×
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

E80 cooper loading

E80 cooper loading

E80 cooper loading

(OP)
Trying to design the thickness of a liner inside a 12inch cast iron. 8ft cover from tracks to water main. In the contract it states that it is to be designed to E80 cooper loading, use 2600lbs/ft. What does this mean 2600lbs/ft mean? 2 tracks of total 34ft in width based on the blue prints. When I use the table, it gives me 11.11 psi for depth of 8ft using E80, but how does this clause that states 2600lbs/ft change this number. Thank you

RE: E80 cooper loading

I think "Cooper E80" loading stems from description in the old American Railway Engineering Association (A.R.E.A) manual of practice. While I guess the assumptions may have been changed from subsequent editions or local codes/practice, I believe this procedure traditionally used Newmark's integration of the Boussinesq formula (unlike the Holl's integration used in some other truck/live loading procedures for buried pipe). This procedure assumed that the surface loading is uniformly applied (I guess in effect by the tie mat below the rails) on a surface loading rectangle with dimensions 20 x 8 feet (with the 8 feet of course being assumed effective length of ties etc., and I believe the 20 being an approximate spacing of the drive locomotive wheels/axles). At least for an early "Cooper E80" loading, I had always been under the impression this rectangle was in turn basically loaded every five feet with an 80,000 pound axle load, applying in effect a uniform surface load of 2,000 psf (13.9 psi) on such rectangle.
I cannot tell you exactly what the specifier means without further information by the "2,600 lb/ft" you state, nor for that matter how it necessarily relates to design for all conceivable effects on any "liner"; however, I believe that number is probably quite close to a sum of the level of live loading pressure you say is applicable at pipe depth (I guess from such integration) plus earth load pressure at pipe depth, converted to a load per foot on a 12"size pipe.

RE: E80 cooper loading

Is the pipe inside a casing under the RR Trax? What kind of pressure in the pipe?

Richard A. Cornelius, P.E.
WWW.amlinereast.com

RE: E80 cooper loading

The 2600 lbs/ft is likely the strip load. The railroads calculate the loading of 80,000 lbs over the 5-foot axle spacing using an 8 1/2 ft long tie for a 1,880 lbs/ft strip load. Some railroads will add an impact factor of 50% to the Cooper E-80 surcharge. Check with the railroad.

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