom of the webs.  The bridge was abandoned and moved to a residence for crossing a small stream.  The original span (28')has been halved by adding a steel support beam at mid-span.  The local fire department has asked for a letter from a structural engineer stating the bridge is safe for a fire truck to cross.  This is a very infrequent load, hopefully.

Does anyone know where I can get load tables for this old section?

I plan to use H20 loading.

Thanks in advance.

RE: 3' wide double tee capacity

Sounds interesting.

I assume you know there are two strands based on the original shop drawings?  Or is that from looking at the ends of the double tees?

Without shop drawings it is difficult to determine the capacity since the strands could be draped or straight, they may be stress-relieved strands(older style of strand) instead of low-relaxation strands, you also wouldn't know the jacking stress of the strands which determines if the double tees would crack under service loads.

Another thing which is concerning is that there has now been an additional support added at the midspan.  It is likely difficult to get three point bearing unless you're very careful about the detail.  Not only that, the double tee would now act as a continuous member, which could lead to cracking at the top due to moment at midspan and the strand eccentricity at the support.

Sorry, that's not a lot of help but maybe consider trying to find out the original manufacturer of the double tees and see if they could give you guidance on the design..

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