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• • <br /> Langford Deck Replacement 4 5 <br /> Structural Calculations <br /> Check deck guard railing: <br /> -IRC does not require design loads on deck guards. <br /> -Use IBC design loads(200 Ibs)for posts and rails <br /> P:= 200 Max deck lateral load(Ibs) <br /> hp := 36 Height above decking (in) <br /> MP := P.hp =7200 Max moment to post(in-Ibs) <br /> Fb := 800 Reference beding stress for Cedar(psi) <br /> CF:= 1.5 Size factor for 4x4 <br /> M <br /> Sr„ := =6 Section modulus required(inA3) <br /> qFb.CF <br /> Use 4x4 cedar posts(S=7.146 inA3) <br /> Check lag bolt tension <br /> d := 7.25 — .75 — .75 =5.75 Lag bolt vertical spacing (in) <br /> Mn <br /> T:= = 1252 Max lag bolt force(Ibs) <br /> d <br /> W38 := 296 Withdrawal design value for 3/8"lag(Ibs) <br /> It:= T =4.23 Required lag embedment(in) <br /> W38 <br /> Use 3/8"lag screws,post to rim board. Provide blocking behind as needed for 4.5"embedment. <br /> OR use 3/8"thru bolts <br /> Check 2x6 top rail w/1 x4 cap: <br /> := 8 Post spacing (ft) <br /> Spost <br /> 'rail 8.12—3.5 =92.5 Length of rail(in) <br /> P'rail <br /> Mrail:_ =4625 Moment to rail(in-Ibs) <br /> 4 <br /> CF:= 1.3 Size factor for 2x6 <br /> Mrail <br /> Srail =4.447 Section modulus required(inA3) <br /> Fb.CF <br /> Use 2x6 rail w/1 x4 cap(S=2.063+3.062=5.125 inA3) <br /> Fasten to posts w/(2)3"deck screws <br /> By:J. Conner, PE, SE Deck Structural Calcs.xmcd <br /> 12/5/2019 <br />