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.


H-25 Loading

H-25 Loading

I am designing a cement-treated base (CTB) using the PCA design guidelines for a pavement over soft ground.  The subgade will be a silty soil.  I was asked by the PM if my design included AASHTO H-25 loading and now I understand it has to do with how axle loads are transferred to drainage structures (culverts?).  The road is rural and most of the heavy traffic is 56,000 pound 4-axle gravel dumptrucks with a tandem axle (the fourth axle is retractable).

The PCA design procedure uses the fatigue factor to estimate CTB thickness.  Does the AASHTO H-25 load diagram apply to the fatigue factor calculation?  


RE: H-25 Loading

The AASHTO H-25 loading is a fictitious theoretical design truck.

Here is a primer on AASHTO pavement design that hopefully will help:

Many other resources are also available online. Google "AASHTO pavement design"


RE: H-25 Loading

In bridge design we normally use HS-20 loading, and if we were asked to use HS-25 loading we would have a corresponding increase in the fatigue distress.  You may need to increase your fatigue values by 25% in this case.

RE: H-25 Loading

Since you are looking at a pavemet, not a structure, you may have better luck looking at ESALS, not H-loading.

How many ESALS per HS-25?

     "...students of traffic are beginning to realize the false economy of mechanically controlled traffic, and hand work by trained officers will again prevail." - Wm. Phelps Eno, ca. 1928

"I'm searching for the questions, so my answers will make sense." - Stephen Brust


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!


eBook: Product Innovation Platform Assessment
Over the past few years, there has been growing interest among industrial companies and solutions providers with regards to Product Innovation Platforms, where design, manufacturing and IoT tools are bundled into a single software package. Download Now

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