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a) Determine the nominal nail head strength for each potential failure mode of the facing <br />and connection system using the methods presented in section 4.5 and in appendix F. <br />As a design aid, the nominal nail head strengths for several soil nail wall typical <br />facing thickness, facing reinforcement and hearing plate connection combinations <br />are tabulated in table 4,2B. <br />b) For each possible failure mode in table 4.4, determine the allowable nail head bad as a <br />fraction of the corresponding nominal nail head strength. The twat column of nail head <br />strength factors of table 4.4 applies to the Lead Combination Group I (table 4.3). For <br />other Load Combination Groups, these Group I nail head strength factors of table 4.4 <br />are increased in accordance with the percentage factors of the final column of table <br />4.3. For soil nail wall applications, Load Combination Groups I, IV and VH are likely <br />to control the design most of the time. The corresponding nail hand strength factors for <br />Load Combination Croups IV and VH are therefore also shown in table 4.4. The <br />^alllloo'w'abblle, nail hee`add load is the loa calculated value for the various failure modes. <br />.. TABLE 4.4 <br />NAIL HEAD STRENGTH <br />FACTORS -SLD <br />Nan Hend <br />Not Head <br />strenglb Factor <br />Nail Heed Strength <br />Strength Fecra <br />Failme Mode <br />(Group I) <br />Fams(amp M <br />(GMUP VD) <br />(Selemic) <br />Feting Flexure <br />1.2$0.67)=0.83 <br />1.33(0.67iIMS9 <br />Poring PunrLiue Shea <br />0.6T - <br />1.s5m67)=0.83 <br />1.33(0.67)=a&9 <br />HeadM-Stud Tenele ltactme- -' <br />ASlMA30713olthsapiel <br />10.50' <br />1.25(0.50>40 <br />1.33(0.50),0.67 <br />ASTM M25 Bolt Matcdn <br />0.59a <br />1.25(059) 074 <br />1.33(0.59)y 78 <br />Obtained by dividing thermrespandng AA&Ir7V IMID resistance factors (taNc 4.7) by a load factor of 1.35 <br />which is the load Retor for the usually dominant self aright load (able 46). <br />Perform a minimum allowable nail head load check for the trial facing design. This <br />empirical check is performed to create that the temporal allowable nail head load exceeds <br />the estimated nail head service load that may actually be developed as a result of soil - <br />structure interaction, .With reference to figure 2.7, the nail head service load actually <br />developed ban'be estimated by using the following empirical equation: <br />b, = FFKAgHSBSv - (4.6)' <br />Unless the designer has site specific rmnitoriug information from walls constructed in <br />similar sells, it is recommended that a value of the nail head service factor, Fp, equal to 0.50 <br />be adopted for design purposes. (See section 2.4.5). <br />119 <br />Page 4 0 276 <br />