First, the design form and characteristics of high-rise building concrete structure
(1) Overview of design forms When high-rise buildings are newly developed, three traditional structures are most commonly used in concrete structure systems, namely frame, shear wall and frame-shear wall. However, with the development of building technology and building materials, as well as the increasing number of building floors, there are three most commonly used building types today: frame tube, multi-tube tube and tube-in-tube system.
1. 1 frame structure system: this system is the most commonly used building structure in low-rise buildings in the past, and generally only applies to low-rise buildings with 10 floors and below. The whole structural system is a rigid integral connection structure with frame beams and columns as the skeleton, which has the advantages of strong seismic capacity, complete structure, light weight and high strength. However, when the building height of the frame structure increases, the lateral force of the frame structure also increases with the height, and the internal force generated by its own horizontal load far exceeds that generated by vertical load; However, the frame structure itself has structural problems such as low stiffness against lateral displacement and sensitivity to uneven settlement of bearings, so the whole building structure is prone to lateral displacement.
1.2 shear wall structure system: This structure system is a better development system than the frame structure system, and is generally suitable for building structures with 25 to 30 floors. The whole structural system is an integral reinforced concrete wall structure composed of transverse and longitudinal directions, which has the advantages of high lateral displacement stiffness, good integrity, small lateral displacement under horizontal force, no exposed components such as beams and columns, etc. It has the functions of building enclosure and division, and can effectively resist horizontal and vertical loads. However, due to the poor ductility of the shear wall structure, the space divided inside the building is narrow, which is only suitable for hotels and residences.
Frame-shear wall structural system of 1.3: This structural system integrates the advantages of the first two structural systems, and is generally suitable for building structures of 10~25 floors. The whole structural system is composed of frame and shear wall, which distributes various loads and pressures to various loads. General horizontal load is borne by shear wall structure, and general vertical load is borne by frame structure. Such diversion can greatly reduce the cross section of column beam, increase the flexibility of building space and enhance the stiffness of lateral displacement, which is a very practical structural system.
1.4 frame-tube structure system: this is a composite structure system, which is generally suitable for high-rise buildings with 30~80 floors. The whole structural system is surrounded by reinforced concrete, with high lateral displacement stiffness. The center of the building is a thin-walled shear wall tube, and the surrounding is a general frame with large column spacing, which has the advantages of high torsional stiffness and lateral displacement stiffness.
1.5 tube-in-tube structural system: This structural system is composed of an inner tube and an outer tube, which has good wind resistance, earthquake resistance and spatial integrity.
1.6 Multi-bundle tube structural system: This structural system is a structure with multiple shear walls and thin-walled tubes in the plane structure, which is generally suitable for buildings with complex plane shapes. (2) Overview of design features Compared with middle and low-rise buildings, high-rise buildings are different in seismic performance, lateral stiffness and bearing capacity. The choice of different structural systems will directly affect the overall construction effect, so it is necessary to consider and select the whole design system through better design concepts, reasonable structural measures and more professional knowledge.
2. 1 Considering lateral force: in low-rise buildings, the lateral displacement force is very small and can be ignored; In high-rise buildings, the lateral displacement force gradually increases with the increase of height; 2.2 Considering load: Due to the influence of many factors, such as soil quality and building materials, different treatment measures should be taken according to different situations when constructing on different foundations or pile foundations, and the load force of the foundation should be consistent with the gravity of the superstructure.
2.3 Consider ductility: As the height of high-rise buildings increases, they need better ductility, and the structure of weak stories needs to be softer, so that the whole building can be deformed to a greater extent under the earthquake.
2.4 Considering strong stiffness: With the increase of building height, the lateral displacement of high-rise buildings also increases accordingly. Therefore, when designing high-rise buildings, it is necessary to consider the strength and stiffness of the whole structure, so that the whole structure can have reasonable natural frequency and displacement control. 2.5 Consider earthquake resistance: When choosing the construction site, choose the area with open and flat terrain and hard and dense geology. And the load force and deformation capacity of the whole structure should be considered.
Second, the high-rise building concrete structure design considerations
Because high-rise buildings and low-rise buildings are different in many aspects, several important problems should be paid attention to in the design of concrete structure of high-rise buildings: 1 Specification problem: Due to the rapid development of the construction industry. The past specification documents are not suitable for today's high-rise buildings; Great changes have taken place in the content of the current new code, adding more restrictive conditions and some mandatory rules. Therefore, when designing the concrete structure of high-rise buildings, designers must strictly follow the requirements of the code and abide by the relevant restrictive conditions and mandatory regulations to avoid affecting the smooth progress of the whole construction process. 2. Height: The most obvious feature of high-rise buildings is height; Although too high a height can increase more living space and improve the utilization rate of land to cope with corresponding natural disasters (earthquakes, typhoons, etc.). ), the height of the building needs to be strictly limited. 3. The problem of embedded end: Because the stability of embedding will affect the stability of the whole, it is necessary to pay attention to the rationality of embedded settings when designing and calculating the stability of the whole.
Third, the optimization measures of high-rise building concrete structure design
1. Increase the ductility of the whole building structure. When encountering high-intensity earthquakes and typhoons, high-rise buildings need strong anti-tilt ability and good ductility to cope with the possible serious consequences caused by their own height. However, due to economic factors, it is only necessary to improve the ductility of some key components. At the same time, for high-rise buildings with different structures, it is also necessary to select corresponding components for reinforcement according to their own characteristics. 2. To enhance the elastic-plastic state of the whole building, besides good ductility, it can also absorb seismic energy and other related natural forces by changing building materials, and form the structural state of strong beams, columns and components. 3. Optimize the overall structural layout of the building. The two most important parts in the whole building system are generally frame and shear wall. Among them, for shear walls, the principle of unified order can be adopted to optimize the plane layout; For the frame, the principle of hardware structure integration should be adopted, and the problem of beautiful structure can be paid attention to at the same time.
Due to the influence of population, economy and other factors, high-rise buildings are the inevitable product of social development in order to improve land utilization and meet the living needs of the population. At present, most building structures are concrete structures. However, due to the short appearance of high-rise buildings and the lack of relevant experience and measures, it is necessary to further explore and develop the optimization of concrete structure design in order to obtain higher economic and social benefits.
I believe that after the above introduction, everyone has a certain understanding of the exploration of concrete structure design of high-rise buildings. Welcome to Zhong Da for more information.
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