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CP 7 : 1997 (ICS 91.080.20)

SINGAPORE STANDARD

Code of practice for the structural use of timber Erratum No. 1 and No. 2 (issued separately) Confirmed in 2014

CP 7 : 1997 (ICS 91.080.20)

SINGAPORE STANDARD

Code of practice for the structural use of timber

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ISBN 9971-67-608-7

SINGAPORE STANDARD CP 7 : 1997

CODE OF PRACTICE FOR SINGAPORE STANDARD CP 7 : 1997

CODE OF PRACTICE FOR ISBN 9971-67-608-7 ABOUT THE NATIONAL STANDARDISATION PROGRAMMECP 7-1997.pdfCONTENTSForewordCODE OF PRACTICESection One. General1.1 Scope1.2 Definitions1.3 Symbols

Section Two. Materials, appliances and components2.1 Materials2.2 Species of timber and their densities and permeabilities2.3 Stress grades for sawn timber2.4 Moisture content of timber2.5 Natural durability of timber

Section Three. Design consideration3.1 General3.2 Timber dimensions3.3 Effective cross-section3.4 Loading3.5 Basic stresses in timber3.6 Grade stresses in sawn timber3.7 Strength groups3.8 Permissible stresses3.9 Modification factors3.10 Flexural members3.11 Compression members3.12 Tension members3.13 Structural frameworks3.14 Floor and roof boarding3.15 Joints3.16 Nailed joints3.17 Screwed joints3.18 Bolted joints3.19 Connectored joints

Section Four. PlywoodSection Five. Workmanship, inspection and maintenance5.1 General5.2 Moisture content5.3 Machining and preparation5.4 Joints5.5 Transportation, storage and handling5.6 Assembly and erection5.7 Treatments5.8 Inspection5.9 Maintenance

Section Six. Testing6.1 General6.2 Test authority6.3 Information required6.4 Quality and manufacture of test structure6.5 Method of testing6.6 Acceptance6.7 Test report6.8 Use of tested structures

APPENDICESA Sizes and grading of tropical structural timbersB Methods for determining the moisture content of timber

TABLES2.1 Names, densities and permeabilities of some structural timbers 2.2 Permeability of timbers to preservatives applied by pressure impregnation at 14 kg/cm22.3 Mositure content of timber for various positions in buildings2.4 Natural durability classification3.1 Green stresses and moduli of elasticity3.2 Dry stresses and moduli of elasticity3.3 Strength group3.4 Green stresses and moduli of elasticity for strength groups3.5 Dry stresses and moduli of elasticity for strength groups3.6 Modification factor K1 for bearing stresses3.7 Modification factor K5 for slenderness ratio and duration of loading on compression members3.8 Maximum depth to breadth ratios (solid members)3.9 Effective length of compression members3.10 Permissible value of sum of stress ratios for compression members subject to bending3.11 Modification of K6 for the effective length of spaced columns3.12 Group classification of timbers for use in determining permissible loads for nails, screws, bolts and connectors3.13 Minimum nail spacings3.14 Basic single shear lateral loads for round wire nails driven at right angles to the grain3.15 Basic withdrawal loads for round wire nails driven at right-angles to the grain3.16 Minimum screws spacings3.17 Basic single shear lateral loads for wood screws inserted at right-angles to the grain3.18 Basic withdrawal loads for wood screws inserted at right angles to the grain3.19 Minimum bolt spacings3.20 Dry basic loads on one bolt in a two-member joint3.21 Sizes of split-ring connectors and minimum sizes of washers3.22 Dimensions of circular grooves for split-ring connectos3.23 Sizes of shear-plate connectors and minimum sizes of washers3.24 End distances for split-ring and shear-plate connectors3.25 Edge distances for split-ring and shear-plate connectors3.26 Spacing for spacing modificaion factor (Ks) for split-ring and shearing plate connectors3.27 Dry basic loads for one split-ring connector unit3.28 Dry basic loads for one shear-plate connector unit3.29 End distance modification factor (Kc) for split-ring and shear-plate connectors3.30 Loaded edge distance modification factor (KD) for split-ring and shear-plate connectors3.31 Limiting values for permissible loads on one shear-plate connector unit6.1 Modification factor K20 for acceptance of strength of timber or plywood structuresA.1 Classification of timbers into shrinkage groupsA.2 Preferred timber sizesA.3 Geometrical properties of square sawn timber at 19% moisture contentA.4 Geometrical properties of surfaced timber at 19% moisture contentA.5 Permissible deviations in curvatureA.6 Grading requirements for multi-purpose stress grades

FIGURES3.1 Position of end bearings3.2 Notched beams3.3 Axes in spaced columns3.4 Joint force acting at an angle to the grain3.5 Split-ring connectors3.6 Shear-plate connectors3.7 Dimensions of circular recesses for shear-plate connector units to BS 15793.8 Connector end and edge distanceA.1 Swivel-handed scribe for determination of slope of grain in woodA.2 Use of scribeA.3 Measurement of slope of grain