Some standard content:
1 Subject content and scope of application
Standard of the Machinery Industry of the People's Republic of China
Standard for seismic design of boiler frames
JB5339-91
1.1 This standard specifies the calculation method of the site index of the site where the boiler frame is located, the calculation method of the seismic action of the frame, the combination method of the seismic action effect and other load effects, and the seismic structural measures of the frame, so as to minimize the damage to the boiler frame during an earthquake and avoid causing a large-scale and long-term power outage in the power system.
1.2 This standard is applicable to the seismic design of boiler frames in areas with a seismic fortification intensity of 6 to 9 degrees. When the seismic fortification intensity is 10 degrees, the seismic design of the boiler frame should be subject to relevant special research and fortification. 2 Basic provisions
2.1 The fortification intensity of the boiler frame is generally based on the basic intensity specified by the state. 2.2 For construction sites that have undergone seismic hazard analysis, the seismic motion parameters obtained from the seismic hazard analysis can be used to design the boiler frame. 2.3 Boiler frames in areas with a basic intensity of 6 degrees generally do not need to be protected. For important power stations built in areas with a basic intensity of 6 degrees, when users need to protect according to 7 degrees, earthquake-resistant structural measures can be taken in accordance with Article 5.10 of this standard. 2.4 Power plant boiler frames with a single unit capacity of less than 6MW generally do not need to be protected. 2.5 When conducting earthquake-resistant design, in addition to the provisions of this standard, other relevant provisions of the "Electric Power Facilities Earthquake-Resistant Design Code", "Steel Structure Design Code" and "Building Structure Load Code" must be met. 3 Site, foundation and foundation liquefaction determination
3.1 Site
3.1.1 The site is evaluated based on the average shear modulus G, kPa and the thickness of the cover layer H, m. The average shear modulus of the site is calculated according to formula (1): C
wherein; G is the average shear modulus of the site, kPa; the thickness of the i-th soil layer, m;
p-the density of the i-th soil layer, t/m;
V. the shear wave velocity of the i-th soil layer, m/s;
n-the number of layers of the covering layer.
When the thickness of the covering soil layer exceeds 20m, take the average shear modulus within the depth range of 20m below the surface; when the thickness of the covering soil layer is less than 20m, take the average shear modulus within the actual thickness range. The site covering thickness H is the distance from the ground to the top surface of the hard soil layer (the soil layer with an average shear modulus G not less than 500000kPa or a shear wave velocity Vs greater than 500m/s).
3.1.2 According to the average shear modulus and the thickness of the covering soil layer of the site where the boiler frame is located, the site index is calculated according to formula (2), and it is used as the comprehensive evaluation mark of the site.
Approved by the Ministry of Machinery and Electronics Industry in 1991-0628
Implemented on 1992-07-01
In the formula: H-site index;
JB5339-91
ai, a2 respectively represent the influence ratio of the site soil stiffness and thickness on the seismic effect. Example: The values are as follows:
M-the contribution of the average shear modulus to the site index, calculated according to formula (3): H.=1-e-0 86(G300· 10
When G≤30000kPa, take μg=0
The contribution of the thickness of the covering soil layer to the site index is calculated according to formula (4): Me-0.5(H-5).10--
When H≤5m, take =1
H--thickness of the covering soil layer;
When G>500000kPa, or H≤5m, take μ=1 in formula (2)3.1.3When determining the seismic measures for the boiler frame, the corresponding relationship between the site name and the site index shall be determined according to Table 1. Table 1 Site index
Site name
Site index
Hard site
1≥μ>0.75
Medium hard site||t t||0.75≥μ>0.35
Medium soft site
0.35≥μ>0.05
Soft site
The selection of the construction site for the boiler frame shall be determined together with the power station in accordance with the "Code for Seismic Design of Electric Power Facilities". Generally determined together with the power station, the average shear modulus and cover thickness of the site shall be provided by the power station design department. Or it can be determined according to Table 1 based on the site name provided by the power station design department. 3.2 Determination of foundation and foundation liquefaction
3.2.1 The determination and verification of the seismic bearing capacity of the foundation soil of the natural foundation shall be carried out in accordance with the "Code for Seismic Design of Electric Power Facilities". 3.2.2 The determination of the liquefaction of the foundation during an earthquake shall be carried out in accordance with the "Code for Seismic Design of Electric Power Facilities". "Anti-capsule design code" is implemented. 4 Calculation method of seismic action on boiler frame
4.1 Calculation of seismic action
4.1.1 Calculate the ground action of boiler frame. Except as provided in Article 4.1.7, the horizontal seismic action is generally calculated in the two main axis directions of the boiler frame, and the seismic strength is checked.
4.1.2 The calculation of seismic action on boiler frame shall be divided into two parts. 4.1.2.1 Calculation of ground action on frame (base shear method) QCaW
Where; C—structural coefficient, take C=0.31
α—seismic influence coefficient, determined according to Article 4.1.2 based on the basic period of the frame; Q. Standard value of seismic action of total horizontal force of structure; (5)||t t||W is the total equivalent gravity load of the structure, which is the representative value of the total gravity load, including the total deadweight of the frame and the supporting load (excluding the weight of the suspended furnace).
The seismic action P of the calculated mass point i of the frame is calculated according to formula (6), see Figure 1. P
W is the representative value of the gravity load of the mass point i; W,H
(1-C)Q.
C,-the correction coefficient of the seismic action at the top of the frame, calculated by formula (7): C=0.081T+0.01
W is the structural self-period of the frame, S. JB5339-91
After the seismic action of each mass point is obtained by formula (6), a horizontal seismic action △AP is added to the top of the frame. △P. is calculated by formula (8). AP.-CQ
4.1.2.2 The seismic action Pi=CαW
of the suspended boiler body acting on the frame through the guide device i: P--the standard value of the horizontal seismic action of the i-th mass point; a structural coefficient, take C=0.3;
seismic influence coefficient, the value is the same as that of formula (5); W; a representative value of the gravity load concentrated on the i-th guide device of the suspended boiler body. ..*(8)
（9）
The seismic action of the cold and hot air ducts, reheat ducts and pulverized coal ducts suspended by the centralized downcomer of the boiler shell acting on the frame is calculated in the same way as the boiler body.
4.1.3 The horizontal seismic influence coefficient of the boiler frame is determined according to Figure 2, and the maximum value α of the horizontal seismic influence coefficient is adopted according to Table 2. 0.45 tons
a frame of sustained collection period,
In Figure 2, the frame of waiting collection period T. Calculate Tc=0.65-0.45u
by formula (10): u-
is a site index, see formula (2).
When μ is less than 0.2 and the basic period of the frame is greater than 1.5s, the T value calculated by formula (10) should be increased by 0.15s. (10)
JB-3339-91
Table 2 Maximum value of horizontal seismic influence coefficient
4.1.1 The seismic action calculated by formula (6) is distributed to each node of the rigid layer according to the vertical load of the furnace frame node. 9
4.1.5 For suspended boilers without guide devices, the seismic action of the frame is calculated according to formula (5) and formula (6) or Appendix A. The seismic action of the furnace body only acts on the top end of the frame, and the following values are taken: 7-degree earthquake P = 0.015Ws
8-degree earthquake P = 0.030W,
9-degree earthquake P = 0.060W,
W. A representative value of the gravity load of the furnace. 4.1.6 When conditions are met, the seismic action of the boiler frame can be calculated using the decomposition response spectrum. The specific method is shown in Appendix A of this standard. 4.1.7 For structures with a span greater than 24m and a large sense width, it is necessary to calculate the vertical seismic action in the 8-degree and 9-degree earthquake zones (this vertical action is not transmitted to other components). The vertical seismic action of the 8-degree earthquake is 10% of the calculated structural gravity; the 9-degree is 20% of the calculated structural gravity. 4.2 Earthquake strength check
4.2.1 The earthquake strength core of the boiler frame section shall satisfy the formula (11) S≤f./YR
Where: S is the load effect value, calculated by formula (12), f,- is the material strength design value of the component:
Ys resistance adjustment coefficient, adopted according to Table 3
Table 3 resistance adjustment coefficient
Other components
Component welds and bolts
4.2.2 The earthquake effect of the boiler frame and other load effects are combined according to formula (12). S=1.2Sp+1.4Sm+1.4Sw
In the formula, Sp is the effect value of the constant load;
S is the effect value of the horizontal earthquake action;
（12）
α is the wind load combination coefficient. Generally, it is taken as =0; but for tower structures with a height greater than 80m and structures with a height-to-width ratio greater than or equal to 5, it is taken as ≤=0.2.
Sw is the effect value of the wind load.
5Structural measures for seismic design of boiler frames
5.1 Overall layout
5.1.1 Boiler frames in earthquake zones should generally be designed as independent systems. When connected with plant buildings, effective measures should be taken to avoid bearing the seismic effects of plant buildings.
5.1.2 The plane and elevation layout of the frame should be regular, symmetrical, and of uniform quality, and structures with sudden changes in stiffness should be avoided as much as possible. 5.1.3 The frame should adopt a truss structure.
5.1.1 Vertical supports and horizontal supports should be arranged continuously so that the earthquake action can be directly transmitted to the foundation. 5.1.5 Vertical supports should be arranged reasonably to avoid excessive upward force on the columns. JB533991
5.1.6 For the supporting frame structure with guard plates, the area where the guard plates are arranged and the guard plates are embedded with the columns and beams can be regarded as the plate plane.
5.1.7 The connection design between the bars should be strengthened to ensure the overall stability of the frame system and coordinate the deformation between the components. 5.2 Column foot
5.2.1 The anchor bolts connected to the column foot should be able to withstand the upward force caused by the earthquake action. 5.2.2 If the side pressure of the bottom plate end face connected to the column foot exceeds the compressive strength of the foundation concrete, a shear plate should be set, see Figure 3. Figure 3
Shear plate
5.2.3 The column base should be embedded, and the embedding depth is determined according to the load-bearing size, generally 300-1000mm5.3 Column segment connection joints
5.3.1 The position and form of the column segment connection joints are determined according to the form of the frame (i.e. frame or truss structure). For frame structures, the joints should be close to the middle of the two nodes, and the nodes should be designed as rigid connections. For truss structures, the joints should be close to the lower node at an elevation of about 1m. S.4 Connection between beams and columns
5.4.1 The connection between beams and columns should be designed according to the form of the frame. The rigid connection should not be lower than the strength of the connected beam, and stiffeners should be set at the corresponding positions of the columns. See Figure 4.
5.5 Connection between furnace roof beam and column top
JB5339-91
5.5.1 The main beam is supported on the column top, and it is preferably connected and fixed by fasteners in a hinged form using arc-shaped supports or other forms. The number of screw inspections is configured according to the earthquake action. After the boiler body is subjected to the water pressure test, the main beam and the column top are welded and fixed with a connecting plate. See Figure 5. Fix the connecting plate after the water pressure test
5.6 Furnace roof beam grid
5.6.1 The furnace roof beam grid is the main load-bearing component of the boiler. In addition to ensuring the strength and rigidity requirements, it is also necessary to set the main beam end support and plane support to ensure the overall stability of the furnace beam grid and improve the plane rigidity, see Figure 6.5.7 Limit device
.7.1 The anti-seismic limit device of the boiler shell of the supported boiler can be set in the middle of the length direction of the boiler shell, that is, the zero point of the expansion of the boiler shell. Its structural form is shown in Figure 7. For the earthquake action perpendicular to the boiler shell, various pressure balances are achieved through rigid connection with the boiler shell, and no limit structure is required. Boiler drum
JB533991
Seismic limit device
5.8 Guide device
5.8.1 The guide device for the suspended boiler body should be arranged at the expansion center line of the boiler to make the furnace body expand in a directional manner. At the same time, it should be able to withstand wind loads and earthquakes. The horizontal force caused by the earthquake on the suspended mass of the boiler body is transmitted to the horizontal support through the guide device and then acts on the vertical frame or extension frame. The guide device is arranged in 3 to 5 layers in the height direction of the furnace part, and the vertical flue is at least two layers. The upper guide device should be set at the ceiling pipe as much as possible. The layout of the guide device of Type II boiler is shown in Figure 8. 5.8.2 The guide device of the steam drum downcomer is generally arranged in 2 to 3 layers in the height direction and is directly fixed on each horizontal support, as shown in Figure 9. 5.9 Various smoke, wind, and pipelines
JB5339-91
Horizontal support technology
Horizontal support
5.9.1 Smoke, wind, pipelines, pulverized coal pipelines; main and reheat steam pipelines and furnace top sealing structures must be equipped with anti-seismic and expansion center devices and the force should be applied to the Yongping and vertical support structures as directly or indirectly as possible. When the structural arrangement is restricted, the bending rods must be checked before they can be installed. Figure 10 is a schematic diagram of the secondary hot air duct seismic device. Water-direction anti-alarm device
Shadow expansion center
*-direction anti-vibration device
Y-direction anti-bag device
Limited fixed point
JB5339-91
Seismic structural measures for boiler frames in areas with a basic intensity of 6 degrees 5.10
Important power stations built in areas with a basic intensity of 6 degrees, when users need to be protected at 7 degrees, their seismic structural measures can be designed according to the following requirements. 5.10.1 The overall layout of the boiler frame in areas with a basic intensity of 6 degrees shall comply with the provisions of Article 5.1.1. The design value of the connection bearing capacity between the frames shall be 120% of the calculated bearing capacity. 5. 10.2
5.10.3 For boiler frames with a single unit capacity greater than 200MW, the anchor bolts of the hinged column feet should not be less than M3°. Shear plates should be installed. 5.10.4 For single web beams with large loads, the lateral stiffness should be appropriately strengthened. 5.10.5 When the height of the frame column is large, appropriate measures such as vertical support or beams can be taken. JB5339-91
Appendix A
Calculation of horizontal seismic action on suspended boiler frame by modal decomposition response spectrum method (supplement)
When using a plane multi-mass system to calculate the ground-exposed action on the boiler frame, the seismic action P of the i-th vibration mode mass point is calculated according to formula (A1), and the schematic diagram is shown in Figure Al:
PuCayXaW;
The displacement D, of the i-th vibration mode mass point is calculated according to formula (A2): D,=Ca;T,y,Xg/4x
In the formula: C—structural coefficient is taken as 0.35;
-j vibration mode seismic influence coefficient, obtained from Article 4.1.3;x(i)The displacement of the i-th vibration mode mass point;| |tt||W,——the gravity of particle i;
T,—i vibration period;
-gravitational acceleration;
-—modal participation coefficient, calculated according to formula (A3): Wa--
The force PS exerted by the furnace body on the frame guide device i, calculated according to formula (A4): k.
PS;=K,[(Dice-1)-D,)-(Y(a-1)Y,)8,]Note i-1,2,n-3
jl,2,.,n.
JB5339-91
The horizontal force PSi-2) exerted by the furnace body on the top plate beam through the hanger of the first vibration mode is calculated according to formula (A5). PSica-2)=K.--[(Di(-)Dic-n)+8hIn the formula; K,—spring constant of the i-th guide device, i=1,2,..,n-3; Dse-u-displacement of the n-1-th particle of the j-th vibration mode:, rotation angle of the furnace body of the i-th vibration mode;
h—the distance from the center of gravity of the furnace to the lower end of the hanger; Y(a-1)-—the distance from the n-1-th particle to the ground; K.-2—horizontal stiffness of the suspended furnace body, calculated according to formula (A6): K.
In the formula: 1—hanger length;
E—elastic modulus of the hanger material;
Ihanger section moment of inertia;
m--total number of hangers.
The ground action of the ith vibration mode of the boiler frame is distributed to the frame nodes according to the provisions of Article 4.1.4. The restraining force of the ith vibration mode acts on the frame guide device, and then the seismic action effect of each vibration mode is calculated. The seismic action effect of each vibration mode is combined according to formula (A7) to obtain the total seismic action effect
Where: S,-—seismic action effect of the ith vibration mode S—total seismic action effect after combination.
Appendix B
Simplified free vibration equation of boiler frame calculation (supplement)
The calculation diagram of the suspended boiler frame is shown in Figure A1, and the free vibration equation is shown in formula (B1): MX+KX=0
Where: M is the mass matrix;
Where, J. The rotational inertia of the furnace body,
X is the displacement vector
Where; 6. is the furnace rotation angle;
K is the elastic gravity stiffness matrix of the boiler frame mz
X- (X,X...)T1 Boiler frames in earthquake zones should generally be designed as independent systems. When connected to a plant building, effective measures should be taken to avoid bearing the seismic effects of the plant building.
5.1.2 The plane and elevation layout of the frame should be regular, symmetrical, and uniform in quality, and structures with sudden changes in stiffness should be avoided as much as possible. 5.1.3 The frame should preferably adopt a truss structure.
5.1.1 Vertical and horizontal supports should be arranged continuously so that the seismic effects are directly transmitted to the foundation. 5.1.5 Vertical supports should be arranged reasonably to avoid excessive upward force on the columns. JB533991
5.1.6 For the supporting frame structure with guard plates, any area with guard plates arranged, and the guard plates and columns and beams are embedded and connected, can be regarded as a plate plane.
5.1.7 The connection design between the bars should be strengthened to ensure the overall stability of the frame system and coordinate the deformation between the components. 5.2 Column foot
5.2.1 The anchor bolts connected to the column foot should be able to withstand the upward pull force caused by earthquake action. 5.2.2 If the side pressure of the bottom plate end face connected to the column foot exceeds the compressive strength of the foundation concrete, a shear plate should be installed, see Figure 3. Figure 3
Shear plate
5.2.3 The column foot should adopt an embedded structure, and the embedding depth is determined according to the load-bearing size, generally 3001000mm5.3 Column section connection joint
5.3.1 The position and form of the column section connection joint are determined according to the form of the frame (i.e. frame or truss structure). For frame structures, the joints should be close to the middle of the two nodes, and the nodes should be designed as rigid connections. For truss structures, the joints should be close to the lower node at an elevation of about 1m. S.4 Connection between beams and columns
5.4.1 The connection between beams and columns should be designed according to the form of the frame. The rigid connection should not be lower than the strength of the connected beam, and the corresponding position of the column should be equipped with reinforcement. See Figure 4.
5.5 Connection between furnace roof beam and column top
JB5339-91
5.5.1 The main beam is supported on the top of the column, and it is advisable to use fasteners to connect and fix in a hinged form using arc supports or other forms. The number of screw inspections is configured according to the earthquake effect. After the boiler body is subjected to water pressure test, the main beam and the column top are welded and fixed with a connecting plate. See Figure 5. After the water pressure test, the connection plate is fixed
5.6 Furnace top beam
5.6.1 The furnace top beam is the main load-bearing component of the boiler. In addition to ensuring the strength and rigidity requirements, the main beam end support and plane support are required to ensure the overall stability of the furnace top beam and improve the plane rigidity, see Figure 6.5.7 Limit device
.7.1 The anti-seismic limit device of the boiler shell of the supported boiler can be set in the middle of the length direction of the boiler shell, that is, the zero point of the expansion of the boiler shell. Its structural form is shown in Figure 7. For the earthquake action perpendicular to the direction of the boiler shell, various pressure balances are achieved through the rigid connection with the boiler shell, and no limit structure is required. Boiler drum
JB533991
Anti-seismic limit device
5.8 Guide device
5.8.1 The guide device of the suspended boiler body should be arranged at the expansion center line of the boiler to make the furnace body expand in a directional manner. At the same time, it should be able to withstand wind loads and earthquakes. The horizontal force of the suspended mass of the boiler body caused by earthquake is transmitted to the horizontal support through the guide device and then acts on the vertical frame or extension frame. The guide device is arranged in 3 to 5 layers in the furnace part along the height direction, and the vertical flue is at least two layers. The upper guide device should be set at the ceiling pipe as much as possible. The layout of the guide device of type II boiler is shown in Figure 8. 5.8.2 The guide device of the drum downcomer is generally set in 2 to 3 layers in the height direction and is directly fixed on each horizontal support, as shown in Figure 9. 5.9 Various smoke, wind, and pipelines
JB5339-91
Horizontal support technologybzxz.net
Horizontal support
5.9.1 Smoke, wind, pipelines, pulverized coal pipelines; main and reheat steam pipelines and furnace top sealing structures must be equipped with anti-seismic and expansion center devices and the force should be directly or indirectly applied to the Yongping and vertical support structures as much as possible. When the structural arrangement is restricted, the bending rods must be checked before they can be installed. Figure 10 is a schematic diagram of the secondary hot air duct seismic device. Water-direction anti-alarm device
Shadow expansion center
*-direction anti-vibration device
Y-direction anti-bag device
Limited fixed point
JB5339-91
Seismic structural measures for boiler frames in areas with a basic intensity of 6 degrees 5.10
Important power stations built in areas with a basic intensity of 6 degrees, when users need to be protected at 7 degrees, their seismic structural measures can be designed according to the following requirements. 5.10.1 The overall layout of the boiler frame in areas with a basic intensity of 6 degrees shall comply with the provisions of Article 5.1.1. The design value of the connection bearing capacity between the frames shall be 120% of the calculated bearing capacity. 5. 10.2
5.10.3 For boiler frames with a single unit capacity greater than 200MW, the anchor bolts of the hinged column feet should not be less than M3°. Shear plates should be installed. 5.10.4 For single web beams with large loads, the lateral stiffness should be appropriately strengthened. 5.10.5 When the height of the frame column is large, appropriate measures such as vertical support or beams can be taken. JB5339-91
Appendix A
Calculation of horizontal seismic action on suspended boiler frame by modal decomposition response spectrum method (supplement)
When using a plane multi-mass system to calculate the ground-exposed action on the boiler frame, the seismic action P of the i-th vibration mode mass point is calculated according to formula (A1), and the schematic diagram is shown in Figure Al:
PuCayXaW;
The displacement D, of the i-th vibration mode mass point is calculated according to formula (A2): D,=Ca;T,y,Xg/4x
In the formula: C—structural coefficient is taken as 0.35;
-j vibration mode seismic influence coefficient, obtained from Article 4.1.3;x(i)The displacement of the i-th vibration mode mass point;| |tt||W,——the gravity of particle i;
T,—i vibration period;
-gravitational acceleration;
-—modal participation coefficient, calculated according to formula (A3): Wa--
The force PS exerted by the furnace body on the frame guide device i, calculated according to formula (A4): k.
PS;=K,[(Dice-1)-D,)-(Y(a-1)Y,)8,]Note i-1,2,n-3
jl,2,.,n.
JB5339-91
The horizontal force PSi-2) exerted by the furnace body on the top plate beam through the hanger of the first vibration mode is calculated according to formula (A5). PSica-2)=K.--[(Di(-)Dic-n)+8hIn the formula; K,—spring constant of the i-th guide device, i=1,2,..,n-3; Dse-u-displacement of the n-1th particle of the j-th vibration mode:, rotation angle of the furnace body of the i-th vibration mode;
h—distance from the center of gravity of the furnace to the lower end of the hanger; Y(a-1)-—distance from the n-1th particle to the ground; K.-2—horizontal stiffness of the suspended furnace body, calculated according to formula (A6): K.
In the formula: 1—length of the hanger;
E—elastic modulus of the hanger material;
Imoment of inertia of the hanger section;
m--total number of hangers.
The ground action of the ith vibration mode of the boiler frame is distributed to the frame nodes according to the provisions of Article 4.1.4. The restraining force of the ith vibration mode acts on the frame guide device, and then the seismic action effect of each vibration mode is calculated. The seismic action effect of each vibration mode is combined according to formula (A7) to obtain the total seismic action effect
Where: S,-—seismic action effect of the ith vibration mode S—total seismic action effect after combination.
Appendix B
Simplified free vibration equation of boiler frame calculation (supplement)
The calculation diagram of the suspended boiler frame is shown in Figure A1, and the free vibration equation is shown in formula (B1): MX+KX=0
Where: M is the mass matrix;
Where, J. The rotational inertia of the furnace body,
X is the displacement vector
Where; 6. is the furnace rotation angle;
K is the elastic gravity stiffness matrix of the boiler frame mz
X- (X,X...)T1 Boiler frames in earthquake zones should generally be designed as independent systems. When connected to a plant building, effective measures should be taken to avoid bearing the seismic effects of the plant building.
5.1.2 The plane and elevation layout of the frame should be regular, symmetrical, and uniform in quality, and structures with sudden changes in stiffness should be avoided as much as possible. 5.1.3 The frame should preferably adopt a truss structure.
5.1.1 Vertical and horizontal supports should be arranged continuously so that the seismic effects are directly transmitted to the foundation. 5.1.5 Vertical supports should be arranged reasonably to avoid excessive upward force on the columns. JB533991
5.1.6 For the supported frame structure with guard plates, any area with guard plates and the guard plates and columns and beams are embedded and connected can be regarded as a plate plane.
5.1.7 The connection design between the bars should be strengthened to ensure the overall stability of the frame system and coordinate the deformation between the components. 5.2 Column foot
5.2.1 The anchor bolts connected to the column foot should be able to withstand the upward pull force caused by earthquake action. 5.2.2 If the side pressure of the bottom plate end face connected to the column foot exceeds the compressive strength of the foundation concrete, a shear plate should be installed, see Figure 3. Figure 3
Shear plate
5.2.3 The column foot should adopt an embedded structure, and the embedding depth is determined according to the load-bearing size, generally 3001000mm5.3 Column section connection joint
5.3.1 The position and form of the column section connection joint are determined according to the form of the frame (i.e. frame or truss structure). For frame structures, the joints should be close to the middle of the two nodes, and the nodes should be designed as rigid connections. For truss structures, the joints should be close to the lower node at an elevation of about 1m. S.4 Connection between beams and columns
5.4.1 The connection between beams and columns should be designed according to the form of the frame. The rigid connection should not be lower than the strength of the connected beam, and the corresponding position of the column should be equipped with reinforcement. See Figure 4.
5.5 Connection between furnace roof beam and column top
JB5339-91
5.5.1 The main beam is supported on the top of the column, and it is advisable to use fasteners to connect and fix in a hinged form using arc supports or other forms. The number of screw inspections is configured according to the earthquake effect. After the boiler body is subjected to water pressure test, the main beam and the column top are welded and fixed with a connecting plate. See Figure 5. After the water pressure test, the connection plate is fixed
5.6 Furnace top beam
5.6.1 The furnace top beam is the main load-bearing component of the boiler. In addition to ensuring the strength and rigidity requirements, the main beam end support and plane support are required to ensure the overall stability of the furnace top beam and improve the plane rigidity, see Figure 6.5.7 Limit device
.7.1 The anti-seismic limit device of the boiler shell of the supported boiler can be set in the middle of the length direction of the boiler shell, that is, the zero point of the expansion of the boiler shell. Its structural form is shown in Figure 7. For the earthquake action perpendicular to the direction of the boiler shell, various pressure balances are achieved through the rigid connection with the boiler shell, and no limit structure is required. Boiler drum
JB533991
Anti-seismic limit device
5.8 Guide device
5.8.1 The guide device of the suspended boiler body should be arranged at the expansion center line of the boiler to make the furnace body expand in a directional manner. At the same time, it should be able to withstand wind loads and earthquakes. The horizontal force of the suspended mass of the boiler body caused by earthquake is transmitted to the horizontal support through the guide device and then acts on the vertical frame or extension frame. The guide device is arranged in 3 to 5 layers in the furnace part along the height direction, and the vertical flue is at least two layers. The upper guide device should be set at the ceiling pipe as much as possible. The layout of the guide device of type II boiler is shown in Figure 8. 5.8.2 The guide device of the drum downcomer is generally set in 2 to 3 layers in the height direction and is directly fixed on each horizontal support, as shown in Figure 9. 5.9 Various smoke, wind, and pipelines
JB5339-91
Horizontal support technology
Horizontal support
5.9.1 Smoke, wind, pipelines, pulverized coal pipelines; main and reheat steam pipelines and furnace top sealing structures must be equipped with earthquake-resistant and expansion center devices and the force should be directly or indirectly applied to the Yongping and vertical support structures as much as possible. When the structural arrangement is restricted, the bending rods must be checked before they can be installed. Figure 10 is a schematic diagram of the secondary hot air duct seismic device. Water-direction anti-alarm device
Shadow expansion center
*-direction anti-vibration device
Y-direction anti-bag device
Limited fixed point
JB5339-91
Seismic structural measures for boiler frames in areas with a basic intensity of 6 degrees 5.10
Important power stations built in areas with a basic intensity of 6 degrees, when users need to be protected at 7 degrees, their seismic structural measures can be designed according to the following requirements. 5.10.1 The overall layout of the boiler frame in areas with a basic intensity of 6 degrees shall comply with the provisions of Article 5.1.1. The design value of the connection bearing capacity between the frames shall be 120% of the calculated bearing capacity. 5. 10.2
5.10.3 For boiler frames with a single unit capacity greater than 200MW, the anchor bolts of the hinged column feet should not be less than M3°. Shear plates should be installed. 5.10.4 For single web beams with large loads, the lateral stiffness should be appropriately strengthened. 5.10.5 When the height of the frame column is large, appropriate measures such as vertical support or beams can be taken. JB5339-91
Appendix A
Calculation of horizontal seismic action on suspended boiler frame by modal decomposition response spectrum method (supplement)
When using a plane multi-mass system to calculate the ground-exposed action on the boiler frame, the seismic action P of the i-th vibration mode mass point is calculated according to formula (A1), and the schematic diagram is shown in Figure Al:
PuCayXaW;
The displacement D, of the i-th vibration mode mass point is calculated according to formula (A2): D,=Ca;T,y,Xg/4x
In the formula: C—structural coefficient is taken as 0.35;
-j vibration mode seismic influence coefficient, obtained from Article 4.1.3;x(i)The displacement of the i-th vibration mode mass point;| |tt||W,——the gravity of particle i;
T,—i vibration period;
-gravitational acceleration;
-—modal participation coefficient, calculated according to formula (A3): Wa--
The force PS exerted by the furnace body on the frame guide device i, calculated according to formula (A4): k.
PS;=K,[(Dice-1)-D,)-(Y(a-1)Y,)8,]Note i-1,2,n-3
jl,2,.,n.
JB5339-91
The horizontal force PSi-2) exerted by the furnace body on the top plate beam through the hanger of the first vibration mode is calculated according to formula (A5). PSica-2)=K.--[(Di(-)Dic-n)+8hIn the formula; K,—spring constant of the i-th guide device, i=1,2,..,n-3; Dse-u-displacement of the n-1th particle of the j-th vibration mode:, rotation angle of the furnace body of the i-th vibration mode;
h—distance from the center of gravity of the furnace to the lower end of the hanger; Y(a-1)-—distance from the n-1th particle to the ground; K.-2—horizontal stiffness of the suspended furnace body, calculated according to formula (A6): K.
In the formula: 1—length of the hanger;
E—elastic modulus of the hanger material;
Imoment of inertia of the hanger section;
m--total number of hangers.
The ground action of the ith vibration mode of the boiler frame is distributed to the frame nodes according to the provisions of Article 4.1.4. The restraining force of the ith vibration mode acts on the frame guide device, and then the seismic action effect of each vibration mode is calculated. The seismic action effect of each vibration mode is combined according to formula (A7) to obtain the total seismic action effect
Where: S,-—seismic action effect of the ith vibration mode S—total seismic action effect after combination.
Appendix B
Simplified free vibration equation for boiler frame calculation (supplement)
The calculation diagram of the suspended boiler frame is shown in Figure A1, and the free vibration equation is shown in formula (B1): MX+KX=0
Where: M is the mass matrix;
Where, J. The rotational inertia of the furnace body,
X is the displacement vector
Where; 6. is the furnace rotation angle;
K is the elastic gravity stiffness matrix of the boiler frame mz
X- (X,X...)T2 If the side pressure of the bottom plate end face of the column foot exceeds the compressive strength of the foundation concrete, a shear plate should be installed, see Figure 3. Figure 3
Shear plate
5.2.3 The column foot should be embedded, and the embedding depth is determined according to the load-bearing size, generally 3001000mm5.3 Column segment connection joint
5.3.1 The position and form of the column segment connection joint are determined according to the form of the frame (i.e. frame or truss structure). For frame structures, the joints should be close to the middle of the two nodes, and the nodes should be designed as rigid connections. For truss structures, the joints should be close to the lower node at an elevation of about 1m. S.4 Connection between beams and columns
5.4.1 The connection between beams and columns should be designed according to the form of the frame. The rigid connection should not be lower than the strength of the connected beam, and stiffeners should be installed at the corresponding positions of the columns. See Figure 4.
5.5 Connection between furnace roof beam and column top
JB5339-91
5.5.1 The main beam is supported on the column top and is fixed by fasteners in a hinged form using arc supports or other forms. The number of screws is configured according to the earthquake effect. After the boiler body is subjected to water pressure test, the main beam and column top are welded and fixed with a connecting plate. See Figure 5. Fix the connecting plate after water pressure test
5.6 Furnace roof beam grid
5.6.1 The furnace roof beam grid is the main load-bearing component of the boiler. In addition to ensuring the strength and rigidity requirements, it is also necessary to set the main beam end support and plane support to ensure the overall stability of the furnace beam grid and improve the plane rigidity, see Figure 6.5.7 Limit device
.7.1 The anti-seismic limit device of the boiler shell of the supported boiler can be set in the middle of the length direction of the boiler shell, that is, the zero point of the expansion of the boiler shell. Its structural form is shown in Figure 7. For the earthquake action perpendicular to the boiler shell, various pressure balances are achieved through rigid connection with the boiler shell, and no limit structure is required. Boiler drum
JB533991
Seismic limit device
5.8 Guide device
5.8.1 The guide device for the suspended boiler body should be arranged at the expansion center line of the boiler to make the furnace body expand in a directional manner. At the same time, it should be able to withstand wind loads and earthquakes. The horizontal force caused by the earthquake on the suspended mass of the boiler body is transmitted to the horizontal support through the guide device and then acts on the vertical frame or extension frame. The guide device is arranged in 3 to 5 layers in the height direction of the furnace part, and the vertical flue is at least two layers. The upper guide device should be set at the ceiling pipe as much as possible. The layout of the guide device of Type II boiler is shown in Figure 8. 5.8.2 The guide device of the steam drum downcomer is generally arranged in 2 to 3 layers in the height direction and is directly fixed on each horizontal support, as shown in Figure 9. 5.9 Various smoke, wind, and pipelines
JB5339-91
Horizontal support technology
Horizontal support
5.9.1 Smoke, wind, pipelines, pulverized coal pipelines; main and reheat steam pipelines and furnace top sealing structures must be equipped with anti-seismic and expansion center devices and the force should be applied to the Yongping and vertical support structures as directly or indirectly as possible. When the structural arrangement is restricted, the bending rods must be checked before they can be installed. Figure 10 is a schematic diagram of the secondary hot air duct seismic device. Water-direction anti-alarm device
Shadow expansion center
*-direction anti-vibration device
Y-direction anti-bag device
Limited fixed point
JB5339-91
Seismic structural measures for boiler frames in areas with a basic intensity of 6 degrees 5.10
Important power stations built in areas with a basic intensity of 6 degrees, when users need to be protected at 7 degrees, their seismic structural measures can be designed according to the following requirements. 5.10.1 The overall layout of the boiler frame in areas with a basic intensity of 6 degrees shall comply with the provisions of Article 5.1.1. The design value of the connection bearing capacity between the frames shall be 120% of the calculated bearing capacity. 5. 10.2
5.10.3 For boiler frames with a single unit capacity greater than 200MW, the anchor bolts of the hinged column feet should not be less than M3°. Shear plates should be installed. 5.10.4 For single web beams with large loads, the lateral stiffness should be appropriately strengthened. 5.10.5 When the height of the frame column is large, appropriate measures such as vertical support or beams can be taken. JB5339-91
Appendix A
Calculation of horizontal seismic action on suspended boiler frame by modal decomposition response spectrum method (supplement)
When using a plane multi-mass system to calculate the ground-exposed action on the boiler frame, the seismic action P of the i-th vibration mode mass point is calculated according to formula (A1), and the schematic diagram is shown in Figure Al:
PuCayXaW;
The displacement D, of the i-th vibration mode mass point is calculated according to formula (A2): D,=Ca;T,y,Xg/4x
In the formula: C—structural coefficient is taken as 0.35;
-j vibration mode seismic influence coefficient, obtained by Article 4.1.3;x(i)The displacement of the i-th vibration mode mass point;| |tt||W,——the gravity of particle i;
T,—i vibration period;
-gravitational acceleration;
-—modal participation coefficient, calculated according to formula (A3): Wa--
The force PS exerted by the furnace body on the frame guide device i, calculated according to formula (A4): k.
PS;=K,[(Dice-1)-D,)-(Y(a-1)Y,)8,]Note i-1,2,n-3
jl,2,.,n.
JB5339-91
The horizontal force PSi-2) exerted by the furnace body on the top plate beam through the hanger of the first vibration mode is calculated according to formula (A5). PSica-2)=K.--[(Di(-)Dic-n)+8hIn the formula; K,—spring constant of the i-th guide device, i=1,2,..,n-3; Dse-u-displacement of the n-1-th particle of the j-th vibration mode:, rotation angle of the furnace body of the i-th vibration mode;
h—the distance from the center of gravity of the furnace to the lower end of the hanger; Y(a-1)-—the distance from the n-1-th particle to the ground; K.-2—horizontal stiffness of the suspended furnace body, calculated according to formula (A6): K.
In the formula: 1—hanger length;
E—elastic modulus of the hanger material;
Ihanger section moment of inertia;
m--total number of hangers.
The ground action of the ith vibration mode of the boiler frame is distributed to the frame nodes according to the provisions of Article 4.1.4. The restraining force of the ith vibration mode acts on the frame guide device, and then the seismic action effect of each vibration mode is calculated. The seismic action effect of each vibration mode is combined according to formula (A7) to obtain the total seismic action effect
Where: S,-—seismic action effect of the ith vibration mode S—total seismic action effect after combination.
Appendix B
Simplified free vibration equation of boiler frame calculation (supplement)
The calculation diagram of the suspended boiler frame is shown in Figure A1, and the free vibration equation is shown in formula (B1): MX+KX=0
Where: M is the mass matrix;
Where, J. The rotational inertia of the furnace body,
X is the displacement vector
Where; 6. is the furnace rotation angle;
K is the elastic gravity stiffness matrix of the boiler frame mz
X- (X,X...)T2 If the side pressure of the bottom plate end face of the column foot exceeds the compressive strength of the foundation concrete, a shear plate should be installed, see Figure 3. Figure 3
Shear plate
5.2.3 The column foot should be embedded, and the embedding depth is determined according to the load-bearing size, generally 3001000mm5.3 Column segment connection joint
5.3.1 The position and form of the column segment connection joint are determined according to the form of the frame (i.e. frame or truss structure). For frame structures, the joints should be close to the middle of the two nodes, and the nodes should be designed as rigid connections. For truss structures, the joints should be close to the lower node at an elevation of about 1m. S.4 Connection between beams and columns
5.4.1 The connection between beams and columns should be designed according to the form of the frame. The rigid connection should not be lower than the strength of the connected beam, and stiffeners should be installed at the corresponding positions of the columns. See Figure 4.
5.5 Connection between furnace roof beam and column top
JB5339-91
5.5.1 The main beam is supported on the column top and is fixed by fasteners in a hinged form using arc supports or other forms. The number of screws is configured according to the earthquake effect. After the boiler body is subjected to water pressure test, the main beam and column top are welded and fixed with a connecting plate. See Figure 5. Fix the connecting plate after water pressure test
5.6 Furnace roof beam grid
5.6.1 The furnace roof beam grid is the main load-bearing component of the boiler. In addition to ensuring the strength and rigidity requirements, it is also necessary to set the main beam end support and plane support to ensure the overall stability of the furnace beam grid and improve the plane rigidity, see Figure 6.5.7 Limit device
.7.1 The anti-seismic limit device of the boiler shell of the supported boiler can be set in the middle of the length direction of the boiler shell, that is, the zero point of the expansion of the boiler shell. Its structural form is shown in Figure 7. For the earthquake action perpendicular to the boiler shell, various pressure balances are achieved through rigid connection with the boiler shell, and no limit structure is required. Boiler drum
JB533991
Seismic limit device
5.8 Guide device
5.8.1 The guide device for the suspended boiler body should be arranged at the expansion center line of the boiler to make the furnace body expand in a directional manner. At the same time, it should be able to withstand wind loads and earthquakes. The horizontal force caused by the earthquake on the suspended mass of the boiler body is transmitted to the horizontal support through the guide device and then acts on the vertical frame or extension frame. The guide device is arranged in 3 to 5 layers in the height direction of the furnace part, and the vertical flue is at least two layers. The upper guide device should be set at the ceiling pipe as much as possible. The layout of the guide device of Type II boiler is shown in Figure 8. 5.8.2 The guide device of the steam drum downcomer is generally arranged in 2 to 3 layers in the height direction and is directly fixed on each horizontal support, as shown in Figure 9. 5.9 Various smoke, wind, and pipelines
JB5339-91
Horizontal support technology
Horizontal support
5.9.1 Smoke, wind, pipelines, pulverized coal pipelines; main and reheat steam pipelines and furnace top sealing structures must be equipped with anti-seismic and expansion center devices and the force should be applied to the Yongping and vertical support structures as directly or indirectly as possible. When the structural arrangement is restricted, the bending rods must be checked before they can be installed. Figure 10 is a schematic diagram of the secondary hot air duct seismic device. Water-direction anti-alarm device
Shadow expansion center
*-direction anti-vibration device
Y-direction anti-bag device
Limited fixed point
JB5339-91
Seismic structural measures for boiler frames in areas with a basic intensity of 6 degrees 5.10
Important power stations built in areas with a basic intensity of 6 degrees, when users need to be protected at 7 degrees, their seismic structural measures can be designed according to the following requirements. 5.10.1 The overall layout of the boiler frame in areas with a basic intensity of 6 degrees shall comply with the provisions of Article 5.1.1. The design value of the connection bearing capacity between the frames shall be 120% of the calculated bearing capacity. 5. 10.2
5.10.3 For boiler frames with a single unit capacity greater than 200MW, the anchor bolts of the hinged column feet should not be less than M3°. Shear plates should be installed. 5.10.4 For single web beams with large loads, the lateral stiffness should be appropriately strengthened. 5.10.5 When the height of the frame column is large, appropriate measures such as vertical support or beams can be taken. JB5339-91
Appendix A
Calculation of horizontal seismic action on suspended boiler frame by modal decomposition response spectrum method (supplement)
When using a plane multi-mass system to calculate the ground-exposed action on the boiler frame, the seismic action P of the i-th vibration mode mass point is calculated according to formula (A1), and the schematic diagram is shown in Figure Al:
PuCayXaW;
The displacement D, of the i-th vibration mode mass point is calculated according to formula (A2): D,=Ca;T,y,Xg/4x
In the formula: C—structural coefficient is taken as 0.35;
-j vibration mode seismic influence coefficient, obtained from Article 4.1.3;x(i)The displacement of the i-th vibration mode mass point;| |tt||W,——the gravity of particle i;
T,—i vibration period;
-gravitational acceleration;
-—modal participation coefficient, calculated according to formula (A3): Wa--
The force PS exerted by the furnace body on the frame guide device i, calculated according to formula (A4): k.
PS;=K,[(Dice-1)-D,)-(Y(a-1)Y,)8,]Note i-1,2,n-3
jl,2,.,n.
JB5339-91
The horizontal force PSi-2) exerted by the furnace body on the top plate beam through the hanger of the first vibration mode is calculated according to formula (A5). PSica-2)=K.--[(Di(-)Dic-n)+8hIn the formula; K,—spring constant of the i-th guide device, i=1,2,..,n-3; Dse-u-displacement of the n-1th particle of the j-th vibration mode:, rotation angle of the furnace body of the i-th vibration mode;
h—distance from the center of gravity of the furnace to the lower end of the hanger; Y(a-1)-—distance from the n-1th particle to the ground; K.-2—horizontal stiffness of the suspended furnace body, calculated according to formula (A6): K.
In the formula: 1—length of the hanger;
E—elastic modulus of the hanger material;
Imoment of inertia of the hanger section;
m--total number of hangers.
The ground action of the ith vibration mode of the boiler frame is distributed to the frame nodes according to the provisions of Article 4.1.4. The restraining force of the ith vibration mode acts on the frame guide device, and then the seismic action effect of each vibration mode is calculated. The seismic action effect of each vibration mode is combined according to formula (A7) to obtain the total seismic action effect
Where: S,-—seismic action effect of the ith vibration mode S—total seismic action effect after combination.
Appendix B
Simplified free vibration equation for boiler frame calculation (supplement)
The calculation diagram of the suspended boiler frame is shown in Figure A1, and the free vibration equation is shown in formula (B1): MX+KX=0
Where: M is the mass matrix;
Where, J. The rotational inertia of the furnace body,
X is the displacement vector
Where; 6. is the furnace rotation angle;
K is the elastic gravity stiffness matrix of the boiler frame mz
X- (X,X...)T1 The guide device of the suspended boiler body should be arranged at the expansion center line of the boiler to make the furnace body expand in a directional manner. At the same time, it should be able to withstand wind loads and earthquakes. The horizontal force caused by earthquakes on the suspended mass of the boiler body is transmitted to the horizontal support through the guide device and then acts on the vertical frame or extension frame. The guide device is arranged in 3 to 5 layers in the height direction of the furnace part, and the vertical flue is at least two layers. The upper guide device should be set at the ceiling pipe as much as possible. The layout of the guide device of Type II boiler is shown in Figure 8. 5.8.2 The guide device of the steam drum downcomer is generally arranged in 2 to 3 layers in the height direction and is directly fixed on each horizontal support, as shown in Figure 9. 5.9 Various smoke, wind, and pipelines
JB5339-91
Horizontal support technology
Horizontal support
5.9.1 Smoke, wind, pipelines, pulverized coal pipelines; main and reheat steam pipelines and furnace top sealing structures must be equipped with anti-seismic and expansion center devices and the force should be applied to the Yongping and vertical support structures as directly or indirectly as possible. When the structural arrangement is restricted, the bending rods must be checked before they can be installed. Figure 10 is a schematic diagram of the secondary hot air duct seismic device. Water-direction anti-alarm device
Shadow expansion center
*-direction anti-vibration device
Y-direction anti-bag device
Limited fixed point
JB5339-91
Seismic structural measures for boiler frames in areas with a basic intensity of 6 degrees 5.10
Important power stations built in areas with a basic intensity of 6 degrees, when users need to be protected at 7 degrees, their seismic structural measures can be designed according to the following requirements. 5.10.1 The overall layout of the boiler frame in areas with a basic intensity of 6 degrees shall comply with the provisions of Article 5.1.1. The design value of the connection bearing capacity between the frames shall be 120% of the calculated bearing capacity. 5. 10.2
5.10.3 For boiler frames with a single unit capacity greater than 200MW, the anchor bolts of the hinged column feet should not be less than M3°. Shear plates should be installed. 5.10.4 For single web beams with large loads, the lateral stiffness should be appropriately strengthened. 5.10.5 When the height of the frame column is large, appropriate measures such as vertical support or beams can be taken. JB5339-91
Appendix A
Calculation of horizontal seismic action on suspended boiler frame by modal decomposition response spectrum method (supplement)
When using a plane multi-mass system to calculate the ground-exposed action on the boiler frame, the seismic action P of the i-th vibration mode mass point is calculated according to formula (A1), and the schematic diagram is shown in Figure Al:
PuCayXaW;
The displacement D, of the i-th vibration mode mass point is calculated according to formula (A2): D,=Ca;T,y,Xg/4x
In the formula: C—structural coefficient is taken as 0.35;
-j vibration mode seismic influence coefficient, obtained from Article 4.1.3;x(i)The displacement of the i-th vibration mode mass point;| |tt||W,——the gravity of particle i;
T,—i vibration period;
-gravitational acceleration;
-—modal participation coefficient, calculated according to formula (A3): Wa--
The force PS exerted by the furnace body on the frame guide device i, calculated according to formula (A4): k.
PS;=K,[(Dice-1)-D,)-(Y(a-1)Y,)8,]Note i-1,2,n-3
jl,2,.,n.
JB5339-91
The horizontal force PSi-2) exerted by the furnace body on the top plate beam through the hanger of the first vibration mode is calculated according to formula (A5). PSica-2)=K.--[(Di(-)Dic-n)+8hIn the formula; K,—spring constant of the i-th guide device, i=1,2,..,n-3; Dse-u-displacement of the n-1-th particle of the j-th vibration mode:, rotation angle of the furnace body of the i-th vibration mode;
h—the distance from the center of gravity of the furnace to the lower end of the hanger; Y(a-1)-—the distance from the n-1-th particle to the ground; K.-2—horizontal stiffness of the suspended furnace body, calculated according to formula (A6): K.
In the formula: 1—hanger length;
E—elastic modulus of the hanger material;
Ihanger section moment of inertia;
m--total number of hangers.
The ground action of the ith vibration mode of the boiler frame is distributed to the frame nodes according to the provisions of Article 4.1.4. The restraining force of the ith vibration mode acts on the frame guide device, and then the seismic action effect of each vibration mode is calculated. The seismic action effect of each vibration mode is combined according to formula (A7) to obtain the total seismic action effect
Where: S,-—seismic action effect of the ith vibration mode S—total seismic action effect after combination.
Appendix B
Simplified free vibration equation of boiler frame calculation (supplement)
The calculation diagram of the suspended boiler frame is shown in Figure A1, and the free vibration equation is shown in formula (B1): MX+KX=0
Where: M is the mass matrix;
Where, J. The rotational inertia of the furnace body,
X is the displacement vector
Where; 6. is the furnace rotation angle;
K is the elastic gravity stiffness matrix of the boiler frame mz
X- (X,X...)T1 The guide device of the suspended boiler body should be arranged at the expansion center line of the boiler to make the furnace body expand in a directional manner. At the same time, it should be able to withstand wind loads and earthquakes. The horizontal force caused by earthquakes on the suspended mass of the boiler body is transmitted to the horizontal support through the guide device and then acts on the vertical frame or extension frame. The guide device is arranged in 3 to 5 layers in the height direction of the furnace part, and the vertical flue is at least two layers. The upper guide device should be set at the ceiling pipe as much as possible. The layout of the guide device of Type II boiler is shown in Figure 8. 5.8.2 The guide device of the steam drum downcomer is generally arranged in 2 to 3 layers in the height direction and is directly fixed on each horizontal support, as shown in Figure 9. 5.9 Various smoke, wind, and pipelines
JB5339-91
Horizontal support technology
Horizontal support
5.9.1 Smoke, wind, pipelines, pulverized coal pipelines; main and reheat steam pipelines and furnace top sealing structures must be equipped with anti-seismic and expansion center devices and the force should be applied to the Yongping and vertical support structures as directly or indirectly as possible. When the structural arrangement is restricted, the bending rods must be checked before they can be installed. Figure 10 is a schematic diagram of the secondary hot air duct seismic device. Water-direction anti-alarm device
Shadow expansion center
*-direction anti-vibration device
Y-direction anti-bag device
Limited fixed point
JB5339-91
Seismic structural measures for boiler frames in areas with a basic intensity of 6 degrees 5.10
Important power stations built in areas with a basic intensity of 6 degrees, when users need to be protected at 7 degrees, their seismic structural measures can be designed according to the following requirements. 5.10.1 The overall layout of the boiler frame in areas with a basic intensity of 6 degrees shall comply with the provisions of Article 5.1.1. The design value of the connection bearing capacity between the frames shall be 120% of the calculated bearing capacity. 5. 10.2
5.10.3 For boiler frames with a single unit capacity greater than 200MW, the anchor bolts of the hinged column feet should not be less than M3°. Shear plates should be installed. 5.10.4 For single web beams with large loads, the lateral stiffness should be appropriately strengthened. 5.10.5 When the height of the frame column is large, appropriate measures such as vertical support or beams can be taken. JB5339-91
Appendix A
Calculation of horizontal seismic action on suspended boiler frame by modal decomposition response spectrum method (supplement)
When using a plane multi-mass system to calculate the ground-exposed action on the boiler frame, the seismic action P of the i-th vibration mode mass point is calculated according to formula (A1), and the schematic diagram is shown in Figure Al:
PuCayXaW;
The displacement D, of the i-th vibration mode mass point is calculated according to formula (A2): D,=Ca;T,y,Xg/4x
In the formula: C—structural coefficient is taken as 0.35;
-j vibration mode seismic influence coefficient, obtained from Article 4.1.3;x(i)The displacement of the i-th vibration mode mass point;| |tt||W,——the gravity of particle i;
T,—i vibration period;
-gravitational acceleration;
-—modal participation coefficient, calculated according to formula (A3): Wa--
The force PS exerted by the furnace body on the frame guide device i, calculated according to formula (A4): k.
PS;=K,[(Dice-1)-D,)-(Y(a-1)Y,)8,]Note i-1,2,n-3
jl,2,.,n.
JB5339-91
The horizontal force PSi-2) exerted by the furnace body on the top plate beam through the hanger of the first vibration mode is calculated according to formula (A5). PSica-2)=K.--[(Di(-)Dic-n)+8hIn the formula; K,—spring constant of the i-th guide device, i=1,2,
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