MSE Wall formulas.........discrepency between Rajapakse and Goswami?

If you guys have the books it is practice problem on page 336 of Raj, and problem 633 of goswami.

My confusion starts when calculating the soil friction and strip lengths.

The standard friction equation is : 2 x ( effective vertical stress x tan(angle of friction)) x area of strip

the factor of 2 is taking into account both sides of the strip, correct?

In Raj formula he is solving for length: 2 x 105 x tan(20) x .5L

My question is where does the .5 come from? It is not used in Goswami's solution of 633?

If needed I can scan the pages in and attach them.........but that might be a cc issue.

You might want to list the book titles you are referring to, not just the authors. It would be helpful if you included the problem questions.

Links to problems:

http://i.imgur.com/MiYpd6q.png

http://i.imgur.com/rZ5hx2L.png

Metal strips are 0.5 m wide (Ruwan Rajapakse's solution)

In the Goswami solution, the width of reinforcing strips are not used because all the analysis is done per unit depth. The reinforcement is in the form of continuos blankets, not discrete 'ribbons' attached to facing blocks.

What an idiot. Thank You..........

I spent hours sifting through that yesterday trying to figure it out, and just missed it. Did nearly the same thing with a piling problem. I think I am getting close to overprepping, everything is starting to run together.

Thanks for the extra set of eyes.

For additional reference on MSE walls, please refer to Sections 12-2 and 12-3 from Bowles, J.E. (1996), Foundation Analysis and Design, 5th edition.

It provides a great description on design procedures, for both internal and external stability, including selecting spacing for reinforcement, determining the required tensile strength and length of the reinforcement, as well as determining the sliding and overturning stability and bearing capacity.