GB 50206-2012 English PDF

GB 50206-2012: Code for acceptance of construction quality of timber structures
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GB 50206-2012
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
UDC
P GB 50206-2012
Code for Acceptance of Construction
Quality of Timber Structures
ISSUED ON: MARCH 30, 2012
IMPLEMENTED ON: AUGUST 1, 2012
Issued by: Ministry of Housing and Urban-Rural Development of the
People's Republic of China;
General Administration of Quality Supervision, Inspection
and Quarantine of the People's Republic of China.
Table of Contents
Foreword ... 4
1 General Provisions ... 8
2 Terms ... 9
3 Basic Requirements ... 14
4 Rough Sawn and Round Timber Structure ... 17
4.1 General Requirements ... 17
4.2 Dominant Items ... 17
4.3 General Items ... 22
5 Glued-laminated Timber Structure ... 25
5.1 General Requirements ... 25
5.2 Dominant Items ... 25
5.3 General Items ... 27
6 Light Wood Frame Construction ... 30
6.1 General Requirements ... 30
6.2 Dominant Items ... 30
6.3 General Items ... 33
7 Protection of Timber Structure ... 37
7.1 General Requirements ... 37
7.2 Dominant Items ... 37
7.3 General Items ... 41
8 Acceptance of Sub-subsection Project of Timber Structure ... 43
Appendix A Timber Strength Grade Inspection Method ... 44
Appendix B Standard for Materials of Rough Sawn Timber, Log and Panel 45
Appendix C Inspection Method for Moisture Content of Timber ... 48
Appendix D Bending Test of Steel Nail ... 50
Appendix E Allowable Error for Manufacture and Installation of Wood
Structure ... 53
Appendix F Test Method for Mechanical Property of Bending Wood Members
... 58
Appendix G Inspection Method for Material Grade of Dimension Lumber 62
Appendix H Mechanical Properties Index of Wood-based Structural Panel 71
Appendix J Requirements for Nailed Connection of Light Wood Frame
Construction Designed Based on Structure ... 73
Appendix K Requirements for Retention and Penetration of Various
Protective-treated Wood Members ... 75
Explanation of Wording in this Code ... 79
List of Quoted Standards ... 80
Code for Acceptance of Construction
Quality of Timber Structures
1 General Provisions
1.0.1 This code is formulated with a view to strengthening the quality management
of construction work, unifying the construction quality acceptance of timber work and
guaranteeing the project quality.
1.0.2 This code is applicable to the construction quality acceptance for timber
structure works like rough sawn and round timber structure, glued-laminated timber
structure and light wood frame construction.
1.0.3 The construction quality acceptance of timber structure work shall be based on
engineering design document. The requirements of construction quality acceptance in
design document and engineering contracting contract shall not be lower than those
specified in this code.
1.0.4 This code shall be used together with the current national standard "Unified
Standard for Constructional Quality Acceptance of Building Engineering" (GB 50300).
1.0.5 The construction quality acceptance for timber structure work shall not only
meet the requirements in this code, but also comply with those specified in the current
relevant ones of the nation.
2 Terms
2.0.1 Rough sawn and round timber structure
Load bearing member structure manufactured from rough sawn timber (including slab)
or log.
2.0.2 Glued-laminated timber structure
Load bearing member structure manufactured from glued-laminated timber.
2.0.3 Light wood frame construction
Wood structure composed of shear wall and tabula (floor system and roof)
manufactured from dimension lumber and wood-based structural panel through nailed
connection, generally used for 1~3F buildings.
2.0.4 Dimension lumber
A kind of wood product made through drying, polishing, grading and stamping on a
series of log sawn timber with section width and height within certain limits.
2.0.5 Visually stress-graded dimension lumber
The dimension lumber for which the lumber and strength grade are divided according
to the severity of various defects visible to naked eyes based on the specified
standard.
2.0.6 Machine stress-grated dimension lumber
The dimension lumber for which nondestructive test is carried out with mechanical
stress determination equipment, and the lumber grade and strength grade are divided
according to the measured elasticity modulus or other physical and mechanical
indexes based on the specified standard, hereinafter referred to as machine
stress-graded dimension lumber.
2.0.7 Log
Cut down trunk, removing bark, branch and treetop.
2.0.8 Rough sawn timber
tension and shear force between members, and are mainly used for connection of
timber truss nodes manufactured with dimension lumbers.
2.0.16 Truss connected with truss plates
The truss made of dimension lumber together with truss plate, which is mainly used
for the floor system and roof load bearing member of the light wood frame
construction.
2.0.17 Nailed connection
A pin connection type transmitting acting force between members through utilizing the
bending resistance and shear capacity of the round nail and the pressure-bearing
capacity of the nail hole wall.
2.0.18 Bolted connection
A pin connection type transmitting acting force between members through utilizing the
bending resistance and shear capacity of the bolt and the pressure-bearing capacity
of the bolt hole wall.
2.0.19 Step joint
A connection type transmitting acting force between members through utilizing the
pressure-bearing and shear capacity where the wood member is grooved to bear
another wood member.
2.0.20 Stud
The vertical member in the wall of light wood frame construction, serving as the main
compression member and guaranteeing the stability and integrity of the out-of-plane
structural sheathing.
2.0.21 Structural sheathing
Wood-based structural panel of light wood frame construction which is nailed on
single side or both sides of the wall timber frame, or on the top surface of the floor joist
or rafter, respectively referred to as wall panel, floor panel and roof panel.
2.0.22 Joist
The bending wood member with relatively small section size (including wood I-joist)
used for floor system or ceiling, which is respectively referred to as floor joist or ceiling
joist.
The stamp pattern indicating the place of origin, manufacturer, quality grade,
specification, executive standard, certification body etc. of the material, member and
accessory.
2.0.32 Inspection lot
The inspection body composed of a certain quantity of samples collected for
inspection according to the same production condition or the specified mode.
2.0.33 Product lot
The inspection scope divided due to the difference of material, manufacturing,
approach time or production batch within the range of the specified inspection lot.
2.0.34 On-site acceptance
The inspection carried out for the materials, members, accessories and equipment
approaching the construction site according to relevant standard requirements so as
to verify whether the product quality is acceptable or not.
2.0.35 Handover inspection
The verification activity for the construction quality through mutual inspection by the
undertaking party of the next procedure and the completing party of the previous
procedure for the completed procedures.
2.0.36 Evidential testing
The test carried out by the testing organization with corresponding qualification
through field sampling by personnel concerned of the construction organization under
the supervision of supervision organization or construction organization.
timber and the timber surface shall be polished with abrasive paper.
2 Grade B: structural member is exposed, the painting on appearance is
mechanically polished; occasional skips-in-planting and tiny defect and gap are
allowable on the surface but the hole on floppy node is unallowable.
3 Grade C: structural member is not exposed, and the member surface is not
required to be processed or polished.
3.0.6 Construction quality of timber structure project shall be controlled according to
the following requirements:
1 Design document of this project shall be provided.
2 On-site acceptance shall be carried out for the timber, wood product, steel and
connector used for the timber structure project. For materials or semi-finished
products involved in structure safety and use function, evidential testing shall be
carried out according to this code or corresponding professional engineering quality
acceptance standard, and the sampling and delivery for inspection shall be carried out
under the supervision of supervision engineer or the technical principal of the
construction organization.
3 Quality control for each procedure shall be carried out according to the relevant
requirements of this code; inspection shall be carried out on completion of each
procedure.
4 Handover inspection shall be carried out for relevant disciplines, and shall be
recorded. The construction of next procedure shall not be carried out without the
inspection by the supervision engineer and the technical principal of construction
organization.
5 Completion documents like completion drawing and written materials of timber
structure project shall be provided.
3.0.7 Where new technology (new material, new structure and new process)
required for timber structure construction hasn't listed in current relevant national
standard, the construction organization shall obtain the approval of the local
competent administrative department of construction engineering quality, and
organize expert panel to demonstrate together with the design, supervision and
construction organizations; meanwhile, it shall determine the construction quality
acceptance method and inspection standard, hereby determine the dominant item for
the construction of relevant timber structure project.
3.0.8 The lumber grade of the material, member and accessory adopted for the
round steel adopted for lower chord of wood-and-steel composite truss, not only the
performance inspection for tensile yield strength, ultimate strength and elongation, but
also the cold bending inspection shall be carried out. It shall also meet the round steel
material standard specified in design document.
Inspection quantity: randomly take 2 pieces from each steel species in each
inspection lot.
Inspection method: the sampling method, sample preparation and tensile test method
shall respectively comply with the relevant requirements of the current national
standards "Rules for Sampling in Mechanical and Technological Testing of Steel
Products" (GB 2975) and "Metallic Materials - Test Pieces for Tensile Testing" (GB
6397) and "Metallic Materials -Tensile Testing at Ambient Temperature" (GB/T 228).
4.2.7 Electrodes shall meet the requirements of the current national standard
"Carbon Steel Covered Electrodes" (GB 5117) and "Low Alloy Steel Covered
Electrodes" (GB 5118); their type shall be matched with the adopted steel and they
shall have product quality certificate.
Inspection quantity: total number of inspection lot.
Inspection method: inspect by comparison between physical object and product
quality certificate.
4.2.8 The bolt and nut shall have product quality certificate, and their performance
shall meet the requirements of the current national standard "Hexagon Head Bolts"
(GB 5782) and "Hexagon Head Bolts - Product Grade C" (GB 5780).
Inspection quantity: total number of inspection lot.
Inspection method: inspect by comparison between physical object and product
quality certificate.
4.2.9 The round nail shall have product quality certificate, and its performance shall
meet the relevant requirements of the current professional standard "Round Nails for
General Uses" (YB/T 5002). Evidential testing for bending strength of nail shall be
carried out where the bending yield strength of nail is specified in design document.
Inspection quantity: randomly take 10 round nails from each specification in each
inspection lot.
Inspection method: inspect the product quality certificate and testing report. Strength
evidential testing method shall meet those specified Appendix D of this code.
4.2.10 Round steel tie bar shall meet the following requirements:
1 The round steel tie bar shall be straight and flat, and double-side splice welding
shall be adopted for the joint. The splice diameter shall not be less than 75% of the tie
bar diameter, and the length on one side of the joint shall not be less than 4 times of
the tie bar diameter. The weld leg height and weld length shall meet the requirements
of the design document.
2 The subplate under the nut shall meet the requirements of the design document
and shall not be less than the requirements of Item 2 in Article 4.3.3 of this code.
3 Where the diameter of the lower chord round steel tie bar of wood-and-steel
composite truss, the main tension web rod of truss and the pedal-type node tie bar
and bolt is greater than 20mm, double-nut self-locking shall be adopted. The
protruding length of screw rod from the nut shall not be less than 80% of the screw rod
diameter.
Inspection quantity: total number of inspection lot.
Inspection method: measurement, inspection of handover inspection report.
4.2.11 For the bearing steel member, the height of node weld leg shall not be less
than the requirements of design document; unless otherwise stated in the design
document, the weld quality shall not be less than Grade III while that of the tension
member working below -30 shall not be less than Grade II.
Inspection quantity: all stressed welds of the inspection lot.
Inspection method: inspect according to the relevant requirements of the current
professional standard "Technical Specification for Welding of Steel Structure of
Building" (JGJ 81), and inspect the handover inspection report.
4.2.12 The specification and quantity of connectors (nails and bolts) used for
nailed connection and bolted connection shall meet the requirements of the
design document.
Inspection quantit...