GB/T 51226-2017 in English

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According to the requirements of Document JIANBIAOBIAOHAN [2015] No.182 - Letter of Standard Rating Department of the Ministry of Housing and Urban-Rural Development on conducting the development of Technical standard for multi-story and high rise timber buildings, the drafting group has developed this standard through extensive investigation and study, careful summarization of practical experience and consultation with relevant international and foreign advanced standards and on the basis of widely soliciting for opinions.

Main technical contents of the standard are as follows: 1. general provisions; 2. terms and symbols; 3. material; 4. action; 5. architectural design; 6. structural design; 7. fire design; 8. design of preservation; 9. manufacture, installation and acceptance; and 10. operation and maintenance.

The Ministry of Housing and Urban-Rural Development of the People's Republic of China is in charge of the administration of this standard, and China Southwest Architectural Design and Research Institute Corp., Ltd. is responsible for the explanation of specific technical contents. During the implementation, the opinions or suggestions, if any, can be posted to China Southwest Architectural Design and Research Institute Corp., Ltd. (Address: No.866, North Section, Tianfu Avenue, Chengdu, Sichuan, 610042, China).




Technical standard for multi-story and high rise timber buildings

1 General provisions

1.0.1 This standard is developed with a view to regulating the design, manufacture, installation, acceptance and maintenance of multi-story and high rise timber buildings, achieving advanced technology, safety, applicability, and economic rationality, ensuring quality and protecting environment.

1.0.2 This standard is applicable to design, manufacture, installation, acceptance and maintenance of multi-story timber civil buildings and high rise timber residential buildings and office buildings.

1.0.3 In addition to the standard, the design, manufacture, installation, acceptance and maintenance of multi-story and high rise timber buildings shall also meet the current relevant standards of the nation.

2 Terms and symbols

2.1 Terms

2.1.1

multi-story and high rise timber buildings

timber buildings with more than 3 stories, with the timber structure divided into pure timber structure and hybrid timber structure

2.1.2

pure timber structure

structural form with load-bearing member made of timber or timberwork, including rough sawn and round timber structure, glued-laminated timber structure, light wood frame construction, etc.

 
2.1.3

hybrid timber structure

structural system bearing the load with timber structural member together with steel structure member and reinforced concrete structural member and with timber structure as the main structural form, including vertical hybrid timber structure with reinforced concrete structure or steel structure at lower part and pure timber structure at upper part, timber structure with concrete tube, etc.

2.1.4

wood post-and-beam structure with bracing system

timber structure with post-and-beam as the main vertical load-bearing member for bracing, which serves as the main lateral force resisting member and whose bracing material may be wood or other materials

2.1.5

post-and-beam structure with wood shear wall system

timber structure with post-and-beam as the main vertical load-bearing member and the shear wall as the main lateral force resisting member, with the shear wall being a wall with light wood frame construction or with cross-laminated timber

2.1.6

cross laminated timber shear wall structure

timber structure with cross laminated timber (CLT) shear wall as the main stressed member

2.1.7

vertical hybrid timber structure

structural system in hybrid timber structure, which is with reinforced concrete structure or steel structure at lower part and pure timber structure at upper part

 
2.1.8

timber structure with concrete tube

structural system in hybrid timber structure, which is with the reinforced concrete tube as the main lateral force resisting member and the wooden members as other load-bearing members

2.2 Symbols

2.2.1 Mechanical property of materials

f——the design value of bending strength of steels;

fc，90——the design value of bearing strength perpendicular to grain of wood material;

——the design tensile strength of ordinary bolts;

2.2.2 Actions and action effects

Gi and Gj——the design value of the gravity load of the i-th and j-th stories respectively;

Nt——the design value of axial tension of bolt;

Rd——the design value of bearing capacity of members;

Sd——the effort design value of load combination;

Vi and Vi＋1——the standard value of seismic shear force of the i-th and i+1-th stories respectively.

2.2.3 Geometric parameters

Ae——the effective sectional area of bolt;

Di——the elastic equivalent lateral stiffness of the i-th story;

EJd——the elastic equivalent lateral stiffness of the structure in a major axis direction;

ei——the offset value of the centroid of the i-th story;

hi and hi＋1——the story heights of the i-th and i+1-th stories;

H——the building height;

LBi——the length of the building at the i-th story perpendicular to seismic action direction;

ri——the radius of rotation of the floor plane in which the corresponding mass point of the i-th story is located;

n——the total number of stories for structure calculation;

△i and △i＋1——the inter-storey displacements of i-th and i+1-th stories respectively under the action of seismic action standard value.

2.2.4 Coefficients

α——the ratio of the lateral stiffness resistance;

β——the amplification coefficient of seismic action;

γ0——the structural importance coefficient;

γ2——the ratio of the lateral stiffness of story considering the story height correction;

γRE——the modified coefficient of seismic bearing capacity;

2.2.5 Miscellaneous

C——the deformation limits specified according to the normal use requirements of structural members.

3 Material

3.1 Structural timber

The structural timber used for multi-story and high rise timber buildings may be divided into rough sawn timber, log, dimension lumber, glued-laminated timber, cross-laminated timber, structural composite lumber, wood-based structural panel and other structural sawn timber, with the material grade meeting the current national standard GB 50005 Code for design of timber structures.

3.1.2 The product quality and strength design indexes of structural timber shall meet those specified in current national standards GB 50005 Code for design of timber structures, GB/T 50708 Technical code of glued laminated timber structures and GB/T 26899 Structural glued laminated timber.

3.1.3 The moisture content of structural timber shall meet the following requirements:

1 It shall not be greater than 18% for rough sawn timber or log when used as a plywood for connecting tensile members or not be greater than 25% for rough sawn timber or log used in other cases;

2 It shall not be greater than 19% for dimension lumber, rough sawn timber graded visually in the factory and other structural sawn timber;

3 It shall not be greater than 15% for glued-laminated timber and cross glued-laminated timber;

4 It shall not be greater than 12% for structural composite lumber;

5 It shall not be greater than 15% for all timber, when used as connector, except for rough sawn timber and log.

3.2 Steel and metal connector

3.2.1 Steel which is used for the load-bearing timber structures should be made of Q235 steel, Q345 steel, Q390 steel or Q420 steel, and shall meet those specified in the current national standards GB/T 700 Carbon structural steels and GB/T 1591 High strength low alloy structural steels.

3.2.2 The load-bearing members or connecting materials under the following circumstances should be Grade D carbon structural steel or Grade D or E high strength low alloy structural steel:

1 Welded members or connectors directly bearing dynamic load or vibration load;

2 Members or connectors with working temperature equal to or less than -30℃.

3.2.3 Steel shall meet those specified in current national standards GB 50017 Code for design of steel structures and GB 50011 Code for seismic design of buildings, and shall be guaranteed in terms of tensile strength, elongation rate, yield strength, and content of sulfur and phosphorus. Welded members or connectors shall be guaranteed in terms of the content of carbon and the pass of cold bending test.

3.2.4 The ordinary bolts shall meet the requirements of the current national standards GB/T 5782 Hexagon head bolts and GB/T 5780 Hexagon head bolts - Product grade C.

3.2.5 The anchor bolts should be made of Q235 steel or Q345 steel.

Foreword ii
1 General provisions
2 Terms and symbols
2.1 Terms
2.2 Symbols
3 Material
3.1 Structural timber
3.2 Steel and metal connector
3.3 Other materials
4 Actions
4.1 Vertical load
4.2 Wind load
4.3 Seismic action
5 Architectural design
5.1 General requirements
5.2 Design of outdoor environment
5.3 Building performance design
5.4 Enclosure structure
6 Structural design
6.1 General requirements
6.2 Structure system and type selection
6.3 Structural analysis
6.4 Design of members
6.5 Design of connections
6.6 Construction details measures
7 Fire protection design
7.1 General requirements
7.2 Fire protection requirements
7.3 Construction details of fire protection
7.4 Fire protection measures on construction site
8 Design of preservation
8.1 General requirements
8.2 Preservation requirements
9 Manufacture, installation and acceptance
9.1 General requirements
9.2 Member manufacture
9.3 Installation
9.4 Acceptance
10 Use and maintenance
10.1 General requirements
10.2 Inspection and monitoring
10.3 Maintenance requirements
Annex A Design regulations of cross-laminated timber members
Explanation of wording in this standard
List of quoted standards