4 6 6 8 8 110 0 112 2 114 4 1188 Shank diameter, mm
Shank diameter, mm 2
4.7(B) SEASONED TIMBER 4.7(B) SEASONED TIMBER
Species
Screw size number Screw size number 4
4 6 6 8 8 110 0 112 2 114 4 1188 Shank diameter, mm
Shank diameter, mm 2
Maximum permissible withdrawal load, N Maximum permissible withdrawal load, N
Screw size number Screw size number 4 screw in withdrawal shall be taken to be given by the lesser screw in withdrawal shall be taken to be given by the lesser of the value give grain, given in Tables 4.7(A) and 4.7(B).
grain, given in Tables 4.7(A) and 4.7(B).
4.4 BOLTED JOINTS.
4.4 BOLTED JOINTS.
4.4.1 General.
4.4.1 General. The The basbasic ic worworkinking g loaloads ds givgiven en in in ClaClauseusess 4.4.2.1 and 4.4.2.2 are applicable to steel bolts as specified 4.4.2.1 and 4.4.2.2 are applicable to steel bolts as specified in
in AS AS 1111111, 1, whewhen n fitfitted ted intinto o prepreborbored ed holholes of es of diadiametmeterer approx
approximatelimately y 10 10 percepercent greater nt greater than the than the bolt diameter andbolt diameter and when fitted with washers as given in Clause 4.4.2.6.
when fitted with washers as given in Clause 4.4.2.6.
Reference shall be made to Paragraph D3, Appendix D for Reference shall be made to Paragraph D3, Appendix D for equations for computing basic working loads for values of equations for computing basic working loads for values of bolt diameters and effective timber thicknesses that are not bolt diameters and effective timber thicknesses that are not included in Tables 4.9 and 4.10.
included in Tables 4.9 and 4.10.
4.4.2 Lateral loads.
4.4.2 Lateral loads.
4.4.2.1
4.4.2.1 Basic working load parallel to the grainBasic working load parallel to the grain. The basic. The basic wo
4.4.2.2 BasiBasic c workworking ing load perpendiload perpendicular to cular to the grainthe grain. The. The b
baassiic woc worrkkiinng g llooaad d ffoor r a sia sinngglle e bboollt bet beaarriinngg perpendicular to the grain and acting in single shear is given perpendicular to the grain and acting in single shear is given fo
for r a a seselelectctioion n of of bobolt lt didiamameteterers s anand d efeffefectctivive e titimbmberer thicknesses in Tables 4.10(B) and 4.10(C).
thicknesses in Tables 4.10(B) and 4.10(C).
4.4.2.3
4.4.2.3 Basic working load for a bolted joint system.Basic working load for a bolted joint system. TheThe basic working load for a bolted joint system, denoted by basic working load for a bolted joint system, denoted by is derived as follows:
(c) For systemFor systems loades loaded at an d at an angle to the graiangle to the grain, the systemn, the system cap means of the nomograms given in Figures 4.3 to 4.6.
means of the nomograms given in Figures 4.3 to 4.6.
4.4.2.4 sideplates of adequate strength, and the bolts are sideplates of adequate strength, and the bolts are a close fit to the holes in these plates provided a close fit to the holes in these plates provided that
that bb / / D D > 5 for loads acting parallel to the grain> 5 for loads acting parallel to the grain and
and bb / / D D > 10 for loads acting perpendicular to> 10 for loads acting perpendicular to the grain (where
the grain (where bb denotes the effective timberdenotes the effective timber thickness and
thickness and DDis the bolt diameter)is the bolt diameter)
=
(a) Loads parallel to grainLoads parallel to grain. The basic working loads given. The basic working loads given in Tables 4.10(A), 4.10(B) and 4.10(C) apply to joints in Tables 4.10(A), 4.10(B) and 4.10(C) apply to joints in which the edge, end and between-fastener spacings in which the edge, end and between-fastener spacings are not
are not lesless s thathan n thothose showse shown n in in FigFigure 4.7(ure 4.7(a). Thea). The distance
distance aa inindidicacateted d in in ththe e fifigugure re shshalall l be be at at leleasastt ((nn - - 2)2) D D with a minimum of 2.5with a minimum of 2.5 D D, where, wherenn is the totalis the total
number of bolts in the joint and
number of bolts in the joint and DD is the diameter of theis the diameter of the bolt.
bolt.
Similarly, the required end distance
Similarly, the required end distance llparparshall be at leastshall be at least 8
8 D Din tension joints in unseasoned timber, 7in tension joints in unseasoned timber, 7 D Din tensionin tension joints
joints in in seasoned timber, seasoned timber, and and 55 D Din compression jointsin compression joints an
and d in in jojoinints ts susubjbjecect t to to bebendndining g momomement nt fofor r bobothth moisture conditions. However, lesser end distances may moisture conditions. However, lesser end distances may be used in tension joints provided that the basic load is be used in tension joints provided that the basic load is reduced in proportion to the reduction in end distance.
reduced in proportion to the reduction in end distance.
Ne
Neveverthrthelelesess, s, in in no no cacase se shshalall l ththe e enend d didiststanance ce forfor tension joints be less than 6
tension joints be less than 6 D Dfor unseasoned timber andfor unseasoned timber and 5
5 D D for seasoned timber.for seasoned timber.
(b)
(b) Loads perpendicular to grainLoads perpendicular to grain. The minimum edge, end. The minimum edge, end and
and betbetweeween-fn-fastasteneener r spaspacincings gs shashall ll not not be be lesless s thathann those shown in Figure 4.7(b). The distance
those shown in Figure 4.7(b). The distance aa shall be atshall be at least 2.5
least 2.5 D D for afor a bb / / D D ratio of 2, and it shall be increasedratio of 2, and it shall be increased proportionately so that it is at least 5
proportionately so that it is at least 5 D D for afor a bb / / D D ratioratio of 6 or more, where
of 6 or more, where bb is the thickness of the memberis the thickness of the member loaded perpendicular to the grain.
loaded perpendicular to the grain.
(c)
(c) Loads acting at an angle to the grainLoads acting at an angle to the grain. For loads acting. For loads acting at an angle 0
at an angle 0°° to 30to 30°° to the grain, the spacings, edgeto the grain, the spacings, edge and end distances may be taken as for loads parallel to and end distances may be taken as for loads parallel to the grain. For loads acting at an angle of 30
the grain. For loads acting at an angle of 30°°to 90to 90°°toto the grain, the spacings, edge and end distances may be the grain, the spacings, edge and end distances may be taken as for loads acting perpendicular to the grain.
taken as for loads acting perpendicular to the grain.
TABLE 4.9 TABLE 4.9
BASIC WORKING LOADS FOR SINGLE BOLTS PARALLEL TO GRAIN BASIC WORKING LOADS FOR SINGLE BOLTS PARALLEL TO GRAIN
(comp
(comprisinrising g TableTables s 4.9(A4.9(A), ), 4.9(B) and 4.9(B) and 4.9(C4.9(C)))) 4.9(A) SYSTEM CAPACITY
4.9(A) SYSTEM CAPACITY
T
Tyyppe e oof f jjooiinnt t EEffffeeccttiivve e ttiimmbbeer r tthhiicckknneessss
System capacity System capacity
1
1. . TTwwo o mmeemmbbeer r SSmmaalllleer r oof f t t 11andand t t 22
2. Three member
2. Three member SmallSmaller er of of t t 22and 2and 2 t t 11
2 2
3
3. . MMuullttiipplle e mmeemmbbeer r ((ii) ) BBeettwweeeen n A A aannd d BB—— smaller of
smaller of t t 11andand t t 22 (i
(ii) i) BeBetwtweeeen B an B and Cnd C—— smaller of
smaller of t t 22andand t t 33 (ii
(iii) i) etcetc
(i) (i)
(ii) (ii) (iii) etc (iii) etc
=
= ssuum m o f o f basic loads basic loads (i), (ii), etc (i), (ii), etc
COPYRIGHT COPYRIGHT
TABLE 4.9(B) TABLE 4.9(B)
IN UNSEASONED TIMBER: PARALLEL TO GRAIN IN UNSEASONED TIMBER: PARALLEL TO GRAIN
Joint
IN SEASONED TlMBER: PARALLEL TO GRAIN IN SEASONED TlMBER: PARALLEL TO GRAIN
Joint
TABLE 4.9(C)
TABLE 4.9(C) ((continued continued ))
Joint
BASIC WORKING LOADS FOR SINGLE BOLTS BASIC WORKING LOADS FOR SINGLE BOLTS
PERPENDICULAR TO THE GRAIN
2. Three member, Type A
2. Three member, Type A t t 22 NOTE: At each interface, the strength of the bolted joint with respect to the member aligned parallel to the NOTE: At each interface, the strength of the bolted joint with respect to the member aligned parallel to the direction of the stress must be checked according to Table 4.9.
direction of the stress must be checked according to Table 4.9.
COPYRIGHT COPYRIGHT
TABLE 4.10(B) TABLE 4.10(B)
IN UNSEASONED TIMBER: PERPENDICULAR TO GRAIN IN UNSEASONED TIMBER: PERPENDICULAR TO GRAIN
Joint
IN SEASONED TIMBER: PERPENDICULAR TO GRAIN IN SEASONED TIMBER: PERPENDICULAR TO GRAIN
Joint
TABLE 4.10(C)
TABLE 4.10(C) ((continued continued ))
Joint
FIGURE 4.3. E 4.3. MOGRAMOGRAM FOR M FOR HANKHANKINSONINSON’S FORMULA’S FORMULA, RANGE I, RANGE I
COPYRIGHT COPYRIGHT
FIGUR
FIGURE 4.4. E 4.4. NOMOGNOMOGRAM FOR HANKINSRAM FOR HANKINSON’S FORMUON’S FORMULA, RANGE IILA, RANGE II
FIGUR
FIGURE 4.5. E 4.5. NOMOGNOMOGRAM FOR HANKINSRAM FOR HANKINSON’S FORMULON’S FORMULA, RANGE IIIA, RANGE III
COPYRIGHT COPYRIGHT
TABL TABLE E 4.114.11 VALUE OF
VALUE OF kk1717, FOR USE IN THE DESIGN OF MULTIPLE CONNECTOR, FOR USE IN THE DESIGN OF MULTIPLE CONNECTOR JOINTS OF BOLTS, COACH SCREWS, SPLIT RINGS AND SHEAR PLATES JOINTS OF BOLTS, COACH SCREWS, SPLIT RINGS AND SHEAR PLATES
Type of joint Type of joint
Values of Values of kk1717
n
naa≤≤44 nn
a
a= = 55 nnaa= = 1010 nnaa= = 1515 nnaa≥≥1616 S
Seeaassoonneed d ttiimmbbeer r 11..0 0 11..0 0 11..0 0 11..0 0 11..00 Unsea
Unseasoned soned timber (no timber (no transvtransverseerse restraint*)
restraint*)
1
1..0 0 00..995 5 00..880 0 00..555 5 00..5500
Unseasoned timber (transverse Unseasoned timber (transverse restraint*)
restraint*)
0
0..5 5 00..5 5 00..5 5 00..5 5 00..55
n
naa = = total numbetotal number of r of rows of fastenerows of fasteners per interfars per interface.ce.
*
* The terThe term ‘tram ‘transvnsverserse restre restrainaint’ refet’ refers to the posrs to the possibsibiliility of restty of restrairaint to timnt to timber shber shrinkrinkage due to the jage due to the jointoint detail.
detail.
FIGUR
FIGURE 4.6. E 4.6. NOMOGNOMOGRAM FOR HANKINSRAM FOR HANKINSON’S FORMUON’S FORMULA, RANGE IVLA, RANGE IV
COPYRIGHT COPYRIGHT
FIGUR
FIGURE 4.7. E 4.7. SPACSPACINGS, EDGE AND END DISTINGS, EDGE AND END DISTANCEANCES FORS FOR BOLTED JOINTS
BOLTED JOINTS
4.4.2.6
4.4.2.6 WashersWashers. In all timber-to-timber bolted structural. In all timber-to-timber bolted structural joints,
joints, every every bolt bolt shall shall be be provided provided with a with a washer washer at at eacheach end, of a size not less than in Table 4.12.
end, of a size not less than in Table 4.12.
If smaller washers are used then the basic working load If smaller washers are used then the basic working load given in Clause 4.4.2 shall be reduced in proportion to the given in Clause 4.4.2 shall be reduced in proportion to the dimension of the washer diameter or side length.
dimension of the washer diameter or side length.
4.4.3 Axial
4.4.3 Axial loads.loads. WhWhere ere bobolts lts are are loaloaded ded axiaxiallally, y, ththee TABLE 4.12
TABLE 4.12
MINIMUM REQUIRED SIZE OF WASHERS MINIMUM REQUIRED SIZE OF WASHERS
FOR STRUCTURAL BOLTED JOINTS FOR STRUCTURAL BOLTED JOINTS
Bolt
basic working load of the bolt shall be taken as the lesser basic working load of the bolt shall be taken as the lesser of the axial strength of the bolt and the bearing strength of the axial strength of the bolt and the bearing strength of the timber under the washer when loaded perpendicular of the timber under the washer when loaded perpendicular to the grain. The design axial strength of bolts and the to the grain. The design axial strength of bolts and the eff
effectective ive diadiametmeter er fofor r use use in in comcompuputinting g the the beabearinringg pressure on the timber are given in Table 4.13.
pressure on the timber are given in Table 4.13.
TABLE 4.13 TABLE 4.13
DESIGN PARAMETERS FOR BOLTS UNDER DESIGN PARAMETERS FOR BOLTS UNDER
AXIAL LOAD
† StanStandard washers are washerdard washers are washers s having the minimumhaving the minimum dimens
dimensions ions shown in Table 4.12. The effective diametshown in Table 4.12. The effective diameter iser is less than the
less than the actual diametactual diameter because it er because it incluincludes an des an allowallowanceance for bending of the washer.
for bending of the washer.
4.5 COACH SCREWS.
4.5 COACH SCREWS.
4.5.1
4.5.1 GeneraGeneral.l. ThThe e basbasic ic worworkiking ng loaloads ds givgiven en in in ththee following clauses are applicable to steel coach screws as following clauses are applicable to steel coach screws as specified in AS 1393.
specified in AS 1393.
4.5.2 Lateral loads.
4.5.2 Lateral loads.For coach screws bearing laterally inFor coach screws bearing laterally in unseasoned timber, the provisions of Clause 4.4 for bolts unseasoned timber, the provisions of Clause 4.4 for bolts shall apply, subject to the following conditions:
shall apply, subject to the following conditions:
(a)
(a) For the puFor the purposrpose of Clause 4.4e of Clause 4.4, a coach screw shal, a coach screw shall bel be considered to be a bolt of diameter equal to the shank considered to be a bolt of diameter equal to the shank diameter of the screw.
(c) In a two-membIn a two-member joint, ther joint, the thinne thinner member shaler member shall havel have a
a mimininimumum m ththicicknknesess s of of ththreree e titimemes s ththe e shshanank k diameter of the coach screw.
diameter of the coach screw.
(d)
(d) The diaThe diametmeter er of the hole for the of the hole for the shashank shalnk shall l be notbe not less than the shank diameter of the screw nor exceed less than the shank diameter of the screw nor exceed it by
it by momore re ththan 1 an 1 mm or mm or 10 10 pepercrcenent t of the of the shshanank k
diameter, whichever is the lesser. The diameter of the diameter, whichever is the lesser. The diameter of the hole for the threaded portion of the screw shall not hole for the threaded portion of the screw shall not exceed the root diameter of the screw.
exceed the root diameter of the screw.
Th
The e dedeptpth h of of ththe e hohole le shshalall l nonot t be be leless ss ththan an ththee intended depth to which the screw is to be driven.
intended depth to which the screw is to be driven.
Th Figure 4.2(a) shall be such that—
Figure 4.2(a) shall be such that—
(i)
(i) thithicknckness oess of firf first mest membember,r, t t 11> > 33 D D;;
(ii
(ii) ) depdepth th of of penpenetretratiation on intinto o secseconond d memmemberber, , forfor speci
species groupes groupss ——
J1, JD1, J2, JD2, JD3 reduced in proportion to the decrease in
reduced in proportion to the decrease in t t ppand theand the coach screw shall
coach screw shall be considered as nonbe considered as non-loadbearing-loadbearing if
if t t ppis less than 4is less than 4 D D..
4.5.3 Withdrawal loads.
4.5.3 Withdrawal loads.
4.5.3.1
4.5.3.1 Basic working loadsBasic working loads. The basic working loads for. The basic working loads for coach screws in withdraw
coach screws in withdrawal al from the from the side grain are side grain are givegivenn in Table 4.14. Basic working loads for coach screws fixed in Table 4.14. Basic working loads for coach screws fixed into end grain shall not exceed 60 percent of the values into end grain shall not exceed 60 percent of the values given in Table 4.14.
given in Table 4.14.
4.5.3.2
4.5.3.2 PermiPermissiblssible e loadsloads. . The The permpermissibissible le withwithdrawdrawalal load Q for a coach screw in withdrawal shall be taken to load Q for a coach screw in withdrawal shall be taken to be given by—
be given by—
Q
Q == kk1313 . . . . . . (4(4..99)) but not greater than the value given in Table 4.1 4(C) but not greater than the value given in Table 4.1 4(C) where
(Comprising Tables 4.14(A), ising Tables 4.14(A), 4.14(B) and 4.14(B) and 4.14(C)4.14(C))) 4.14(A) UNSEASONED TIMBER
4.14(A) UNSEASONED TIMBER
Species Shank diameter, mm Shank diameter, mm 6
4.14(B) SEASONED TIMBER 4.14(B) SEASONED TIMBER
Species Shank diameter, mm Shank diameter, mm 6
TABLE 4.14(C) TABLE 4.14(C)
MAXIMUM PERMISSIBLE WITHDRAWAL MAXIMUM PERMISSIBLE WITHDRAWAL
LOAD PER COACH SCREW LOAD PER COACH SCREW
Nominal diameter of coach Nominal diameter of coach
screw screw mm mm
Maximum
Maximum permissibpermissiblele withdrawal load withdrawal load
N N 6
6 8 8 10 10
2 000 2 000 4 000 4 000 6 000 6 000 12
12 16 16 20 20
9 000 9 000 20 000 20 000 31 500 31 500