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CR LAURENCE Z-SERIES GLASS CLAMPS (03/27/2014) Page 6 of 19 <br /> Screw strength: ,Y "' <br /> Tension strength,At=0.0524 in2,Fnt=56 ksi <br /> Ts=0AtFnt/1.6 =0.75*.0524*56/1.6= 1,375# ' s1-4$' <br /> Shear strength,Av=0.0613 int,Fnt= 33.7 ksir__ <br /> Vs=0 A.,Fnv/1.6 =0.65*0.0613*33.7/1.6 = 840# I } cH0RIZ0TAI <br /> Moment strength of attachment: � ,IAD, <br /> Msh= 1,375#*(0.935"/2) =643"# flllAiuld'i'1I hI <br /> Hs=643"#/1.48" =434# � i' .,, /�� <br /> Shear load on screw <br /> Z= (H2+V2)112 <br /> Glass dead load based on tributary area: 6.5psf*3'*5'/4=24.4# <br /> Z= (4342+24.42)1/2=435# <br /> combined shear and tension: <br /> 1375/1375+435/840= 1.51 > 1.2 <br /> Must reduce tension load: 1.2/1.51*1,375 = 1,093# <br /> Msh= 1,093#*(0.935"/2) =511"# <br /> Hs=511"#/1.48"=345# <br /> combined shear and tension: <br /> 1,093/1375+345/840= 1.20 s 1.20 <br /> Allowable horizontal load on Z-clamp bolted to steel post: <br /> 1/4"glass clamp - <br /> H= 345#: w=345*4/(3*5) =92 psf <br /> D =24.4#(3'x5'xl/2" glass light) <br /> 3/8" glass clamp - <br /> H= 1.166*345#=402: w=402*4/(3*5) = 107.2 psf <br /> 1/2"glass clamp - <br /> H= 1.294*345#=446: w =446*4/(3*5) = 119 psf <br /> WOOD ATTACHMENT <br /> Pullout strength of lag screw into wood post: <br /> 5/16"x 2"lag screw <br /> Withdrawal strength of lag screw based on NDS Table 11.2A <br /> Typical embed depth= 2"-5/8"-3/16"= 1.1875" <br /> WI= 220#/in (5/16"diameter with G=0.44) and Cd= 1.33 for guard application <br /> W1=220#/in*1.1875"*1.33 = 347# <br /> Moment strength of attachment: <br /> Msh=347#*(0.935"12) = 162.2"# , <br /> Hs= 162.2"#/1.48"= 110# <br /> Lag screw withdrawal strength is not reduced for shear load on lag. <br /> Allowable shear on lag screw from NDS Table 11K, 1/4" side plate with G>_0.43 <br /> ZT= 170# (horizontal load) <br /> Z11=250#(vertical load) <br /> EDWARD C.ROBISON,PE <br /> 10012 Creviston Dr NW <br /> Gig Harbor,WA 98329 <br /> 253-858-0855/Fax 253-858-0856 elrobison@narrows.com <br />