Specification for design of boiler steel structures
1 Scope
This document specifies the design principles and methods of supported and suspended boiler steel structures.
This document is applicable to the design of supported and suspended boiler steel structures.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 700 Carbon structural steels
GB/T 1228 High strength bolts with large hexagon head for steel structures
GB/T 1229 High strength large hexagon nuts for steel structures
GB/T 1230 High strength plain washers for steel structures
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 for steel structures
GB/T 5117 Covered electrodes for manual metal arc welding of non-alloy and fine grain steels
GB/T 5118 Covered electrodes for manual metal arc welding of creep-resisting steels
GB/T 5293 Solid wire electrodes, tubular cored electrodes and electrode/flux combinations for submerged arc welding of non alloy and fine grain steels
GB/ T 5313 Steel plate with through-thickness characteristics
GB/T 12470 Solid wire electrodes, tubular cored electrodes and electrode/ flux combinations for submerged arc welding of creep-resisting steels
GB 50009 Load code for the design of building structures
GB 50011 Code for seismic design of buildings
GB 50017-2017 Standard for design of steel structures
GB 50019 Design code for heating ventilation and air conditioning of industrial buildings
GB 50205 Code for acceptance of construction quality of steel structures
GB 50661 Code for welding of steel structures
JGJ 82 Technical specification for high strength bolt connections of steel structures
JGJ 99-2015 Technical specification for steel structure of tall building
NB/T 47043 Technical specification for manufacture of boiler steel structures
NB/T 47055 Painting and packing specification of boiler
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
frame structure
structure with shear and bending resistance composed of rigid connections between columns and girder
3.2
frame-bracing structure
structure of lateral resistant system composed of frame and bracing
3.3
bracing structure
structure with resistance to lateral action by the axial stiffness of the bracing member obliquely arranged in the plane where the girder-column member is located
3.4
main column
column that mainly bears the load of boiler body, wind load and seismic action
3.5
main boiler support level
general name of the load girder suspended or supported by the boiler body at the top of the boiler steel structure
3.6
main girder
girder in the main boiler support level that directly transmits the load of the boiler body to the column
3.7
secondary girder
girder connected to the main girder and transmitting load to the main girder
3.8
horizontal split girder
girder consisting of upper and lower parts (or multiple parts), which are bolted or welded together to work
3.9
deep beam
simply supported single span beam with height span ratio greater than 1/6
3.10
boiler guide
limiting structure for "expansion center" of suspended boiler
4 General
4.1 The boiler steel structure shall be capable of supporting the components of the boiler body and maintaining their relative positions, bearing wind loads, snow loads and seismic actions, and bearing the loads provided by the design unit of the power station and agreed to act on the boiler steel structure. Unless otherwise specified, the boiler steel structure shall not directly bear the dynamic load.
4.2 In the design of boiler steel structure, the structural scheme, materials, connection methods and structural measures shall be reasonably selected to meet the strength, stability and stiffness requirements of structural members during transportation, installation and use.
4.3 The limit state design method based on probability theory shall be adopted for the boiler steel structure, which shall be calculated by partial factor design expression and designed according to the ultimate limit state and serviceability limit state.
4.4 The ultimate limit state shall include: strength failure and brittle fracture of member or connection, inapplicability to continuous load carrying due to excessive deformation, loss of stability of the structure or member, transformation of the structure into maneuvering system, and overturning of structure; the serviceability limit state shall include: deformation affecting the normal service or appearance of structure, member and non-structural member, vibration affecting the serviceability, and local damage affecting the serviceability or durability.
4.5 When the boiler steel structure is designed according to the ultimate limit state, the basic combination and accidental combination of load (action) effect shall be adopted. When the boiler steel structure is designed according to the serviceability limit state, the standard combination of load (action) effect shall be adopted.
4.6 Boiler steel structures in the areas with a seismic fortification intensity of 6 degrees or above shall be subjected to seismic design. This document is applicable to the design of boiler steel structure in areas with seismic fortification intensity of 6 to 9 degrees. When the seismic fortification intensity is greater than 9 degrees, it shall be implemented according to special regulations.
4.7 Open-air layout and tight closed boiler steel structure shall be checked for wind resistance.
4.8 Members shall avoid high temperature (above 150°C). For members subjected to high temperature for a long time, heat insulation or cooling measures shall be taken in addition to selecting appropriate steel.
4.9 The length of temperature section (spacing of expansion joints) of boiler steel structure shall not exceed 120m when arranged in the open air and not exceed 150m when closed tightly, and the influence of temperature stress and temperature deformation may not be included.
4.10 In the design of boiler steel structure located in cold area, measures shall be taken to improve the brittle fracture resistance of the structure.
4.11 No matter what connection form is adopted for the joints of boiler steel structure, when the joints are regarded as rigid connections, the assumption that the intersection angle of members at the joints is unchanged during the stress process shall apply, and the connections shall have sufficient strength to bear all the most unfavorable internal forces transmitted at the ends of the intersection members. When the joint is regarded as articulated, the joint shall have sufficient rotational capacity, but can effectively transmit transverse shear force and axial force.
4.12 The structural safety level of boiler steel structure is Level II, and the importance coefficient (0) shall be taken as 1.0.
4.13 The natural environment conditions required for boiler steel structure design include:
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 General
5 Provisions on materials, design indexes and structural (member) deformation
6 Layout of boiler steel structure
7 Actions and combinations of effects
8 Analysis of structure
9 Beam design
10 Design of column
11 Design of bracing system
12 Design of connections
13 Seismic bearing capacity checking calculation and seismic structure measures of boiler steel structure connection nodes
14 Rust-proof and corrosion resistance treatment of boiler steel structure
