NZS AS 1720.1:2022 (Includes AS Text)
Timber Structures
Standard sets out general requirements for the verification of timber structures and elements. It includes calculation methods and design data appropriate for commonly encountered structural elements and materials. This New Zealand standard is an adoption with national modifications and has been reproduced from AS 1720.1:2010 Timber structures Part 1: Design methods (Incorporating Amendments No. 1, 2, and 3), and supersedes NZS 3603:1993. A list of modifications can be found under ‘Foreword’ section of the standard.
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NZS AS 1720.1:2022 Timber structures Part 1: Design methods
Committee representation
Acknowledgement
Copyright
CONTENTS
Referenced documents
Latest revisions
Review of standards
Foreword
Appendix ZZ – Variations to AS 1720.1:2010 for New Zealand
ZZ1 SCOPE AND GENERAL
ZZ1.1 Scope and application
ZZ1.3 Timber
ZZ1.4 General design considerations
ZZ1.5 Design and supervision
ZZ1.7 Definitions
ZZ1.8 Notation
ZZ1.10 Abbreviations
ZZ2 DESIGN PROPERTIES OF STRUCTURAL TIMBER ELEMENTS
ZZ2.2 Design properties
ZZ2.3 Capacity factor
ZZ3 DESIGN CAPACITY OF BASIC STRUCTURAL MEMBERS
ZZ4 DESIGN CAPACITIES OF JOINTS IN TIMBER STRUCTURES
ZZ4.0 General
ZZ4.1 Simplified method – Nails, screws, bolts, and coach screws
ZZ4.2 Simplified method – Design of nailed joints
ZZ4.3 Simplified method – Design of screwed joints
ZZ4.4 Simplified method – Design of bolted joints
ZZ4.5 Simplified method – Design of coach-screwed joints
ZZ4A.1 Detailed method – Nails, screws, rivets, bolts, dowels, and coach screws
ZZ4A.2 Detailed method – Definitions
ZZ4A.3 Detailed method – Design considerations
ZZ4A.4 Detailed method – Material properties
ZZ4A.5 Detailed method – Configuration parameters
ZZ4A.6 Detailed methods – Withdrawal strength
ZZ4A.7 Detailed methods – Lateral strength
ZZ4.8 Other types of mechanical fasteners
ZZ4A.8 Deformation
ZZ4.9 Glued joints
ZZ5 PLYWOOD
ZZ6 ROUND TIMBERS
ZZ6.1 General
ZZ6.2 Characteristic properties and elastic moduli
ZZ6.3 Design
ZZ6.4 Modification factor k21 for trimming (peeling or shaving)
ZZ6.5 Modification factor k23 for preservative treatment involving steaming
ZZ6.6 Modification factor k22 for seasoned use conditions
ZZ6.7 Effective sections
ZZ7 GLUE-LAMINATED TIMBER CONSTRUCTION
ZZ8 STRUCTURAL LAMINATED VENEER LUMBER (LVL)
ZZ8.3 Design properties
ZZ9 SEISMIC DESIGN
ZZ9.1 Scope
ZZ9.2 Structural design requirements
ZZ9.3 Seismic design actions
ZZ10 FLOOR AND ROOF DIAPHRAGMS
ZZ10.1 Scope
ZZ10.2 General principles and design requirements
Appendix
APPENDIX ZZC – Joints in timber structures
APPENDIX ZZE – Further design methods for members
APPENDIX ZZF – Notation and factors
Appendix ZZG – Miscellaneous design information
APPENDIX ZZH – Design properties for structural graded timber
TABLES
Table ZZ2.1 – Characteristic properties for New Zealand-verified timber
Table ZZ2.2 – Properties for New Zealand non-verified timber
Table ZZ3.1 – Material constant (ρb) for sawn timber beams
Table ZZ3.2 – Material constant (ρc) for sawn timber columns
Table ZZ4.1 – Limitations on timber joints for nails, screws, bolts, and coach screws
Table ZZ4.2 – Residual member brittle failures and strengths at a joint
Table ZZ4.3 – Capacity factors used in joint strength equations
Table ZZ4.4 – Factor k15 for nails, rivets, screws, bolts, dowels, and coach screws where in-service timber moisture content can exceed 15%
Table ZZ4.5 – Minimum end distance for parallel-to-grain loading
Table ZZ4.6 – Minimum end distance for perpendicular-to-grain loading
Table ZZ4.7 – Fastener yielding failure and strength for single-shear joints
Table ZZ4.8 – Fastener yielding failure and strength for double shear joints
Table ZZ4.9 – Fastener group brittle failure and strength for parallel to grain loading – Small dowel-type fasteners
Table ZZ4.10 – Member fastener group brittle failure and strength for perpendicular-to-grain loading – Small dowel-type fasteners
Table ZZ4.11 – Effective thickness factor for elastic wood failure (Cr)
Table ZZ4.12 – Fastener yielding failure and strength for single-shear joints
Table ZZ4.13 – Fastener yielding failure and strength for double-shear joints
Table ZZ4.14 – Fastener group brittle failure and strength for parallel-to-grain loading – Large dowel-type fasteners
Table ZZ4.15 – Member fastener group brittle failure and strength for perpendicular-to-grain loading – Large dowel-type fasteners
Table ZZ4.16 – Duration-of load-factor (k37)
Table ZZ5.1 – Characteristic properties for structural plywood (moisture content 15% or less)
Table ZZ6.1 – Characteristic properties (MPa) and modulus of elasticity (GPa) for naturally round softwood timber in unseasoned condition
Table ZZ6.2 – Peeling or shaving factor (k21)
Table ZZ6.3 – Preservative treatment involving steaming factor (k23)
Table ZZ6.4 – Seasoned use factor (k22)
Table ZZ7.1 – Characteristic values for structural design – GL grades (moisture content 15% or less)
Table ZZ8.1 – Characteristic values for design – Structural LVL used ‘on-edge’ (moisture content 15% or less)
Table ZZ9.1 – Strain or deformation limits for specific potential ductile elements
Table ZZ9.2 – Maximum structural ductility factor (µ) for ULS loading
Table ZZE1 – Material constant (ρb) – Seasoned timber beams
Table ZZE2 – Material constant (ρb) – Unseasoned timber beams
Table ZZE3 – Material constant (ρc) – Seasoned timber columns
Table ZZE4 – Material constant (ρc) – Unseasoned timber columns
Table ZZF1 – Quantity symbols
Table ZZF2 – Modification factors for strength (k)
FIGURES
Figure ZZ4.1a – Configuration requirements – Load applied parallel to grain – Member in tension
Figure ZZ4.1b – Configuration requirements – Load applied parallel to grain – Member in compression
Figure ZZ4.2a – Configuration requirements – Load applied perpendicular to grain – End joint
Figure ZZ4.2b – Configuration requirements – Load applied perpendicular to grain – Internal
Figure ZZ4.3 – Minimum nail spacing in radiata pine sawn timber
Figure ZZ4.4 – Definition of connection, joint, and member
Figure ZZ4.5 – Example of the maximum distance perpendicular to grain when in-service shrinkage or swelling of timber is likely, unless consideration is given to limit shrinkage stresses
Figure ZZ4.6a – Configuration definitions – Load parallel to grain – Member in tension
Figure ZZ4.6b – Configuration definitions – Load parallel to grain – Member in compression
Figure ZZ4.7a – Configuration definitions – Load perpendicular to grain – End joint
Figure ZZ4.7b – Configuration definitions – Load perpendicular to grain – Internal joints
Figure ZZ4.8 – Nail diameters
Figure ZZ4.9a – Applicable thickness of members in nailed joints – Single shear
Figure ZZ4.9b – Applicable thickness of members in nailed joints – Single shear
Figure ZZ4.9c – Applicable thickness of members in nailed joints – Double shear
Figure ZZ4.10a – Minimum spacing of nails – No pre-boring
Figure ZZ4.10b – Minimum spacing of nails – No pre-boring – Sawn radiata pine only
Figure ZZ4.10c – Minimum spacing of nails – Pre-bored to 0.8D
Figure ZZ4.11 – Screw diameters
Figure ZZ4.12a – Applicable thickness of members in screwed joints – Single shear
Figure ZZ4.12b – Applicable thickness of members in screwed joints – Single shear
Figure ZZ4.12c – Applicable thickness of members in screwed joints – Double shear
Figure ZZ4.13 – Minimum screw spacing requirements
Figure ZZ4.14 – Example of rivet dimensions meeting the requirements of ZZ4A.5.4.1
Figure ZZ4.15a – Rivet joint thicknesses and penetration definitions – Member loaded on one surface
Figure ZZ4.15b – Rivet joint thicknesses and penetration definitions – Member loaded on two surfaces
Figure ZZ4.16 – Applicable thicknesses of members in bolt or dowel connection
Figure ZZ4.17 – Minimum bolt spacing requirements – Parallel to grain
Figure ZZ4.18 – Minimum bolt spacing requirements – Perpendicular to grain
Figure ZZ4.19a – Separation of side members in dowel joints
Figure ZZ4.19b – Separation of side members in dowel joints – One possible prevention measure
Figure ZZ4.20 – Applicable thickness of timber member for a coach screw laterally loaded
Figure ZZ4.21 – Minimum coach screw spacing requirements – Parallel to grain
Figure ZZ4.22 – Minimum coach screw spacing requirements – Perpendicular to grain
Figure ZZ4.23 – Load-deformation curve for fastener group and failure modes
Figure ZZ4.24 – Example of possible member brittle failures of all fastener groups in a joint
Figure ZZ4.25 – Example of possible brittle failures of all fastener groups
Figure ZZ4.26 – Loaded surface factor (KLS) values
AS 1720.1—2010 Timber structures Part 1: Design methods
PREFACE
SECTION 1 SCOPE AND GENERAL
1.1 SCOPE AND APPLICATION
1.1.1 Scope
1.1.2 Application
1.2 NORMATIVE REFERENCES
1.3 TIMBER
1.3.1 General
1.3.2 Identification
1.3.3 Change of grade
1.3.4 Special provisions
1.3.5 Treated timber
1.4 GENERAL DESIGN CONSIDERATIONS
1.4.1 Loads
1.4.1.1 General
1.4.1.2 Duration of load
1.4.2 Design methods
1.4.2.1 General
1.4.2.2 Strength limit state
1.4.2.3 Stability limit state
1.4.2.4 Serviceability limit state
1.4.2.5 Experimentally based design
1.4.3 Timber dimensions for engineering calculations
1.4.4 Other design considerations
1.4.4.1 Buckling restraints
1.4.4.2 Erection and other extraneous forces
1.4.4.3 Secondary stresses
1.4.4.4 Shrinkage
1.4.4.5 Durability
1.5 DESIGN AND SUPERVISION
1.5.1 Design
1.5.2 Design information
1.5.3 Design details
1.5.4 Supervision
1.6 WORKMANSHIP AND MAINTENANCE
1.6.1 General
1.6.2 Moisture content
1.6.3 Corrosion
1.6.4 Shop drawings
1.6.5 Fabrication and erection
1.6.6 Maintenance
1.7 DEFINITIONS
1.7.1 Administrative definitions
1.7.1.1 Building authority or other regulatory authority
1.7.1.2 Professional engineer
1.7.2 Technical definitions
1.7.2.1 A17-grade timber
1.7.2.2 Characteristic capacity
1.7.2.3 Capacity factor
1.7.2.4 Design characteristic value/characteristic value for design
1.7.2.5 Collapse-susceptible timber
1.7.2.6 Corewood
1.7.2.7 Design action effect or design load effect
1.7.2.8 Design action or design load
1.7.2.9 Design capacity
1.7.2.10 Design life
1.7.2.11 Design resistance effect
1.7.2.12 Duration of loading
1.7.2.13 F-grade timber
1.7.2.14 Hardwood
1.7.2.15 Joint group
1.7.2.16 Limit state
1.7.2.17 MGP grade timber
1.7.2.18 Primary structural element
1.7.2.19 Proof testing
1.7.2.20 Prototype testing
1.7.2.21 Seasoned timber
1.7.2.22 Secondary structural elements
1.7.2.23 Serviceability limit state
1.7.2.24 Softwood
1.7.2.25 Stability limit state
1.7.2.26 Strength group
1.7.2.27 Strength limit state
1.7.2.28 Stress grade
1.7.2.29 Structural element
1.7.2.30 Structural timber
1.7.2.31 Unseasoned timber
1.8 NOTATION
1.9 UNITS
SECTION 2 DESIGN PROPERTIES OF STRUCTURAL TIMBER ELEMENTS
2.1 GENERAL
2.1.1 General procedure
2.1.2 Member design capacity
2.1.3 Design rigidity of members
2.1.4 Design capacity of joints
2.2 DESIGN PROPERTIES
2.2.1 Characteristic values for calculating the design capacity of members
2.2.2 Characteristic values for calculating the design capacity of joints
2.3 CAPACITY FACTOR
2.4 MODIFICATION FACTORS
2.4.1 Duration of load
2.4.1.1 Effect on strength
2.4.1.2 Effect on deformation
2.4.2 Moisture condition
2.4.2.1 General
2.4.2.2 Unseasoned timber
2.4.2.3 Seasoned timber
2.4.3 Temperature
2.4.4 Length and position of bearing
2.4.5 Strength sharing between parallel members
2.4.5.1 General
2.4.5.2 Strength-sharing structural systems
2.4.5.3 Modification factor for strength sharing
2.4.6 Stability factor
SECTION 3 DESIGN CAPACITY OF BASIC STRUCTURAL MEMBERS
3.1 GENERAL
3.2 BEAM DESIGN
3.2.1 Bending strength
3.2.1.1 Design capacity
3.2.1.2 Bending about both axes
3.2.2 Effective span
3.2.3 Slenderness coefficient for lateral buckling under bending
3.2.3.1 General
3.2.3.2 Beams of rectangular cross-section
3.2.4 Stability factor
3.2.5 Flexural shear strength
3.2.6 Bearing capacity
3.2.6.1 Design capacity in bearing perpendicular to the grain
3.2.6.2 Design capacity in bearing parallel to grain
3.2.6.3 Design bearing capacity at an angle to grain
3.2.7 Strength of notched beams
3.2.8 Concentrated loads and partial area loads on grid systems
3.3 COLUMN DESIGN
3.3.1 Compressive strength
3.3.1.1 Design compressive capacity parallel to grain
3.3.1.2 Buckling about both axes
3.3.2 Slenderness coefficient for lateral buckling under compression
3.3.2.1 General
3.3.2.2 Columns of rectangular cross-section
3.3.3 Stability factor
3.3.4 Strength of notched columns
3.3.5 Spaced columns
3.4 TENSION MEMBER DESIGN
3.4.1 Design tensile capacity parallel to grain
3.4.2 Design capacity in tension perpendicular to grain
3.5 COMBINED BENDING AND AXIAL ACTIONS
3.5.1 Combined bending and compression
3.5.2 Combined bending and tension
SECTION 4 DESIGN CAPACITY OF JOINTS IN TIMBER STRUCTURES
4.1 GENERAL
4.1.1 Scope of Section
4.1.2 Joint groups
4.1.3 Joint types
4.1.4 Strength-reducing characteristics at joints
4.1.5 Tendency to split
4.1.6 Eccentric joints
4.2 DESIGN OF NAILED JOINTS
4.2.1 General
4.2.2 Characteristic capacities for nails
4.2.2.1 General
4.2.2.2 Type 1 joints
4.2.2.3 Type 2 joints
4.2.3 Design capacity for nailed joints
4.2.3.1 General
4.2.3.2 Type 1 joint to resist direct loads
4.2.3.3 Type 1 joint to resist in-plane moment
4.2.3.4 Type 2 joint
4.2.4 Spacing, edge and end distances for nails
4.2.5 Nail length and timber thickness
4.2.6 Avoidance of splitting
4.3 DESIGN OF SCREWED JOINTS
4.3.1 General
4.3.2 Characteristic capacities for screws
4.3.2.1 General
4.3.2.2 Type 1 joints
4.3.2.3 Type 2 joints
4.3.2.4 Maximum tensile load capacity
4.3.2.5 Interpolation
4.3.3 Design capacity of screwed joints
4.3.3.1 General
4.3.3.2 Type 1 joint to resist direct loads
4.3.3.3 Type 1 joint to resist in-plane bending moments
4.3.3.4 Type 2 joint
4.3.4 Spacing, edge and end distances for screws
4.3.5 Screw length and timber thickness
4.3.6 Preboring
4.4 DESIGN OF BOLTED JOINTS
4.4.1 General
4.4.2 Characteristic capacities for bolts
4.4.2.1 General
4.4.2.2 Characteristic capacity parallel to the grain
4.4.2.3 Characteristic capacity perpendicular to grain
4.4.2.4 Characteristic capacity for a bolted joint system
4.4.2.5 Maximum tensile load capacity
4.4.3 Design capacity for bolted connections
4.4.3.1 General
4.4.3.2 Type 1 joint
4.4.3.3 Type 2 joints
4.4.3.4 Bolted joints with loads at an angle to the bolt axis
4.4.4 Spacings, edge and end distances for bolts
4.4.4.1 General
4.4.4.2 Loads parallel to grain
4.4.4.3 Loads perpendicular to grain
4.4.4.4 Loads acting at an angle to the grain
4.4.5 Washers
4.4.6 Eccentric joints
4.5 DESIGN OF COACH SCREWED JOINTS
4.5.1 General
4.5.2 Characteristic capacities for coach screws
4.5.2.1 Type 1 joints
4.5.2.2 Type 2 joints
4.5.2.3 Maximum tensile capacity
4.5.3 Design capacity of coach screwed joints
4.5.3.1 Type 1 joints
4.5.3.2 Type 2 joints
4.5.4 Spacings, edge and end distances for coach screws
4.6 DESIGN OF SPLIT-RING FASTENER JOINTS
4.6.1 General
4.6.2 Characteristic capacities for split-ring fasteners
4.6.3 Design capacity for split-ring fastener joints
4.6.4 Spacings, edge and end distances for split-ring fasteners
4.7 DESIGN OF SHEAR-PLATE FASTENER JOINTS
4.7.1 General
4.7.2 Characteristic capacities for shear-plate fasteners
4.7.3 Design capacity for joints with shear-plates
4.7.4 Spacings, edge and end distances for shear-plate fasteners
SECTION 5 PLYWOOD
5.1 GENERAL
5.2 DESIGN PROPERTIES
5.2.1 Characteristic values for structural design
5.2.2 Capacity factor
5.3 MODIFICATION FACTORS
5.3.1 General
5.3.2 Duration of load
5.3.3 Moisture condition
5.3.4 Temperature
5.3.5 Plywood assembly factor
5.4 LOADING NORMAL TO THE PLANE OF THE PLYWOOD PANEL
5.4.1 General
5.4.2 Bending strength
5.4.3 Shear strength (interlamina shear)
5.4.4 Bearing strength
5.4.5 Deflection in bending
5.5 LOADING IN THE PLANE OF THE PLYWOOD PANEL
5.5.1 General
5.5.2 Bending strength
5.5.3 Shear strength
5.5.4 Tension strength
5.5.5 Compression strength
5.5.6 Combined loads
5.5.7 Deflection in bending
5.5.8 Shear deformation
5.6 JOINTS IN COMPOSITE PLYWOOD TO TIMBER CONSTRUCTION
5.6.1 Nailed and screwed joints
5.6.2 Shear strength at glued interfaces
SECTION 6 ROUND TIMBERS
6.1 GENERAL
6.2 CHARACTERISTIC VALUES FOR STRUCTURAL DESIGN
6.3 DESIGN
6.3.1 Bending strength
6.3.2 Shear strength
6.3.3 Compressive strength
6.3.4 Deflections
6.4 ADDITIONAL MODIFICATION FACTORS
6.4.1 Factor for immaturity
6.4.2 Shaving factor
6.5 DESIGN DETAILS
6.5.1 Effective cross-section of untreated timber
6.5.2 Moisture content of timbers in ground contact
6.5.3 Joints
SECTION 7 GLUED-LAMINATED TIMBER CONSTRUCTION
7.1 GENERAL
7.2 STRUCTURAL DESIGN
7.3 DESIGN PROPERTIES
7.3.1 Characteristic values for strength and stiffness properties
7.3.2 Capacity factor
7.3.3 Non-GL-grade properties
7.4 MODIFICATION FACTORS
7.4.1 General
7.4.2 Duration of load
7.4.3 Strength sharing between parallel members
7.4.4 Stability factor
SECTION 8 STRUCTURAL LAMINATED VENEER LUMBER
8.1 GENERAL
8.2 STRUCTURAL DESIGN
8.3 DESIGN PROPERTIES
8.3.1 Characteristic values for strength properties and elastic moduli
8.3.2 Modulus of rigidity
8.3.3 Section properties
8.3.4 Capacity factors
8.4 MODIFICATION FACTORS
8.4.1 General
8.4.2 Duration of load
8.4.3 Moisture condition
8.4.4 Temperature
8.4.5 Length and position of bearing
8.4.6 Strength sharing between parallel members
8.4.7 Stability factor
8.5 JOINT DESIGN
8.5.1 General
8.5.2 Joint group
8.5.3 Characteristic fastener capacities
APPENDIX A
NORMATIVE REFERENCES
(Normative)
APPENDIX B
GUIDELINES FOR SERVICEABILITY
(Informative)
B1 GENERAL
B2 SERVICEABILITY CONSIDERATIONS
APPENDIX C
JOINTS IN TIMBER STRUCTURES
(Normative)
C1 GENERAL
C2 FASTENERS FOR PLYWOOD
C2.1 General
C2.2 Strength of joints with plywood
C2.2.1 Joint strength grouping
C2.2.2 Design capacity for laterally loaded nails and screws in plywood
C3 DEFORMATION OF JOINTS
C3.1 General
C3.2 Displacement of nailed and screwed joints in solid timber
C3.3 Displacement of solid timber joints fabricated with bolts, split-rings and shear-plates
C3.3.1 General
C3.3.2 For loads acting parallel to the grain
C3.3.3 For loadings acting perpendicular to the grain
C4 EQUATIONS AND TABLES FOR CHARACTERISTIC CAPACITIES FOR BOLTS
C4.1 Load Qkl
C4.2 Load Qkp
APPENDIX D
ACCEPTANCE TESTING OF TIMBER STRUCTURES AND ELEMENTS
(Normative)
D1 GENERAL
D1.1 Limitations of acceptance testing
D1.2 Circumstances requiring tests
D1.3 Information required
D2 DEFINITIONS
D2.1 Prototype testing
D2.2 Proof testing
D3 METHOD OF TESTING
D3.1 General
D3.2 Test load
D3.3 Eccentricities
D3.4 Load-deflection curve
D4 PROOF TESTING
D4.1 Equivalent test load
D4.2 Loading
D4.3 Acceptance for strength
D4.4 Acceptance of deflection
D5 PROTOTYPE TESTING
D5.1 General
D5.2 Materials
D5.3 Manufacture
D5.4 Equivalent test load
D5.5 Test procedure
D5.5.1 Preloads
D5.5.2 Test loading
D5.6 Acceptance of prototype
D5.6.1 For strength
D5.6.2 For deflection
D5.6.3 Acceptance of production units
D6 REPORT OF TESTS
APPENDIX E
FURTHER DESIGN METHODS FOR MEMBERS
(Normative)
E1 SCOPE
E2 THE MATERIAL CONSTANT
E3 SLENDERNESS COEFFICIENTS FOR COLUMNS
E3.1 End supported columns
E3.2 Continuously restrained columns
E4 SPACED COLUMNS
E4.1 Geometry of spaced columns
E4.2 Special requirements for spaced columns
E4.2.1 Size of connecting pieces
E4.2.2 Bolted connections
E4.2.3 Glued connections
E4.2.4 Spacing of intermediate packing pieces and batten plates
E4.2.5 Distance between shafts
E4.2.6 Battened columns
E4.3 Shear between components
E4.3.1 Design shear force
E4.3.2 Force effects on packing pieces
E4.3.3 Force effects on batten plates
E4.4 Design capacity
E4.4.1 Slenderness coefficients
E4.4.1.1 Slenderness coefficients of individual shafts
E4.4.1.2 Slenderness coefficient of composite cross-sections
E4.4.2 Design procedure
E5 BEAM-COLUMN BENT ABOUT BOTH AXES
E6 SLENDERNESS COEFFICIENTS FOR BEAMS
E6.1 General
E6.2 End-supported beams
E6.2.1 General
E6.2.2 Beams with intermediate buckling restraints
E6.3 Beams with no intermediate buckling restraints but with torsional restraints at the ends
E6.4 Continuously restrained beams
E7 BUCKLING RESTRAINTS
E7.1 Effectiveness of buckling restraints
E7.2 Notation
E7.3 Columns
E7.3.1 Load capacity
E7.3.2 Force on lateral restraints
E7.4 Beam with lateral restraints
E7.4.1 Load capacity
E7.4.2 Force on lateral restraints
E7.5 Beam with torsional restraints
E7.5.1 Load capacity
E7.5.2 Torque on torsional restraints
E8 CONCENTRATED LOADS AND PARTIAL AREA LOADS ON GRID SYSTEMS
E8.1 General
E8.2 Concentrated action
E8.3 Partial area load
E9 NOTCHED BEAMS
E10 NOTCHED COLUMNS
E11 NOTCHED TENSION MEMBERS
E12 SINGLE-TAPERED STRAIGHT BEAMS
E12.1 Geometry
E12.2 Design bending capacity of single-tapered beams
E12.3 Critical section for bending
E12.4 Grain orientation modification factor (ktg)
E12.5 Taper angle factor (ktb)
E13 DOUBLE-TAPERED, CURVED AND PITCHED-CAMBERED BEAMS
E13.1 Geometry
E13.2 Double-tapered, curved and pitched-cambered beams
E13.2.1 Design capacity
E13.2.2 Critical section for bending
E13.2.3 Shape factor (ksh)
E13.2.4 Radius of curvature factor (kr)
E13.2.5 Volume/size factor (kv)
E13.2.6 Radial stress factor (ktp)
APPENDIX F
NOTATION AND FACTORS
(Normative)
APPENDIX G
MISCELLANEOUS DESIGN INFORMATION
(Informative)
G1 ADDITIONAL INFORMATION
G2 EXAMPLES OF LOAD DURATION FACTORS FOR TYPICAL LOAD COMBINATIONS
APPENDIX H
DESIGN PROPERTIES FOR STRUCTURAL GRADED TIMBER
(Normative)
H1 GENERAL
H2 DESIGN PROPERTIES FOR F-GRADES
H2.1 General
H2.2 Characteristic values for bending and shear of beams, tension and compression and elastic moduli parallel to the grain
H2.3 Characteristic values for bearing, shear at joint details, tension perpendicular to the grain and design density
H2.4 Strength group and joint group classifications for seasoned and unseasoned, hardwood and softwood timber
H3 DESIGN PROPERTIES FOR MGP10, MGP12 AND MGP15 AND A17 STRESS GRADES
APPENDIX I
BUCKLING STRENGTH OF PLYWOOD DIAPHRAGMS
(Normative)
I1 SCOPE
I2 BUCKLING STRENGTH FOR DIAPHRAGMS LOADED IN-PLANE
I2.1 Application
I2.2 Diaphragms with lateral edges supported and subjected to uniformly loaded edge forces
I2.2.1 Slenderness coefficient
I2.2.2 Stability factor for edge shear forces
I2.2.3 Stability factor for edge compression and edge bending moment
I2.3 Diaphragms with lateral edges free and subjected to uniformly loaded edge forces
I2.4 Diaphragms subjected to concentrated edge forces
I2.4.1 Effective width
I2.4.2 Slenderness coefficients
I2.4.3 Stability factor
I2.5 Stiffeners for beam webs
I3 METHOD OF CALCULATION OF SECTION PROPERTIES
I3.1 General
I3.2 Definitions for use in calculation of section properties
I3.3 Calculation method
I3.3.1 Face grain parallel to the span
I3.3.2 Face grain perpendicular to the span
I4 SECTION PROPERTIES FOR STANDARD CONSTRUCTIONS
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AS/NZS 1328.1:1998
Glued laminated structural timber - Performance requirements and minimum production requirements -
AS/NZS 1328.1:1998 A1
Glued laminated structural timber - Performance requirements and minimum production requirements: Amendment 1 -
AS/NZS 1491:1996
Finger jointed structural timber
-
AS/NZS 4364:2010
Timber - Bond performance of structural adhesives
NZS AS 1720.1:2022 Timber structures Part 1: Design methods
Committee representation
Acknowledgement
Copyright
CONTENTS
Referenced documents
Latest revisions
Review of standards
Foreword
Appendix ZZ – Variations to AS 1720.1:2010 for New Zealand
ZZ1 SCOPE AND GENERAL
ZZ1.1 Scope and application
ZZ1.3 Timber
ZZ1.4 General design considerations
ZZ1.5 Design and supervision
ZZ1.7 Definitions
ZZ1.8 Notation
ZZ1.10 Abbreviations
ZZ2 DESIGN PROPERTIES OF STRUCTURAL TIMBER ELEMENTS
ZZ2.2 Design properties
ZZ2.3 Capacity factor
ZZ3 DESIGN CAPACITY OF BASIC STRUCTURAL MEMBERS
ZZ4 DESIGN CAPACITIES OF JOINTS IN TIMBER STRUCTURES
ZZ4.0 General
ZZ4.1 Simplified method – Nails, screws, bolts, and coach screws
ZZ4.2 Simplified method – Design of nailed joints
ZZ4.3 Simplified method – Design of screwed joints
ZZ4.4 Simplified method – Design of bolted joints
ZZ4.5 Simplified method – Design of coach-screwed joints
ZZ4A.1 Detailed method – Nails, screws, rivets, bolts, dowels, and coach screws
ZZ4A.2 Detailed method – Definitions
ZZ4A.3 Detailed method – Design considerations
ZZ4A.4 Detailed method – Material properties
ZZ4A.5 Detailed method – Configuration parameters
ZZ4A.6 Detailed methods – Withdrawal strength
ZZ4A.7 Detailed methods – Lateral strength
ZZ4.8 Other types of mechanical fasteners
ZZ4A.8 Deformation
ZZ4.9 Glued joints
ZZ5 PLYWOOD
ZZ6 ROUND TIMBERS
ZZ6.1 General
ZZ6.2 Characteristic properties and elastic moduli
ZZ6.3 Design
ZZ6.4 Modification factor k21 for trimming (peeling or shaving)
ZZ6.5 Modification factor k23 for preservative treatment involving steaming
ZZ6.6 Modification factor k22 for seasoned use conditions
ZZ6.7 Effective sections
ZZ7 GLUE-LAMINATED TIMBER CONSTRUCTION
ZZ8 STRUCTURAL LAMINATED VENEER LUMBER (LVL)
ZZ8.3 Design properties
ZZ9 SEISMIC DESIGN
ZZ9.1 Scope
ZZ9.2 Structural design requirements
ZZ9.3 Seismic design actions
ZZ10 FLOOR AND ROOF DIAPHRAGMS
ZZ10.1 Scope
ZZ10.2 General principles and design requirements
Appendix
APPENDIX ZZC – Joints in timber structures
APPENDIX ZZE – Further design methods for members
APPENDIX ZZF – Notation and factors
Appendix ZZG – Miscellaneous design information
APPENDIX ZZH – Design properties for structural graded timber
TABLES
Table ZZ2.1 – Characteristic properties for New Zealand-verified timber
Table ZZ2.2 – Properties for New Zealand non-verified timber
Table ZZ3.1 – Material constant (ρb) for sawn timber beams
Table ZZ3.2 – Material constant (ρc) for sawn timber columns
Table ZZ4.1 – Limitations on timber joints for nails, screws, bolts, and coach screws
Table ZZ4.2 – Residual member brittle failures and strengths at a joint
Table ZZ4.3 – Capacity factors used in joint strength equations
Table ZZ4.4 – Factor k15 for nails, rivets, screws, bolts, dowels, and coach screws where in-service timber moisture content can exceed 15%
Table ZZ4.5 – Minimum end distance for parallel-to-grain loading
Table ZZ4.6 – Minimum end distance for perpendicular-to-grain loading
Table ZZ4.7 – Fastener yielding failure and strength for single-shear joints
Table ZZ4.8 – Fastener yielding failure and strength for double shear joints
Table ZZ4.9 – Fastener group brittle failure and strength for parallel to grain loading – Small dowel-type fasteners
Table ZZ4.10 – Member fastener group brittle failure and strength for perpendicular-to-grain loading – Small dowel-type fasteners
Table ZZ4.11 – Effective thickness factor for elastic wood failure (Cr)
Table ZZ4.12 – Fastener yielding failure and strength for single-shear joints
Table ZZ4.13 – Fastener yielding failure and strength for double-shear joints
Table ZZ4.14 – Fastener group brittle failure and strength for parallel-to-grain loading – Large dowel-type fasteners
Table ZZ4.15 – Member fastener group brittle failure and strength for perpendicular-to-grain loading – Large dowel-type fasteners
Table ZZ4.16 – Duration-of load-factor (k37)
Table ZZ5.1 – Characteristic properties for structural plywood (moisture content 15% or less)
Table ZZ6.1 – Characteristic properties (MPa) and modulus of elasticity (GPa) for naturally round softwood timber in unseasoned condition
Table ZZ6.2 – Peeling or shaving factor (k21)
Table ZZ6.3 – Preservative treatment involving steaming factor (k23)
Table ZZ6.4 – Seasoned use factor (k22)
Table ZZ7.1 – Characteristic values for structural design – GL grades (moisture content 15% or less)
Table ZZ8.1 – Characteristic values for design – Structural LVL used ‘on-edge’ (moisture content 15% or less)
Table ZZ9.1 – Strain or deformation limits for specific potential ductile elements
Table ZZ9.2 – Maximum structural ductility factor (µ) for ULS loading
Table ZZE1 – Material constant (ρb) – Seasoned timber beams
Table ZZE2 – Material constant (ρb) – Unseasoned timber beams
Table ZZE3 – Material constant (ρc) – Seasoned timber columns
Table ZZE4 – Material constant (ρc) – Unseasoned timber columns
Table ZZF1 – Quantity symbols
Table ZZF2 – Modification factors for strength (k)
FIGURES
Figure ZZ4.1a – Configuration requirements – Load applied parallel to grain – Member in tension
Figure ZZ4.1b – Configuration requirements – Load applied parallel to grain – Member in compression
Figure ZZ4.2a – Configuration requirements – Load applied perpendicular to grain – End joint
Figure ZZ4.2b – Configuration requirements – Load applied perpendicular to grain – Internal
Figure ZZ4.3 – Minimum nail spacing in radiata pine sawn timber
Figure ZZ4.4 – Definition of connection, joint, and member
Figure ZZ4.5 – Example of the maximum distance perpendicular to grain when in-service shrinkage or swelling of timber is likely, unless consideration is given to limit shrinkage stresses
Figure ZZ4.6a – Configuration definitions – Load parallel to grain – Member in tension
Figure ZZ4.6b – Configuration definitions – Load parallel to grain – Member in compression
Figure ZZ4.7a – Configuration definitions – Load perpendicular to grain – End joint
Figure ZZ4.7b – Configuration definitions – Load perpendicular to grain – Internal joints
Figure ZZ4.8 – Nail diameters
Figure ZZ4.9a – Applicable thickness of members in nailed joints – Single shear
Figure ZZ4.9b – Applicable thickness of members in nailed joints – Single shear
Figure ZZ4.9c – Applicable thickness of members in nailed joints – Double shear
Figure ZZ4.10a – Minimum spacing of nails – No pre-boring
Figure ZZ4.10b – Minimum spacing of nails – No pre-boring – Sawn radiata pine only
Figure ZZ4.10c – Minimum spacing of nails – Pre-bored to 0.8D
Figure ZZ4.11 – Screw diameters
Figure ZZ4.12a – Applicable thickness of members in screwed joints – Single shear
Figure ZZ4.12b – Applicable thickness of members in screwed joints – Single shear
Figure ZZ4.12c – Applicable thickness of members in screwed joints – Double shear
Figure ZZ4.13 – Minimum screw spacing requirements
Figure ZZ4.14 – Example of rivet dimensions meeting the requirements of ZZ4A.5.4.1
Figure ZZ4.15a – Rivet joint thicknesses and penetration definitions – Member loaded on one surface
Figure ZZ4.15b – Rivet joint thicknesses and penetration definitions – Member loaded on two surfaces
Figure ZZ4.16 – Applicable thicknesses of members in bolt or dowel connection
Figure ZZ4.17 – Minimum bolt spacing requirements – Parallel to grain
Figure ZZ4.18 – Minimum bolt spacing requirements – Perpendicular to grain
Figure ZZ4.19a – Separation of side members in dowel joints
Figure ZZ4.19b – Separation of side members in dowel joints – One possible prevention measure
Figure ZZ4.20 – Applicable thickness of timber member for a coach screw laterally loaded
Figure ZZ4.21 – Minimum coach screw spacing requirements – Parallel to grain
Figure ZZ4.22 – Minimum coach screw spacing requirements – Perpendicular to grain
Figure ZZ4.23 – Load-deformation curve for fastener group and failure modes
Figure ZZ4.24 – Example of possible member brittle failures of all fastener groups in a joint
Figure ZZ4.25 – Example of possible brittle failures of all fastener groups
Figure ZZ4.26 – Loaded surface factor (KLS) values
AS 1720.1—2010 Timber structures Part 1: Design methods
PREFACE
SECTION 1 SCOPE AND GENERAL
1.1 SCOPE AND APPLICATION
1.1.1 Scope
1.1.2 Application
1.2 NORMATIVE REFERENCES
1.3 TIMBER
1.3.1 General
1.3.2 Identification
1.3.3 Change of grade
1.3.4 Special provisions
1.3.5 Treated timber
1.4 GENERAL DESIGN CONSIDERATIONS
1.4.1 Loads
1.4.1.1 General
1.4.1.2 Duration of load
1.4.2 Design methods
1.4.2.1 General
1.4.2.2 Strength limit state
1.4.2.3 Stability limit state
1.4.2.4 Serviceability limit state
1.4.2.5 Experimentally based design
1.4.3 Timber dimensions for engineering calculations
1.4.4 Other design considerations
1.4.4.1 Buckling restraints
1.4.4.2 Erection and other extraneous forces
1.4.4.3 Secondary stresses
1.4.4.4 Shrinkage
1.4.4.5 Durability
1.5 DESIGN AND SUPERVISION
1.5.1 Design
1.5.2 Design information
1.5.3 Design details
1.5.4 Supervision
1.6 WORKMANSHIP AND MAINTENANCE
1.6.1 General
1.6.2 Moisture content
1.6.3 Corrosion
1.6.4 Shop drawings
1.6.5 Fabrication and erection
1.6.6 Maintenance
1.7 DEFINITIONS
1.7.1 Administrative definitions
1.7.1.1 Building authority or other regulatory authority
1.7.1.2 Professional engineer
1.7.2 Technical definitions
1.7.2.1 A17-grade timber
1.7.2.2 Characteristic capacity
1.7.2.3 Capacity factor
1.7.2.4 Design characteristic value/characteristic value for design
1.7.2.5 Collapse-susceptible timber
1.7.2.6 Corewood
1.7.2.7 Design action effect or design load effect
1.7.2.8 Design action or design load
1.7.2.9 Design capacity
1.7.2.10 Design life
1.7.2.11 Design resistance effect
1.7.2.12 Duration of loading
1.7.2.13 F-grade timber
1.7.2.14 Hardwood
1.7.2.15 Joint group
1.7.2.16 Limit state
1.7.2.17 MGP grade timber
1.7.2.18 Primary structural element
1.7.2.19 Proof testing
1.7.2.20 Prototype testing
1.7.2.21 Seasoned timber
1.7.2.22 Secondary structural elements
1.7.2.23 Serviceability limit state
1.7.2.24 Softwood
1.7.2.25 Stability limit state
1.7.2.26 Strength group
1.7.2.27 Strength limit state
1.7.2.28 Stress grade
1.7.2.29 Structural element
1.7.2.30 Structural timber
1.7.2.31 Unseasoned timber
1.8 NOTATION
1.9 UNITS
SECTION 2 DESIGN PROPERTIES OF STRUCTURAL TIMBER ELEMENTS
2.1 GENERAL
2.1.1 General procedure
2.1.2 Member design capacity
2.1.3 Design rigidity of members
2.1.4 Design capacity of joints
2.2 DESIGN PROPERTIES
2.2.1 Characteristic values for calculating the design capacity of members
2.2.2 Characteristic values for calculating the design capacity of joints
2.3 CAPACITY FACTOR
2.4 MODIFICATION FACTORS
2.4.1 Duration of load
2.4.1.1 Effect on strength
2.4.1.2 Effect on deformation
2.4.2 Moisture condition
2.4.2.1 General
2.4.2.2 Unseasoned timber
2.4.2.3 Seasoned timber
2.4.3 Temperature
2.4.4 Length and position of bearing
2.4.5 Strength sharing between parallel members
2.4.5.1 General
2.4.5.2 Strength-sharing structural systems
2.4.5.3 Modification factor for strength sharing
2.4.6 Stability factor
SECTION 3 DESIGN CAPACITY OF BASIC STRUCTURAL MEMBERS
3.1 GENERAL
3.2 BEAM DESIGN
3.2.1 Bending strength
3.2.1.1 Design capacity
3.2.1.2 Bending about both axes
3.2.2 Effective span
3.2.3 Slenderness coefficient for lateral buckling under bending
3.2.3.1 General
3.2.3.2 Beams of rectangular cross-section
3.2.4 Stability factor
3.2.5 Flexural shear strength
3.2.6 Bearing capacity
3.2.6.1 Design capacity in bearing perpendicular to the grain
3.2.6.2 Design capacity in bearing parallel to grain
3.2.6.3 Design bearing capacity at an angle to grain
3.2.7 Strength of notched beams
3.2.8 Concentrated loads and partial area loads on grid systems
3.3 COLUMN DESIGN
3.3.1 Compressive strength
3.3.1.1 Design compressive capacity parallel to grain
3.3.1.2 Buckling about both axes
3.3.2 Slenderness coefficient for lateral buckling under compression
3.3.2.1 General
3.3.2.2 Columns of rectangular cross-section
3.3.3 Stability factor
3.3.4 Strength of notched columns
3.3.5 Spaced columns
3.4 TENSION MEMBER DESIGN
3.4.1 Design tensile capacity parallel to grain
3.4.2 Design capacity in tension perpendicular to grain
3.5 COMBINED BENDING AND AXIAL ACTIONS
3.5.1 Combined bending and compression
3.5.2 Combined bending and tension
SECTION 4 DESIGN CAPACITY OF JOINTS IN TIMBER STRUCTURES
4.1 GENERAL
4.1.1 Scope of Section
4.1.2 Joint groups
4.1.3 Joint types
4.1.4 Strength-reducing characteristics at joints
4.1.5 Tendency to split
4.1.6 Eccentric joints
4.2 DESIGN OF NAILED JOINTS
4.2.1 General
4.2.2 Characteristic capacities for nails
4.2.2.1 General
4.2.2.2 Type 1 joints
4.2.2.3 Type 2 joints
4.2.3 Design capacity for nailed joints
4.2.3.1 General
4.2.3.2 Type 1 joint to resist direct loads
4.2.3.3 Type 1 joint to resist in-plane moment
4.2.3.4 Type 2 joint
4.2.4 Spacing, edge and end distances for nails
4.2.5 Nail length and timber thickness
4.2.6 Avoidance of splitting
4.3 DESIGN OF SCREWED JOINTS
4.3.1 General
4.3.2 Characteristic capacities for screws
4.3.2.1 General
4.3.2.2 Type 1 joints
4.3.2.3 Type 2 joints
4.3.2.4 Maximum tensile load capacity
4.3.2.5 Interpolation
4.3.3 Design capacity of screwed joints
4.3.3.1 General
4.3.3.2 Type 1 joint to resist direct loads
4.3.3.3 Type 1 joint to resist in-plane bending moments
4.3.3.4 Type 2 joint
4.3.4 Spacing, edge and end distances for screws
4.3.5 Screw length and timber thickness
4.3.6 Preboring
4.4 DESIGN OF BOLTED JOINTS
4.4.1 General
4.4.2 Characteristic capacities for bolts
4.4.2.1 General
4.4.2.2 Characteristic capacity parallel to the grain
4.4.2.3 Characteristic capacity perpendicular to grain
4.4.2.4 Characteristic capacity for a bolted joint system
4.4.2.5 Maximum tensile load capacity
4.4.3 Design capacity for bolted connections
4.4.3.1 General
4.4.3.2 Type 1 joint
4.4.3.3 Type 2 joints
4.4.3.4 Bolted joints with loads at an angle to the bolt axis
4.4.4 Spacings, edge and end distances for bolts
4.4.4.1 General
4.4.4.2 Loads parallel to grain
4.4.4.3 Loads perpendicular to grain
4.4.4.4 Loads acting at an angle to the grain
4.4.5 Washers
4.4.6 Eccentric joints
4.5 DESIGN OF COACH SCREWED JOINTS
4.5.1 General
4.5.2 Characteristic capacities for coach screws
4.5.2.1 Type 1 joints
4.5.2.2 Type 2 joints
4.5.2.3 Maximum tensile capacity
4.5.3 Design capacity of coach screwed joints
4.5.3.1 Type 1 joints
4.5.3.2 Type 2 joints
4.5.4 Spacings, edge and end distances for coach screws
4.6 DESIGN OF SPLIT-RING FASTENER JOINTS
4.6.1 General
4.6.2 Characteristic capacities for split-ring fasteners
4.6.3 Design capacity for split-ring fastener joints
4.6.4 Spacings, edge and end distances for split-ring fasteners
4.7 DESIGN OF SHEAR-PLATE FASTENER JOINTS
4.7.1 General
4.7.2 Characteristic capacities for shear-plate fasteners
4.7.3 Design capacity for joints with shear-plates
4.7.4 Spacings, edge and end distances for shear-plate fasteners
SECTION 5 PLYWOOD
5.1 GENERAL
5.2 DESIGN PROPERTIES
5.2.1 Characteristic values for structural design
5.2.2 Capacity factor
5.3 MODIFICATION FACTORS
5.3.1 General
5.3.2 Duration of load
5.3.3 Moisture condition
5.3.4 Temperature
5.3.5 Plywood assembly factor
5.4 LOADING NORMAL TO THE PLANE OF THE PLYWOOD PANEL
5.4.1 General
5.4.2 Bending strength
5.4.3 Shear strength (interlamina shear)
5.4.4 Bearing strength
5.4.5 Deflection in bending
5.5 LOADING IN THE PLANE OF THE PLYWOOD PANEL
5.5.1 General
5.5.2 Bending strength
5.5.3 Shear strength
5.5.4 Tension strength
5.5.5 Compression strength
5.5.6 Combined loads
5.5.7 Deflection in bending
5.5.8 Shear deformation
5.6 JOINTS IN COMPOSITE PLYWOOD TO TIMBER CONSTRUCTION
5.6.1 Nailed and screwed joints
5.6.2 Shear strength at glued interfaces
SECTION 6 ROUND TIMBERS
6.1 GENERAL
6.2 CHARACTERISTIC VALUES FOR STRUCTURAL DESIGN
6.3 DESIGN
6.3.1 Bending strength
6.3.2 Shear strength
6.3.3 Compressive strength
6.3.4 Deflections
6.4 ADDITIONAL MODIFICATION FACTORS
6.4.1 Factor for immaturity
6.4.2 Shaving factor
6.5 DESIGN DETAILS
6.5.1 Effective cross-section of untreated timber
6.5.2 Moisture content of timbers in ground contact
6.5.3 Joints
SECTION 7 GLUED-LAMINATED TIMBER CONSTRUCTION
7.1 GENERAL
7.2 STRUCTURAL DESIGN
7.3 DESIGN PROPERTIES
7.3.1 Characteristic values for strength and stiffness properties
7.3.2 Capacity factor
7.3.3 Non-GL-grade properties
7.4 MODIFICATION FACTORS
7.4.1 General
7.4.2 Duration of load
7.4.3 Strength sharing between parallel members
7.4.4 Stability factor
SECTION 8 STRUCTURAL LAMINATED VENEER LUMBER
8.1 GENERAL
8.2 STRUCTURAL DESIGN
8.3 DESIGN PROPERTIES
8.3.1 Characteristic values for strength properties and elastic moduli
8.3.2 Modulus of rigidity
8.3.3 Section properties
8.3.4 Capacity factors
8.4 MODIFICATION FACTORS
8.4.1 General
8.4.2 Duration of load
8.4.3 Moisture condition
8.4.4 Temperature
8.4.5 Length and position of bearing
8.4.6 Strength sharing between parallel members
8.4.7 Stability factor
8.5 JOINT DESIGN
8.5.1 General
8.5.2 Joint group
8.5.3 Characteristic fastener capacities
APPENDIX A
NORMATIVE REFERENCES
(Normative)
APPENDIX B
GUIDELINES FOR SERVICEABILITY
(Informative)
B1 GENERAL
B2 SERVICEABILITY CONSIDERATIONS
APPENDIX C
JOINTS IN TIMBER STRUCTURES
(Normative)
C1 GENERAL
C2 FASTENERS FOR PLYWOOD
C2.1 General
C2.2 Strength of joints with plywood
C2.2.1 Joint strength grouping
C2.2.2 Design capacity for laterally loaded nails and screws in plywood
C3 DEFORMATION OF JOINTS
C3.1 General
C3.2 Displacement of nailed and screwed joints in solid timber
C3.3 Displacement of solid timber joints fabricated with bolts, split-rings and shear-plates
C3.3.1 General
C3.3.2 For loads acting parallel to the grain
C3.3.3 For loadings acting perpendicular to the grain
C4 EQUATIONS AND TABLES FOR CHARACTERISTIC CAPACITIES FOR BOLTS
C4.1 Load Qkl
C4.2 Load Qkp
APPENDIX D
ACCEPTANCE TESTING OF TIMBER STRUCTURES AND ELEMENTS
(Normative)
D1 GENERAL
D1.1 Limitations of acceptance testing
D1.2 Circumstances requiring tests
D1.3 Information required
D2 DEFINITIONS
D2.1 Prototype testing
D2.2 Proof testing
D3 METHOD OF TESTING
D3.1 General
D3.2 Test load
D3.3 Eccentricities
D3.4 Load-deflection curve
D4 PROOF TESTING
D4.1 Equivalent test load
D4.2 Loading
D4.3 Acceptance for strength
D4.4 Acceptance of deflection
D5 PROTOTYPE TESTING
D5.1 General
D5.2 Materials
D5.3 Manufacture
D5.4 Equivalent test load
D5.5 Test procedure
D5.5.1 Preloads
D5.5.2 Test loading
D5.6 Acceptance of prototype
D5.6.1 For strength
D5.6.2 For deflection
D5.6.3 Acceptance of production units
D6 REPORT OF TESTS
APPENDIX E
FURTHER DESIGN METHODS FOR MEMBERS
(Normative)
E1 SCOPE
E2 THE MATERIAL CONSTANT
E3 SLENDERNESS COEFFICIENTS FOR COLUMNS
E3.1 End supported columns
E3.2 Continuously restrained columns
E4 SPACED COLUMNS
E4.1 Geometry of spaced columns
E4.2 Special requirements for spaced columns
E4.2.1 Size of connecting pieces
E4.2.2 Bolted connections
E4.2.3 Glued connections
E4.2.4 Spacing of intermediate packing pieces and batten plates
E4.2.5 Distance between shafts
E4.2.6 Battened columns
E4.3 Shear between components
E4.3.1 Design shear force
E4.3.2 Force effects on packing pieces
E4.3.3 Force effects on batten plates
E4.4 Design capacity
E4.4.1 Slenderness coefficients
E4.4.1.1 Slenderness coefficients of individual shafts
E4.4.1.2 Slenderness coefficient of composite cross-sections
E4.4.2 Design procedure
E5 BEAM-COLUMN BENT ABOUT BOTH AXES
E6 SLENDERNESS COEFFICIENTS FOR BEAMS
E6.1 General
E6.2 End-supported beams
E6.2.1 General
E6.2.2 Beams with intermediate buckling restraints
E6.3 Beams with no intermediate buckling restraints but with torsional restraints at the ends
E6.4 Continuously restrained beams
E7 BUCKLING RESTRAINTS
E7.1 Effectiveness of buckling restraints
E7.2 Notation
E7.3 Columns
E7.3.1 Load capacity
E7.3.2 Force on lateral restraints
E7.4 Beam with lateral restraints
E7.4.1 Load capacity
E7.4.2 Force on lateral restraints
E7.5 Beam with torsional restraints
E7.5.1 Load capacity
E7.5.2 Torque on torsional restraints
E8 CONCENTRATED LOADS AND PARTIAL AREA LOADS ON GRID SYSTEMS
E8.1 General
E8.2 Concentrated action
E8.3 Partial area load
E9 NOTCHED BEAMS
E10 NOTCHED COLUMNS
E11 NOTCHED TENSION MEMBERS
E12 SINGLE-TAPERED STRAIGHT BEAMS
E12.1 Geometry
E12.2 Design bending capacity of single-tapered beams
E12.3 Critical section for bending
E12.4 Grain orientation modification factor (ktg)
E12.5 Taper angle factor (ktb)
E13 DOUBLE-TAPERED, CURVED AND PITCHED-CAMBERED BEAMS
E13.1 Geometry
E13.2 Double-tapered, curved and pitched-cambered beams
E13.2.1 Design capacity
E13.2.2 Critical section for bending
E13.2.3 Shape factor (ksh)
E13.2.4 Radius of curvature factor (kr)
E13.2.5 Volume/size factor (kv)
E13.2.6 Radial stress factor (ktp)
APPENDIX F
NOTATION AND FACTORS
(Normative)
APPENDIX G
MISCELLANEOUS DESIGN INFORMATION
(Informative)
G1 ADDITIONAL INFORMATION
G2 EXAMPLES OF LOAD DURATION FACTORS FOR TYPICAL LOAD COMBINATIONS
APPENDIX H
DESIGN PROPERTIES FOR STRUCTURAL GRADED TIMBER
(Normative)
H1 GENERAL
H2 DESIGN PROPERTIES FOR F-GRADES
H2.1 General
H2.2 Characteristic values for bending and shear of beams, tension and compression and elastic moduli parallel to the grain
H2.3 Characteristic values for bearing, shear at joint details, tension perpendicular to the grain and design density
H2.4 Strength group and joint group classifications for seasoned and unseasoned, hardwood and softwood timber
H3 DESIGN PROPERTIES FOR MGP10, MGP12 AND MGP15 AND A17 STRESS GRADES
APPENDIX I
BUCKLING STRENGTH OF PLYWOOD DIAPHRAGMS
(Normative)
I1 SCOPE
I2 BUCKLING STRENGTH FOR DIAPHRAGMS LOADED IN-PLANE
I2.1 Application
I2.2 Diaphragms with lateral edges supported and subjected to uniformly loaded edge forces
I2.2.1 Slenderness coefficient
I2.2.2 Stability factor for edge shear forces
I2.2.3 Stability factor for edge compression and edge bending moment
I2.3 Diaphragms with lateral edges free and subjected to uniformly loaded edge forces
I2.4 Diaphragms subjected to concentrated edge forces
I2.4.1 Effective width
I2.4.2 Slenderness coefficients
I2.4.3 Stability factor
I2.5 Stiffeners for beam webs
I3 METHOD OF CALCULATION OF SECTION PROPERTIES
I3.1 General
I3.2 Definitions for use in calculation of section properties
I3.3 Calculation method
I3.3.1 Face grain parallel to the span
I3.3.2 Face grain perpendicular to the span
I4 SECTION PROPERTIES FOR STANDARD CONSTRUCTIONS
Previous versions
NZS AS 1720.1:2022 (Includes AS Text)
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