Moody's Coefficients for Abutment design

[Usman Tanveer]

Greetings.So, I am designing an abutment together with a wingwall. However I am unable to accurately determine these moody's coefficients for mid or support sections. Can someone tell me what should be the values of x/a and y/b for stem wall, wing wall and base slab for Mx/My?//

Greetings.

 

[BridgeSmith]

Sorry, I've never tried to use those for abutment design. I typically use the moment distribution method. Most younger designers use one of the many readily available beam analysis programs or spreadsheet-based analysis.

Rod Smith, P.E., The artist formerly known as HotRod10

 

[bridgebuster]

The entire publication by Moody is attached. There are illustrations to explain boundary and load conditions. Back in the day, we only used Moody for counterfort walls because the stem is considered to be a plate supported on three edges. From the tables we could come up with the moments and design the stem as a beam in the horizontal direction.

As BridgeSmith said, the stem of a cantilever abutment & wingwall can be done by beam analysis. Although if you're following AASHTO LRFD it's a bit annoying. If you have access to MathCAD Prime, below is a link to NYSDOT worksheets for abutment and wingwall design.

Link

 

[Usman Tanveer]

Thankyou for your replies. The thing which bugs me is what values we have to use for finding Stem center moment coefficient. Either NYSDOT does not define this properly or I am not able to understand .For example for Stem Coefficient, the value of x/a can be 1 with corresponding value of y/b=1,y/b=0.5 or y/b=0. The same ambiguity lies for support moment coefficients ,For x/a=0,y/b can be 0,0.5 or 1.

 

[bridgebuster]

The NYSDOT Mathcad doesn't use the Moody method.