Unformatted text preview: 0.40-0.50 0.30-0.40 0.25-0.30 A factor of safety of 4 to 6 may be used in Eq. (8.101) to obtain the allowable load-bearing capacity of a pile. The Michigan State Highway Commission (1965) undertook a study to obtain a rational pile-driving equation. At three diverse sites, a total of 88 piles were driven. Based on these tests, Michigan adopted a modified ENR formula: Q _ 1.25H B W R + nZW p U-S+ C W R + W p where H B = manufacturer's maximum rated hammer energy Ob·in.) C = 0.1 in. The unit of S is in inches in Eq. (8.102). A factor of safety of 6 is recommended. (8.102)...
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- Fall '08
- ENR, Pile Material, piles Wooden Piles, hammers Drop hammers, fonn-the modified ENR, ENR pile-driving fonnula