DEADWEIGHT ANCHOR DESIGN PROCEDURES 



>nless Seafloor: Deadweight Anchor Design Procedure 



Loads 

 Soil 



Weight (in water) required 

 to resist sliding 



Anchor width (min) : 

 with shear keys 



without shear keys 



Shear keys 

 number 



Equation 

 r^, F^ (given) 

 Y^, ♦ (given) 



W =- 



-^ F 



tan(* - 5°) 

 6 W F. 



Y^(W - F^ - 0.3 F^) 

 1/3 



w - r,)J 



Y5(W 

 200 (W - F ) tan(*-5'') 



K Y. B" 

 P b 



t = 0.042 



^) 



1/2 



embedBcnt force for ODe 

 sbe«r key 



MaxianiiB pull height 



W^. = 0.05 Vjj B'' t 



400 



[20 t N + B tan(* - 5")) 

 B(W - F ) 



with or without 

 shear keys 



"b " 



■es shear key penetration = 0.05 B. 



ienti of P.ii>ivc Uleril E.rlh Prciturc. K , 

 Iwtithl She.r Key* (.ftcr Tscbcbot.tiof t, 1?62) 



« (dcg) 



K 



10 



1.56 



12.5 



1 



76 



15 



1 



9S 



17.5 



2 



25 



20 



2 



59 



25 



3 



(6 



30 



« 



7e 



35 



6 



88 



U 



10 



38 



l^tiODt: ». shear 

 b. mil • 



1; ";i/ 



key will it V 

 urfece it hor 

 ■ OOQ-coheBi* 

 of ».U frict 



zontil 

 , t = 

 OB, "6 = 0.5» 



6 F, 





Cohesive Seafloor: Deadweight Anchor Design Procedure 



Item 

 Loads 

 Soil 

 Anchor width: 



without shear keys 



with shear keys 



Shear keys 

 aufflber, n 



thickness, t 

 weight per shear key, W, 



embednent force for one 

 shear key, q 



Submerged weight 



(1) to resist overtumiagr 



(a) for H = 0.2 B, 



z^ = 0.1 B 



(b) for H minimized, 



z = O.I B 



s 



(c) for H ninunized, 



z = 



s 



Subaerged weight (continued) 



(2) to c«bed shear keys: 



(a) oani-directional anchor 



(b) uni-directioD«l anchor 



Equation 



1/2 



R = B (6 + 0.2 s ) 



W = 0.1 Yt B* t 







6 



h 



^^ 



1 



- 



BAY. 

 F^ 







6 



h 



h » 



Assumes cutting edge penetration =0.] B, anchor squar 

 LIST OF SYMBOLS 



plan. 



Horizontal and verti 

 load components 



Soil undreined shear 

 strength 



Soil sensivity 



Submerged unit weight of 

 soil 



Anchor width 



Undrained shear strength 

 at seafloor surface 



Anchor lateral load 

 resistance 



Soil undrained shear 

 strength at depth z 



Average soil strength 

 between surface and z 



Anchor shear key 

 peoetration into seafloor 



Allowable steel stress 



Shear key height 



30 



Subaerged unit weight of 

 shear key 



Buoyant unit weight of 

 deadweight 



Effective angle of 

 intemsl friction 



Submerged weight of the 

 anchor 



Coefficient of lateral 

 earth pressure 



Coefficient ol passive 

 lateral earth pressure 



