OKiryu: In reply to your comment, placing enough safety factor on a soil rupture failure might be the practice of some, but not me. The question on determining the settlement for granular soils may set some back in doing that computation, but in my experience settlement allowable governs the recommendation for soil bearing for most foundations on most soil types. Look up the ASCE Journal of Soil Mechanics and Foundations, paper number 2135 of SM 4 group by B.K. Hough labeled "Compressibility as the Basis for Soil Bering Value". That was in August 1959 and it had more discussions on the subject that any ASCE paper before it. Of course Peck and others got into the argument. Hough was my undergrad and grad soils engineering professor at Cornell and later I worked a few years for him in his private Prentice. In later work places and in private practice I used his methods and have passed them on to those I have worked with, with success, no failures. Hough's new term "Bearing Capacity Index" has worked out great for me. Where shear strength values are known, yes a safety factor is applied, but only RARELY governs the design recommendations. I've given this same "sermon" before on these rooms so a search on this WEB site may bring up more details for those interested. The second edition of Hough's text (Basic Soil Engineering)is sufficient to get one going on how to use it on a spreadsheet. Some improvement modifications of the original paper methods are needed then.