1 General Provisions
1.0.1 This code is formulated with view to implementing the national technical and economic policies in the design, member manufacturing and project construction of concrete filled steel tubular structures and realizing safety, applicability and economy.
1.0.2 This code is applicable to the design, member manufacturing and construction of industrial and civil buildings and general structures of concrete filled steel tubular structures.
1.0.3 The design, member manufacturing and construction of concrete filled steel tubular structures shall not only meet the requirements stipulated in this code, but also comply with those in the current relevant national standards.
2 Terms and Symbols
2.1 Terms
2.1.1 Concrete filled steel tubular members
Members with steel tubes filled with concrete, including solid and hollow concrete filled steel tubular members. Their sections may be circular, rectangle and polygonal; hereinafter referred to as CFST members.
2.1.2 Concrete filled steel tubular structures
Structures with concrete filled steel tubular members as the primary load-carrying members, hereinafter referred to as CFST structures.
2.1.3 Solid concrete filled steel tubular members
Members with steel tube filled up with concrete, hereinafter referred to as S-CFST members.
2.1.4 Hollow concrete filled steel tubular members
Hollow concrete filled steel tubular members made through centrifugation method by injecting a certain amount of concrete into the empty steel tubes, hereinafter referred to as H-CFST members.
2.1.5 Steel ratio
The ratio of steel tube area to concrete area on the member section.
2.1.6 Hollow ratio
The ratio of the area of hollow part to the total area of concrete and hollow part on the section of hollow concrete filled steel tubular member.
2.1.7 Confinement coefficient
The ratio of the product of steel tube area and design steel strength to that of the concrete area and design concrete strength on the member section.
2.1.8 Sea sand concrete filled steel tubular members
Concrete filled steel tubular members manufactured with sea sand concrete.
2.1.9 Recycled concrete filled steel tubular members
Concrete filled steel tubular members manufactured with recycled aggregate concrete.
2.2 Symbols
2.2.1 Action, action effect and resistance
N - the design value of axial pressure;
Nt - the design value of axial tension;
, and - the design values for tensile, compressive and shear capacities of a plain bolt;
Nu, Nut, Mu, Tu and Vu - the design values for axial compression, axial tension, bending, torsion and shear capacities;
Nl - the design value of local axial pressure;
Nul - the design value for local compressive capacity of CFST column;
M - the design value of bending moment;
T - the design value of torque;
V - the design value of bend shear.
Foreword I
1 General Provisions 1
2 Terms and Symbols 2
2.1 Terms 2
2.2 Symbols 2
3 Materials 5
3.1 Steel 5
3.2 Concrete 5
3.3 Connecting Materials 5
4 Basic Requirements 7
4.1 General Requirements 7
4.2 Structural Analysis and Design Principle 8
4.3 S-CFST Structure 10
4.4 Hollow-CFST Structure 14
5 Design of Load-carrying Capacities for Circular and Polygonal CFST Members 15
5.1 Load-carrying Capacities and Rigidity Calculations of Single CFST Columns under Single Stress Condition 15
5.2 Load-carrying Capacity Calculation of Latticed CFST Member under Single Stress Condition 22
5.3 Load-carrying Capacity Calculation of CFST Members under Complex Stress Conditions 26
5.4 Effects of Concrete Creep on Load-carrying Capacity of Member 28
6 Design of Load-carrying Capacities for Solid Circular CFST Members 29
6.1 Load-carrying Capacity Calculation of Single Axial Loaded Column 29
6.2 Calculation of Horizontal Shear Capacity for Single Column 33
6.3 Calculation of Local Compression 34
6.4 Load-carrying Capacity Calculation of CFST Latticed Column 35
7 Design of Connection and Joints 42
7.1 General Requirements 42
7.2 Solid-CFST Members Connections and Joints 43
7.3 Hollow-CFST Members Connections and Joints 56
7.4 Column Base Joint 67
8 Fireproofing Design 70
9 Manufacture and Construction 75
9.1 Manufacture of Steel Tube 75
9.2 Rust Removal and Preservative Coating of CFST Members 76
9.3 Concrete Pouring and Construction of S-CFST Members 76
9.4 Manufacture of Hollow-CFST Members 78
9.5 Construction of CFST Structures 79
Appendix A Shape Constants for Various Sections 80
Appendix B Design Values for Compressive Strength of CFST Members 81
Appendix C Joint Design of Steel Beam with CFST Column by Outside Stiffener Rings 88
Appendix D RC Beam to Circular CFST Column Ring-beam Joints Calculation Methods 91
Appendix E CFST Members Fireproofing Calculation Methods 96
Explanation of Wording in This Code 102
List of Quoted Standards 103
