1 Scope
This specification specifies the structural design, construction and other requirements of derrick of exhaust and flare stack in petrochemical industry.
This specification is applicable to the design of derrick of exhaust and flare stack in petrochemical industry with a height of 150m or below.
2 Normative references
The following documents are indispensable for the application of this specification. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 700 Carbon structural steels
GB/T 1228 High strength bolts with large hexagon head for steel structures
GB/T 1229 High strength large hexagon nuts for steel structures
GB/T 1230 High strength plain washers for steel structures
GB/T 1231 Specifications of high strength bolts with large hexagon head, large hexagon nuts, plain washers for steel structures
GB/T 1591 High strength low alloy structural steels
GB/T 3632 Sets of torshear type high strength bolt hexagon nut and plain washer for steel structures
GB/T 3633 Technical requirement for sets of torshear type high strength bolt hexagon nut and plain washer for steel structures
GB/T 5117 Carbon steel covered electrodes
GB/T 5118 Low alloy steel covered electrodes
GB/T 5313 Steel plates with through-thickness characteristics
GB/T 8923 Rust grades and preparation grades of steel surfaces before application of paints and related products
GB 50007 Code for design of building foundation
GB 50009 Load code for the design of building structures
GB 50010 Code for design of concrete structures
GB 50011 Code for seismic design of buildings
GB 50017 Code for design of steel structures
GB 50046 Code for anticorrosion design of industrial constructions
GB 50135 Code for design of high-rising structures
GB 50212 Code for construction of building anticorrosive engineering
GB 50453 Standard for classification of seismic protection of buildings and special structures in petrochemical engineering
SH/T 3406 Steel pipe flanges for petrochemical industry
SH/T 3507 Acceptance specification for construction quality of steel structure in petrochemical industry
3 Terms and symbols
3.1 Terms
For the purposes of this specification, the following terms and definitions apply.
3.1.1
derrick
Self-supporting high-rise steel structure that is used to support the derrick of exhaust and flare stack
3.2 Symbols
For the purpose of this specification, the following symbols apply.
3.2.1 Action and action effect
fb——the maximum value (absolute value) of axial stress produced by axial force of transverse web member under seismic action combination;
fc——the maximum value (absolute value) of axial stress of the derrick column under the seismic action combination;
fbr——the maximum value (absolute value) of axial stress produced by axial force of diagonal web member under seismic action combination;
Gi, Gj——the representative values of gravity load concentrated on mass points i and j;
Geq——the equivalent total gravity load of the derrick;
GE——the representative value of total gravity load of the derrick for seismic action calculation;
Mx——the bending moment of the calculation section about X-axis;
My——the bending moment of the calculation section about Y-axis;
Mmax——the maximum bending moment within the calculation range;
Mby——the design value of bending capacity of out-of-plane section of transverse web member;
Mu, Qu, Nu——the ultimate flexural, shear and tensile capacity of the connection respectively;
Muy——the lateral flexural capacity of the connection;
Mp.c.b——the reduced flexural capacity of in-plane plastic section of the transverse web member;
Mc.br——the reduced flexural capacity of in-plane section of the diagonal web member;
Mbr.y——the flexural capacity of out-of-plane section of the diagonal web member;
, ——the flexural capacity of plastic sections on the left and right sides of the transverse web member link;
, ——the reduced flexural capacity of plastic sections on the left and right sides of the transverse web member link respectively;
N——the axial tensile force or compression force;
NEX——the Euler's critical force;
Ne——the axial force of any member;
P——the internal force of member bar;
Pf——the soil reaction force on foundation bottom area under design load;
Qb, Nb——the design values of shear and tensile capacity of the transverse web member respectively;
Qbr, Nbr——the shear and tensile capacity of the section of the diagonal web member respectively;
qa——the ice load per unit surface area of the member with non-circular section;
qe——the ice load per unit length of the member with circular section;
R——the design value of support reaction force perpendicular to the rotating shaft;
Sj——the action effect produced by horizontal seismic action in the j-th vibration mode;
∑Mp.b——the sum of the reduced flexural capacity of plastic section of the transverse web members on both sides of the joint;
V——the wind velocity and shear force;
Vb——the design value of shear capacity of the transverse web member link;
W——the wind load acting along the derrick height;
Wo——the basic wind pressure;
Xji——the horizontal relative displacement at the mass point i in the j-th vibration mode;
YH——the horizontal displacement at the derrick top when the unit horizontal force F=1N acts on the derrick top.
3.2.2 Calculation parameters
FEVk——the total vertical seismic action (standard value) of the derrick ;
FVi——the vertical seismic action (standard value) at the mass point;
Fji——the horizontal seismic action (standard value) of the derrick at the mass point i in the j-th vibration mode;
f——the design value of basic strength of steels, the design value of bearing capacity of foundation, the coefficient of friction between column foot and foundation;
——the design value of basic strength of fillet weld;
——the design value of basic shear strength of weld on fusion line;
——the design value of basic tensile strength of the bolt;
——the design value of basic shear strength of the bolt;
——the design value of basic bearing strength of the bolt;
fy——the yield strength of steels;
fy.b——the yield strength of steels for the transverse web member;
fv.b——the shear strength of steels for the transverse web member;
fy.br——the yield strength of steels for the diagonal web member;
fv.br——the shear strength of steels for the diagonal web member;
Nc——the compressive capacity of the spherical node;
Nt——the tensile capacity of the spherical node;
——the design value of shear capacity of a bolt;
——the design value of tensile capacity of a bolt;
NE.b, VE.b——the design values of axial force and shear force of the transverse web member under seismic combination respectively;
Nbr——the required design value of compressive capacity of the diagonal web member;
NEbr——the design value of axial force of the diagonal web member under seismic combination;
NEc, VEc, MEc——the design values of axial force, shear force and bending moment of derrick column under seismic combination;
Nc, Vc, Mc——the required design values of axial force resistance, shear and flexural capacity of the derrick column;
3.2.3 Geometric parameters and calculation coefficients
A——the gross sectional area of the member and the sectional area of the shaft;
Ag——the effective gross area of the web member;
Am——the average value of the upper side length and the lower side length of the oblique section of the punching shear failure cone;
An——the net sectional area of the member;
An1——the effective axial force resisting area of the transverse web member;
An2——the effective shear area of the transverse web member;
An.br——the net sectional area of the diagonal web member;
bmin——the minimum effective width of the gusset plate;
b——the ice thickness;
D——the outside diameter of the spherical node;
Do——the diameter of the circle where the bolt center is located;
d——the diameter of round member, steel pipe member, bolt and bolt hole, and the diameter of rotating shaft;
de——the effective diameter of the bolt at thread;
Hi, Hj——the calculated height concentrated on the mass points i and j;
he——the effective thickness of the fillet weld;
hR——the distance from the edge of the member to the center of the bolt;
h0——the effective height of foundation punching shear failure cone;
ℓZ(0)——the width of the windward side of the derrick at the bottom;
ℓZ(H)——the width of the windward side of the derrick at the top;
Lwi——the total calculated length of the fillet weld;
m——the number of vibration modes;
n——the number of the derrick columns and the number of bolts connected at one end of the member;
ni——the number of bolts on the calculation section (at the outermost row of bolts);
Foreword i
1 Scope
2 Normative references
3 Terms and symbols
3.1 Terms
3.2 Symbols
4 Design principles
4.1 General
4.2 Derrick type
4.3 Material
4.4 Hoisting
5 Loads and action
5.1 Loads and combination
5.2 Wind loads
5.3 Seismic action
5.4 Ice load
6 Derrick calculation
7 Connection calculation
7.1 Gusset plate connection
7.2 Spherical node connection
7.3 Pipe welding connection
7.4 Flange connection
7.5 Wrist hinged connection
8 Details
8.1 General
8.2 Details of gusset plate connection
8.3 Details of spherical node connection
8.4 Details of pipe welding connection
8.5 Details of flange connection
9 Seismic measures
9.1 General for seismic design
9.2 Derrick with seismic fortification intensity 1
10 Foundation
11 Anti-corrosive design
12 Requirements for construction
Annex A (Informative) Design information
Annex B (Informative) Capacity design value for weld and bolt connection
Annex C (Informative) Anticorrosive design example
Explanation of wording in this specification
