AREMA Trial Wedge Method

[elzooo]

Im designing wingwalls for a bridge and was told to use the Trial wedge method of earth pressure computation in AREMA. part of that computation involves ho=(2*c/w)*tan(45deg+phi/2). but if my c=0 as with cohesionless soils then I get ho=0. does anyone have any good examples or insite on the trial wedge method with cohesionless soils?

 

[Jalthi]

The formula looks like it calculates the depth of tension crack, which is not applicable to c=0 soils.

 

[elzooo]

I'm going to assume with cohesionless soils that ho=0 and that is O.K.

the example on AREMA (Figure C-8-5-4)has calculated wedge vector. for wedge 1-i'm assuming wedge BC1 the area is 19.56 x 7/2 + 5.77x7=108.9. Where are they getting the 19.56 and 7/2 numbers?

 

[Jalthi]

Would you mind posting those pages. Don't have AREMA handy.