×
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

Wheel Load Distribution on Road Plate

Wheel Load Distribution on Road Plate

Wheel Load Distribution on Road Plate

(OP)
A collegue of mine asked me about the proper wheel load distribution for H-20 loading on a temporary "road plate" used to cover a trench.

Looking through the AASHTO code, I didn't find anything applicable to spanning with plate steel.  Did I miss it somewhere?

Thanks for all of the tips.  I read much more than I post...

RE: Wheel Load Distribution on Road Plate

Use the simple span distribution of the wheel load if you are concerned with the reactions at each end of  the trench , but conservatively in this situation I would assume the load is 1/2 the axle load, say 16 Kips.Road plate is not typically designed.  The distribution of the wheel load is more for stringer and girder design. There is a distribution for flat slabs that are loaded perpendicular to traffic, but this is more for concrete slab bridges.

RE: Wheel Load Distribution on Road Plate

There are formulas in AASHTO. One for point loads and one for uniform loads, that will give you the percentage of load that is carried by each direction.

with a: being the short span
b: being the long span

Point load short span is b^3/(a^3+b^3)

Point load long span is a^3/(a^3+b^3)

Some judgement will be required to establish the effective width of plate that carries the wheel. But with the wheel contact area of 20", I would not hesitate to double that width for the effective width of plate.

RE: Wheel Load Distribution on Road Plate

I would assume that the plate would fail by bending at a line in the middle, and solve for average moment at that line.  Treating the wheel load as a point at the center of the plate would be conservative.  You could assume pressure approximately equal to tire pressure to spread it out over a larger area (75-100 psi for large trucks).

Is that AASHTO distribution above based on plate supported on two sides or is that for support on four sides?

RE: Wheel Load Distribution on Road Plate

The distribution formulas are for two way action.

RE: Wheel Load Distribution on Road Plate

Seems like the load carried in the transverse direction would be zero if the the sides of the plate are unsupported.  There's no place to carry that load to.

RE: Wheel Load Distribution on Road Plate

(OP)
Thanks for all of the comments.  It's a continuous trench for practical purposes, so the sides are unsupported.  I would have thought double the wheel contact area reasonable, but was looking for something to back it up with.

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