Wheel Loads on Box Culver Design
2

Question

Wheel Loads on Box Culver Design

tranquilito (Structural)

(OP)

25 Aug 03 15:43

Hello. I'm modeling a box culvert for traffic use. This culvert is supported on springs as it is directly supported on an elastic soil. The top slab is being designed to resist the earth weight and the live load of the highway. AASHTO is very explicit on how we distribute the concentrated wheel loads trhought the earth fill. My model covers the loads per foot of culvert. The bottom slab needs to resist the traffic loads directly applyied on it, but I want to know how the wheel load distributes on the slab. I need to know the aplication area of the wheel load or how much of the culvert contributes to resist the concentrated load.
Thanks a lot.

tincan (Civil/Environmental) · Answer 1 · 2003-08-26 11:09:03

For the top slab see AASHTO 12.11.2==>4.6.2.1 & 4.6.3.2 for spans < 15feet for the strip widths.
   +M = 26.0 + 6.6S < 144
   -M = 48.0 + 3.0S < 144
For 2+feet of fill distribute over (tire area)X1.15.
For <2feet the effect of fill on distribution is neglected.

For the bottom slab, treat the wheel loads as uniformly distributed over the bottom of the RCB with a width = to the top slab strip widths.  ASSHTO 12.11.2.2 requires that the width of the top slab used for distribution of wheel loads to be used in determing the M, V, in the side walls and bottom slab.

tranquilito (Structural) · Answer 2 · 2003-08-27 10:19:33

thanks a lot. I was looking the AASHTO Standar Specifications for Highway Bridges, but I also have the
AASHTO LRFD Bridge Design Specifications. Your reference was very usefull.

tedmed (Civil/Environmental) · Answer 3 · 2003-08-27 15:04:27

Although they model the bottom slab differently, the Missouri DOT Bridge Manual, Section 3.30, has some very good information on distributing loads on box culverts and general design practices for box culverts. You can find it at:

http://www.modot.state.mo.us/business/bridgedesign.htm

tranquilito (Structural) · Answer 4 · 2003-08-29 11:04:36

I'm checking the Missouri DOT Bridge Manual and It is a very complete reference.

Thank you very much.

Zisco (Civil/Environmental) · Answer 5 · 2003-08-29 11:45:37

Creo que aca ya te han resuelto la mayoria de tus dudas...de todas maneras te aconsejo que leas tus codigos que te mande a comprar para que no andes por ahi haciendo estas preguntas...

saludos,

Focht3 (Geotechnical) · Answer 6 · 2003-08-29 12:30:11

For those of us that don't read/speak Spanish, the following translation of Zisco's post was provided by Google (my interpretation in non-italicized text in parenthese):

I believe that aca already has solved you mayoria (majority) of your doubts (problem?)... of all ways I advise to you that you read your codigos that so that sends to you to buy you do not walk by ahi making these questions (?) ... greetings,

Please see FAQ731-376 by VPL for tips on how to make the best use of Eng-Tips Fora.

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Wheel Loads on Box Culver Design
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