EWPAA Structural Plywood and LVL Design Manual - Engineered ...

For lesser values of t p reduce load proportionally to decrease in t p , until t p = 4D s ,after which coach screw is non-load bearing.FIGURE 13.13: Coach screw depth of penetration and timber thicknessFor lateral loads in end grain as shown in FIGURE 13.1(b):• characteristic capacities must not exceed 60% of values obtained for lateral loadsin side grain.13.20 Design Capacity of Type 1 Coach Screwed Joints (Cl.4.5.3)Equation 13.22 gives the design capacity (ΦN j ) for a Type 1 joint containing (n) coachscrews to resist the applied load.For the strength limit state to be satisfied:where:and:ΦN j ≥ N* (13.22)ΦN j = Φk 1 k 13 k 16 k 17 nQ sk(13.23)N* = Design action due to applied factored loads onthe connectionΦ = capacity factork 13 = 1.0 withdrawal from side grain;= 0.6 withdrawal from end grain;k 16k 17nQsk= head fixity factor= 1.2 for coach screws through rigid side plates;= 1.0 others;= multiple screw factor= total number of coach screws resisting appliedload= characteristic capacity for a single screw byCl.4.4.2.4 and whose innermost memberthickness is taken as t p .214