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am likely to control the design inmost cases. Therefore, the corresponding nail strength <br />factors for Load Combination Groups IV and VIf are also shown in table 4.5. <br />TABLE 45 <br />STRENGTH FACTORS AND FACTORS OF SAFETY -SLD <br />Element <br />Strength Factor <br />Strength Factor <br />Strength Factor <br />(Group 1) <br />(GroupM <br />(Group Vlp <br />a - <br />(Seismic) <br />Nail Head Strength - <br />og- 4.4 <br />see Table 4.4 <br />see Table 4.4 <br />Nail Tendon Tensile <br />art=0.15 <br />1.25(0.55)=0.69 <br />1.33(0.55)=0.73 <br />Suers <br />Ground -Grout Pullout <br />a4= .50 <br />1.25(0.50)=0.63 <br />1.33(d.50)=0.67 <br />Resistance <br />Soil <br />F=1.35 I.50*) <br />1.08(120*) <br />LOl 1.13* <br />Sod -Temporary Construction <br />F=1.20 (1.35*) <br />NA <br />NA <br />Condition} <br />Noms: <br />Allowable Nail Head Load (Tr)=or(Nominel Neil Head Strength)= nr Tau <br />Allowable Nail Tendon load Cre)=on (Teflon Yield Slrenglh)=as Tac <br />Allowable Pugnut Resistance (Q)=eq ((]inmate Pullout Resurface)-aq Qe <br />Mirdmum Rryuired Global Soil Factor of Safety" (Group 0=1.35(= 650 for critical ivixmef). <br />Minimum Required Global Soil Factor orSasery '(Group IV)=13MIM=1.08 (=1.20 fro critical <br />structure. <br />Minimum RegWm[ Global Soil Fanor of Safety'F (Group VH)=13 133=1.01 (=1.13 for critical <br />anuctures). <br />Minimum R.equ"nod Global Soil Facror of Salary' '- Ternpmmy Canatruction Couditiw=1.20(=1.53 <br />for critical sWcmrts). <br />• Sml Factorsof Sefetyfw Critical Sn cum . <br />t Sagas rommporery condition existing following cut excavation but before nail installation. I3msnm <br />offer to "temporary' earns; pernunenr' wall. <br />Ste5 - SelectTrial Nail SRigines and Lents <br />As discussed in section 4.3.2 and as shown on figure 4.7, satisfaction of the strength limit <br />statemquirements will not of itself easum an appropriate design. Additional constraints are <br />required to provide for an appropriate nail layout. The following empirical constraints on <br />the design analysis nail length pattern am therefore recommended for use when performing <br />the ]hmitipg egpilibrium design calculations: <br />(a) Nails with heads located in the upper half of the wall height should be of uniform <br />laugth.. <br />- (b) Nails with heads located in the lower half of the wall height should be considered <br />m have a reduced length in accordance with the recommendations given on figure <br />121 <br />Page 5 of 276 <br />