This code is formulated to implement the national technical and economic policies in the design of reinforced concrete thin shell structures, to achieve advanced technology, economic rationality, safety and applicability, and to ensure quality. This code is applicable to the design of monolithic or assembled monolithic reinforced concrete and prestressed concrete thin shell structures. JGJ/T 22-1998 Code for Design of Reinforced Concrete Thin Shell Structures JGJ/T22-98 JGJ/T22-1998 Standard download decompression password: www.bzxz.net

Industry Standard of the People's Republic of China
Specification for Design of Reinforced Concrete Thin Shell Structures
3G1/ T 22—98
Editor: China Academy of Building ResearchApproval: Ministry of Construction of the People's Republic of ChinaEffective Date: December 1, 1998
3—10—1
Notice on Issuing the Industry Standard "Design Code for Reinforced Concrete Thin Shell Structures"
Construction Standard [1998] No. 126
According to the requirements of the Ministry of Construction's "Notice on Issuing the Plan for the Development and Revision of Engineering Construction Industry Standards in the Next Year (the First Batch of the Ministry of Construction)" (Construction Standard [1992] No. 227), the "Design Code for Reinforced Concrete Thin Shell Structures" edited by the China Academy of Building Research has been reviewed and approved as a recommended industry standard, numbered JGT22-, and will be implemented from December 1, 1998: the original Ministry standard "Design Calculation Code for Reinforced Concrete Thin Roof and Floor Structures" BTG16—65 will be abolished at the same time.
This code is based on the Ministry of Construction's "Construction Standard [199 2】According to the requirements of Document No. 227, the China Academy of Building Research, together with relevant scientific research, design and planning units and universities, revised the original "Design and Calculation Code for Reinforced Concrete Thin Shell Pre-cover and Floor Slab Structures BJG16-65". During the revision process, the revision group summarized the main scientific research and design data on thin-shell structures at home and abroad, investigated and summarized the domestic scientific research achievements and engineering experience in recent years, proposed a revised draft, and widely solicited opinions from relevant units across the country in various ways. After repeated revisions, it was finally reviewed and determined by the relevant competent authorities:
This code is divided into 8 chapters and 5 appendices. It supplements and summarizes the original code and comprehensively organizes the original provisions. The main contents are:
1: According to the requirements of the national standard "Uniform Standard for Building Structure Design" (GJ68-4), the design principles and calculation methods are stipulated. According to the national standard "Standard for Terminology and Symbols for Building Structure Design" 3-10- 2
This standard is managed by the China Academy of Building Research, the technical unit responsible for building engineering standards under the Ministry of Construction, and is responsible for the specific interpretation of the standard
This standard is organized by the Standardization and Norms Research Institute of the Ministry of Construction and published by China Building Industry Press:
Ministry of Construction of the People's Republic of China
On June 9, 1998
The symbols, measurement units and basic technical terms of GE/T50083-97 were modified:
2. Design based on the probability limit state The allowable force design method adopted in the original code is replaced by the calculation method:
3. The expression of the controlling partial differential equation of the fan end, the verification of the ground cover effect of the thin shell structure, the shell plate thickness value and the reinforcement structure suggestion are added; the internal force and displacement calculation of the circular bottom rotating thin end under various concentrated loads and the corresponding diagrams are supplemented; the design of the continuous pseudo-shell, the design of the membrane shoulder shell, the solution of the control equation of the effective curved fan shell under arbitrary boundary shapes and conditions: various semi-analytical methods and numerical methods are introduced; in addition, the solution of the control equation of the auxiliary shell is explained in detail. This code must be used in conjunction with national standards (unified standard for building structure design GBJ68, building structure load code GHI9, concrete structure design code GEJ10, etc. General provisions
2 Terms and symbols
2.1 Terms...
2.2 Symbols
Basic provisions
Structural selection...
Calculation principles
3—10-—4
.. 3-[0--5
—10—7
.... 310-7
.. 3107
Analysis of internal forces and deformations of thin structures3—10—93.3
Structure and reinforcement of shells
Assembled integral bodies
Preloaded thin shell structures
Temperature effects
Circular bottom rotating thin shells
Calculation methods
Under concentrated loads and annular loads
: 3—10-9
3-10—11
.. 3--10——12
3—10—13
.- 3—-10-13
3—10—15
3--10--15
Calculation and drawing of hole stress concentration. 3—10—18, calculation under wind load
and stability verification
4.4 Calculation of ribbed end
Internal force of ring beam
Structural requirements
Hyperbolic shallow shell
Geometric dimensions
Calculation of internal force under uniform load
3—10—23
... 3—1023
310—24
3—10—25
310—26
3—10—26
3—10—26
Calculation of internal forces and
displacements under normal center load
3—10—28
Calculation of internal forces and
displacements under half-side load, filling load and horizontal load 5.4
Calculation of internal forces and displacements under
-.. 310--30
5.5 Stability verification
5.6 Calculation of ribbed shell
5.7 Side extension member
5.8 Construction and reinforcement
Cylindrical shell
...... 31031
... 31.-31
... 3--1031
3—1032
Geometry and calculation
6.2 Calculation of auxiliary shell
6.3 Edge components
6.4 Construction requirements
Hyperbolic paraboloid flat torsion shell
7.1 Geometric dimensions
7.2 Calculation method
7.3 Edge components
7.4 Construction requirements
Membrane-type shallow shell
Appendix A
Applicable scope and geometric dimensions
Forming calculation
Over-edge construction
Construction requirements
Calculation of circular-bottomed thin shells of revolution
Internal forces near the shell edge
Correction values
3—10--32
3—10-33
3—10—33
3—10—34
3—10—35
: 3—10—35
3-10—36
3-1036
.3—10—37
.. 31038
...3—10—38
： 3——10—38
：3-10—41
3—10—41
.. 3142
3—10—42
Calculation formula of membrane internal force and displacement of rotating thin shell
Appendix H
Calculation of internal force and displacement of hyperbolic fan shell
and coefficient table
Solution of internal force and displacement control equations...·
Coefficient table of internal force and displacement.
3—10—51
. 3-10-51
3—10-51
...3—10—52
Calculation method of internal forces of cylindrical shells
and coefficient table…
C.1 Calculation of internal forces of long shells
C.2 Calculation of internal forces of short shells
3—10-62
3-10—62
3--10-100
Appendix D Calculation of internal forces and displacements of hyperbolic paraboloidal flat torsion shells
Appendix E
Explanation of terms used in this code
Additional explanation
3——114
3—10—141
3—10—142
3—10- 3
1..1 In order to implement the national technical and economic policies in the design of reinforced concrete thin shell structures, to achieve technical excellence, economic rationality, safety and applicability, and to ensure quality, this code is formulated. 1.0.2 This code is applicable to the design of integral or assembled integral reinforced concrete and prestressed concrete thin shell structures. 1.03 This code is formulated in accordance with the principles stipulated in the national standard "Unified Standard for Design of Building Structures" GB68-84. The symbols, measurement units and basic terms are adopted in accordance with the provisions of the national standard "Standard for Terms and Symbols for Design of Building Structures" (/T5H0R3-97). 1.0.4 This code is compiled based on the current national standards (Code for Loads on Building Structures (GB 5099, Code for Design of Concrete Structures (GB 10), Code for Design of Buildings for Lightning Resistance (GB 11), Code for Construction and Acceptance of Concrete Structures (GB 50214) and other relevant codes, and combined with the design requirements, practical experience and scientific research results of reinforced concrete shell structures.
1.0.5 In addition to implementing this code, the design of steel reinforced concrete thin shell structures shall also comply with the provisions of the current relevant national standards. 2 Terms and Symbols
2.1 Technical
2.1.1 Shell plate
An object defined by two curved surfaces, and the distance between the two surfaces is smaller than the size of the curved surfaces.
2.1.2 Shell structure
An object with a certain load-bearing capacity composed of a shell plate (sometimes with stiffening ribs on the flow plate) and the edge members on its boundaries. 2.1.3 Shell surface
surlece
The surface of the shell.
2,1.4 Shell thickness Shell thicknrs The distance between two plates perpendicular to the mid-surface is called the shell thickness. 2.1,5 Nidlte qurface of shell] The surface that can define the abstract shape of the shell in theoretical analysis, and is the surface that bisects the thickness of the shell.
2.1. Principal curvature of shell The maximum and minimum normal curvatures at a point on the mid-surface of the shell. 2.1.7 Thin shell
The ratio of the shell thickness to the radius of curvature of the mid-surface is not greater than 1/20.
2.1.8 Rise of shell structureThe maximum vertical distance from the highest level of the mid-curve of the shell plate to the bottom plane of the shell.
2.1.9
The maximum vertical distance from the highest level of the mid-curve of the shell plate to the bottom plane of the shell.
310- 4
2.1.10 Side lenagth of shellThe length of the projection of the curve where the mid-curve of the shell plate intersects the center plane of the edge member on the bottom plane.
Single-sided plane curveplane curve withexut2.1.11
counterflexure
Smooth plane curve with the center of the curvature radius on the same side of the curve2.1.12 Galiss curvature of the shell plateThe product of the two curvatures of the shell plate.
2.1,13 Positive Gauss curvaturepositive Gauss curvatureGaussian curvature when the centers of the two principal curvatures are on the same side of the surface
2.1.14megaliveGaussian curvatureGaussian curvature when the centers of the two principal curvatures are on different sides of the surface.
2.1. 15zero Gaussian curvaturezuru Grass cunvakure: one of the two lower curvatures is a Gaussian curvature. 2.1.16shell with positive Gausscurvatute
shell with zero Gaussian curvature.
2,1.,17shell with negative Gausscurvature
shell with negative Gaussian curvature.
curvatuire
shell with zero Gaussian curvatureshell with zero Gaussian curvature.
2.1.19 Shell af revolutior A perfect body formed by the rotation of a generatrix (a straight line or a single-cut plane curve) on an axis of the space mirror. The bottom surface is generally circular, and is called a threshold-bottomed rotation shell.
2.1.20 Shalloy shell
A thin shell whose ratio of the length of the light plate to the shortest side of the shell is greater than 1/5.
2.1.21 Spherical shell A rotation shell whose generatrix is ​​an arc. The reciprocal of the principal curvature at each point is equal to the radius of the sphere. A spherical shell whose ratio of the height of the shell plate to the diameter of the shell bottom is not greater than 1/5 is called an oblate spherical shell.
2.1.22 Vticxalliptical shell A rotation shell whose generatrix is ​​a circumference.
2.1.23 Rotational paraboliceal shell A rotation shell whose generatrix is ​​a parabola.
2.1.24 Translational shell Translational shell A shell formed by the translation of a generatrix (a straight line or a single-sided plane curve) in space along two directrixes (a straight line or a single-sided plane curve). 2.1.25 Double curvature shallow shell A translational shell whose generatrix and directrix are both single-sided plane curves (usually parabolas or circular curves) and has a positive Gaussian curvature. 2.1.26 Cylindrical shell Cylindrical shell A translational shell whose generatrix is ​​a straight line and whose directrix is ​​a single-sided plane curve.
2.t.27 Hyperbolic parabolic shell A translational shell whose generatrix is ​​a parabola and whose directrix is ​​a single-sided plane curve and has a negative Gaussian curvature.
2.1.28 Membrane scallop A flat shell in which the two principal compressive stresses are upward and the internal forces are blocked by the shell.
Closed shell with openings
A shell with no openings on the shell surface.
2.1.30 Non-closed shell with openings.
2.1.31 Shell membrane internal force ntthrane fear(es nf shell The internal force on the shell section obtained by ignoring the bending, torsion and shear forces perpendicular to the element surface on the shell section under various forces: 2.1.32 Adverse edge stress dg :f:r:1
The stress or internal force generated by the displacement coordination at the connection between the shell and the edge member
2.1,33 Tangential diructien The direction along the coordinate axis in the tangent plane of the shell mid-surface. 2.1.34 Normal direction
The direction of the normal to the shell mid-surface.
2.2.1 Action
Vertical concentrated load:
Normal concentrated load;
Concentrated load in 2-axis direction;
Central load in y-axis direction
Uniform linear load;
Vertical uniform linear load on the inner ring of the rotating shell:
Normal uniform load on the middle surface of the shell plate:Vertical uniform load on the middle surface of the shell plate:Distributed snow load on the horizontal projection surface of the middle surface of the shell plate
On the middle surface of the 9x-complete plate:Uniform load distribution in the axial direction:
Uniform load component in the axial direction on the middle surface of the shell plate;
Uniform load distribution in the axial direction on the middle surface of the shell plate:
|Uniformly distributed load component in the longitudinal direction on the mid-surface of the rotating shell plate;
Uniformly distributed load component in the normal direction on the mid-surface of the shell plate;Given uniformly distributed line pressure on the melting surface of the membrane-type shallow shell;Total load of the membrane-type shallow shell;
Distributed reaction force perpendicular to the bottom plane around the shell of the membrane-type fan shell:
Distributed snow load on the horizontal projection surface of the mid-surface of the solid cylindrical shell plate:
Actual uniformly distributed position load on the mid-surface of the shell plate of the hanging shell:
Vertical distributed line load on the edge beam of the cylindrical shell, including the self-reinforcement of the wing beam;
Effective prestressed force acting on the cross section of the edge of the cylindrical shell;
The edge of the shell plate of the cylindrical long shell.Horizontal distributed edge disturbance force:
Vertical distributed edge force on the edge of the cylindrical long shell plate;
Tangential distributed edge disturbance force on the edge of the cylindrical long shell plate;
Distributed edge moment on the edge of the long shell plate;
Tangential distributed edge force on the edge of the short shell plate of a cylindrical surface;
Distributed edge disturbance force on the edge of the short shell plate of a circular surface;
Annular distributed edge disturbance force on the edge of the short shell plate of a circular surface:
Distributed edge moment on the edge of the short shell plate of a cylindrical surface;
Circumferential distributed edge disturbance force on the edge of the short shell plate of a circular surface Horizontal distributed edge disturbance on the edge of the long shell edge beam;
Vertical distributed edge disturbance force on the edge of the long shell edge beam of the cylindrical surface;
Tangential distributed edge disturbance force on the edge of the long shell edge beam of the cylindrical surface:
Distributed edge moment on the edge of the long shell edge of the circular surface:
Horizontal external edge disturbance force on the edge of the short shell edge beam of the cylindrical surface:
Vertical distributed edge disturbance force on the edge of the short shell edge beam of the cylindrical surface;
Edge of the short shell edge beam of the cylindrical surface: Distributed reverse edge force along the tangential direction:
Distributed edge moment on the edge of the short cylindrical edge beam.
2.2.2 Effects
Meridional distributed axial force on the cross section of the rotating shell plate: or circumferential distributed axial force on the cross section of the cylindrical shell plate:
——Circumferential distributed axial force on the cross section of the rotating shell plate
Rrs ny
-Distributed axial force on the shell plate section in the axial direction: Distributed axial force on the shell plate surface along the tangent line of the axial mid-curve surface:
3-10—5
2, the corresponding distributed membrane internal force on the shell plate section in the y, 2 coordinate system;
-The corresponding distributed membrane internal force on the light plate section in the 8, 9, 2 coordinate system:
The horizontal distributed internal thrust on the edge of the rotating shell plate,
The horizontal distributed membrane internal thrust on the edge of the outer ring of the rotating shell;
The horizontal distributed membrane internal thrust on the edge of the inner ring of the rotating shell ：
Distributed shear force on the section of shell plate:
Distributed shear force normal to the shell plate surface;
---Distributed shear force on the section of shell plate
Vertical distributed shear force on the shell plate surface;
Horizontal distributed shear force on the section of complete plate:
Distributed shear force on the corner point of flat shell: VltV2
Nm, N
Vertical distributed shear force on the section of shell plate parallel to the axis:
Distributed shear force normal to the section of rotating shell plate perpendicular to the longitudinal direction:
Shell Distributed torque on the plate section;
Distributed torque on the corner section of the shallow shell:
Distributed moment on the section parallel to the axis of the shell plate:
Distributed bending moment in the longitudinal direction on the section of the rotating shell plate; or the circumferential distribution on the cylindrical shell plate:
Distributed bending moment in the circumferential direction on the section of the rotating shell plate; Axial force on the outer and inner ring sections of the rotating shell; Displacement of the shell in the axial direction;
Displacement in the shell axial direction:
Displacement in the shell axial direction:
-Displacement in the shell normal direction:
Horizontal displacement of the rotating shell calculated according to the film theory;
The rotation angle of the shell:
The longitudinal rotation angle of the rotating shell calculated according to the film theory:
The horizontal displacement at the outer ring edge of the rotating shell; The horizontal displacement at the connection between the outer ring beam of the rotating shell and the shell plate;
The horizontal displacement at the inner ring edge of the rotating element plate: #a
The horizontal displacement at the connection between the inner ring beam of the rotating shell and the shell plate;
The longitudinal rotation angle at the outer ring of the rotating shell plate: The longitudinal rotation angle at the inner ring edge of the rotating shell plate; 3-10- 6
The longitudinal rotation angle at the connection between the outer ring beam of the rotating shell and the shell plate;
The longitudinal rotation angle at the connection between the inner ring beam of the rotating shell and the smooth plate;
The horizontal displacement of the edge of the shell plate of the side shell; the horizontal displacement of the connection between the side beam of the cylindrical shell and the shell plate;
The vertical displacement of the edge of the shell plate of the cylindrical shell; the vertical displacement of the connection between the side beam of the cylindrical shell and the shell plate;
The annular rotation angle of the edge of the shell plate of the cylindrical shell: a—
The annular rotation angle at the connection between the side beam of the cylindrical shell and the shell plate;
The normal stress at the midpoint of the upper edge of the side frame section of the side shell;
The normal force at the midpoint of the lower edge of the cylindrical shell side beam.
2.2.3Geometric characteristics
r, e, -
Coordinate system of rotating shell;
Coordinate system of cylindrical shell:
Coordinate system of sick spherical element;
Rectangular coordinate system of shell:
Thickness of shell plate:
Loss of height of shell plate;
Low height of shell;
Permanent height on the edge and side of hyperbolic shallow shell;
Thickness of shell with auxiliary shell in 2 and axial directions calculated by section bundle
Moment:
Shell with auxiliary shell in, The thickness converted according to the cross-sectional area between the axes:
the thickness of the assisted rotation shell in the meridional direction converted according to the section inertia moment;
the thickness of the ribbed rotation shell in the circumferential direction converted according to the section inertia moment;
the thickness of the assisted rotation shell in the meridional direction converted according to the cross-sectional area; or the thickness of the ribbed cylindrical shell in the circumferential direction converted according to the cross-sectional area;
the thickness of the assisted rotation shell in the circumferential direction converted according to the cross-sectional area;
a ribbed cylindrical shell in. The thickness converted according to the cut surface stiffness in the axial direction:
The thickness of the ribbed cylindrical shell in the annular direction converted according to the section stiffness;
The thickness of the ribbed cylindrical shell in the axial direction converted according to the section area:
The curvature of the shell with equal curvature,
*1, K2—the principal curvature of the surface in the shell; K—the distortion rate of the surface in the shell;
The optical path of the spherical surface: or the radius of curvature of the equal-curved shell:
The optical path of the curvature in the meridian direction of any point on the surface of the rotating shell;
The curvature in the latitudinal direction of any point on the surface of the rotating shell half 2
The radius of curvature in the latitudinal direction at the outer ring edge of the rotating surface: | |tt||The radius of curvature at the inner ring edge of the curved surface in the rotating shell;
The stiffness per unit length of the shell plate section;
The arc length from the rotation axis to the outer ring edge of the rotating shell along the meridian direction;
The length from the inner ring edge to the outer ring edge of the rotating shell along the meridian direction:
The meridian arc length of the rotating shell measured from the outer edge of the shell,
The meridian arc length of the rotating shell measured from the inner ring edge of the rotating shell:
The inclination on the periphery of the membrane-type fan shell;
A"·The center of the circle corresponding to the connection between the right side beam and the plate of the cylindrical shell to a certain point on the surface:| |tt||The central angle of the circle corresponding to the symmetry line of the circular shell cross section to the shell plate
The steel cross-sectional area of ​​the edge components of the rectangular bottom membrane type fan shell:
A%, A--the steel cross-sectional area of ​​the edge components of the rectangular bottom membrane type fan.
2.2.4 Other
shell characteristic length parameters;
The characteristic length parameters at the outer edge of the rotating element and the inner edge:
-the characteristic length of the curved flat shell, the axial direction is more than t
3 Basic provisions
3.1 Structural selection
3.1.1 Thin shell structure The type is determined according to the design requirements, construction conditions and economic rationality.
3.1.2 The shell type with a circular bottom can be a spherical shell, an ellipsoidal shell, a rotating surface shell and a membrane-type flat shell. 3.1.3 The shell type with a rectangular bottom can be a hyperbolic shell, a cylindrical shell, a hyperbolic paraboloid torsion shell and a membrane-type fan-shaped shell. 3.1.4 The ratio of the bottom length to the width of the peripherally supported rectangular bottom hyperbolic shell, hyperbolic paraboloid torsion shell and waist-shaped flat shell should be small. 2.3.1.5 When the load distribution changes greatly or the diameter of the circular bottom is greater than 8m and the length of the largest side of the rectangular bottom is greater than 6m, it is not appropriate to use a membrane-type flat element. 3.2 Calculation principle
3.2.1 The calculated curvature of the shell should use the typical curvature of the mid-curve surface. 3.2.2 The shell plate and its edge components can analyze their internal forces and displacements according to the elastic theory. When the ratio of the shell's height to the smallest side length is not greater than 1/5, the fan shell theory can be used for calculation. Except for special provisions in this code, the cross-section design of the shell shall comply with the provisions of the current national standard "Concrete Structure Design Code". The looseness ratio of concrete can be ignored:
3.2.3 The shell section should be verified for bearing capacity. The maximum principal tensile stress of the shell plate should not be greater than 4 times the concrete anti-corrosion strength design. The maximum tensile stress at the bottom of the cylindrical shell edge beam should not be greater than 1/5 times the concrete upper tensile strength design ratio:
3.2.4 The deformation of the edge components of the light body should be calculated under the service limit state. Unless otherwise specified, the deflection value under the combination of short-term load effects shall not be greater than 1/1000 of the span when the span is greater than 7m, and shall not be greater than 1/500 of the span when the span is less than 7m; the deflection value under the combination of long-term load effects shall not be greater than 1/500 of the span when the span is greater than 7m, and shall not be greater than 17/250 of the span when the span is less than 7m.
3.2.5 For shells that are not prone to cracks under the service limit state, The maximum principal tensile stress obtained according to the standard load value and considering the influence of Li moment shall comply with the provisions of the current national standard "Specifications for Design of Concrete Structures".
3.2.6 The deadweight of the shell plate can be calculated by converting the actual total weight of the shell plate into the semi-average thickness weight.
3.2.7 The design of thin shell structures in the service stage shall comply with the following provisions: 3.2.7.1 When non-resistance design is required, the design value of the load effect combination of structural components shall be calculated according to the following formula:
S = YeCeG1 Yq CoQik+Yaywtek
(3.2.7 1)
The design value of the load effect combination of structural components: s
Ye Yel Yw-
Gu.Qik.Wk
Partial coefficient of dead load, live load and wind load
Standard of dead load, live load and wind load
CG, Co1, C—Load effect coefficient of dead load, live load and wind load:
Combined value coefficient of wind load,
3.2.7.2 In non-resistance design, the load partial coefficient shall be used in accordance with the following provisions:
(1) In bearing capacity calculation:
Partial coefficient of dead load (Yc):
When the effect of dead load is unfavorable to the structure, it is divided into two cases: when the converted thickness of shell plate is not more than 50mm, take 1.25; when the converted thickness of shell plate is more than 50m, take 1.2.
When the dead load effect is favorable to the structure, take 1.0. Live load partial factor (Yol): When the live load standard is not less than 4kN/m2, take 1.3; otherwise take 1.4. Wind load partial factor (m) take 1.4.
(2) When calculating deformation, all partial factors are taken as 1.0. 3.2.7.3 When designing the anti-wing, the basic combination of load effect and ground effect should be considered. The design value of the combined effect of structural components shall be calculated according to the following formula:
S-YaCGx+YmCenFa+ECeFEk
(3.2.7-2)
wherein Gg, Fe, Fkd, uk
Ca Cheh. Chv. C-
Ye. Yh, Yeus Yu.
representative value of gravity, standard value of horizontal ground action, standard value of vertical ground action, standard value of wind load:
gravity. The effect system of horizontal ground pipe action, vertical ground cover action and wind load interception is
corresponding action sub-item system
-wind load interception group storage coefficient.
3.1.7.4 During the design of anti-expansion, the partial factors of the load and the required earth action for the bearing capacity calculation shall be adopted in accordance with the following provisions: (1) Partial factor of the dead load shear (c):
When the dead load shear effect is unfavorable to the structure, it is divided into two cases: when the shell plate reduced thickness is not greater than 50mm, it is taken as 1.25; when the shell plate reduced thickness is greater than 50mm, it is taken as 1.20.
When the dead load shear effect is favorable to the structure, it is taken as 1.0. (2) Partial factor of horizontal earth action (m): When the horizontal earthquake action effect is unfavorable to the structure, it is taken as 1.3. (3) Vertical ground action partial factor (Y): When the vertical ground action effect is unfavorable to the structure and the age is greater than 24m, take 0.5 yuan
3.2.8 For fan-spherical shells, hyperbolic fan shells, cylindrical shells (except skirt-shaped cylindrical shells with shell surface inclination angle greater than 0), double parabolic torsion shells and membrane-type shallow shells, the effect of wind load on the shell plate can be ignored, but the effect of wind load on the edge components must be considered. For rotating shells and sawtooth cylindrical shells with shell surface inclination angle greater than 0, the effect of wind load on the shell must be considered.
3.2.9 The standard wind load on the shell surface shall be calculated according to the following formula:
uh = Pgp
wherein k
-standard value of wind load, kN/m2;
Wind vibration coefficient at 2 degrees;
Wind load body shape coefficient;
H--wind pressure height variation coefficient
wo--basic wind pressure, N/nz.
3-10-8
The basic wind pressure, wind pressure height variation coefficient and wind vibration coefficient shall be adopted in accordance with the provisions of the current national standard "Code for Loads on Building Structures" GBJ9--87.
The wind load body shape coefficient related to the shell surface form can be adopted in accordance with 3.2.9.
The wind load body shape coefficient of the shell of revolution and the serrated cylindrical shell is produced in 3.2.9
Type!
Spherical shell
Rotary parabola
Surface burning!
D|||T cover figure
refers only to the end, group
body coefficient
> 士,
D.5sugsinB g
十,
shell surface normal and the sharp angle between
Bo:
shell surface normal projection on the water
surface and the water
plane axis
The angle
should be determined by test. When there is no
test data, it is approximately
according to the spherical shell
When 0≤. -15\,=
When -30,±. When 260°, ,=0.8
When it is equal to the above values, the temporary insertion method can be used. 3.2.10 The standard value of snow load on the horizontal projection surface of the shell should be calculated using the following formula:
sk=ns
Standard value of snow load. kN/ml;
Shell area distribution coefficient;
Basic snow pressure, kN/mz, according to different regions according to the current national standard building structure load code (BJ9-87).
The value of the shell area distribution coefficient is related to the shell surface shape. For the whole rotation shell (including oblate spheroidal light) and circular hanging surface shell, its value is adopted according to Table 3.2.10: For the hyperbolic flat shell, hyperbolic paraboloid torsion shell and membrane flat shell, its value should be 1. Center,
3,211 The anti-carbon calculation of thin shell structure shall comply with the following provisions: 3.2.11.1 Anti-fortification In areas with a seismic intensity of 7 degrees, horizontal seismic calculations may not be performed for thin shell structures with peripheral supports and a span of less than 24m, and horizontal expansion calculations shall be performed for thin shell structures with a span of more than 24m; in areas with a seismic intensity of 8 or 9 degrees, horizontal expansion calculations shall be performed for all types of filling structures. The distribution coefficient of the filling and cylindrical filling shell is as shown in Table 3.2.10, but it shall not be less than 1 or less than 1. When it is greater than 37, calculate according to Article 4.3.1. The point is calculated as follows: un=1 Ha-2 side beam width H— -Full span
3.2.11.2 For areas with a seismic fortification intensity of 7 degrees, the shell structure may not be subject to vertical decomposition verification: For earthquake zones with a seismic fortification intensity of 8 or 9 degrees, thin structures shall be subject to vertical decomposition verification 3.2.11.3 For shell structures with a large span and thin shell structures with a span greater than 24m, when the fortification intensity is 8 or 9 degrees, the vertical decomposition action value can be taken as 10% or 20% of the deadweight of the structure for simplified calculation.
3.2.11.4 For shell structures with complex shapes and thin shell structures with a span greater than 24m, the modal decomposition response spectrum method or time history analysis method can be used for special vertical decomposition analysis and Verification, 3.2.12 When designing thin shell structures, the following important parts should be fully verified: shell plate, edge member assembly type thin shell structure connection.
3.2.13 The edge member should have sufficient brushing in its own surface. When the edge member is a steel screen concrete shelter, the internal force analysis can be carried out according to the load concentration on the upper chord node, and the moment caused by the eccentric action of the load and shear force between the filter nodes on the upper chord should be considered. 3.2.14 The prefabricated components of the assembled integral thin structure must be verified for internal force and crack resistance during the assembly process. The verification load includes white weight, construction load and lifting load.
For curved plate components, it is advisable to calculate according to micro-plate. 3.3 Analysis of internal forces and deformations of thin shell structures
3.3.1 The following methods can be used to analyze the internal forces and deformations of thin shell structures: direct solution of partial differential equations, semi-analytical method and numerical method. 3.3.2 When the bottom projection of a thin shell structure is relatively regular and is subjected to uniformly distributed loads or regularly distributed loads, the calculation of its internal forces and displacements, structural measures and design of edge components shall comply with the provisions of Chapters 4, 5, 6, 7 and 1B of this Code.
3.3.3 When the bottom projection of a thin shell structure is irregular, or the bottom projection is relatively regular but is not covered by Chapters 4-8 of this Code, its internal forces and displacements should be solved by semi-analytical or numerical methods, and its calculation and structural measures should comply with the provisions of relevant chapters of this Code. 3.3.4 When the thin shell structure has a complex shape, the finite element method should be used for overall analysis.
3.4 ​​Shell structure and reinforcement
3.4.1 The thickness of the shell plate should not only meet the strength requirements, but also be determined by the performance of the shell plate, construction requirements and other factors, including the reinforcement arrangement of the shell plate, the thickness of the protective layer, the quality assurance of the construction, the structural stability and the deformation control of the shell plate and auxiliary components, and the fire protection requirements of the structure should be considered.
3.4.2 The thickness of the shell plate can be selected between 50mm and 80mm. In the parts of the shell plate close to the edge and the supporting components, it is advisable to increase the thickness to 23 times of the middle thickness and increase the number of bending reinforcements. The shell plate should be gradually thickened to ensure smoothness. The range of the tower thickness should be at least 5-10 times the thickening thickness
3.4.3 The shell concrete protective layer should meet the following requirements: 3.4.3.1 The thickness of the concrete + protective layer of the shell plate reinforcement can be the same as that of the shell plate.
The minimum concrete protective layer of edge members and supporting members 3.4.3,2
The thickness of the protective layer should comply with the relevant provisions of the current national standard "Concrete Structure Design Code". The thickness of the protective layer of the shell plate reinforcement extending into the edge member can maintain the thickness of the plate.
3.4.3.3 When the shell plate surface is completely exposed to the atmosphere, the thickness of the protective layer of the shell plate should be increased accordingly, and the thickness of the protective layer should be determined according to the lightness of the shell plate and the conditions of the inner and outer surfaces. 3.4.3.5 For areas with steep surface of the filling plate and double-sided formwork, the thickness of the protective layer should be increased.
3.4.3.6 The minimum protective layer thickness should not be less than the diameter of the large particles of concrete aggregate, nor should it be less than the diameter of the steel bar. When the minimum protective layer thickness cannot meet the fire protection requirements, the protective layer thickness should be increased at the stress relief reinforcement and stress reinforcement.
3.4.4 The screen without plate shall comply with the following provisions: 3.4.4.1 In the thin shell structure, membrane force reinforcement, bending moment reinforcement and special reinforcement at the edge of the body and near the hole shall be provided. The membrane internal force reinforcement can be set on the middle surface of the shell, and it is composed of a single layer of orthogonal steel screens, and the bending short reinforcement should be set close to the surface of the shell plate. 3.4.4.2 The equipment should use smaller diameter steel bars: except for welded steel mesh, all deformed steel bars should be used and the steel bar spacing should be determined. 3.4.4.3 It is not suitable to use steel bars with a tensile strength standard value greater than 340N/mm, otherwise the design value of such steel bars should be limited. 3.4.4.4 The internal force reinforcement of the membrane may not be arranged in the direction of the principal stress. When the principal tensile stress is large, an additional layer of membrane internal reinforcement may be added in the direction of the principal tensile stress in this area.
3.4.4.5 The minimum internal force reinforcement of the membrane shall be a single layer. The minimum diameter of the orthogonal steel bars shall be 6mm if deformation bars are used; if welded screens are used, 5mm shall be used for concrete cleaning and 4mm may be used for prefabrication. For the internal force reinforcement of the damp film, the minimum reinforcement ratio in one direction shall be 0.2%, and the sum in two directions shall not be less than 0.6%: The maximum reinforcement ratio of the internal force of the membrane may be calculated according to the following formula: 3.4.4.6
f<28N/mm
(3.4.4-1)
3—10-9
fu 28N/rmt
(3.4.4-2)
The cross-sectional area of ​​the shell reinforcement;
A. The cross-sectional area of ​​the shell given;
fu—the standard value of the axial compressive strength of concrete, N/rumfk—the standard value of the tensile strength of the reinforcement, N/mmThe above formula is applicable to the case where the arrangement of the reinforcement is consistent with the principal stress line of the shell. If the angle between the direction of the reinforcement arrangement and the principal stress line is greater than 10, the maximum reinforcement ratio shall be reduced by the reduction factor Y corresponding to 3.4.4.7.
3.4.4.7 The deflection angle between the thin internal force reinforcement and the principal stress line should not be greater than 10°. If the deflection angle is less than 10°, the design value of the reinforcement strength shall be reduced. The reduction factor can be determined based on the deflection angle and the ratio of the two principal stresses. In the ratio of the two principal stresses, the one with the larger absolute value of the principal stress is the lower.
In actual engineering, the more important situation is α=-1: At this time, the sparseness coefficient should be adopted according to the following formula:
,=1.0,@10°
7=1.3 -0.03p,104-2)
Slab steel bar cross-sectional area;
A. Shell plate given cross-sectional area;
fu—concrete axial compressive strength standard value, N/rumfk—steel tensile strength standard value, N/mmThe above formula is applicable to the case where the arrangement of the steel bars is consistent with the principal stress line of the shell. If the angle between the direction of the steel bar arrangement and the principal stress line is greater than 10, the maximum reinforcement ratio shall be reduced by the new reduction factor Y in accordance with 3.4.4.7.
3.4.4.7 The deflection angle between the thin internal force reinforcement and the principal stress line should not be greater than 10°. If the deflection angle is greater than 10°, the design value of the steel bar strength shall be reduced. The reduction factor can be determined based on the deflection angle and the ratio of the two principal stresses. In the ratio of the two principal stresses, the one with the larger absolute value of the principal stress is the lower.
In actual engineering, the more important situation is α=-1: At this time, the sparseness coefficient should be adopted according to the following formula:
,=1.0,@10°
7=1.3 -0.03p,104-2)
Slab steel bar cross-sectional area;bzxZ.net
A. Shell plate given cross-sectional area;
fu—concrete axial compressive strength standard value, N/rumfk—steel tensile strength standard value, N/mmThe above formula is applicable to the case where the arrangement of the steel bars is consistent with the principal stress line of the shell. If the angle between the direction of the steel bar arrangement and the principal stress line is greater than 10, the maximum reinforcement ratio shall be reduced by the new reduction factor Y in accordance with 3.4.4.7.
3.4.4.7 The deflection angle between the thin internal force reinforcement and the principal stress line should not be greater than 10°. If the deflection angle is greater than 10°, the design value of the steel bar strength shall be reduced. The reduction factor can be determined based on the deflection angle and the ratio of the two principal stresses. In the ratio of the two principal stresses, the one with the larger absolute value of the principal stress is the lower.
In actual engineering, the more important situation is α=-1: At this time, the sparseness coefficient should be adopted according to the following formula:
,=1.0,@10°
7=1.3 -0.03p,10
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