Note: when the building height exceeds the value specified in above table, reliable basis shall be available for structural design and effective strengthening measures shall be taken.
3.1.3 The maximum height-width ratio applicable to the structure with specially shaped columns should not exceed the limits listed in Table 3.1.3.
Table 3.1.3 Maximum height-width ratio applicable to the structure with specially shaped columns
Structure system Non-seismic design Seismic design
Intensity 6 Intensity 7 Intensity 8
0.05g 0.10g 0.15g 0.20g 0.30g
Frame structure 4.5 4.0 3.5 3.0 2.5 —
Frame-shear wall structure 5.0 5.0 4.5 4.0 3.5 3
3.1.4 The structure system with specially shaped columns shall be determined through comprehensive analysis and comparison in terms of technical, economic and service conditions, and in addition to the relevant requirements for ordinary reinforced concrete structures given in the current national standards, it shall also comply with the following requirements:
1 Composite structure type formed by the frame with specially shaped columns and load-bearing masonry wall shall not be adopted.
2 In seismic design, single-span frame structure shall not be adopted, and complex structure forms such as connected structure and staggered-floor structure should not be adopted.
3 For staircase and elevator shaft, the shear wall, general frame column or the specially shaped column with embedded column at the leg end should be reasonably arranged according to the layout and stress requirements of the building; the seismic design of staircase shall meet the requirements of the current national standard GB 50011 Code for seismic design of buildings;
4 All columns, beams and shear walls of the structure with specially shaped columns shall be of cast-in-situ structure. In seismic design, cast-in-situ slab should be adopted, or the integrated monolithic composite slab with cast-in-situ thickness not less than 60mm may be adopted; in non-seismic design, cast-in-situ slab should be adopted, or the integrated monolithic composite slab with cast-in-situ course may be adopted.
3.1.5 The infilled wall and partition wall of the structure with specially shaped columns shall meet the following requirements:
1 Non-load-bearing masonry or wallboard of lightweight materials should be adopted for infill wall and partition wall according to different requirements and conditions;
2 For non-load-bearing wall, the thickness should be consistent with the thickness of leg of specially shaped column, and the wall body material shall meet the requirements for heat preservation, thermal insulation, energy saving, sound insulation, waterproofing and fireproofing;
3 The arrangement, material and connection construction of infilled wall and partition wall shall meet the requirements of relevant current national standards.
3.1.6 For special-shaped column frame-shear wall structure under seismic design, the corresponding design method shall be determined according to the ratio of the seismic overturning moment borne by the bottom frame of the structure to the total seismic overturning moment of the structure under the specified horizontal force, and shall meet the following requirements:
1 Where the seismic overturning moment borne by the frame is not greater than 10% the total seismic overturning moment of the structure, the structure shall be designed as a shear wall structure, wherein, the frame shall be designed as a frame-shear wall structure;
2 Where the seismic overturning moment borne by the frame is greater than 10% but not greater than 50% the total seismic overturning moment of the structure, the structure shall be designed as a frame-shear wall structure;
3 Where the seismic overturning moment borne by the frame is greater than 50% but not greater than 80% the total seismic overturning moment of the structure, the structure shall be designed as a frame-shear wall structure, for which, the applicable maximum height may be properly increased compared with that of frame structure. The seismic level and axial compression ratio limit of frame should be adopted in accordance with the requirements of frame structure;
4 Where the seismic overturning moment borne by the frame is greater than 80% the total seismic overturning moment of the structure, the structure shall be designed as a frame-shear wall structure, for which, the applicable maximum height may be adopted according that of frame structure. The seismic level and axial compression ratio of frame shall be adopted in accordance with the requirements of frame structure.
3.2 Structure scheme
3.2.1 For the structure with specially shaped columns, the regular structural design scheme should be adopted. For the structure with specially shaped columns under seismic design, the structural design scheme complying with the requirements of seismic concept design shall be adopted, while the severely irregular structural design scheme shall not be adopted.
3.2.2 In seismic design, in addition to the requirements of current national standard GB 50011 Code for seismic design of buildings, the regularity judgment on the structure with specially shaped columns and the design requirements for irregular structure with specially shaped columns shall also comply with the relevant requirements given in 3.2.3~3.2.5.
3.2.3 The plane layout of the structure with specially shaped columns shall meet the following requirements:
1 In an independent element of the structure with specially shaped columns, the plane shape of structure should be simple, regular and symmetrical, and the mass, stiffness and bearing capacity should be uniformly distributed.
2 For the structure with specially shaped columns, the axis of the longitudinal and horizontal column grid of the frame should be respectively aligned and connected; the centerline of leg thickness of the section of specially shaped column should be aligned with the centerlines of frame beam and shear wall.
3 Frame-shear wall structure with specially shaped column should be evenly arranged. In seismic design, the shear wall should be arranged so that the lateral stiffness in each main axial direction is similar. The spacing between shear walls should not exceed the limit (whichever is smaller) in Table 3.2.3; where it exceeds such limit, the influence of the in-plane deformation of floor system and roof system shall be counted in the structural calculation.
Table 3.2.3 Maximum spacing (m) between shear walls of the structure with specially shaped columns
Floor system and roof system type Non-seismic design Seismic design
Note: B in this table is the floor system width (m);
3.2.4 The vertical layout of structure with specially shaped columns shall meet the following requirements:
1 The elevation and vertical profile of building should be regular and uniform to avoid overlarge outward projection and inward contraction;
2 The lateral stiffness of the structure should be similar or evenly vary in vertical direction so as to avoid vertical sudden change of lateral stiffness and bearing capacity; the lateral stiffness of the adjacent floor of the high-rise frame-shear wall structure with specially shaped structure shall conform to the relevant requirements of the current professional standard JGJ 3 Technical specification for concrete structures of tall building.
3 The shear wall of the frame-shear wall structure system with specially shaped columns shall be vertically aligned and continuously run through the full height of the building.
3.2.5 The seismic design for the irregular structure with specially shaped columns shall meet the following requirements:
1 In case of irregular torsion, the torsion effect shall be considered, and the ratio of the maximum elastic horizontal displacement and inter-floor displacement of vertical members of a floor respectively to the average elastic horizontal displacement and inter-floor displacement at both ends of this floor shall not be greater than 1.45;
2 In case of irregular lateral stiffness, the seismic shear of the floor with low stiffness shall be multiplied by an amplification coefficient not less than 1.15;
3 In case of sudden change in bearing capacity of a floor, the seismic shear corresponding to characteristic value under earthquake action on the weak floor shall be multiplied by the amplification coefficient of 1.25; the shear bearing capacity of this floor shall not be less than 65% that of the adjacent upper floor;
4 In case of discontinuity of the vertical lateral-force-resistant member, the seismic internal force transmitted from this member to the horizontal transition member shall be multiplied by the amplification coefficient of 1.25~1.50;
5 For columns in positions under complex and unfavorable stress, specially shaped column with embedded column at the leg end or ordinary frame column should be adopted.
3.2.6 The structure with specially shaped columns under strict seismic safety and service function requirements may be subjected to seismic isolation design. The seismic isolation design, where adopted, shall meet the relevant requirements of the current national standard GB 50011 Code for seismic design of buildings.
3.3 Seismic levels of structure
3.3.1 In seismic design, different seismic levels shall be adopted for the structure with specially shaped columns in accordance with those specified in Table 3.3.1 based on the seismic fortification intensity, building site category, structural type and building height, and corresponding requirements of calculation and construction measures shall be met. In case of Category I building site, except for Intensity 6, it shall be allowable to take seismic construction measures based on the corresponding seismic level obtained by reducing the local seismic fortification intensity by one intensity degree, however, the corresponding calculation requirements shall not be lowered.
Foreword i 1 General provisions 2 Terms and symbols 2.1 Terms 2.2 Symbols 3 Basic requirements for structural design 3.1 Structure system 3.2 Structure scheme 3.3 Seismic levels of structure 4 Structural calculation and analysis 4.1 Limit state design 4.2 Load and earthquake action 4.3 Structural analysis model and calculation parameters 4.4 Horizontal displacement limit 5 Section design 5.1 Calculation on bearing capacity of normal section of specially shaped column 5.2 Calculation on inclined section shear capacity of specially shaped column 5.3 Calculation on shear capacity in core area of beam-column joints of frame with specially shaped column 6 Structure construction 6.1 General requirements 6.2 Structure with specially shaped columns 6.3 Joints of frame with specially shaped columns 7 Construction and acceptance of structure with specially shaped column Appendix A Specially shaped column structure with transition-storeys Explanation of wording in this specification List of quoted standards
0.05g 0.10g 0.15g 0.20g 0.30g
Frame structure 28 24 21 18 12 Not adopted
Frame-shear wall structure 58 55 48 40 28 21
Note: when the building height exceeds the value specified in above table, reliable basis shall be available for structural design and effective strengthening measures shall be taken.
3.1.3 The maximum height-width ratio applicable to the structure with specially shaped columns should not exceed the limits listed in Table 3.1.3.
Table 3.1.3 Maximum height-width ratio applicable to the structure with specially shaped columns
Structure system Non-seismic design Seismic design
Intensity 6 Intensity 7 Intensity 8
0.05g 0.10g 0.15g 0.20g 0.30g
Frame structure 4.5 4.0 3.5 3.0 2.5 —
Frame-shear wall structure 5.0 5.0 4.5 4.0 3.5 3
3.1.4 The structure system with specially shaped columns shall be determined through comprehensive analysis and comparison in terms of technical, economic and service conditions, and in addition to the relevant requirements for ordinary reinforced concrete structures given in the current national standards, it shall also comply with the following requirements:
1 Composite structure type formed by the frame with specially shaped columns and load-bearing masonry wall shall not be adopted.
2 In seismic design, single-span frame structure shall not be adopted, and complex structure forms such as connected structure and staggered-floor structure should not be adopted.
3 For staircase and elevator shaft, the shear wall, general frame column or the specially shaped column with embedded column at the leg end should be reasonably arranged according to the layout and stress requirements of the building; the seismic design of staircase shall meet the requirements of the current national standard GB 50011 Code for seismic design of buildings;
4 All columns, beams and shear walls of the structure with specially shaped columns shall be of cast-in-situ structure. In seismic design, cast-in-situ slab should be adopted, or the integrated monolithic composite slab with cast-in-situ thickness not less than 60mm may be adopted; in non-seismic design, cast-in-situ slab should be adopted, or the integrated monolithic composite slab with cast-in-situ course may be adopted.
3.1.5 The infilled wall and partition wall of the structure with specially shaped columns shall meet the following requirements:
1 Non-load-bearing masonry or wallboard of lightweight materials should be adopted for infill wall and partition wall according to different requirements and conditions;
2 For non-load-bearing wall, the thickness should be consistent with the thickness of leg of specially shaped column, and the wall body material shall meet the requirements for heat preservation, thermal insulation, energy saving, sound insulation, waterproofing and fireproofing;
3 The arrangement, material and connection construction of infilled wall and partition wall shall meet the requirements of relevant current national standards.
3.1.6 For special-shaped column frame-shear wall structure under seismic design, the corresponding design method shall be determined according to the ratio of the seismic overturning moment borne by the bottom frame of the structure to the total seismic overturning moment of the structure under the specified horizontal force, and shall meet the following requirements:
1 Where the seismic overturning moment borne by the frame is not greater than 10% the total seismic overturning moment of the structure, the structure shall be designed as a shear wall structure, wherein, the frame shall be designed as a frame-shear wall structure;
2 Where the seismic overturning moment borne by the frame is greater than 10% but not greater than 50% the total seismic overturning moment of the structure, the structure shall be designed as a frame-shear wall structure;
3 Where the seismic overturning moment borne by the frame is greater than 50% but not greater than 80% the total seismic overturning moment of the structure, the structure shall be designed as a frame-shear wall structure, for which, the applicable maximum height may be properly increased compared with that of frame structure. The seismic level and axial compression ratio limit of frame should be adopted in accordance with the requirements of frame structure;
4 Where the seismic overturning moment borne by the frame is greater than 80% the total seismic overturning moment of the structure, the structure shall be designed as a frame-shear wall structure, for which, the applicable maximum height may be adopted according that of frame structure. The seismic level and axial compression ratio of frame shall be adopted in accordance with the requirements of frame structure.
3.2 Structure scheme
3.2.1 For the structure with specially shaped columns, the regular structural design scheme should be adopted. For the structure with specially shaped columns under seismic design, the structural design scheme complying with the requirements of seismic concept design shall be adopted, while the severely irregular structural design scheme shall not be adopted.
3.2.2 In seismic design, in addition to the requirements of current national standard GB 50011 Code for seismic design of buildings, the regularity judgment on the structure with specially shaped columns and the design requirements for irregular structure with specially shaped columns shall also comply with the relevant requirements given in 3.2.3~3.2.5.
3.2.3 The plane layout of the structure with specially shaped columns shall meet the following requirements:
1 In an independent element of the structure with specially shaped columns, the plane shape of structure should be simple, regular and symmetrical, and the mass, stiffness and bearing capacity should be uniformly distributed.
2 For the structure with specially shaped columns, the axis of the longitudinal and horizontal column grid of the frame should be respectively aligned and connected; the centerline of leg thickness of the section of specially shaped column should be aligned with the centerlines of frame beam and shear wall.
3 Frame-shear wall structure with specially shaped column should be evenly arranged. In seismic design, the shear wall should be arranged so that the lateral stiffness in each main axial direction is similar. The spacing between shear walls should not exceed the limit (whichever is smaller) in Table 3.2.3; where it exceeds such limit, the influence of the in-plane deformation of floor system and roof system shall be counted in the structural calculation.
Table 3.2.3 Maximum spacing (m) between shear walls of the structure with specially shaped columns
Floor system and roof system type Non-seismic design Seismic design
Intensity 6 Intensity 7 Intensity 8
0.05g 0.10g 0.15g 0.20g 0.30g
Cast-in-situ 4.5B, 55 4.0B, 50 3.5B, 45 3.0B, 40 2.5B, 35 2.0B, 25
Assembled monolithic 3.0B, 45 — — — — —
Note: B in this table is the floor system width (m);
3.2.4 The vertical layout of structure with specially shaped columns shall meet the following requirements:
1 The elevation and vertical profile of building should be regular and uniform to avoid overlarge outward projection and inward contraction;
2 The lateral stiffness of the structure should be similar or evenly vary in vertical direction so as to avoid vertical sudden change of lateral stiffness and bearing capacity; the lateral stiffness of the adjacent floor of the high-rise frame-shear wall structure with specially shaped structure shall conform to the relevant requirements of the current professional standard JGJ 3 Technical specification for concrete structures of tall building.
3 The shear wall of the frame-shear wall structure system with specially shaped columns shall be vertically aligned and continuously run through the full height of the building.
3.2.5 The seismic design for the irregular structure with specially shaped columns shall meet the following requirements:
1 In case of irregular torsion, the torsion effect shall be considered, and the ratio of the maximum elastic horizontal displacement and inter-floor displacement of vertical members of a floor respectively to the average elastic horizontal displacement and inter-floor displacement at both ends of this floor shall not be greater than 1.45;
2 In case of irregular lateral stiffness, the seismic shear of the floor with low stiffness shall be multiplied by an amplification coefficient not less than 1.15;
3 In case of sudden change in bearing capacity of a floor, the seismic shear corresponding to characteristic value under earthquake action on the weak floor shall be multiplied by the amplification coefficient of 1.25; the shear bearing capacity of this floor shall not be less than 65% that of the adjacent upper floor;
4 In case of discontinuity of the vertical lateral-force-resistant member, the seismic internal force transmitted from this member to the horizontal transition member shall be multiplied by the amplification coefficient of 1.25~1.50;
5 For columns in positions under complex and unfavorable stress, specially shaped column with embedded column at the leg end or ordinary frame column should be adopted.
3.2.6 The structure with specially shaped columns under strict seismic safety and service function requirements may be subjected to seismic isolation design. The seismic isolation design, where adopted, shall meet the relevant requirements of the current national standard GB 50011 Code for seismic design of buildings.
3.3 Seismic levels of structure
3.3.1 In seismic design, different seismic levels shall be adopted for the structure with specially shaped columns in accordance with those specified in Table 3.3.1 based on the seismic fortification intensity, building site category, structural type and building height, and corresponding requirements of calculation and construction measures shall be met. In case of Category I building site, except for Intensity 6, it shall be allowable to take seismic construction measures based on the corresponding seismic level obtained by reducing the local seismic fortification intensity by one intensity degree, however, the corresponding calculation requirements shall not be lowered.
Contents of JGJ 149-2017
Foreword i
1 General provisions
2 Terms and symbols
2.1 Terms
2.2 Symbols
3 Basic requirements for structural design
3.1 Structure system
3.2 Structure scheme
3.3 Seismic levels of structure
4 Structural calculation and analysis
4.1 Limit state design
4.2 Load and earthquake action
4.3 Structural analysis model and calculation parameters
4.4 Horizontal displacement limit
5 Section design
5.1 Calculation on bearing capacity of normal section of specially shaped column
5.2 Calculation on inclined section shear capacity of specially shaped column
5.3 Calculation on shear capacity in core area of beam-column joints of frame with specially shaped column
6 Structure construction
6.1 General requirements
6.2 Structure with specially shaped columns
6.3 Joints of frame with specially shaped columns
7 Construction and acceptance of structure with specially shaped column
Appendix A Specially shaped column structure with transition-storeys
Explanation of wording in this specification
List of quoted standards
