Factors of Safety for Retaining Wall Design

[ruready]

Typically when we receive friction values and passive pressures from the geotechnical engineer they will either specify whether the values are ultimate or have a FS of 1.5. Assuming the values have the factor of safety in it, when you are designing the footing for sliding would you increase the values to ultimate and then design the footing so your FS is 1.5 or keep them as they are and have the force = resistance (still have a FS of 1.5 b/c the values given are factored down) or keep the values as is and design the footing so the FS is 1.5 on the output... Hope that makes sense! Thanks

 

[MSEMan]

For many typical retaining walls, you'd ignore passive (unless its on the shear key) and even then you need to be careful because the retaining wall may not be able to tolerate the movement necessary to generate full passive resistance.