APPENDIX B-Continued 



WALE SIZE (OMign Step B) 



Bending moment tn wales 

 a Front Male 



Max moment over support 



Wli, 10 - 1 600 X 8' 10 « 10 200 lbs per loot 

 Deduct 2 inch width for lie rod Mole 



For 12 X 10 wale, widtti - 115-20 =■ 95 depth 



- 9 5 



Section modulus - 95X95^/6 - 143 inches' 



Bending stress - (10.200 X 12) '143 = 850 psi 

 3 1 600X 4 



Horizontal shear = X Q5y'a"c" " 107 psi 



b Anchor Wale 

 Max moment over support = 

 Wa'/3 - 1.600 X3V2 - 7.200 lbs per loot 

 For 12 X 10 wale with 2 inch width squared deducted 

 for tie rod hole, bending stress = (7200 X 12) '143 

 =: 600 psi 



Max moment at L span = WI'/8 — Wa',2 = 1.600 



X 8 3 -7.200 =" 5.600 



Section modulus (no hole) = 115X936 = 173 



inch' 



Bending stress = 5 600 X 12. 173 = 390 psi 



PASSIVE RESISTANCE ANCHORAGE (Design Step 9) 



The anchorage for the bulkhuad shown on Fig 3 (Part 

 1) relies on passive resistance To locate this anchor- 

 age at a sale distance behind the bulkhead, a slope 

 line IS drawn Iron-, the botto:ri ol the sheet piles to the 

 finished grade at an angle to the horizontal where 

 is the angle of internal friction of the material For 

 the Sana backnll assumed C is idken as JO c*cc;ioes 

 The upper edge of the ancnorage should be located 

 beneath this slope line 



For a continuous anchoiage. like that for the bulk- 

 head shown on Fig. 2 (Pari 1) in which the height of 



bearing contact is only one foot, with center of bearing 

 contact located 5 5 feet below the ground surface the 

 ultimate resistance is approximately equal to Ihe bear- 

 ing capacity of a continuous stnp of footing of one 

 toot width located at a depth ol 5 5 feet See Ret 2. 

 p 231 The overburden pressure is 5 5 feet X 100 

 pounds per cubic toot which is 550 pounds per square 

 fool 



Then by Rel 2. p 125 

 Ultimate Resistance - 



Ultimate Resistance 



550 Na where Nit is a bear- 

 ing capacity factor to be 

 taken from curve Nq is read 

 as 7.0 

 550 X 7 = 3 850 psf 



For 7 foot length of anchor wale to each tie rod. Ihe 

 ultimate resistance ol the anchor wale is 7 x 1 x 

 3.850 = 26,950 pounds per tie rod With a lie rod 

 reaclicn ol 1,600 pounds per foot, x 8 feet = 12.800 

 pounds, the factor ol safety is 25.950. 12.800 = 2 1 

 The res.starce ol the anchor post would increase this 

 salely factoi son;ewhat A value of 2 is ccnsideied 

 adequate II an arbitrary limi! of 3.0C0 pounds per 

 square fool (1 5 tons) is assumed for Ihe ultimate 

 res.sla"ce as shown in Fig. 7 the total resistance 

 including the nnchc post will still provide a safety 

 factor of 2 0, 



REFERENCES 



1 Cheiiis Roberto., rae Foundafio/;s. McGraw-Hill. 

 1961 



SUE Arrr.y— Coastal Enginecting Research Center. 

 Shore Prclecticn. Pia'tning and Design. Technical 

 Report Wo 4. Third Edition. 1966 



3 Terzaghi Karl. "Anchored Bulkheads.' Transac- 

 tions. ASCE 1954 (Vol. 119) pp. 1243 to 1324 



318 



