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

13.16 Design of Type 2 Bolted ConnectionsEquation 13.15 gives the design capacity (ΦN j ) for a type 2 joint containing (n) bolts which are loaded indirect tension.For the strength limit state to be satisfied:where ΦNj is the lesser of:ΦN jΦN j≥ N* (13.15)= n(Φ Ntb ) (13.16)OR where crushing under the washer results in a limit on strength :and:ΦN j = Φ.k 1 .k 7 .nf”pj.Aw (13.17)N* = design action due to factored tensile loadsN = number of bolts in the jointΦN tb = design tensile capacity of bolts (Table 4.12)Φ = capacity factork 1 = duration of load factorK7= length of bearing factor of washer (Table 4.12)f’ pjA= characteristic bearing strength of timber in joints= effective area of washer for bearing.(Table C6)wMoment Resisting and Eccentric Bolted JointsAS 17201.1-1997 only real concern regarding moment joints for bolted connections is thatassociated with joint eccentricity. No guidance is given concerning the design of boltedmoment joints required to sustain large applied moments as can occur, for example, inportal frame knee joints.The design of bolted moment joints incorporating rigid steel side plates can be effected byapplication of the classical mechanics formula τ =Tρ/J. However, the objective of this Manualis to provide guidance to designers using plywood and LVL and moment joints with thesematerials are best done using nails as the connector as described in Chapter 10.Eccentric joints arise when the centre lines of action of their member forces, for example,those of a truss joint do not intersect at a common point as shown in FIGURE 13.10. Thisindiscretion can cause fairly high shear and moments to develop and tensile stressesperpendicular to the grain may also be high.FIGURE 13.10: Eccentric joint207