Table of Contents

Section 1 General

1.1 Scope

1.2 Interpretation

1.3 Definitions

1.4 Symbols

1.5 Design

1.6 Construction review

1.7 Materials and workmanship

Section 2 Stresses and elastic moduli for sawn timber

2.1 General

2.2 Characteristic stresses

2.3 Properties of timber species not listed

2.4 Basis of design

2.5 Strength reduction factors

2.6 Secondary stresses

2.7 Modification factors, k1 and k2 for duration of load

2.8 Modification factor, k3 for bearing area

2.9 Modification factors, k4, k5 and k6 for load sharing

2.10 Modification factor, K8 for stability

2.11 Temperature effects

2.12 Earthquake effects

Section 3 Design of structural members

3.1 General

3.2 Beam design

3.3 Column design

3.4 Tension member design

3.5 Combined bending and compression

3.6 Combined bending and tension

Section 4 Joints

4.1 General

4.2 Nails

4.3 Screws

4.4 Bolts

4.5 Coach screws

4.6 Other mechanical fasteners

4.7 Glued joints

Section 5 Design of special structures

5.1 Timber decking

5.2 Shear walls and diaphragms

Section 6 Plywood

6.1 General

6.2 Stresses and moduli

6.3 Modification factors

6.4 Loading perpendicular to the plane of the sheet

6.5 Loading in the plane of the sheet

6.6 Plywood components

Section 7 Round Timbers

7.1 General

7.2 Characteristic stresses and elastic moduli

7.3 Design

7.4 Modification factor, k20 for trimminf or shaving

7.5 Modification factor, k21 for preservative treatment involving steaming

7.6 Modification factor, k22 for dry use conditions

7.7 Effective sections

Section 8 Glued laminated timber

8.1 Scope

8.2 Specification

8.3 Standard sizes

8.4 Finish

8.5 Moisture content

8.6 Design

8.7 Modification factors

8.9 Butt joints

8.10 Camber

8.11 Holes drilled in fabricated members

8.12 Naile plate joints

Section 9 Design for fire resistance

9.1 Scope

9.2 Fire resistance ratings

9.3 Loads

9.4 Calculation of fire resistance rating of timber elements

9.5 Details of construction

Section 10 Testing of timber structures

10.1 General

10.2 Testing authority

10.3 Testing conditions

10.4 Test procedure

10.5 Acceptance criteria

10.6 Prototype or sample testing

10.7 Proof testing

10.8 Reportinf of tests

Table

2.1 Condition to be assumed for determination of characteristic stresses, modulus of elasticity, joint design and dimensions

2.2 Characteristic stresses for visually graded timber (MPa)

2.3 Characteristic stresses for mechanically graded timber (MPa)

2.4 Duration of load factor, k1 for strength

2.5 Duration of load factor, k2 for deflection

2.6 Bearing area factor, k3

2.7 Parallel support factor, k4 or k6

2.8 Stability factor, k8

3.1 Notch coefficient, k7

4.1 Classification of timber species for joint design

4.2 Minimum spacing of nails and screws in joints

4.3 Characteristic strengths (N) for one plain steel wire nail in single shear in side grain in dry timber

4.4 Characteristic withdrawal strength per millimetre of nail penentration (N/mm) for one plain steel wire nail in side grain

4.5 Characteristic strength (N) for one steel wood screw in single shear in side grain in dry timber

4.6 Maximum design withdrawal strength for one steel screw in dry timber

4.7 Characteristic withdrawal strength per millimetre of screw thread penetration (N/mm) for wood screw inserted at right angles to the grain of dry timber

4.8 Values of fcj for bolted joints in dry timber

4.9 Characteristic strength for a single bolt in dry timber loaded parallel to the grain

4.10 Characteristic strength, Qski (kN) for a single bolt in a two-member joint in dry timber loaded parallele to the grain

4.11 Values of fpi doe bolted joints in dry timber

4.12 Characteristic strength for a single bolt in dry timber loaded perpendicular to the grain

4.13 Characteristic strength, Qskp (kN) for a single bolt in a two-member joint in dry timber loaded perpendicular to grain

4.14 Factor, k12 for bolt and coach screw joints in green timber

4.15 Factor, k13 for the design of multiple-bolt and multiple-coach-screw joints

4.16 Characteristic withdrawal strength per millimetre of penetration of thread (N/mm) for a coach screw in dry timber

5.1 Maximum nail diameters (mm)

6.1 Characteristic stresses for structural plywood

6.2 Face grain orientation factor, k15 for strength

6.3 Face grain orientation factor, k16 for siffness

6.4 Face grain orientation factors for shear

7.1 Characteristic stresses (MPa) and modulus of elasticity (GPa) for naturally round softwood timber in green condition

7.2 Peeling or shaving factor, k20

7.3 Steaming factor, k21

7.4 Dry use factor, k22

8.1 Laminated members – standard widths

8.2 Minimum radius of curvature

8.3 Size factor for beams and tension members

8.4 Values of constants for calculation of radial stresses in pitched beams

10.1 Compensation factor, k30

10.2 Compensation factor, k31

10.3 Sampling factor, k32

10.4 Likely values of coefficients of variation

C1 Coefficients for slenderness factor of bisymmetrical beams with intermediate buckling restraints

C2 Coefficients for slenderness factors of bisymmetrical beams with no intermediate buckling restraints

E1 Duration of load factor, K37

G1 Maximum length to width (L/w) ratios for plate bending action in plywood

G2 Formulae for plywood plates spanning in two directions

G3 Values of constants, C3 to C7 inclusive

H1 Stability factor, k8 for compression

H2 Maximum width to thickness (w/t) ratios for plywood panels stable in compression

J1 Percentages of plywood design strength transmitted across scarf joints

J2 Minimum overall length of splice plates for glued joints

J3 Percentages of design strngth transmitted across spliced butt joints

Figure

2.1 Length of bearing surface (mm)

2.2 Parallel support system

2.3 Grid system

2.4 k8 factor

3.1 k8 for beams – dry timber

3.2 k8 for beams – green timber

3.3 Notation fo a notch

3.4 Graph for factor, k10

3.5 Effective length factor, k10

4.1 Positioning of fasteners

4.2 Timber thickness and nail length

4.3 Eccentric joints

4.4 Characteristic strength for a bolt in a two-member joint in dry radiata pine or Douglas fir

4.5 Graph of Hankinson forula for stresses and loads

5.1 Tpes of decking lay-up for floors and roofing

5.2 Shear flow in a panel sheathed shear wall or diaphragm

5.3 Distribution of loading for horizontal diaphragm and shear wall system

6.1 Moisture content factor, k14

6.2 Critical sections in some plywood components

6.3 Stiffener spacing for plywood webs in flexural components

8.1 Determination of k25 factor for pitchewd beams

8.2 Simple span tapered beams

9.1 Radius of arris rounding

B1 Intermediate restraints

C1 Continuously restrained beam

D1 Continuously restrained column

F1 Dimensions and nomenclature used in Appendix F

Appendix

A The determination of characteristic strengths for metal fasteners for timber

B Lateral and torsional buckling restraints

C Slenderness coefficients for beams

D Slenderness coefficients for columns

E Deformation and displacement modulu of mechanically fastened joints

F Method of computing effective section properties of plywood

G Design of plywood panels spanning in two directions

H Local buckling of plywood elements in compression

J Design of end or edge joints in plywood