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  • AS 1720.1-1988

    Superseded A superseded Standard is one, which is fully replaced by another Standard, which is a new edition of the same Standard.
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    Timber structures (known as the SAA Timber Structures Code) - Design methods

    Available format(s):  Hardcopy, PDF 1 User, PDF 3 Users, PDF 5 Users, PDF 9 Users

    Superseded date:  30-06-2017

    Language(s): 

    Published date:  01-01-1988

    Publisher:  Standards Australia

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    Table of Contents - (Show below) - (Hide below)

    1 - AS 1720.1-1988 SAA TIMBER STRUCTURES CODE - DESIGN METHODS
    4 - PREFACE
    5 - CONTENTS
    7 - SECTION 1. SCOPE AND GENERAL
    7 - 1.1 SCOPE.
    7 - 1.2 REFERENCED DOCUMENTS.
    7 - 1.3 NEW MATERIALS AND METHODS.
    7 - 1.4 TIMBER QUALITY.
    7 - 1.5 GENERAL DESIGN CONSIDERATIONS.
    7 - 1.5.1 Loads.
    7 - 1.5.1.1 General.
    7 - 1.5.1.2 Load duration.
    8 - 1.5.2 Design methods.
    8 - 1.5.2.1 General.
    8 - 1.5.2.2 Stress analysis.
    8 - 1.5.2.3 Experimentally based design.
    8 - 1.5.3 Other design considerations.
    8 - 1.5.3.1 Stability.
    8 - 1.5.3.2 Buckling restraints.
    8 - 1.5.3.3 Erection and other extraneous forces.
    8 - 1.5.3.4 Secondary stresses.
    8 - 1.5.3.5 Shrinkage.
    8 - 1.5.3.6 Deformations.
    8 - 1.5.3.7 Timber dimensions for engineering calculations.
    8 - 1.5.3.8 Timber in natural pole form.
    8 - 1.5.3.9 Biological deterioration.
    8 - 1.6 DESIGN AND SUPERVISION.
    8 - 1.6.1 Design.
    8 - 1.6.2 Supervision.
    9 - 1.7 WORKMANSHIP AND MAINTENANCE.
    9 - 1.7.1 General.
    9 - 1.7.2 Moisture content.
    9 - 1.7.3 Corrosion.
    9 - 1.7.4 Maintenance.
    9 - 1.8 DEFINITIONS.
    9 - 1.8.1 Administrative definitions.
    9 - 1.8.2 Technical definitions.
    9 - 1.9 NOTATION.
    9 - 1.10 UNITS.
    10 - SECTION 2. BASIC PROPERTIES OF STRUCTURAL TIMBER
    10 - 2.1 GENERAL.
    10 - 2.2 STRUCTURAL CLASSIFICATIONS.
    10 - 2.3 BASIC WORKING STRESSES AND MODULUS OF ELASTICITY.
    10 - 2.3.1 Basic working stresses parallel to grain, and shear stresses in beams.
    10 - 2.3.2 Basic working stress in compression perpendicular to the grain and shear stress at joint details.
    10 - 2.3.3 Basic working stress in compression at an angle to the grain.
    10 - 2.3.4 Modulus of elasticity and rigidity.
    10 - 2.3.5 Basic working stresses in tension (softwoods only).
    10 - 2.4 DESIGN.
    10 - 2.4.1 Permissible stresses.
    10 - 2.4.2 Deflections.
    10 - 2.5 MODIFICATION FACTORS.
    10 - 2.5.1 Duration of load.
    10 - 2.5.1.1 Effect on strength.
    16 - 2.5.1.2 Effect on stiffness.
    17 - 2.5.2 Moisture condition.
    18 - 2.5.3 Temperature.
    18 - 2.5.4 Length and position of bearing.
    18 - 2.5.5 Load sharing.
    18 - 2.5.6 Size factor for flexural and tension members.
    19 - 2.5.7 Stability factor.
    19 - 2.5.8 Material and application factor.
    20 - SECTION 3. DESIGN OF BASIC STRUCTURAL MEMBERS
    20 - 3.1 GENERAL.
    20 - 3.2 BEAM DESIGN.
    20 - 3.2.1 Maximum stresses.
    20 - 3.2.2 Effective span.
    20 - 3.2.3 Slenderness coefficient for lateral buckling.
    21 - 3.2.4 Stability factor.
    21 - 3.2.5 Allowable nominal bending stress.
    21 - 3.2.6 Strength of notched beams.
    21 - 3.2.7 Concentrated loads and partial area loads on grid systems.
    23 - 3.3 COLUMN DESIGN.
    23 - 3.3.1 Maximum stresses.
    23 - 3.3.2 Slenderness coefficients for lateral buckling.
    23 - 3.3.3 Stability factor.
    23 - 3.3.4 Allowable nominal axial stress.
    24 - 3.3.5 Strength of notched columns.
    24 - 3.3.6 Spaced columns.
    24 - 3.4 TENSION MEMBER DESIGN.
    24 - 3.4.1 Axial stress in tension members.
    24 - 3.4.2 Slenderness coefficient.
    24 - 3.4.3 Notched tension members.
    24 - 3.5 COMBINED BENDING AND AXIAL STRESSES.
    24 - 3.5.1 Combined bending and compression.
    24 - 3.5.2 Combined bending and tension.
    25 - SECTION 4. CONNECTIONS
    25 - 4.1 GENERAL.
    25 - 4.1.1 Scope of section.
    25 - 4.1.2 Joint groups.
    25 - 4.1.3 Timber grade.
    25 - 4.1.4 Tendency to split.
    25 - 4.1.5 Eccentric joints.
    25 - 4.2 NAILED JOINTS.
    25 - 4.2.1 Lateral loads.
    27 - 4.2.2 Withdrawal loads.
    28 - 4.3 SCREWED JOINTS.
    28 - 4.3.1 Lateral loads.
    28 - 4.3.2 Withdrawal loads.
    29 - 4.4 BOLTED JOINTS.
    29 - 4.4.1 General.
    29 - 4.4.2 Lateral loads.
    38 - 4.4.3 Axial loads.
    38 - 4.5 COACH SCREWS.
    38 - 4.5.1 General.
    38 - 4.5.2 Lateral loads.
    38 - 4.5.3 Withdrawal loads.
    39 - 4.6 SPLIT-RING CONNECTORS.
    39 - 4.6.1 General.
    39 - 4.6.2 Basic loads.
    39 - 4.6.3 Permissible loads.
    39 - 4.6.4 Spacings, edge and end distances.
    39 - 4.7 SHEAR PLATE CONNECTORS.
    39 - 4.7.1 General.
    39 - 4.7.2 Basic loads.
    39 - 4.7.3 Permissible loads.
    39 - 4.7.4 Spacings, edge and end distances.
    42 - SECTION 5. PLYWOOD
    42 - 5.1 GENERAL.
    42 - 5.2 BASIC WORKING STRESSES AND STIFFNESS.
    42 - 5.3 DESIGN.
    42 - 5.3.1 Permissible stresses.
    42 - 5.3.2 Deflections.
    42 - 5.4 MODIFICATION FACTORS.
    42 - 5.4.1 Duration of load.
    42 - 5.4.2 Moisture condition.
    42 - 5.4.3 Temperature.
    42 - 5.4.4 Plywood assembly factor.
    42 - 5.4.5 Stability factors.
    42 - 5.5 JOINTS.
    42 - 5.5.1 Nailed and screwed joints.
    42 - 5.5.2 Glued joints.
    45 - SECTION 6. ROUND TIMBERS
    45 - 6.1 GENERAL.
    45 - 6.2 BASIC WORKING STRESSES AND STIFFNESS.
    45 - 6.3 DESIGN.
    45 - 6.3.1 Permissible stresses.
    45 - 6.3.2 Deflections.
    45 - 6.4 ADDITIONAL MODIFICATION FACTORS.
    45 - 6.4.1 Factor for immaturity.
    45 - 6.4.2 Shaving factor.
    45 - 6.5 DESIGN DETAILS.
    45 - 6.5.1 Effective pole cross-section.
    45 - 6.5.2 Effective cross-section of untreated timber.
    45 - 6.5.3 Moisture content of timbers in ground contact.
    45 - 6.5.4 Connectors.
    47 - SECTION 7. GLUED-LAMINATED CONSTRUCTION
    47 - 7.1 GENERAL.
    47 - 7.2 DESIGN.
    47 - 7.2.1 Basic and permissible stresses.
    47 - 7.2.2 Deflections.
    47 - 7.3 MODIFICATION FACTORS.
    47 - 7.3.1 Moisture condition.
    47 - 7.3.2 Lamination effects.
    47 - 7.4 OTHER REQUIREMENTS.
    47 - 7.4.1 General.
    47 - 7.4.2 End joints in laminations.
    48 - 7.4.3 Edge joints in laminations.
    48 - 7.4.4 Lamination thickness.
    48 - 7.4.5 Combination of grades of timbers.
    48 - 7.4.6 Combination of species.
    48 - 7.4.7 Curved and tapered members.
    49 - APPENDIX A - ACCEPTANCE TESTING OF TIMBER STRUCTURES AND ELEMENTS
    49 - A1 GENERAL.
    49 - A1.1 Limitations of acceptance testing.
    49 - A1.2 Circumstances requiring tests.
    49 - A1.3 Testing authority.
    49 - A1.4 Information required.
    49 - A2 DEFINITIONS.
    49 - A2.1 Prototype testing-
    49 - A2.2 Proof testing-
    50 - A3 METHOD OF TESTING.
    50 - A3.1 General.
    50 - A3.2 Test load.
    50 - A3.3 Eccentricities.
    50 - A3.4 Load-deflection curve.
    50 - A4 PROOF TESTING.
    50 - A4.1 Equivalent test load.
    50 - A4.2 Loading.
    51 - A4.3 Acceptance for strength.
    51 - A4.4 Acceptance of deflection.
    51 - A5 PROTOTYPE TESTING.
    51 - A5.1 General.
    51 - A5.2 Materials.
    51 - A5.3 Manufacture.
    51 - A5.4 Equivalent test load.
    52 - A5.5 Test procedure.
    52 - A5.5.1 Preloads.
    52 - A5.5.2 Test loading.
    52 - A5.6 Acceptance of prototype.
    52 - A5.6.1 For strength.
    52 - A5.6.2 For deflection.
    52 - A5.6.3 Acceptance of production units.
    52 - A6 REPORT OF TESTS.
    53 - A7 USE OF TESTED STRUCTURES.
    54 - APPENDIX B - BASIC DESIGN PROPERTIES OF STRUCTURAL TIMBER
    55 - APPENDIX C - DESIGN OF BASIC STRUCTURAL MEMBERS
    55 - C1 SCOPE.
    55 - C2 THE MATERIAL CONSTANT .
    56 - C3 SLENDERNESS COEFFICIENTS FOR BEAMS.
    56 - C3.1 General.
    56 - C3.2 End-supported beams.
    56 - C3.2.1 General.
    57 - C3.2.2 Beams with intermediate buckling restraints.
    58 - C3.3 Beams with no intermediate buckling restraints.
    58 - C3.4 Continuously restrained beams.
    58 - C4 SLENDERNESS COEFFICIENTS FOR COLUMNS.
    58 - C4.1 End supported columns.
    58 - C4.2 Continuously restrained columns.
    61 - C5 BEAM-COLUMN BENT ABOUT BOTH AXES.
    61 - C6 SPACED COLUMNS.
    61 - C6.1 Definitions.
    61 - C6.2 Special requirements for spaced columns.
    61 - C6.2.1 Size of connecting pieces.
    61 - C6.2.2 Bolted connections.
    61 - C6.2.3 Glued connections.
    61 - C6.2.4 Spacing of intermediate packing pieces and batten plates.
    61 - C6.2.5 Distance between shafts.
    61 - C6.2.6 Battened columns.
    61 - C6.3 Shear between components.
    61 - C6.3.1 The design shear force.
    62 - C6.3.2 Force effects on packing pieces.
    63 - C6.3.3 Force effects on batten plates.
    63 - C6.4 Permissible loads.
    63 - C6.4.1 Slenderness coefficients.
    63 - C6.4.1.1 Slenderness coefficients of individual shafts.
    63 - C6.4.1.2 Slenderness coefficient of composite cross-sections.
    63 - C6.4.2 Design procedure.
    63 - C7 BUCKLING RESTRAINTS.
    63 - C7.1 Definitions.
    64 - C7.2 Notation.
    64 - C7.3 Columns.
    65 - C7.4 Beam with lateral restraints.
    65 - C7.5 Beam with torsional restraints.
    65 - C8 CONCENTRATED LOADS AND PARTIAL AREA LOADS ON GRID SYSTEMS.
    65 - C8.1 General.
    65 - C8.2 Concentrated load.
    67 - C8.3 Partial area load.
    67 - C9 NOTCHED BEAMS.
    68 - C10 NOTCHED COLUMNS.
    68 - C11 NOTCHED TENSION MEMBERS.
    69 - APPENDIX D - JOINTS IN TIMBER STRUCTURES
    69 - D1 CONNECTORS FOR PLYWOOD.
    69 - D1.1 General.
    69 - D1.2 Strength of joints with plywood.
    70 - D2 DEFORMATION OF JOINTS.
    70 - D2.1 General.
    70 - D2.2 Displacement of nailed and screwed joints in solid timber.
    70 - D2.3 Displacement of solid timber joints fabricated with bolts, split-ring connectors and shear plates connectors.
    72 - D3 EQUATIONS AND TABLES FOR BASIC WORKING LOADS FOR BOLTS.
    72 - D3.1 Load
    72 - D3.2 Load
    73 - APPENDIX E - BUCKLING STRENGTH OF PLYWOOD DIAPHRAGMS
    73 - E1 SCOPE.
    73 - E2 BUCKLING STRENGTH FOR DIAPHRAGMS LOADED IN-PLANE.
    73 - E2.1 General.
    73 - E2.2 Diaphragms with lateral edges supported and subjected to uniformly loaded edge forces.
    75 - E2.3 Diaphragms with lateral edges free and subjected to uniformly loaded edge forces.
    75 - E2.4 Diaphragms subjected to concentrated edge forces.
    76 - E2.5 Stiffeners for beam webs.
    78 - APPENDIX F - CONNECTIONS FOR ROUND TIMBERS
    79 - APPENDIX G - GLUED-LAMINATED CONSTRUCTION - SPECIAL CONDITIONS
    79 - G1 SPECIAL LAMINATION FACTOR.
    79 - G2 DESIGN STRENGTH OF BUTT JOINTS.
    79 - G2.1 General.
    79 - G2.2 Tension members and horizontally laminated beams.
    80 - G2.3 Vertically laminated beams.
    80 - G2.4 Columns.
    80 - G2.5 Conditions of use.
    81 - APPENDIX H - REFERENCED AND RELATED DOCUMENTS
    82 - APPENDIX I - NOTATION AND FACTORS
    87 - INDEX

    Abstract - (Show below) - (Hide below)

    Sets out the methods to be used in the design or appraisal of structural elts out the methods to be used in the design or appraisal of structuralements comprised of timber or wood products, and of structures comprised substantially of timber. It provides design data for sawn timber, glued-laminated timber, timber in pole form, plywood, and various types of fastenings. In addition, it provides methods of test for components or assemblies of unconventional design which are not readily amenable to detailed analysis.

    Scope - (Show below) - (Hide below)

    This Standard sets out the design methods for the structural use of timber which are based on the principles of structural mechanics and on data established by research. The Standard is intended for use in the design or appraisal of structural elements comprised of timber or wood products and of structures comprised substantially of timber. To this end, the Standard provides design data for sawn timber, laminated timber, timber in pole form, plywood and various types of fastenings. In addition, it provides methods of test for components or assemblies of unconventional design which may not be readily amenable to detailed analysis. For ease of use, the simpler design situations are covered in the main body of the text. Related appendices, which form an integral part of the Standard, give acceptable procedures for detailed design situations.

    General Product Information - (Show below) - (Hide below)

    Committee TM-001
    Document Type Standard
    Product Note See also AS 1720.1-1997
    Publisher Standards Australia
    Status Superseded
    Superseded By
    Supersedes

    History - (Show below) - (Hide below)

    Under Revision See DR 94276

    Standards Referencing This Book - (Show below) - (Hide below)

    AS 2870-1996 Residential slabs and footings - Construction
    AS 3826-1998 Strengthening existing buildings for earthquake
    HB 132.2-1999 Structural upgrading of older houses Cyclone areas
    AS 4219-1994 Timber - Stumps and sole plates
    AS/NZS 1328.2:1998 Glued laminated structural timber Guidelines for AS/NZS 1328: Pt 1 for the selection, production and installation of glued laminated structural timber
    AS 2159-1995 Piling - Design and installation
    AS 1649-1998 Timber - Methods of test for mechanical fasteners and connectors - Basic working loads and characteristic strengths
    AS 2050-1995 Installation of roof tiles
    AS 1684-1992 National Timber Framing Code
    AS 3610-1995 Formwork for concrete
    AS/NZS 1576.1:1995 Scaffolding General requirements
    AS 1170.4-1993 Minimum design loads on structures (known as the SAA Loading Code) - Earthquake loads
    HB 132.1-1999 Structural upgrading of older houses Non-cyclone areas
    AS 2424-1991 Plastics building sheets - General installation requirements and design of roofing systems
    AS 3519-1993 Timber - Machine proof-grading
    AS/NZS 1748:1997 Timber - Stress-graded - Product requirements for mechanically stress-graded timber
    HB 2.2-1998 Australian Standards for civil engineering students - Structural engineering
    AS 4132.3-1993 Boat and ship design and construction - Fibre-reinforced plastics construction
    AS 1576.1-1991 Scaffolding - General requirements
    AS 4440-1997 Installation of nailplated timber trusses
    AS 1657-1992 Fixed platforms, walkways, stairways and ladders - Design, construction and installation
    AS/NZS 2269:1994 Plywood - Structural
    AS 3610 SUPP 2-1996 Formwork for concrete - Commentary (Supplement to AS 3610-1995)
    AS/NZS 2589.1:1997 Gypsum linings in residential and light commercial construction - Application and finishing Gypsum plasterboard
    AS 4597-1999 Installation of roof slates and shingles (Non-interlocking type)
    AS/NZS 4357:1995 Structural Laminated Veneer Lumber
    AS 3533.1-1997 Amusement rides and devices - Design and construction
    AS/NZS 1562.3:1996 Design and installation of sheet roof and wall cladding Plastic
    AS/NZS 1562.2:1999 Design and installation of sheet roof and wall cladding Corrugated fibre-reinforced cement (Reconfirmed 2020)
    AS 1576.4-1991 Scaffolding - Suspended scaffolding
    AS 3785.5-1991 Underground mining - Shaft equipment - Headframes
    AS 3818.1-1998 Timber - Heavy structural products - Visually graded General requirements
    AS 1604-1993 Timber - Preservative-treated - Sawn and round
    AS 3818.2-1998 Timber - Heavy structural products - Visually graded Railway track timbers
    AS 3785.5-1998 Underground mining - Shaft equipment Headframes
    AS 3958.2-1992 Ceramic tiles Guide to the selection of a ceramic tiling system
    AS 1418.1-1994 Cranes (including hoists and winches) - General requirements
    AS/NZS 4490:1997 Timber - Stress-graded - Procedures for monitoring structural properties
    AS/NZS 4063:1992 Timber - Stress-graded - In-grade strength and stiffness evaluation
    AS/NZS 2589.2:1997 Gypsum linings in residential and light commercial construction - Application and finishing - Fibre reinforced gypsum plaster
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