The design of prefabricated concrete buildings must conform to the provisions of national policies, regulations and local standards. On the premise of meeting the function and performance of the building, the modular, standardized and integrated design method is adopted, and the design principle of "less specifications and more combinations" is practiced. Implement modular combination and standardized design of connection technologies of various building components, components and structures, establish a reasonable, reliable and feasible general system of building technology, and realize assembly construction of buildings.
In the design, we should follow the principle of modular coordination, so as to achieve modular design of buildings and components, as well as modular coordination between components. Various modules are integrated under the principle of module coordination. Using standardized design, the modules of building components are combined into standard units according to functional attributes, and standardized interfaces are adopted between components to form a multi-level functional module combination system. Integrated design is adopted to integrate the main structure system, peripheral protection system, equipment and pipeline system and built-in system. It can improve the functional quality, quality accuracy and efficiency of the building, realize one-time construction and meet the design requirements of assembled buildings.
standard design
Modular design is the basis of standardized design of prefabricated buildings. The main structure, interior decoration and dimensional coordination among components are realized by adopting the methods of basic module, extended module and divided module. Modular design should comply with the current national standard "Building Modularity Coordination Standard" GB/T 50002.
Based on the principle of module coordination, the dimensions of width and depth are integrated, and diversified architectural planes are formed through the combination of basic space modules. The horizontal extension module series of 2nM and 3nM(n is a natural number) should be adopted in the graphic design of buildings to achieve the dimensional coordination in the design, manufacture and installation of parts.
The determination of building height and door and window opening height involves the specifications and dimensions of prefabricated components and parts. Facade design should follow the principle of modular coordination, determine reasonable design parameters, and adopt vertical extension of modular series nM to ensure the requirements of component fabrication and easy installation during construction.
The modular coordination method is used to determine the design dimensions of building components and connection nodes, so that all components become a whole. Modular coordination of building nodes can realize the standardization of components and connecting nodes and improve the universality and interchangeability of components. The section size of beams, columns, walls and other components should adopt the vertical expansion modulus series nm; The interface dimensions of nodes and components shall adopt modular series nM/2, nM/5 and nM/ 10.
The dimensional positioning of architectural design should combine the central positioning method with the interface positioning method, the horizontal positioning of components should adopt the central positioning method, and the vertical positioning of components and components should adopt the interface positioning method.
Standardized design
The standardized design of prefabricated concrete buildings adopts modular, modularized and serialized design methods, and follows the principle of "fewer specifications and more combinations" to meet the requirements of high repetition rate, fewer specifications and more combinations as much as possible. The basic unit modules of the building are diversified and combined according to the functional requirements through standardized interfaces, and multi-level building combination modules are established to form reproducible and expandable building units.
In residential building design, basic unit modules such as kitchen module, bathroom module, living room module and balcony module can be combined into a complete unit module, and nested module, corridor module and core tube module can be combined into a standard floor module, and so on, and finally a reproducible modular building can be formed.
The core of internal and external combination of each module is standardized design. Only the standardization of module interfaces can form the coordination between modules and realize the assembly of various modules in the building.
integrated design
The key of prefabricated concrete building is integration, which is not a simple addition under the traditional production mode, nor is it an prefabricated building under the traditional design, construction and management mode. Only by integrating the main structure, envelope and internal parts into a complete system can a real prefabricated building reflect the overall advantages of the prefabricated building and achieve the purposes of improving quality, reducing labor, reducing waste and increasing efficiency.
In the design stage of prefabricated buildings, the overall planning should be carried out in the early stage to coordinate the whole process of planning and design, component production, construction and operation and maintenance. Considering the corresponding objective conditions and technical problems of each link, technical standards and scheme selection should be determined before technical design. In the technical design stage, the integrated design of architecture, structure, mechanical and electrical equipment and interior decoration should be carried out, and the technical systems of various disciplines should be fully coordinated to avoid technical contradictions caused by overlapping construction periods. In the technical design stage, technical connection with subsequent prefabricated components, equipment and components should be considered to ensure smooth connection during construction. For prefabricated components, the more integrated technologies, the easier the subsequent construction process, which is the development direction of prefabricated components.
The system integration of prefabricated buildings includes the system and technology integration of the main structure of the building, the system and technology integration of the envelope structure, the system and technology integration of equipment and pipelines and the system and technology integration of the interior decoration of the building. The main structure system of a building can integrate building structure technology, component separation and connection technology, building and installation technology, etc. , and integrate the reserved conditions required by the equipment and interior decoration specialty into the building components; The envelope system should combine the appearance of the building and the performance of the envelope structure, consider the combination of external windows, sunshade, air conditioning partition and prefabricated external wall panels, and integrate technologies such as bearing, heat preservation and external decoration; Equipment and pipeline system can apply pipeline system intensive technology and equipment energy efficiency technology to ensure the integration and efficiency of the system; The interior decoration system of the building should adopt integrated dry construction technology, and CSI residential building system with separated structure and decoration body can be adopted to realize rapid installation, nondestructive maintenance, high quality and environmental protection.
The integration technology of prefabricated buildings should be the key research content of the development of prefabricated buildings, and it is the key to improve the quality and efficiency of prefabricated buildings. The whole professional and whole process of technology pre-positioning is the core of integrated design.
1. Plane Design of Assembled Concrete Building
On the basis of meeting the plane function, the plane design of prefabricated concrete buildings should consider the requirements conducive to the construction of prefabricated buildings and follow the principle of "fewer specifications and more combinations". The building plane should be standardized and stereotyped, and standardized component modules, functional modules and space modules should be established to realize the multi-component application of modules and improve the reuse rate of basic modules, components and parts, which is conducive to improving building quality, improving construction efficiency and controlling construction costs.
(1) general layout design
The general layout design of prefabricated concrete buildings should meet the requirements of the overall urban planning, and meet the national norms and construction standards. In the pre-planning and overall design stage, clear requirements should be put forward for project positioning, technical route, cost control and benefit objectives. Fully consider the component production capacity, construction and assembly capacity, on-site transportation and hoisting conditions in the project area, cooperate with each other, and arrange the technical route, implementation position and scale of prefabricated building structures in combination with the production and transportation conditions of prefabricated components and engineering economy. When making the overall construction plan on site, fully consider the setting of component transportation channel, prefabricated component hoisting and temporary storage yard.
Considering the particularity of prefabricated buildings, the general layout design must consider the following three aspects:
(1) External transportation conditions: the prefabricated components are transported from the component production place to the temporary parking area covered by tower cranes on the construction site, and the road width, load, turning radius and clear height during the whole transportation process meet the traffic conditions. If the traffic conditions are limited, other temporary passages, entrances and exits or temporary road reinforcement measures should be considered as a whole, or the space size, specifications and weight of prefabricated members should be changed to ensure the smooth arrival of prefabricated members.
(2) Internal space site: Most prefabricated components are transported to the site. After being stored for a short time or hoisted immediately, the size and location of the storage site directly affect the efficiency and order of construction. In the general layout design, the construction sequence, tower crane radius, tower crane capacity, etc. The storage site of components should be integrated and set reasonably, and the construction excavation area should be avoided as far as possible.
(3) Dynamic line of internal installation: Compared with the traditional construction method, the construction organization scheme of precast component installation and the effective connection of each construction process are higher, and the general layout design should be comprehensively considered in combination with the construction organization and dynamic line of component installation. It is generally required that the general layout design should reserve enough space for the transportation, stacking and hoisting of components during the production and construction of prefabricated buildings. In the absence of temporary storage yard, site conditions should be reserved for tower cranes, and construction should be carried out in combination with construction organization as soon as possible.
(2) Architectural graphic design
The plane design of assembled concrete building should not only meet the functional requirements of the building, but also consider the requirements conducive to the construction of assembled concrete building. Architectural graphic design needs the concept of overall design. Graphic design should not only consider the use scale of each functional space of the building, but also consider the spatial adaptability of the whole life cycle of the building, so that the architectural space can adapt to the different needs of different periods in use. Architectural graphic design should meet the design requirements of prefabricated buildings in the following aspects.
Large space structure form
The design of large space structure is conducive to reducing the number and types of prefabricated components, improving production and construction efficiency, reducing labor and saving costs. The design should try to design the unit space of public buildings or the apartment space of houses according to a structural space. According to the stress characteristics of the structure, the dimensions of prefabricated components and parts should be designed reasonably, and the positioning dimensions of prefabricated components and parts should meet the needs of plane function and conform to the principle of modular coordination.
The division of indoor space should try to use light partition walls. Lightweight partition walls such as light steel keel gypsum board, light lath and furniture partition wall can be used to separate the space flexibly. Light partition wall can use its cavity to arrange equipment and pipes, which is convenient for maintenance and reconstruction, saves space and forms a complete partition wall system, which is conducive to the sustainable development of buildings.
flat shape
The plane shape, component shape and layout of the assembled concrete building have great influence on the seismic performance of the structure, which should comply with the relevant provisions of the current national standard Code for Seismic Design of Buildings (GB500 1 1). The design of plane modeling and architectural form should pay attention to the influence of its regularity on structural safety and economic rationality, and it is advisable to choose a regular form instead of a seriously irregular plane layout. It is advisable to choose the plane layout of large space with structural unit space as functional module, rationally arrange the positions of columns, walls and core tubes, intensively arrange public transportation space and centrally arrange vertical pipelines and wells to meet the flexibility and variability of the use space.
Technical Specification for Assembled Concrete Structures (JGJ 1) has the following provisions on plane layout:
(1) The plane shape should be simple, regular and symmetrical, and the distribution of mass and stiffness should be uniform; Serious irregular plane layout should not be adopted;
(2) The plane length should not be too long, and the aspect ratio (L/B) should be adopted according to Table 3. 1;
(3) The length L and width B of the plane protruding part should not be too large or too small, and l/Bmax and L/B should be adopted according to the table;
(4) The plane should not be arranged with overlapping angles or thin waist.
In plane design, vertical components such as load-bearing walls and columns should be continuous from top to bottom, and the vertical layout of the structure should be uniform and reasonable, so as to avoid sudden changes in lateral stiffness and bearing capacity of the lateral force resistant structure along the vertical direction and meet the seismic design requirements of the structure.
Standardized design method
The plane design of prefabricated concrete buildings should adopt standardized, modular and serialized design methods, and should follow the principle of "fewer specifications and more combinations". The basic units, connecting structures, components, building parts and equipment pipelines of buildings should meet the requirements of high repetition rate, few specifications and multiple combinations as much as possible.
In graphic design, the width and depth of the bay should adopt a unified module size series, and the size specifications conducive to combination should be optimized as much as possible. The reuse rate of building units, prefabricated components and building components is an important index of engineering standardization. In the same project, the same type of components are generally controlled at about three specifications and the proportion of the total number increases, which can control and reflect the degree of standardization. For components with simple specifications, control the number of components of one specification.
The requirements of the grading rules in the Evaluation Standard for Industrialized Buildings (GB/T 5 1 129) for standardized design are shown in the following table.
The basic unit of public buildings mainly refers to the standard structural space. Residential buildings are designed with Xing Tao as the basic unit, and the design of Xing Tao unit usually adopts modular combination. For functional module spaces with high component combination requirements, such as residential kitchens and bathrooms, the plane layout should be compact and reasonable. The design should be based on the net mold size to meet the equipment, facilities and decoration requirements of the whole kitchen and bathroom. The requirements of high reuse rate, few specifications and many combinations of basic units, components and building parts of buildings also determine that the design method of standardization, modularization and serialization must be adopted in prefabricated buildings.
Modular design of residence
The design of prefabricated concrete buildings should be combined with basic units or basic sets as modules. In the plane design of assembled residence, the modular design method is adopted, and the optimized sleeve module and core tube module are combined in diversified planes.
Nested modules can be decomposed into several independent and interrelated functional modules, and different functions can be set for different modules in order to better solve complex and large-scale functional problems. A module should have the attributes of "interface, function, logic and state". Among them, interface, function and state reflect the external attributes of the module, and logic reflects the internal attributes of the module. Modules shall be combinable, detachable and replaceable. Nested modules should be carefully designed, serialization requirements should be considered, there should be certain logical and derivative relationships between nested modules in the same series, and unified interfaces should be reserved.
Residential Xing Tao module consists of living room, bedroom, hall, dining room, kitchen, bathroom, balcony and other functional modules. On the premise of meeting the housing demand, provide appropriate space scale control and solidify with large space.
The design of nesting module can be composed of standard module and variable module. Based on the analysis of the functional modules of the suite, the large structural space is used to meet the requirements of high parallelism of various functional spaces, and the standard modules (such as the combination of living room and bedroom) are established by designing the method of functional module integration and flexible arrangement. The variable module is a supplementary module, and the plane size is relatively free, which can be customized according to the project requirements, and it is convenient to adjust the size for diversified combinations (kitchen+hall combination, etc.). ). Variable modules and standard modules are combined into a complete nested module.
(1) Living room module: According to the positioning of the suite, it meets the functional needs of residents in daily life, entertainment and meeting guests. , and pay attention to control the number and position of doors opening to the living room to ensure the integrity of the wall and facilitate the layout of various functional areas.
(2) Bedroom module: According to the functional requirements, it can be divided into three types: double room, single room and combination of bedroom and life. When the bedroom and living room are combined into one, it should not be lower than the standard of living room, meet the function of sleeping, and properly consider the diversity of spatial layout.
(3) Dining room module: including independent dining room and living room dining area. When the kitchen area is insufficient and there is no room for the refrigerator, it is necessary to increase the space for the refrigerator in the dining room or the living room of the dining room, set a sideboard beside the dining table, and place kitchen appliances such as microwave ovens.
(4) Hall module: including storage, makeup, decoration and other functions. All functions can be reasonably laid out according to general living habits, and refined design can be carried out in combination with the storage part.
(5) Kitchen module: including washing, operation, cooking, storage, refrigerator, electrical appliances and other functions and facilities, which should be arranged reasonably according to the positioning of the suite. Kitchen pipeline wells should be centrally arranged, and maintenance openings should be reserved. The kitchen design should follow the modular coordination standard, optimize the appropriate size series to carry out modular coordination design of indoor finishing control, design standardized kitchen modules to meet functional requirements, and realize factory production and on-site dry construction. The integrated kitchen should be the first choice in the design of prefabricated houses.
(6) Toilet module: including toilet, washing, washing, bathing, laundry, storage and other functions, which should be arranged reasonably according to the location, general use frequency and living habits of the suite. The bathroom design should follow the standard of modular coordination, design standardized bathroom modules, meet functional requirements and realize factory production and dry construction on site, giving priority to the whole bathroom with drainage on the same floor.
The design of core tube module should meet the requirements of use function and specification, and its module is mainly composed of functional sub-modules such as stairwell, elevator shaft, front room, public corridor, elevator waiting hall, equipment pipeline shaft and pressurized air supply shaft. The space size of each sub-module and the reasonable layout between them should be reasonably determined, and standardized design should be carried out according to the use requirements to meet the use requirements, specification requirements and economic requirements. The design of core basket module should consider the following requirements.
(1) On the basis of meeting the relevant national standards, the functional modules are reasonably arranged from the perspective of safety and convenient transportation, considering comfort and economy.
(2) Elevator installation is an important part of the core tube design, and its quantity, specifications and combination will directly affect the use and quality of the building.
(3) The design of stairs should meet the evacuation requirements, and the location and number of stairs should be set reasonably, so as to save the public transportation area to the maximum extent and improve the utilization rate. Stair design should be standardized, which is convenient for later factory prefabrication and assembly construction.
(4) The front room, elevator waiting hall and public corridor are related to the comfort of use, and the front room and elevator waiting hall should have good lighting and ventilation conditions.
(5) Mechanical and electrical equipment pipelines should be arranged centrally in the equipment tube well, with reasonable layout, saving area and reserving maintenance space. In terms of functional layout, we should consider the requirements of not using the tube well with strong and weak electricity equipment, the strong electricity is not adjacent to the water heating tube well, the smoke exhaust well is set in the corner as far as possible, and the public toilet and water boiling room are as close to the tube well as possible.
2. Facade and section design of assembled concrete building
In the facade design of prefabricated concrete buildings, standardized design methods should be adopted, and the personalized and diversified effects of building facades should be realized through modular coordination according to the characteristics of construction methods and plane combination design of prefabricated buildings.
According to the construction requirements of prefabricated buildings, standardized prefabricated components should be considered to the maximum extent, and the specifications and types of prefabricated components on the facade should be reduced as much as possible. Facade design should use various methods such as repetition, rotation and symmetry of standardized components, as well as changes in texture and color of external walls, showing diverse design logic and modeling styles, and realizing both regular unity and rhythmic personality changes of building facades.
(1) facade design
The facade of prefabricated concrete building is the integration and unification of standardized prefabricated components and components after assembly in its facade form. In the facade design, according to the requirements of technical planning, prefabricated components should be considered as much as possible, and the specifications of prefabricated components should be reduced as much as possible according to the design principle of "fewer specifications and more combinations".
The facade of the building should be regular, the external wall should be free from convexity and concavity, the opening of the facade should be unified, the decorative components should be reduced, and the complicated external wall components should be avoided as far as possible. The basic units of residential buildings or public buildings should be unified as far as possible under the premise of meeting the allocation ratio required by the project. Through simple copying and orderly combination of standard units, the high repetition rate of standard layer combination mode is realized, and the standardization and type minimization of facade external wall components are realized. The facade of the building presents a unified, concise and exquisite rhythm effect, which has the characteristics of prefabricated buildings.
Figure 3.4 Facade Design of Assembled Building
The vertical dimension of the building should meet the requirements of modularization, and the dimensions such as height, door and window openings, and facade framing should be coordinated and unified as much as possible. Doors and windows openings should be aligned up and down, arranged in columns, and their plane position and size should meet the design requirements of structural stress and prefabricated members. Windows and doors should adopt standardized components and be reliably connected with the wall by reserving auxiliary frames or embedding them. The external windows should adopt reasonable sunshade integration technology, and the supporting components such as building envelope, balcony and air conditioning panel should adopt industrialized and standardized products.
(2) Building height and story height
Assembled concrete buildings adopt different structural forms, and the maximum building height can be different. See the structural design section for the maximum applicable height of the assembled single building.
The storey height requirements of prefabricated buildings are the same as those of cast-in-place concrete buildings, which should be determined according to the requirements of different building types and functions, and should meet the requirements of storey height and clear height in the Code for Design of Special Buildings.
The factors that affect the building height include the clear height required by the building, the thickness of beam and slab, the height of ceiling, etc. For example, the height of SI system design is different from the traditional height. The traditional floor method is to embed electrical pipelines and weak current wiring in the cast-in-place layer of composite floor, and embed equipment pipelines, such as water supply pipes, heating pipes and solar energy pipelines, in the building cushion on the ground. In the design of SI system, the building structure is separated from the building interior and equipment pipelines, and the pipelines in the floor and wall of the structure are not pre-embedded, but the pipelines are installed by combining suspended ceiling, raised floor and light double-layer wall.
The height design of architecture specialty should be combined with the design of structure, electromechanical and interior decoration specialty. With the help of determining the height of beam and the thickness of floor, the electromechanical pipelines in the ceiling should be arranged reasonably to avoid crossing, minimize the space occupation, and reasonably determine the height and clear height of the building to meet the use requirements of the building.
(A) Traditional building practices (B) Precast building built-in system practices
Figure 3.5 Comparison of storey height design of SI indoor system in assembled building
(3) Exterior wall facade framing and decorative materials
The vertical grid of prefabricated concrete buildings should be coordinated with the joints of component combinations to achieve the unity of architectural effect and structural rationality.
For prefabricated buildings, we should fully consider the production conditions of prefabrication plant, combine the stress points of structural cast-in-place joints and external wall panels, select appropriate building decoration materials, reasonably design the vertical partition, and determine the combination mode of external wall panels. Facade elements should have certain architectural functions, such as external walls, balconies, air conditioning panels, railings, etc. , to avoid a large number of decorative components, especially components with different service life, affecting the sustainability of building use, which is not conducive to saving materials and energy.
Precast exterior wall panels are usually divided into whole panels and slats. The size of the whole board is usually the length of a bay, and the height is usually the height of a floor. Slabs are usually divided into horizontal plates, vertical plates, etc. It can also be designed as a non-rectangular plate or a non-planar plate and assembled into a whole on site. The vertical grid of precast external wall panels should be divided according to the design requirements in combination with doors, windows, balconies, air conditioning panels and decorative components, and the precast sub-wallboard should adopt the same blocking method and node practice as the lower wallboard structure.
The selection and construction of exterior wall facing materials of prefabricated concrete buildings should be combined with the characteristics of prefabricated buildings, taking into account the principle of economy and meeting the requirements of green buildings.
Prefabricated exterior wall facing is completed in component factory, and the quality, effect and durability are much better than those of field operation, saving time and effort and improving efficiency. The exterior decoration should use durable, pollution-free and easy-to-maintain materials, which can better maintain the design style, visual effect and green and healthy living environment of the building, reduce the cost of material replacement and maintenance in the whole life cycle of the building, and reduce the emission of harmful substances, dust and noise generated by on-site construction. Concrete, weather-resistant paint, brick and stone can be selected for the exterior wall surface. Precast concrete exterior walls can be processed into colored concrete, fair-faced concrete, fair-faced concrete and expansive concrete with decorative patterns on the surface. Different surface textures and colors can meet the diversified requirements of facade effect design, and the paint finish has strong overall feeling, good decoration, simple construction, convenient maintenance and relative economy; Brick veneer and stone veneer are durable, with good durability and texture, and easy to maintain. In the production process, the facing material and the external wall panel are formed once by reverse stamping process, which reduces the on-site working procedures, ensures the quality and prolongs the service life of the facing material.
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