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!

*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.

Jobs

AREMA DPG Bridge Cross Frame Design for Derailment Load

AREMA DPG Bridge Cross Frame Design for Derailment Load

(OP)
I'm designing a new 64' DPG bridge for Cooper E80 load and sizing the "X" configuration cross frame diagonals (at 60 degrees with the vertical) with top and bottom horizontal braces (cross frames at 8' spacing with 8' c/c girders) and the derailment loads (AREMA MRE Article 15-1.3.10) I'm getting are in the order 200 kips, which still allows me to use 2-L6x4x1/2 for the top horizontal brace (with the 150% allowable overstress), but when checking the end connections and gusset plates, I required approximately 9 bolts in double shear when using the 17 ksi allowable shear stress for bolts (slip-critical). This seems quite high...when most sample bridges I've seen only have 3 or 4 bolts at each end.

This requiring appears to have been added to the manual in 2005 and I'm wondering if designers are actually designing the cross frames for the derailment load? If so, do these loads appear to make sense and does anyone have any guidance on designing the cross frames for this load. Is using the slip-critical allowable stress the correct approach given that this is an "exceptional" load case?

Thanks in advance for any assistance!

Pat

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


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close