APPENDIX B-Continued 



AWPI Technical Guidelines 



For PrcMiir* Tr«it*d Wood 



S4 



1V70 



Bulkheads: Design and Construction— Part ill 



SUMMARY 



This bulletin discusses tne remaining eight (8) pro- 

 cedures which are required in the design (or anchored 

 bulkhead construction Part II o( the series on Bulk- 

 heads Design and Construction. presente.d nine (9) 

 design steps and discussed Steps la through 1g The 

 slep-by-slep descriptions' which include some basic 

 information arc presented in dftaii Irom steps two (?) 

 through nine (9) 



EARTH PRESSURE DIAGRAMS (Design Step 2) 

 The sheet piles are driven into the groui.d to hold 

 earth on one side ol the wall at a higher level than on 

 the other The pressure exerted against the sheet piles 

 by the retained earth is tailed acrive earth pressure 

 The pressure exerted l>y the earth on the low side m 

 resistance to lateral movemeni o( the sheet p.l.ng is 

 known as the passive earth pressure Because cohe- 

 sive soils can resist higher forces than Ihey can 

 create, the allowable passive pressure is virtually 

 always higher than the aclive_ pressure occasionally 

 nearly ten times as much 



The magnitude and distribution ct active pressure 

 against a sheet pile wall depends on a number ol lac- 

 tors. These (actors include the physical properties o( 

 the retained earth, the (fiction between the earth and 

 the sheet pile wall, the amount of deflection of the 

 wall, and the flexibility o( the sheet piles. Similar lac- 



tors influence the magnitude and distribution of the 

 passive earth pressure. For a discussion of the 

 behavior of sheetpile walls and the influence of var- 

 ious (actors on the active and passive earth pressures, 

 see Ret 1 



Customarily, the lateral eadh pressures are propor- 

 tional to the vertical pressure at any given level If 

 the symbol P., oesignates the vertical pressure al any 

 give': level {weight of overlying soil) the lateral pres- 

 surei are expressed as K^Pv for active pressure and 

 as KpPi lor passive The symbols K» and Kp, arc known 

 as coef'icients of earth pressure In determining the 

 veriical pressure Pv at any level in the soil for bulk- 

 head design, the unit weight is that of moist earth 

 above and that ol submerged earth below, the free 

 water surface 



Sands are classified as dense, medium or loose, to 

 approximately describe the density, and as clean or 

 silty to inoicate the absence or presence ol (me mate- 

 rials These physical properties influence both the unit 

 weights of the material and the earth pressure coeffi- 

 cients Table 1 showing some physical properties (or 

 clean and silly sand, is Iron; Re( 1. p, 1268 



For designing limber sheet pile walls backdiled with 

 predominately grandular materials and driven into nat- 

 ural undisturbed deposits, the following average values 

 may be used for the unit weights of sand and for the 

 earth pressure coefficients: 



Table 1: Unit Weights o( Soils and Coefficients of Earth "ressure 



Type 

 of 

 Soil 



Unit Weight of Soil 

 Pounds per cubic loot 



Active Earth Pressure 



Passive Earth Pressure 



Moist 



Submerged 



CkJetficient. Ka 



Angles 



of 

 Friction 

 Degrees 



Coefficient. Ka 



(or 

 Soils in Place 



Angles 



ol 

 Friction 

 Degrees 



Mm. 



Max. 



Min. 



Max. 



Backfill 



Soils 



in 



Place 



Clean Sand: 

 Dense 

 Medium 

 Loose 



110 

 110 

 90 



140 



130 

 125 



65 

 60 

 56 



78 

 68 

 63 



035 



0.20 

 025 

 0,30 



38 20 

 34 17 

 30 15 



90 

 7.0 

 5.0 



38 25 

 34 23 



30 20 



Silty Sand 

 Dense 

 Medium 

 Loose 



110 

 95 

 80 



150 

 130 

 125 



70 

 60 

 50 



88 

 68 

 63 



50 



25 

 030 

 35 





70 

 50 

 30 





1970 AMERICAN WOOD PRESERVERS INSTITUTE, 1651 Old Meodow Rood, McLean. Va. 22101 



315 



