GB/T 22395-2008 English PDF (GB/T22395-2008)

GB/T 22395-2008: Specification for design of boiler steel structures
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GB/T 22395-2008
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 27.060.30
J 98
Specification for Design of Boiler Steel Structures
ISSUED ON: SEPTEMBER26, 2008
IMPLEMENTED ON: MARCH 1, 2009
Issued by: General Administration of Quality Supervision, Inspection and
Quarantine of the People's Republic of China;
Standardization Administration of the People's Republic of China.
Table of Contents
Foreword ... 3 
1 Scope ... 5 
2 Normative References ... 5 
3 Symbols and Abbreviations ... 6 
4 General Requirements ... 9 
5 Requirements for Material, Design Index and Structure (Member) Deformation . 11 
6 Arrangement of Boiler Steel Structure ... 17 
7 Action and Its Effect Combination ... 20 
8 Static Analysis ... 36 
9 Beam Design ... 39 
10 Column Design ... 64 
11 Design of Brace System ... 100 
12 Connection Design ... 108 
13 Seismic Structural Measures and Relevant Requirements of Boiler Steel
Structure ... 132 
14 Stiffening Bar Design ... 134 
15 Design of Boiler Platform and Stair ... 139 
16 Anti-rust and Anti-corrosion Treatment of Boiler Steel Structure ... 142 
Specification for Design of Boiler Steel Structures
1 Scope
This standard specifies the design principles and methods of bottom-supported and
top-supported boiler steel structures.
This standard is applicable to the design of bottom-supported and top-supported boiler steel
structures.
2 Normative References
The following normative documents contain provisions which, through reference in this text,
constitute provisions of this standard. For dated references, subsequent amendments to
(excluding amending errors in the text), or revisions of, any of these publications do not apply.
However, all parties coming to an agreement according to this standard are encouraged to
study whether the latest edition of the normative document is applicable. For undated
references, the latest edition of the normative document applies.
GB/T 700 Carbon Structural Steels (GB/T 700-2006, ISO 630: 1995, Structural
Steels - Plates, Wide Flats, Bars, Sections and Profiles, NEQ)
GB/T 1228 High Strength Bolts with Large Hexagon Head for Steel Structures [GB/T
1228-2006, ISO 7412: 1984, Hexagon Bolts for High Structural Bolting
with Large Width across Flats(Short Thread Length) - Product Grade C -
Property Classes 8.8 and 10.9, NEQ]
GB/T 1229 High Strength Large Hexagon Nuts for Steel Structures (GB/T 1229-2006,
ISO 4775: 1984, Hexagon Nuts for High Strength Structural Bolting with
Large Width across Flats - Product Grade B - Property Classes 8 and 10,
NEQ)
GB/T 1230 High Strength Plain Washers for Steel Structures (GB/T 1230-2006, ISO
7416: 1984, Plain Washers, Chamfered, Hardened and Tempered for
High Strength Structural Bolting, NEQ)
GB/T 1231 Specifications of High Strength Bolts with Large Hexagon Head, Large
Hexagon Nuts, Plain Washers for Steel Structures
GB/T 1591 High Strength Low Alloy Structural Steels
GB/T 3632 Sets of Torshear Type High Strength Bolt Hexagon Nut and Plain Washer
μz - the height variation coefficient of wind pressure;
ξ - the pulsation enhancement coefficient of wind load; the parameter used to calculate the
overall stability of beam;
v - the pulsation influence coefficient of wind load;
φz - the structural vibration mode coefficient;
ζ - the Structural damping ratio;
φ - the stability coefficient of axial compressive member;
φb and φ′b - the overall stability coefficient of beam;
γRE - the seismic adjustment coefficient of bearing capacity;
ψ - the combination value coefficient.
4 General Requirements
4.1 This standard is formulated in order to implement the current national standard in the
boiler steel structure design and achieve advanced technology, economic rationality, safety
and usability and guaranteed quality by considering the particularity of boiler steel structure
4.2 Boiler steel structure shall support all components of boiler body and maintain the
relative position between them, and shall also bear wind load, snow load, earthquake action
and other load provided by other design organization through the agreement of boiler design
organization acted on the boiler steel structure. Except the particular requirements, boiler steel
structure shall not directly bear the dynamic load.
4.3 The boiler steel structure shall adopt limit state design method based on probability
theory, adopt the design expression of partial coefficient for calculation and adopt limit state
of bearing capacity and limit state of normal use for design.
4.4 If the boiler steel structure is designed based on the limit state of bearing capacity, the
fundamental combination of load (action) effect shall be considered; where necessary, the
occasional combination of load (action) effect shall be considered. If the boiler steel structure
is designed based on the limit state of normal use, the characteristic combination of load
(action) effect shall be considered.
4.5 The boiler steel structure in area with seismic fortification intensity of Degree 6 or
above shall be subjected to seismic design. This standard is applicable to the design of boiler
steel structure with seismic fortification intensity of Degrees 6~9. If the intensity is greater
than Degree 9, it shall be in accordance with the relevant requirements.
4.6 Checking calculation of wind resistance shall be carried out to the boiler steel structure
arranged in the open air or closed tightly.
4.7 The member shall avoid high temperature (above 150℃) action as possible, as for the
member subjected to high temperature action for long term, suitable steel shall be selected
and meanwhile necessary thermal insulation or cooling measures shall be taken.
4.8 During the design of boiler steel structure set at cold area, measures shall be taken to
improve the brittle fracture resistance of steel structure.
4.9 No matter what connection type is adopted for the node of boiler steel structure, where
the node is regarded as rigid connection, it shall meet the assumption that the intersection
angle of member at node point is unchanged in load-bearing process, at the same time, the
connection shall be provided with sufficient strength to bear all the most unfavorable internal
force transmitted from the intersectional member end; where the node is regarded as hinged
connection, the connection shall be provided with sufficient rotation capacity but it shall be
able to transmit the horizontal shear force and axial force effectively.
4.10 Unless otherwise specified, the importance coefficient γ0 of boiler steel structure shall
be 1.0.
4.11 The natural environmental conditions required for design of boiler steel structure
include:
a) Basic wind pressure;
b) Ground roughness category;
c) Reference snow pressure;
d) Seismic fortification intensity (design basic seismic acceleration);
e) Design earthquake group;
f) Site category;
g) Working temperature.
4.12 The design of boiler steel structure shall be in accordance with the supply contract and
technical agreement signed with the user and shall cooperate closely and intercoordinate with
other design organization.
6.1.7 Combination type boiler steel structure has certain connection with boiler plant structure,
for example: the boiler top beam gird is directly placed on the boiler plant structure, or the
boiler steel structure has several connections with boiler plant structure, when one structure
bears the load, it will affect the other structure. Combination type boiler steel structure should
not be adopted generally.
6.2 Arrangement principle for boiler steel structure
6.2.1 Economic and reasonable structural system with good load carrying performance shall
be selected for the boiler steel structure according to the features and external conditions of
boiler. Plane and facade arrangement shall be regular and symmetrical and provided with good
integrity to avoid structural stiffness mutation as possible.
6.2.2 In order to ensure the space working of structure, improve the integral stiffness of
structure, bear and transmit horizontal force, avoid the lateral instability of compression rod and
ensure the stability during structure installation, reliable brace system shall be arranged with
different conditions of structure.
6.2.3 The arrangement of boiler steel structure shall consider the following items:
a) Space and channel required for the support, hanging, installation, operation and
maintenance of boiler body and accessory equipment.
b) Where there are seismic and wind resistance requirements, truss-type boiler steel
structure should be selected.
c) The structure shall consider economic requirements:
1) The boiler steel structure and its components shall have simple structure and be
convenient for manufacture;
2) Necessary member arrangement: boiler steel structure shall be arranged with
member necessary for keeping its strength, stiffness and stability;
3) Direct transmission of load: the member shall transmit force explicitly to transmit
the load to the foundation through beam, column and bracing in the shortest way;
4) The arrangement of column and beam shall ensure the minimum quantity of
column; the length of beam should not be overlong; the arrangement of column
and beam shall be analyzed and compared to adopt the most economical scheme;
5) Make the member be multi-use as possible and make full use of the characteristics
of the member to make it bear multiple actions.
d) Easy of transportation and installation: the member shall avoid overweight and
over-limit transportation and be ease of installation and emplacement.
7.2.7 Wind load distribution:
a) The boiler closed tightly or the boiler arranged outdoor without guiding device:
distribute the wind load to the load-bearing node of boiler steel structure according to
the wind area borne by each node of boiler steel structure based on the characteristic
value of wind load of different height.
b) The boiler arranged outdoor with guiding device: calculate the wind load borne by each
guiding device according to characteristic value of wind load of different height and the
wind area of furnace restricted by the guiding device, and act it on the corresponding
position of boiler steel structure. In this case, the wind load borne by each node of
boiler steel structure shall be calculated by adopting appropriate wind area according to
relevant requirements.
7.3 Earthquake action
7.3.1 Boiler steel structure after seismic fortification: under the effect of local frequent
earthquakes, the buildings are generally free from any damage or can be in service continually
without any repair; under the effect of the earthquakes at the local seismic fortification intensity,
the buildings are possible to be damaged but still can be in service continually after general
repair or without any repair; under the impact of the rare earthquake stronger than the local
seismic fortification intensity estimation, the buildings are not collapsed or occurs
life-threatening serious damage.
7.3.2 The seismic fortification intensity must be determined according to the document
(drawing) examined, approved and issued by the authority as prescribed by the nation; generally,
the basic seismic intensity in China's zonation map of ground motion parameter may be
adopted.
7.3.3 For boiler steel structure with seismic fortification intensity of Degree 6, built in
Category IV site and belongs to Category B building, boiler steel structure with Degree 7 or
above, seismic checking of section under the action of frequent earthquakes shall be carried out.
For boiler steel structure with irregular structural layout and visible weak layer, with height
greater than 150m, or built in Degree 9 area and belongs to Category B buildings, elastic-plastic
deformation under the action of rare earthquakes shall be carried out.
Where the seismic fortification intensity is Degree 6, besides the boiler steel structure built in
Category IV site and belongs to Category B buildings, earthquake action calculation and
seismic checking of section may not be carried out.
7.3.4 Power plant boiler steel structure with unit capacity of 300MW or above or planning
capacity of 800MW or above belongs to Category B buildings and its earthquake action shall
meet the requirements of local seismic fortification intensity. Generally, its seismic measures
are: where the seismic fortification intensity is Degree 6~8, it shall meet the requirements of
local seismic fortification intensity increased by 1; where the seismic fortification intensity is
8.1.7 In order to carry out static analysis, the following operations shall be carried out
according to the data provided in the general drawing of boiler and by the other design
department:
a) Determine the arrangement of column plane;
b) Determine the arrangement of vertical bracing;
c) Determine the elevation and arrangement of main plane of horizontal bracing;
d) Perfect the arrangement of platform stairs;
e) Look up in the Contract and the Technical Agreement to meet the customer's demands;
f) Count and distribute the load (action).
8.1.8 In order to reach the planned target, the arrangement and section of rod piece shall be
adjusted during calculation process with the purpose of optimization.
8.1.9 The following drawing information shall be completed after the calculation result is
confirmed to be reasonable and correct through analytical judgement:
a) Foundation load drawing. The plane position of column at 0m elevation and the vertical
force, horizontal force and bending moment acted on the foundation under various
working conditions shall be shown in the drawing.
b) Plan drawing of all vertical bracings. Generally, the interrelationship dimension of each
member, beam elevation, column joint elevation, name and sectional dimension of
column, name, sectional dimension and internal force of vertical bracing shall be
marked in the drawing.
c) All horizontal plan drawings. Generally, the interrelationship dimension of each
member,...