Entering Figure 6-6 with seven load cycles and using the curve for 

 medium density soils, the double amplitude cyclic load is found to be 

 about 43% of static capacity or 333 kN (43% of 775 kN) (74,900 lb). 

 This limit applies when the quasi- static load does not exceed one- third 

 of the static capacity or 258 kN (775 kN/3) (58,000 lb). Applying a 

 factor of safety of 1.25 to the determined double amplitude cyclic and 

 the quasi-static loads as recommended in paragraph 6.2, the allowable 

 double amplitude cyclic component is 266 kN (333/1.25) (59,900 lb) on a 

 206-kN (258/1.25) (46,400-lb) quasi-static load. 



7.2.6.2 Cyclic Creep . Cyclic creep is determined from paragraph 

 6.2.2 and Figure 6-7. Over the two-year life of the anchor, 630,000 

 loading cycles (n T = 30,000 + (15)(2)(20,000)) are expected. From 

 Figure 6-7 for denser granular soils, the double amplitude cyclic load 

 allowed is found to be 28% of the allowable short-term holding capacity 

 or 217 kN (28% of 775 kN) (48,800 lb). The value applies when the 

 quasi- static load component is less than 20% of the static holding capa- 

 city or 155 kN (20% of 775 kN) (34,800 lb). Applying the recommended 

 factor of safety (1.25; paragraph 6.2) to the double amplitude cyclic 

 and quasi-static loads, the allowable loads for creep are a 174-kN 

 (217/1.25) (39,000-lb) cyclic component on a 124-kN (155/1.25) 

 (27,900-lb) quasi-static load. 



7.2.6.3 Earthquake Loading . Procedures for determining the 

 effects of earthquake loading are given in paragraph 6.3. Using 

 Figure 6-9, the maximum acceleration at the site is found to be about 

 0.15g for the 40-km (25-mile) earthquake fault distance and magnitude 

 7.5 earthquake given. Next, Figure 6-10 is entered using this accel- 

 eration, the depth of the anchor (4.8 m; 15.7 ft), and the relative soil 

 density (medium dense). Using Figure 6-10a for 0.15g ground accelera- 

 tion, it is noted that for the soil and depth given, liquefaction potential 

 borders between very unlikely and possible. 



68 



