4. Find the expected value and confidence limits of the parameter K according 

 to the equation 



K = A(p)K' 



5. Multiply the quantity p/K S obtained in Step 2 by the values of K' calculated 

 in Step 4 to obtain values of p/S. Invert these and multiply by p to obtain the 

 expected value and 95% confidence limits of the settlement S. 



6. Recalculate S according to the bearing capacity equation (Equation 12). 



7. Use either the upper confidence limit of S from Step 5 or S calculated from 

 Step 6, whichever is larger, as a conservative design settlement. The expected 

 value of S calculated from Step 5 will usually give the most nearly correct 

 estimate of the settlement. 



Example 



Given: An 18-inch-diameter circular footing has a bearing pressure of 0.2 tsf. 

 Least squares fit of vane shear strength data has yielded the parameters 

 K' = 0.02 tcf and H' = 0.45 foot. Average submerged unit weight of 

 soil is 0.01 tcf. 



Calculate; Expected immediate settlement. 



Solution: (Step numbers are the same as those used in the discussion above.) 



1. K' = 0.02 tcf and H' = 0.45 foot 



2. H'/D = 0.45/1.50 = 0.30 

 From Figure 17, p/KS = 1.75 



3. From Figure 18, A(p)e^pe^^g^ = 11.1 



A(p)ucL = 15.8 

 A(p)lcl = 6.5 

 where UCL = upper confidence limit 

 LCL = lower confidence limit 



4. ^e.pecxe6 = (11.1)(0.02) = 0.222 tcf 



KucL = (15.8) (0.02) = 0.316 tcf 

 'K.p, = (6.5) (0.02) = 0.1 30 tcf 



28 



