The shape of the building plane should be simple and regular, and regular and symmetrical planes such as square and rectangular should be used, and the lateral force-resisting center of the structure should coincide with the horizontal resultant force center as much as possible. The bays and depth of the building should be unified.

In the tube-in-tube structural system, when the peripheral steel frame columns adopt H-shaped cross-section columns, the strong axis direction of the column section should be arranged in the plane of the peripheral cylinder; the corner columns should adopt cross-shaped, square or circular cross-sections;

The main beams of the floor should not rest on the connecting beams of the core tube or inner tube.

The lateral stiffness and bearing capacity of the structure should change evenly along the vertical direction, and the component cross-section should gradually decrease from bottom to top without sudden changes;

When the upper and lower parts of the frame columns are of different types and materials, a transition layer should be set;

Reliable transition strengthening measures should be taken for floors with sudden changes in stiffness, such as transfer floors, reinforced floors, open top floors, top protrusions, the interface between steel concrete frames and steel frames, and adjacent floors;

When supporting the steel frame part, eccentric supports and energy-dissipating supports should be used. The supports should be arranged continuously, and should be arranged in two mutually perpendicular directions and interconnected with each other; the support frame is in the underground part and should be extended to the foundation.

The floor-to-ceiling shear wall and the bottom wall of the cylinder should be thickened;

The lateral stiffness ratio between the upper structure and the lower structure of the transfer layer shall comply with the provisions of Appendix E of this regulation;

Floor slabs around the frame support layer should not be arranged at staggered levels;

The openings of floor-to-ceiling shear walls and cylinders should be arranged in the middle of the wall;

It is not appropriate to set up side door openings in the wall on the first floor above the frame-supported shear wall transfer beam, nor to set up door openings above the center column;

The spacing l of floor-to-ceiling shear walls in long rectangular plan buildings should comply with the following regulations:

The distance between the floor-to-ceiling shear wall and the adjacent frame support should not be greater than 12m when the frame supports the 1st or 2nd floor, and should not exceed 10m when the frame supports the 3rd floor or above.

When the number of frame pillars per floor is no more than 10, when the frame support layer is 1 to 2 stories, the shear force on each column should be at least 2% of the base shear force; when the frame support layer is 3 stories and above 3 stories, the shear force on each column should be at least 3% of the base shear force;

When the number of frame pillars per layer is more than 10, when the frame support layer is 1 to 2 stories, the sum of the shear force of each frame pillar should be taken as 20% of the base shear force; when the frame support layer is 3 stories and When there are more than 3 floors, the sum of the shear forces of the frame pillars on each floor should be 30% of the base shear force.

After the shear force of the frame pillar is adjusted, the bending moment of the frame pillar and the shear force and bending moment of the column end beam (excluding the conversion beam) should be adjusted accordingly. The axial force of the frame pillar does not need to be adjusted.

The minimum reinforcement ratio of the upper and lower longitudinal steel bars of the beam should not be less than 0.30% respectively in non-seismic design; in seismic design, the special first, first and second grade should not be less than 0.60%, 0.50% and 0.40% respectively;

For a frame-supported beam under eccentric tension, at least 50% of the upper longitudinal steel bars of the support should run through the entire length of the beam, and all the lower longitudinal steel bars should pass straight into the column; waist bars with a spacing of no more than 200mm and a diameter of no less than 16mm should be configured along the beam height;

The stirrups at the frame support beam support (within the height of the beam section 1.5 from the column edge) should be dense. The diameter of the stirrups in the dense area should not be less than 10mm, and the spacing should not be greater than 100mm. The minimum area stirrup ratio in the densification area shall not be less than 0.9ft/fyv in non-seismic design; in seismic design, the special first, first and second grade shall not be less than 1.3ft/fyv, 1.2ft/fyv and 1.1ft/ respectively. fyv.

The center lines of the frame support beams and frame support sections should coincide;

The cross-sectional width of the frame-supported beam should not be greater than the cross-sectional width of the frame support in the corresponding direction, and should not be less than twice the cross-sectional thickness of the wall above it, and should not be less than 400mm; when supporting columns on the beam, it should not be less than the column cross-section width in the beam width direction. . The height of the beam section should not be less than 1/6 of the calculated span in seismic design, and should not be less than 1/8 of the calculated span in non-seismic design; frame-supported beams can use haunched beams;

The maximum shear design value of the frame-supported beam section combination should meet the following requirements:

When the wall above the frame support beam has a door opening or a support column on the beam, the stirrups of the frame support beam in this part should be densely arranged, and the stirrup diameter, spacing and stirrup ratio should not be lower than Article 10.2.8 of this regulation According to the provisions of paragraph 3; when the opening is close to the end of the frame-supported beam and the shear bearing capacity of the beam does not meet the requirements, measures such as adding haunches to the frame-supported beam or increasing the stiffness of the connecting beams at the frame-supported wall opening can be taken;

The longitudinal steel bar joints of beams should be mechanically connected. The cross-sectional area of ​​the joint steel bars in the same section should not exceed 50% of the cross-sectional area of ​​all longitudinal bars. The joint location should avoid the openings in the upper wall, the supporting columns on the beams, and the areas with greater stress. parts;

The anchorage of the upper and lower longitudinal steel bars and waist bars of the beam should comply with the requirements of Figure 10.2.9; when the upper part of the beam is equipped with multiple rows of longitudinal steel bars, the length of the inner row of steel bars anchored into the column can be appropriately reduced, but should not be shorter than the steel bars Anchorage length 1a (non-seismic design) or 1aE (seismic design);

It is not suitable to make holes in frame support beams. If a hole is needed, the hole should be located away from the edge of the frame pillar. The upper and lower chords should be reinforced with shear reinforcement. The hole should be equipped with reinforced steel bars or reinforced with section steel. The section weakened by the hole should be calculated for bearing capacity.

The reinforcement ratio of all longitudinal steel bars in the column shall comply with the provisions of Article 6.4.3 of this regulation;

During seismic design, the stirrups of the frame pillars should be composite spiral hoops or tic-shaped composite hoops. The stirrup diameter should not be less than 10mm, and the stirrup spacing should not be greater than the smaller of 100mm and 6 times the diameter of the longitudinal steel bars, and should be installed along the full height of the column. encryption;

During seismic design, the characteristic value of the stirrup configuration in the primary and secondary column density areas should be increased by 0.02 from the value specified in Table 6.4.7 of this regulation, and the volume stirrup ratio of the column stirrups should not be less than 1.5%.

The combined maximum shear design value of the frame support section should meet the following requirements:

The width of the column section should not be less than 400mm in non-seismic design, and should not be less than 450mm in seismic design; the column section height should not be less than 1/15 of the frame support beam span in non-seismic design, and should not be less than 1/15 of the frame support beam span in seismic design. /12;

The combined bending moment values ​​of the upper end of the first and second level columns connected to the conversion members and the lower end of the column on the ground floor should be multiplied by the increase coefficients 1.5 and 1.25 respectively. The design values ​​of the bending moments at the column ends of other floor frame pillars should comply with Article 6.2 of this regulation. The provisions of Article 1;

1. The design value of the shear force of the secondary column end section shall comply with the provisions of Article 6.2.3 of this regulation;

The design values ​​of bending moment and shear force of frame-supported corner columns shall be multiplied by an increase factor of 1.1 on the basis of paragraphs 3 and 4 of this article respectively;

The axial force generated by the earthquake action on the primary and secondary frame pillars should be multiplied by the increase factors 1.5 and 1.2 respectively, but this increase factor should not be considered when calculating the column axial pressure ratio;

The spacing between longitudinal steel bars should not be greater than 200mm in seismic design; it should not be greater than 250mm in non-seismic design, and should not be less than 80mm. During seismic design, the reinforcement ratio of all longitudinal steel bars in the column should not be greater than 4.0%;

The longitudinal steel bars of the frame pillars within the upper wall should extend into the upper wall for no less than one layer, and the remaining column bars should be anchored into the beams or slabs. The length of the steel bars anchored into the beam shall not be less than 1aE (seismic design) or 1a (non-seismic design) from the column edge;

In non-seismic design, the frame pillars should use composite spiral hoops or tic-shaped composite hoops. The stirrup volume ratio should not be less than 0.8%, the stirrup diameter should not be less than 10mm, and the stirrup spacing should not be greater than 150mm.

When there is a side door opening in the wall above the frame support beam, the wall beside the opening should be equipped with flange walls, end columns or thickened (Figure 10.2.13), and the edge components should be restrained in accordance with Article 7.2.16 of this regulation. Reinforcement design is required;

The anchoring length of the vertical steel bars of the wall on the frame support beam in the transfer beam should not be less than laE in seismic design, and should not be less than la in non-seismic design;

The reinforcement of the wall on the first floor above the frame support beam should be calculated according to the following formula:

The horizontal construction joint between the transfer beam and its upper wall should be checked for slip resistance in accordance with Article 7.2.13 of this regulation.

The thickness of the converted thick plate can be determined by calculation of bending resistance, shear resistance and punching resistance;

The thick plate can be converted into a partial thin plate, and the junction between the thin plate and the thick plate can be added with a haunch; the thick plate can also be partly made into a sandwich plate;

The converted thick plate should be designed in section according to the design values ​​of shear force and bending moment of the main cross-beam system divided in the overall calculation, and the reinforcement should be checked according to the analysis results of the finite element method. Bending longitudinal steel bars can be arranged in two directions along the double layer and lower part of the transfer plate. The total reinforcement ratio in each direction should not be less than 0.6%. The area reinforcement ratio of the concealed beam shear stirrups in the transfer plate should not be less than 0.45%;

In order to prevent lamellar horizontal cracks along the thickness direction at the ends of the converted thick plates, it is advisable to configure a steel skeleton mesh around the outer periphery of the thick plates for reinforcement;

The longitudinal steel bars of the shear walls and columns at the upper and lower parts of the transfer slab should be reliably anchored within the transfer slab.

The floor slabs on the conversion thick slab and the next floor should be appropriately strengthened, and the thickness of the floor slab should not be less than 150mm.

When the upper dense columns of frame-core tube structures and tube-in-tube structures are converted into lower sparse columns, conversion beams or conversion trusses can be used. The conversion trusses should be set up on the full floor, and the intersection of the diagonal rods should be used as the fulcrum of the upper dense columns. The nodes of the transfer truss should be strengthened with reinforcement and structural measures to prevent the adverse effects caused by stress concentration.

When using a Vierendeel truss transfer layer, the Vierendeel truss should be set up on the full floor, and it should have sufficient stiffness to ensure its overall stress. The upper and lower chords of the open-web truss should consider the floor function. The vertical web bars should be reinforced according to strong shear and weak bending, strengthen the stirrup configuration, and strengthen the connection structure with the upper and lower chords. Vierendeel trusses should strengthen the anchoring connection structure between the upper and lower chords and frame columns.

The location and number of reinforcement layers must be reasonable and effective. When arranging one reinforcement layer, the location can be near 0.6 times the height of the house; when arranging two reinforcement layers, the location can be near the top floor and 0.5 times the height of the house; when arranging multiple reinforcement layers When layering, the reinforcing layer should be evenly arranged vertically from the top layer downward;

The horizontal outrigger components of the reinforced layer should penetrate the core tube, and their plan layout should be located at the corners and T-points of the core tube; the connection between the horizontal outrigger components and the surrounding frame should be hinged or semi-rigid. In the calculation of structural internal forces and displacements, the deformation in the floor plane should be considered for floors with horizontal outrigger trusses;

Damage caused by increased internal forces of the reinforced layer and its adjacent layer frame columns should be avoided. The reinforcement structure of the reinforced layer and its upper and lower frame columns should be strengthened; the reinforcement of the core tube of the reinforced layer and its adjacent layers should be strengthened;

The stiffness and reinforcement of the reinforced layer and its adjacent floors should be strengthened;

Measures should be taken in the construction procedures and connection structures to reduce the impact of vertical temperature deformation and axial compression of the structure on the reinforcement layer.

The seismic resistance grade of the frame columns and core tube shear walls of the reinforced layer and its adjacent layers should be raised by one level, and the first level should be raised to the special first grade. If the original seismic grade is the special first grade, it will not be improved;

The stirrups of the reinforced layer and the frame columns of the adjacent floors above and below should be densely packed throughout the column section, and the axial compression ratio limit should be reduced by 0.05 from the value specified in Table 6.4.2 of this regulation.

The connector structure and the main structure should be rigidly connected. If necessary, the connector structure can be extended to the inner cylinder of the main part and reliably connected to the inner cylinder.

When the connector structure is non-rigidly connected to the main structure, the bearing slippage should be able to meet the displacement requirements in both directions under rare earthquakes.

The connector structure should strengthen structural measures. The side beam cross-section of the connector structure should be enlarged. The thickness of the floor slab should not be less than 150mm. Double-layer two-way steel mesh should be used. The reinforcement ratio of each layer of steel mesh in each direction should not be less than 0.25%.

The connector structure can be equipped with steel beams, steel trusses and profiled steel concrete beams. The profiled steel should extend into the main structure and strengthen the anchorage.

When the connecting structure contains multiple floors, the design and construction of the bottom one to two floors should be particularly strengthened.

Wall limbs should be arranged evenly and symmetrically;

It is not advisable to open holes near the corners of the cylinder. When unavoidable, the distance from the inner wall of the cylinder corner to the opening should not be less than 500mm and the cross-sectional thickness of the hole wall;

The cross-sectional thickness of the core tube outer wall should not be less than 1/20 and 200mm of the floor height. The bottom reinforcement part for the first and second level seismic design should not be less than 1/16 and 200mm of the floor height. If it is not satisfied, the thickness should be determined according to the appendix of this regulation. D Calculate the stability of the wall, and add buttress columns or buttress walls if necessary; when meeting the bearing capacity requirements and the axial pressure ratio limit (only for earthquake resistance design), the inner wall of the core tube can be appropriately thinned, but it should not be smaller than 160mm;

The horizontal and vertical reinforcement of the cylinder wall should not be less than two rows

During seismic design, the ductility of the coupling beams of the core tube should be improved by configuring cross-concealed bracing, setting up horizontal joints, or reducing the height-to-width ratio of the beam section.

The distance between columns should not be greater than 4m. The long side of the section of the frame column should be arranged along the direction of the column wall. If necessary, a T-shaped section can be used;

The area of ​​the opening should not be greater than 60% of the wall area, and the height-to-width ratio of the opening should be similar to the ratio of floor height to column spacing;

The cross-sectional height of the outer frame tube beam can be taken as 1/4 of the column clear distance;

The cross-sectional area of ​​the corner columns can be 1 to 2 times that of the center column.

In non-seismic design, the stirrup diameter should not be less than 8mm; in seismic design, the stirrup diameter should not be less than 10mm;

In non-seismic design, the stirrup spacing should not be greater than 150mm; in seismic design, the stirrup spacing should not be greater than 100mm along the length of the beam. When cross braces are installed in the beam, the stirrup spacing should not be greater than 150mm;

The diameter of the upper and lower longitudinal steel bars of the frame tube beam should not be less than 16mm, the diameter of the waist bars should not be less than 10mm, and the distance between the waist bars should not be greater than 200mm.

1. The cross-sectional width of the beam should not be less than 300mm;

2 All shear forces should be borne by concealed braces. Each concealed brace should be composed of 4 longitudinal steel bars. The diameter of the longitudinal bars should not be less than 14mm. Its total area As should be calculated according to the following formula:

The longitudinal steel bars for diagonal bracing in both directions should be tied together with rectangular stirrups or spiral stirrups. The stirrup diameter should not be less than 8mm, and the stirrup spacing should not be greater than 200mm and half the beam cross-section width; the stirrups in the end density area should not be less than 8mm. The spacing between ribs should not be greater than 100mm, and the length of the dense area should not be less than 600mm and twice the width of the beam section;

The length of the longitudinal reinforcement extending into the vertical member should not be less than 1a1. In non-seismic design, 1a1 can be taken as 1a; in seismic design, 1a1 should be taken as 1.151a;

The configuration of ordinary stirrups within the beam shall comply with the structural requirements of Article 9.3.7 of this regulation.

In frame-shear wall structures, the frame and shear walls carry both vertical loads and lateral forces.

Under the action of vertical load, the frame and shear wall respectively bear the vertical force within their load range.

Under the action of lateral forces, the frame and shear walls work together to resist the lateral forces.

Since the deformation characteristics of frames and shear walls are completely different when they bear lateral forces alone, the distribution of lateral forces between frames and shear walls is not only related to the stiffness ratio between the frame and shear walls, but also Varies with altitude.

When the lateral force acts alone on the frame structure, the lateral displacement curve of the structure is shear-shaped, as shown in Figure 15-38(a); when the lateral force acts alone on the hand-shear wall structure, the lateral displacement curve of the structure is curved. , Figure 15-38(b). When lateral forces act on the frame-shear wall structure, it is due to the connection effect of the floor structure. If the overall torsion of the structure does not occur, the frame and shear wall must have the same lateral displacement at each floor. The coordinated lateral displacement curve of the structure is shown in Figure 15-38 (C), which is a bending-shear type.

It can be seen that the influence of the frame and shear wall on the lateral displacement curve of the entire structure changes along the height direction of the structure. At the bottom of the structure, the inter-story displacement of the frame structure is large, and the inter-story displacement of the shear wall structure is small. The shear wall plays a greater role, and the deformation of the frame structure is "constrained" by the shear wall structure; while at the At the top of the structure, the inter-story displacement of the frame structure is small, but the inter-story displacement of the shear wall structure is large. The shear wall is "supported" by the frame structure, as shown in Figure 15-38 (c) and (d). The above-mentioned interaction between the frame and the shear wall is realized with the help of the shear force in the plane of the floor structure. Therefore, in the frame-shear wall structure, the integrity and in-plane stiffness of the floor structure must be guaranteed.

The lateral displacement curve of the frame-shear wall structure is bending-shear type, and the lateral displacement curve of the structure changes with the change of the stiffness characteristic value λ of the frame-shear wall structure. For bending-type lateral displacement curves, the maximum inter-story displacement is at the top layer of the structure; for shear-type lateral displacement curves, the maximum inter-story displacement is at the bottom layer of the structure; for bending-shear type curves, the maximum inter-story displacement is at the middle of the structure .

In the frame-shear wall structure, the number of shear walls directly affects the seismic performance of the entire structure and the civil construction cost. With more shear walls arranged, the lateral stiffness of the structure is large and the lateral displacement is small; but the amount of material increases, and at the same time, due to the shortened natural vibration period of the structure, the self-weight of the structure increases, resulting in an increase in the seismic response, that is, the lateral force get bigger. On the contrary, less shear walls are arranged, and the amount of material is reduced. Because the structure is softer, the natural vibration period becomes longer, and the seismic response, that is, the seismic force becomes smaller; but the lateral stiffness of the structure is small, the lateral displacement is large, and the earthquake The rear structure is cracked or severely damaged.

In the expanded preliminary design stage or as a principle of structural design, the layout of shear walls should meet the requirements of the lateral stiffness of the structure. That is, while the apex displacement of the structure and the maximum inter-story displacement of the structure are calculated to meet the high-standard limit values, they should also be checked. Control the natural vibration period of the structure within a reasonable range. It is generally believed that when the basic natural vibration period of the structure T = (0.1~0.15)n (n is the number of structural layers), the number of shear walls and the cross-sectional size of the components are more reasonable.

Shear walls should be evenly arranged near the periphery of the building, in stairwells, elevator rooms, and locations with changes in plane shape and large dead loads. The spacing between shear walls should not be too large;

When the plane shape has large concavities and convexities, it is advisable to arrange shear walls near the ends of the protruding parts;

Longitudinal and transverse shear walls should be formed into L-shaped, T-shaped, [-shaped and other types;

The horizontal shear force borne by the bottom of the single-piece shear wall should not exceed 40% of the total horizontal shear force at the bottom of the structure;

The shear wall should run through the entire height of the building, and sudden changes in stiffness should be avoided; when openings are opened in the shear wall, the openings should be aligned up and down;

Shafts such as buildings and elevator rooms should be arranged in conjunction with nearby lateral force-resistant structures as much as possible;

During seismic design, the shear walls should be arranged so that the lateral stiffness in each main axis direction of the structure is close to each other.

For floors that meet the requirements of type (8.1.4), the total frame shear force does not need to be adjusted; for floors that do not meet the requirements of type (8.1.4), the total frame shear force should be based on 0.2V0 and 1.5Vf, max 2 The smaller value shall be used; Vf≥0.2V0

After the total seismic shear force borne by each floor frame is adjusted according to paragraph 1 of this article, the standard values ​​of shear force and end bending moment of each frame column and the frame beam connected to it shall be adjusted according to the ratio of the total shear force before and after adjustment. , the standard value of the axial force of the frame column does not need to be adjusted;

When calculating seismic effects based on the mode decomposition response spectrum method, the adjustments specified in paragraph 1 of this article may be made after the mode combination.

The spacing of transverse shear walls along the length direction should meet the requirements of Table 8.1.8. When there are large openings in the floor between these shear walls, the spacing of the shear walls should be appropriately reduced;

Longitudinal shear walls should not be concentrated at both ends of the house.

Shear walls generally have I-shaped, L-shaped, T-shaped, [-shaped, Z-shaped and other cross-sectional forms.

The height of the shear wall is generally the same as the height of the entire house, and its width is determined according to the building layout; relatively speaking, its thickness is very thin, generally only 20 to 30mm.

The lateral stiffness of a shear wall within the plane of the wall is very large, but the stiffness outside the plane of the wall is very small and can generally be ignored.

In shear wall structures, shear walls should be arranged in two directions along the main axis or other directions; for shear wall structures designed for earthquake resistance, structural arrangements with walls in only one direction should be avoided. The cross-section of shear wall piers should be simple and regular. The lateral stiffness of the shear wall structure should not be too large.

High-rise building structures should not adopt shear wall structures that are all short-leg shear walls.

Class B high-rise buildings and Class A high-rise buildings with 9-degree seismic resistance design should not adopt shear wall structures with many short-leg shear walls as specified in Article 7.1.2 of this regulation.

The door and window openings of shear walls should be aligned up and down and arranged in rows to form clear wall limbs and connecting beams. It is advisable to avoid openings with wall piers with widely different stiffnesses. In seismic design, staggered-hole walls should not be used for the bottom reinforcement of shear walls with first, second, and third-level seismic resistance levels; superimposed staggered-hole walls should not be used for shear walls with first, second, and third-level seismic resistance levels.

Longer shear walls should be opened with openings and divided into several wall segments with relatively uniform lengths. Weak connecting beams should be used to connect the wall segments. The ratio of the total height of each independent wall segment to its cross-sectional height should not be less than 2. The height of wall pier section should not be greater than 8m.

Shear walls should be arranged continuously from bottom to top to avoid sudden changes in stiffness.

Bending moments out of the plane of the shear wall should be controlled.

Coupling beams with a span-to-height ratio less than 5 formed by openings in shear walls shall be designed in accordance with the relevant provisions of this chapter. When the span-to-height ratio is not less than 5, they should be designed as frame beams.

In seismic design, generally the height of the reinforced part at the bottom of a shear wall structure can be taken as the greater of 1/8 of the total height of the wall limbs and the two bottom floors. When the height of the shear wall exceeds 150m, the height of the reinforced part at the bottom can be taken as 1/10 of the total height of the wall piers; the height of the reinforced part at the bottom of the partially frame-supported shear wall structure shall comply with the provisions of Article 10.2.4 of this regulation.

It is not appropriate to support the main floor beams on the connecting beams between shear walls.

When floor beams are connected to shear walls, the longitudinal steel bars in the beams should extend into the wall and be reliably anchored.

The plane layout should be simple and regular, and should be arranged bidirectionally along the two main axes or other directions. The lateral stiffness in the two directions should not differ too much. When designing for earthquake resistance, structural arrangements with walls in only one direction should not be adopted.

It should be arranged continuously from bottom to top to avoid sudden changes in stiffness.

Door and window openings should be aligned up and down and arranged in rows to form clear wall limbs and connecting beams; openings that cause wide differences in the width of wall limbs should be avoided; during seismic design, the bottom reinforcement parts of first-, second-, and third-level shear walls should not be used If the upper and lower openings are not aligned with each other, it is not appropriate to use a superimposed staggered wall with partially overlapping openings throughout the entire height.

It should comply with the wall stability verification requirements in Appendix D of the high-tech regulations.

Secondary shear wall: the reinforced part at the bottom should not be less than 200mm, and other parts should not be less than 160mm; the reinforced part at the bottom of a straight-line independent shear wall should not be less than 220mm, and other parts should not be less than 180mm.

Level 3 and 4 shear walls: should not be less than 160mm, and the bottom reinforced part of the straight-shaped independent shear wall should not be less than 180mm.

In non-seismic design, it should not be less than 160mm.

In shear wall shafts, the section thickness of the wall limbs that separate the elevator shaft or pipe shaft can be appropriately reduced, but should not be less than 160mm.

High-rise building structures should not adopt shear wall structures that are all short-leg shear walls. When there are many short-limb shear walls, the cylinder (or general shear wall) should be arranged to form a shear wall structure in which the short-limb shear wall and the cylinder (or general shear wall) jointly resist horizontal force, and should comply with the following Regulation:

The strip foundation is arranged in a strip shape, and the cross section is generally in the shape of an inverted T. Its function is to transfer the load of the upper structure from each column to the foundation more evenly, and at the same time, it connects the upper frame structures into a whole to increase the The integrity of the structure reduces uneven settlement. The strip foundation can be arranged longitudinally or transversely.

The cross-shaped foundation is arranged in a cross shape, that is, strip foundations are arranged along the vertical and horizontal directions of the column network, which not only expands the load-bearing area of ​​the base, but also allows the superstructure to be connected in both vertical and horizontal directions, and has strong overall spatial stiffness.

If the bottom area of ​​the cross-shaped foundation cannot meet the requirements for the bearing capacity of the foundation and the allowable deformation of the superstructure, the bottom area of ​​the foundation can be expanded until the bottom plates are connected into one piece, which becomes a raft foundation. The raft foundation can be made into flat plate or beam plate type. The flat-plate raft foundation is actually a flat plate of equal thickness, and the construction is simple and convenient, but the amount of concrete is large; the beam-slab raft foundation generally arranges ribs along the column network in the vertical and horizontal directions, which can reduce the thickness of the bottom plate and enhance the structural stiffness, but The construction is more complicated.

The choice of foundation type depends on factors such as the on-site engineering geological conditions, the size of the superstructure load, the sensitivity of the superstructure to uneven settlement and tilt of the foundation soil, and construction conditions. Necessary technical and economic comparisons should be made during design and determined after comprehensive consideration.

The purpose of the building, whether there is a basement, equipment foundation and underground facilities, the form and construction of the foundation.

The magnitude and nature of the loads acting on the foundation.

Engineering geology and hydrogeological conditions.

The depth of foundations of adjacent buildings.

Effects of frost heaving and melting subsidence of foundation soil.

Definition: In my country's "Technical Regulations for Concrete Structures of High-Rise Buildings" (hereinafter referred to as "High-rise Regulations"), it is stipulated that high-rise civil buildings with concrete structures of 10 floors and above or the height of the building exceeds 28m are called high-rise buildings, and conventional height The high-rise buildings are called Class A high-rise buildings, and the high-rise buildings whose height exceeds the Class A height limit are called Class B high-rise buildings. (High-rise residential buildings with concrete structures of ten floors or more or with a building height exceeding 28 meters or public buildings with a height exceeding 24 meters are called high-rise buildings. High-rise buildings with regular heights are called high-rise buildings with a height of Class A, and those with a height exceeding Class A are called high-rise buildings. The high-rise buildings with the height limit are called B-height high-rise buildings).

Height calculation:

In high-rise building structures, under the action of vertical loads, the axial force in the column increases with the increase in the number of floors. It can be approximately considered that the axial force has a linear relationship with the number of floors, see Figure 15-l(a);

The horizontal wind load or earthquake force can be approximately considered to be distributed in a triangle or an inverted triangle. The bending moment generated by this distributed force at the bottom of the structure is proportional to the cubic height of the structure, see Figure 15-1 (b) ,

The lateral displacement of the structure's vertex under the action of horizontal force is proportional to the fourth power of the height, see Figure 15-1(c). The above-mentioned bending moments and lateral displacements often become the controlling factors that determine the structural plan, structural layout and component section size.

Advantages: High-rise buildings can bring obvious socio-economic benefits: first, they concentrate the population, and the vertical and horizontal traffic inside the building can be used to shorten the contact distance between departments, thus improving efficiency; second, they can make the land used for large-area buildings larger The scope is reduced, and it is possible to select a site in the center of the city; third, it can reduce municipal construction investment and shorten the construction period. Fourth, high-rise buildings have better ventilation and higher air quality in areas away from the ground. Finally, high-rise buildings are also a symbol of a city's development level.

Disadvantages: ① Regarding urban economic and environmental benefits, construction should be based on the location and control height designated by the urban planning department, and cannot be completely based on the needs of the building itself. ② Due to the increased stress of high-rise buildings, the level of equipment and decoration must be improved, and the construction difficulty increases, so the cost must be much higher than that of multi-story buildings. Therefore, designers from all walks of life need to work closely together to make the floor plan reasonable, improve the utilization factor, achieve a simple structure, light weight, easy installation, and comprehensively reduce the cost. ③The most prominent thing about high-rise buildings is fire safety design. Designers from all industries should strictly abide by the regulations on fire protection design of high-rise buildings. Fire problems in high-rise buildings are often mentioned in the news, which shows that its fire safety design is relatively difficult.

Under normal conditions of use, high-rise buildings should be in an elastic state and have sufficient stiffness. To this end, the "High-rise Regulations" stipulate the ratio of the maximum displacement between floors to the floor height Δu/h as follows.

(1) It should have the necessary bearing capacity, stiffness and deformation capacity;

(2) It should be avoided that the entire structure loses its ability to withstand gravity load, wind load and earthquake action due to damage to part of the structure or components;

(3) Effective measures should be taken to strengthen possible weak areas.

(4) The vertical and horizontal layout of the structure should have reasonable stiffness and bearing capacity distribution to avoid weak spots caused by local mutation and torsion effects;

(5) It is advisable to have multiple anti-seismic defense lines.

(6) In addition to complying with the above regulations, the design of complex high-rise building structures and hybrid structures should also comply with relevant regulations on the design of complex high-rise building structures and hybrid structures.

The vertical structural systems of reinforced concrete high-rise buildings include:

Horizontal structure refers to floor and roof structures

In high-rise buildings, the main role of horizontal structures

In an independent structural unit of a high-rise building, the structure plane shape should be simple and regular, and the stiffness and bearing capacity should be evenly distributed. Severely irregular floor plans should not be used.

High-rise buildings should choose a plan shape with less wind effect.

For grade A reinforced concrete high-rise buildings designed for earthquake resistance, the layout should meet the following requirements:

For seismic-resistant grade B reinforced concrete high-rise buildings, mixed-structure high-rise buildings and complex high-rise buildings referred to in high-rise buildings, the layout should be simple and regular to reduce eccentricity.

The structural floor plan should be designed to reduce the effects of torsion.

When the floor plane is relatively long and narrow, and there are large recesses and openings that cause the floor to be greatly weakened, the adverse effects of floor weakening should be considered in the design.

For buildings with large extension lengths such as L-shaped and tic-shaped buildings, when the central part of the building and the elevator room greatly weaken the floor, the structural measures of the floor and the connecting wall should be strengthened, and if necessary, grooves in the extended section should be strengthened. Install connecting beams or connecting plates.

After the large hole in the floor is weakened, the following structural measures should be taken to strengthen it:

During seismic design, high-rise buildings should adjust their plane shape and structural layout to avoid irregular structures and no seismic joints. When the building's plane shape is complex and its plane shape and structural layout cannot be adjusted to make it a more regular structure, it is appropriate to set up earthquake-proof joints to divide it into several simpler structural units.

When setting up anti-seismic joints, the relevant regulations of high standards should be complied with.

(1) The vertical shape of high-rise buildings should be regular and uniform, and excessive overhangs and inwards should be avoided. The lateral stiffness of the structure should be larger at the bottom and smaller at the top, and change gradually and evenly. Structures with severely irregular vertical layout should not be used.

(2) For high-rise building structures designed for earthquake resistance, the lateral stiffness of floors should not be less than 70% of the lateral stiffness of the adjacent upper floor or 80% of the average lateral stiffness of the three adjacent floors above it.

(3) The shear bearing capacity of the lateral force-resistant structure between floors of a Grade A high-rise building should not be less than 80% of the shear bearing capacity of the upper floor, and should not be less than 65% of the shear bearing capacity of the upper floor; The shear bearing capacity of the lateral force-resistant structure between floors of a Class B high-rise building shall not be less than 75% of the shear bearing capacity of the floor above it.

Note: The shear bearing capacity of the lateral force-resistant structure between floors refers to the sum of the shear bearing capacity of all columns and shear walls of the floor in the direction of horizontal earthquake action considered.

(4) During seismic design, the vertical lateral force-resisting members of the structure should be continuous from top to bottom.

(5) During seismic design, when the ratio of the height H1 of the retracted part of the upper floor of the structure to the outdoor ground and the height H of the house is greater than 0.2, the retracted horizontal dimension B1 of the upper floor should not be less than 0.75 times the horizontal dimension B of the lower floor ( Height Plan 4.4.5a, b); when the upper structure floor overhangs relative to the lower floor, the horizontal dimension B of the lower floor should not be less than 0.9 times the horizontal dimension B1 of the upper floor, and the horizontal overhang dimension a should not be greater than 4m (high Figure 4.4.5c, d).

(6) When some walls and columns are removed from the top floor of the structure to form an open room, elastic dynamic time history analysis and calculation should be carried out and effective structural measures should be taken.

(7) High-rise buildings should have basements.

(1) The floor live load of high-rise building structures should be adopted in accordance with the relevant provisions of the current national standard "Code for Loading of Building Structures" GB50009.

(2) When using wall-attached towers, climbing towers and other lifting machinery or other construction equipment that have an impact on the structural stress during construction, the impact of the construction load on the structure should be checked based on the specific circumstances.

(3) The dead weight of the revolving restaurant track and driving equipment should be determined according to the actual situation.

(4) The size and position of cleaning equipment such as window cleaning machines should be determined according to their actual conditions.

(5) The live load of the helicopter platform should be the load that can produce the maximum internal force on the platform from the following two types:

Basic wind pressure: The benchmark pressure of wind load, generally based on the 10min average wind speed observation data at a height of 10m on the local open flat ground. Through probability statistics, the wind speed determined by the maximum value once in 50 years is obtained, and then the corresponding air density is considered. The wind pressure determined by formula ( ).

When calculating the main structure, the standard value of the wind load perpendicular to the building surface should be calculated according to the following formula, and the wind load action area should be the maximum projected area perpendicular to the wind direction.

The basic wind pressure should be adopted in accordance with the current national standard "Code for Loading of Building Structures" GB 50009. For high-rise buildings that are particularly important or sensitive to wind loads, the basic wind pressure should be based on the wind pressure value with a 100-year return period.

For high-rise buildings located on flat or slightly undulating terrain, the wind pressure height variation coefficient should be determined according to Table 3.2.3 of the height regulation according to the ground roughness category. Ground roughness should be divided into four categories: Category A refers to offshore sea surfaces and islands, coasts, lakeshores and desert areas; Category B refers to fields, villages, jungles, hills, towns and urban suburbs with sparse houses; Category C refers to dense buildings Category D refers to urban areas with dense building groups and taller houses.

For high-rise buildings located in mountainous areas, after determining the wind pressure height change coefficient according to Article 3.2.3 of the High-rise Regulations, it should be revised according to the relevant provisions of the current national standard "Load Code for Building Structures" GB 50009.

When calculating the wind load effect of the main structure, the wind load type coefficient μs can be used according to the following regulations:

In situations where more detailed wind load calculations are required, the wind load type coefficient can be adopted in accordance with Appendix A of the high-level regulations, or determined by wind tunnel testing.

The wind vibration coefficient βz of high-rise buildings can be calculated as follows:

When multiple or clustered high-rise buildings are close to each other, the group effect of mutual wind interference should be considered.

When the height of the house is greater than 200m, a wind tunnel test should be used to determine the wind load of the building; when the height of the house is greater than 150m and one of the following conditions occurs, a wind tunnel test should be used to determine the wind load of the building:

For horizontal components such as cornices, awnings, sunshades, and balconies, when calculating local floating wind loads, the wind load type coefficient μs should not be less than 2.0.

When designing building curtain walls, wind loads should be adopted in accordance with the current national design standards for building curtain walls.

The calculation of seismic effects of high-rise buildings of various seismic fortification categories should comply with the following regulations:

High-rise building structures should consider earthquake effects according to the following principles:

The influence of accidental eccentricity should be considered when calculating unidirectional seismic effects. The offset value of the centroid of each layer along the direction perpendicular to the earthquake action can be used as follows:

High-rise building structures should adopt the following calculation methods according to different situations:

When conducting dynamic time history analysis according to high-level regulations, the following requirements should be met:

When calculating earthquake effects, the representative value of the gravity load of the building structure should be the sum of the standard value of the permanent load and the combined value of the variable load. The combination value coefficient of variable load should be adopted according to the following provisions:

When the vertical seismic action is taken into account for long horizontal cantilever members, long-span structures and the overhanging parts of the upper floors of the structure, the standard values ​​of the vertical seismic action can be represented by the gravity load borne by the structure or component respectively when the fortification is at 8 degrees and 9 degrees. 10% and 20% of the value.

The natural vibration period of the structure used to calculate the seismic influence coefficient of each vibration mode should be reduced by considering the stiffness effect of non-load-bearing walls.

Calculation of horizontal and vertical seismic effects

There are three main types of temperature changes that cause internal temperature forces in high-rise building structures, namely: indoor and outdoor temperature differences, sunlight temperature differences and seasonal temperature differences.

Generally speaking. The restraining force within a structure due to temperature changes is proportional to the number of floors within the structure. Structural deformations caused by temperature changes generally include the following:

Generally speaking, for buildings with less than 10 floors and when the building plane length is less than 6Om, the effect of temperature change can be ignored. For buildings with 10 to 30 floors, the deformation caused by temperature differences gradually increases. The size of the temperature effect mainly depends on the degree of structural exposure, the stiffness of the floor structure and the height of the structure. As long as appropriate processing is done in the building insulation structure and structural reinforcement structure, the effect of temperature can still be ignored in the calculation of internal forces. For super high-rise buildings with more than 30 floors or more than 10Om, the temperature effect must be paid attention to in the design to prevent structural and non-structural damage to the building.

At present, in our country, there are no specific regulations on how to consider the effect of temperature in the structural design of high-rise buildings. Accurate and practical internal force calculation methods and specific and effective structural measures need to be further studied.

A rack structure with a column height (measured from the top surface of the foundation) less than 8m;

The roof has a rack structure without heat preservation and insulation measures;

Structures located in dry climate areas, areas with hot summers and frequent heavy rains, or structures that are often exposed to high temperatures;

Various wall structures constructed using slip form technology;

The concrete material shrinks greatly and is exposed for a long time during the construction period.

Take measures to reduce concrete shrinkage or temperature changes;

Adopt special prestressing or additional structural steel measures;

Low-shrinkage concrete materials are used, and construction methods such as skip pouring, post-casting tape, and control joints are adopted, and maintenance construction is strengthened.

The minimum width of anti-seismic joints should meet the following requirements:

50% of the value is used, but neither should be less than 100mm. 2 When the structural systems on both sides of the anti-seismic joint are different, the width of the anti-seismic joint should be determined according to the unfavorable structural type;

When the heights of the houses on both sides of the earthquake-proof joint are different, the width of the earthquake-proof joint should be determined according to the lower height of the house;

8. For a frame structure house with a 9-degree seismic design, when the structural heights on both sides of the seismic joint are quite different, the stirrups of the frame columns on both sides of the seismic joint should be densely packed along the full height of the house, and can be placed on both sides of the joint along the full height of the house as needed. Set up no less than two seismic walls perpendicular to the seismic joints;

When there is a large settlement difference between the foundations of adjacent structures, the width of the anti-seismic joints should be increased;

Seismic joints are set along the entire height of the house. There are no seismic joints in the basement and foundation, but the structure and connection are strengthened at the corresponding places with the upper seismic joints;

It is not advisable to use corbel joists to set earthquake-proof joints between structural units or between the main building and the podium. Otherwise, reliable measures should be taken.

Ancient

modern times

Category 1: 9~16 floors, height not exceeding 50m

Category 2: 17~25 floors, height not exceeding 75m

Category III: 26~40 floors, height not exceeding 100m

Category III: 26~40 floors, height not exceeding 100m

Advantages: high strength, high toughness, good seismic resistance, easy to process, can shorten the on-site construction period, and is convenient for construction.

Disadvantages: A large amount of steel is used, the cost is high, and the fire resistance is poor.

Advantages: low cost, rich sources of materials, can be cast into various complex cross-sectional shapes, and can be composed of various structural systems; can save steel, has high load-bearing capacity, and can obtain better seismic performance after reasonable design.

Disadvantages: The component section is large, it occupies a large area, and it is heavy.

Advantages: Based on the reinforced concrete structure, it fully utilizes the excellent tensile properties of the steel structure and the compressive properties of the concrete structure to further reduce the weight of the structure and improve the ductility of the structure.

type

frame

shear wall

cylinder

Frame structure system: The structure composed of beams and column members connected through nodes is called a frame. The frame structure is the main structural form of multi-story houses and the basic structural unit of high-rise buildings.

shear wall structural system

Frame-shear wall structural system

Tube-in-tube structural system

multi-tube system

megastructure system